Pedestrian zone

Source: Frank Spooner Pictures


THE URBAN (ECO)SYSTEM

Many concerns for the state of the environment first developed in urban areas where changes in environmental conditions began to affect human health. Today, virtually all cities share concern for the quality of their environment. It is also in cities that many regional and global environmental problems originate. Concerns for the sustainability of cities have increased rapidly, as it has become evident that the environmental challenges of the future will be confronted in an increasingly urbanised world (Box 10A).

As part of ecological systems, cities affect and are affected by natural cycles. Cities depend on the availability of natural resources. They import water, energy and materials which are transformed into goods and services and ultimately returned to the environment in the form of emissions and waste. Their high concentration of people and activities make cities major contributors to local, regional and global environmental change. On the other hand it is the same concentration of people that provides unique opportunities for economies of scale and resource conservation. Thus, it is in cities that many environmental problems can be effectively addressed and resolved.

This chapter analyses the quality of the urban environment in Europe. The flows of natural resources that sustain cities are described to illustrate the interdependence between urban systems and the regional and global environment. Current patterns of urban development are examined in relation to the degree of pollution and exploitation of natural resources. An experimental set of urban environmental indicators are used to identify major urban environmental problems in a selected number of European cities and to assess regional differences and priorities (Map 10.1). Finally, the options for improving the urban environment and successful examples in several European cities are examined.

European urban areas

In Europe more than two thirds of the total population live in urban areas. The net result of urbanisation processes between 1950 and 1990 has been an overall increase of urban population. However, different patterns of urbanisation have occurred across Europe as a result of differences in economic and social development (Figure 10.2). In Southern and Eastern European cities, rural-to-urban migration combined with high birth rate continued to produce rapid population growth throughout the 1960s and the 1970s. During the same period, Western European cities have experienced an alternate cycle of growth and decline in the form of population concentration followed by geographic expansion and suburbanisation and finally de-urbanisation. Parallel to this trend has been the faster growth of smaller and medium cities. During the 1980s the pattern of urban decline spread from the largest to the smaller cities and from northwestern to Southern and Eastern Europe (CEC, 1992).

In contrast with past trends of urban decline are the most recent signs of re-urbanisation. European cities have responded to the crisis of the 1980s with programmes for urban renewal and restructuring. The common purpose of these programmes is economic revitalisation and the improvement of the quality of life of the urban population that both the rapid urbanisation and urban decline have caused to deteriorate. The quality of the urban environment is increasingly recognised to be a key ingredient of the economic regeneration of European cities. Understanding the common causes of degradation of Europe's urban environment is one crucial condition for their success.

Urban systems and the environment

Cities can be described according to their geographical position, climate and morphology. Alternatively, they can be described according to their population, social relationships and economic activities. The urban form, structure and landuse are other important variables which affect the quality of the urban environment and the impact of urban settlements on the regional and global environment. In terms of systems ecology, the city can be compared to an ecosystem with its own structure, functions and metabolism. Describing the interactions between the urban system and the environment is, however, a difficult task because of the complex relationships that take place in cities between physical, social and economic variables.

An analysis of the urban dimension of environmental change in Europe should consider both the state of the environment in cities and the impacts that cities have on the regional and global environment. Changes in the quality of the urban environment are rooted in the patterns of urban activities. Urban density, mobility and lifestyles are reflected in the demand for space and the flow of resources. Concentration of people and activities in a limited space places a heavy demand on local natural habitats. However, the impact of cities on the global environment is not an attribute of the city itself, but depends on the activities cities accommodate, their spatial arrangement and the management of natural resources that support these activities. From a global perspective, cities can thus play an important role in achieving global sustainability.

Urban sustainability

Ecological sustainability requires that development should allow response to present needs of the human population without impairing the capacity of future generations to satisfy their own needs. Translating this concept to the urban scale requires that inhabitants' needs are met without imposing unsustainable demands on local, as well as on global, natural systems. Indeed no city sustains itself within its own boundaries. Although cities are generally described as discrete geographical entities, the total area required to sustain an urban region is much greater than that contained within urban boundaries (Rees, 1992). Inputs of energy, water and materials are made into the urban system, where resources are processed, used and converted into residuals. Based on available data in selected European cities and national data, it is estimated that on average a city of 1 million inhabitants in Europe every day requires 11 500 tonnes of fossil fuels, 320 000 tonnes of water and 2000 tonnes of food. It also produces 300 000 tonnes of wastewater, 25 000 tonnes of CO2 and 1600 tonnes of solid waste.

The interdependence between the local and the global environment is crucial to understand the relationships between global and local sustainability. Since cities sustain themselves by drawing on the natural capital of other regions, achieving sustainability at the local level does not ensure ecological sustainability at the global level. Cities may achieve good local environmental conditions in the short term (eg, reducing local air pollution) by placing unsustainable demands on natural resources elsewhere (eg, importing large quantities of energy and exporting large amounts of waste). It is only when seen from a long-term perspective that the link between local quality and global sustainability becomes evident. Indeed these same cities will also suffer from the effects of global environmental problems such as climate change, acidification and stratospheric ozone depletion.

Selected urban indicators

In an attempt to assess the state of Europe's urban environment, 55 urban environmental indicators grouped into 16 urban attributes have been selected, focusing on urban patterns, urban flows and urban environmental quality (Table 10.1). The experimental set of 55 indicators has been selected to identify major urban environmental problems on the basis of the best available information and is not claimed to provide a complete picture of the complex relationships between cities and the environment. A systematic analysis of these relationships would have required a far more complete and detailed list of indicators.

The indicators applied were selected on the basis of their relevance for a preliminary assessment in 72 European cities, acknowledging the constraints imposed by the limited comparable information that is available or could be obtained from existing sources. Cities were selected in order to account for the wide variety of city size, geographic location and predominant economic activities. The list and regional classification of cities as referred to in this chapter are given in Table 10.2. The range of city size in the sample finally included in the report (Table 10.3) was between 12 000 (Valletta) and 8 818 000 (Moscow) inhabitants. Half of the sample cities had over 500 000 inhabitants, one third over 1 000 000 and one third less than 300 000. Three cities (Moscow, London and St Petersburg) had more than 4 500 000 inhabitants. City area ranged between 2 (Valletta) and 1578 (London) km2.

Because of the lack of data in several cities, only a limited number of indicators (20) proposed for the assessment of the urban environment are presented in this report. Data reported are also limited to 51 cities out of the 72 originally selected. A great deal of attention has been given to ensure the quality of the data. However, much caution should be exercised in comparing and analysing the data, since different methods of measurement and variations in accuracy limit comparability. All figures summarised in the indicator table can be found in the Statistical Compendium. Other sources of data cited in this chapter derive from international, national and municipal reports as well as from a number of case studies that compensate for the paucity of available data on historical trends at the urban scale. Additional information is obtained from recent studies on urban energy and on urban carbon dioxide emissions in a number of European cities (ICLEI, 1993; LRC, 1993; IBGE, 1993). The results of a recent survey on urban travel in OECD cities were also used (OECD/ECMT, 1993).

The need for better urban environmental information

The current analysis shows that knowledge of the European urban environment is incomplete. Even when data exist, it is extremely difficult to obtain them. Environmental data at the urban scale are often dispersed among various local agencies and levels of government dealing with different urban environmental aspects. The attempt made for this report to apply an experimental set of indicators shows the areas of environmental information that are lacking or inadequate for a comprehensive assessment of urban environmental problems. An overview of the state of environmental information at the urban scale in Europe is given in Table 10.4.

Monitoring activities at the urban scale are well established in certain areas, such as for example air pollution, where environmental quality standards are available. Such activities are generally less developed for acoustic quality and green space. Data on electricity consumption, water use and waste production can be easily obtained at the municipal level, although their comparability is uncertain due to different measurement methods. Statistics on fossil fuels and consumption of materials are not collected at the urban scale and only a few cities have inventories of energy consumption by fuels, activities or districts. Data on landuse, mobility and infrastructure, when available, are difficult to compare due to different definitions and classification systems. Data availability and reliability vary also from city to city and between regions. In most large cities in Europe, environmental monitoring activities are well established. However, in many others, environmental monitoring has begun only recently.

It is clear that the capacity to address urban environmental problems requires improved information. The importance of different problem areas and contributing causes will only be understood when adequate information becomes available on the urban scale. Increased attention to urban patterns and their relationships to the use of natural resources will be crucial to measuring local and global environmental impacts and exploring alternatives for urban development. The success of important efforts undertaken by local authorities to improve information on the state of the urban environment is essential for a better understanding of priority problems in different urban areas. It is clear, however, that the desired quality and comparability of information across European cities will not be available in the short term. Making use of the best available information now is required.

URBAN ENVIRONMENTAL QUALITY

The quality of the urban environment depends on both physical elements and conditions for community life. Essential to urban life are clean air, water and soil, but also adequate housing, green areas and open space. Other important elements are safety, accessibility and opportunities for economic activities, social interaction and recreation. In cities these factors are interdependent. An attempt has been made to a certain extent to underline the relationships between the state of the urban environment and socio-economic change. However, an analysis of social and economic trends of European cities is beyond the scope of this report. This chapter focuses on the quality of the physical urban environment.

Table 10.5 provides a summary of different environmental problem areas in the 51 European cities examined in this report. While the poor quality of the urban environment emerges as a major concern for Europe, the importance and severity of various problems varies widely between European cities. Air quality is a major concern in most cities. In cities where data are available, unacceptable levels of noise affect between 10 and 50 per cent of urban residents. Traffic accidents are another dominant feature of most European urban centres: in 25 per cent of cases more than 50 people out of every 10 000 inhabitants are injured every year, and one in every 10 000 inhabitants is killed. Housing quality is a particular concern in Eastern European cities, where floor area per capita is half as much as in Western European cities. Access to green areas within a 15-minute walking distance is possible for more than 50 per cent of urban residents in the majority of European cities, and for more than 90 per cent in two thirds of cases where data are available. However, the size and quality of green areas and open spaces vary widely between cities. Although land degradation is a shared concern in most European cities, few data are available on derelict land.

Urban air quality

Major air pollutants in urban areas are sulphur dioxide (SO2), particulate matter, nitrogen oxides (NOx), carbon monoxide (CO), ozone (O3), lead (Pb), other heavy metals and organic compounds arising from various activities. The results of the air quality survey made for this report show that in 70 to 80 per cent of the European cities with more than 500 000 inhabitants, air pollution levels of one or more pollutants exceed WHO Air Quality Guidelines (AQGs) at least once in a typical year (Chapter 4). Major sources are space heating, electricity generation, industrial activities and road traffic. Concentrations of air pollutants vary considerably across European cities depending on the density of activities, fuel mix and technologies employed. Relevant differences in the occurrence and frequency of high concentration episodes can be associated with different local meteorological and topographical conditions. (An extensive assessment of local air pollution is presented in Chapter 4.)

Important changes in the level and composition of urban air pollution in Europe have occurred during the last 20 years. Air quality trends in London and Moscow, two of the ten world 'megacities' recently studied by UNEP and WHO, illustrate well the different patterns occurring in Western and Eastern European cities (UNEP/WHO, 1992) (Boxes 10B and 10C). A major improvement in Northern and Western European cities, and to a lesser extent in Southern European cities, is reflected by the decreasing trend in SO2 concentrations achieved by imposing strict emission standards. In most cities, concentrations of SO2 are less than their level in the late 1970s. Helsinki, Stockholm, Gothenburg, Oslo and Copenhagen, for example, show a decrease of 80 per cent (Bernes, 1993). In the majority of cities surveyed, annual means of SO2 concentrations detected at individual sites are generally less than 50 µg/m3. However, there are still a large number of cities in all parts of Europe where concentrations exceed a short-term WHO Air Quality Guideline (AQG) level (24-hour) for SO2 and/or total suspended particulates (TSP)/black smoke (winter smog) (Table 10.5).

During the last decade, SO2 concentrations in Central and Eastern European urban areas were lowered due to the adoption of several technical measures. Recently, because of economic stagnation and restructuring of industries, air quality has considerably improved. For example, in Prague, Bratislava and Warsaw, SO2 annual means have declined by half between 1985 and 1990 (OECD, 1993d). However, the exceedences of WHO guidelines for combined exposure to SO2 and particulate matter of 50 µg/m3 (annual average) and 125 µg/m3 (24-hour average) show that both short-term and long term SO2 exposure levels are still unacceptably high. Several Central, Eastern and Southern European cities, regularly exceed WHO guidelines for SO2 many times over. In Toru´n SO2 concentrations above 1000 µg/m3 (1-hour/average) are not rare. This is often due to the burning of high-sulphur fuels for heating and industrial purposes, and to outdated technologies.

A downward trend with relative variations between cities can be detected for particulate concentrations (OECD, 1993c). In the majority of cities, suspended particulate concentrations range between 50 µg/m3 and 100 µg/m3. However, TSP concentrations are generally higher than SO2 concentrations. In several cities, especially in Central and Eastern Europe, but also in Southern Europe, particulate concentrations show upward trends. High TSP and black smoke concentration levels in Athens originate from the combined effects of various emission sources (Box 10D).

In contrast to SO2 and TSP trends, is the stability or upward trend in NOx and CO concentrations in all European cities (OECD, 1993c), which is mainly due to the increase in urban traffic. In Western cities, road traffic is a significant contributor to emissions, ranging from 30 to 50 per cent of total NOx and 90 per cent of CO emissions. The share of road traffic in urban air pollution in Eastern European cities is expected to rise substantially in the next few years.

Nitrogen oxides, together with VOCs, are also precursors of ozone, which is a major constituent of photochemical smog (see Chapter 32). Photochemical smog occurs frequently in the majority of European cities. WHO computation of maximum potential for excess ozone exposure in urban areas indicates that up to 93 per cent of Europe's total urban population of 278 million was exposed in 1989 to levels above the 150 µg/m3 (or 75 ppb) hourly limit value and up to 57 per cent to levels above 200 µg/m3 (or 100 ppb).

The urban population in Europe is also exposed to varying concentrations of heavy metals and persistent organic pollutants. Although concentrations of heavy metals (eg, lead, mercury, cadmium) are monitored in several European cities, measurements are incomplete. Even fewer data are available for trace organics (eg, benzene, benzo(a)pyrene (BaP), dioxins and furans, formaldehyde) that are measured in only a few cities. Existing data show contrasting patterns across Europe. Lead concentrations have substantially declined in urban areas in those countries (mostly in Northern and Western Europe) which have reduced the content of lead in petrol. Exposure to high ambient levels of lead, however, is still a problem in several Central and Eastern European cities, especially in mining towns. Estimates from model calculations (RIVM, 1992) suggest that benzene is likely to exceed acceptable limits in most European cities and BaP particularly in Eastern European cities (see also Chapter 4).

Urban air pollution can be exacerbated by local weather conditions and wind patterns. Some towns are situated in valleys where polluted air accumulates and directly affects the urban population. Prague is one example (see Box 10I). Other examples are Sofia, which is situated in a basin attracting heavily polluted air from industries around the city, and Ljubljana, where, due to its specific meteorological situation, air pollution can reach levels three times above WHO standards. In Cracow (Poland), polluted air from the Nowa-Huta metallurgy complex located to the east of the city is drawn into the lower lying city. Levels of SO2 are relatively high in Cracow particularly in winter, due to individual domestic heating installations fuelled with high sulphur-content coal.

Particularly relevant for its combined effect with air pollution is the phenomenon of the urban heat island ­ the air being warmer above cities than above the surrounding countryside. This urban heat island is generated by the urban structure with its dense built-up area and paved surfaces together with building and traffic heat losses. As a consequence, precipitation and evaporation patterns are heavily influenced above large cities (Box 10E).

Urban water

An assessment of the quantity and quality of Europe's water resources is presented in Chapter 5. Urban management of water supply and wastewater is treated in the 'Urban flows' section of this chapter. Threats to water resources become visible in cities, where the supply for drinking water, and for recreational purposes, is endangered. Cities affect and are affected by modifications of the hydrological regime, and changes in the groundwater table may affect the urban structure. Coastal cities are at an increased risk from coastal erosion and flooding. New threats for coastal cities derive from the potential impact of a possible sea-level rise related to climate change (see Chapter 27).

Surface water is an important visual feature, determining the character of most European cities and towns. But its importance is more evident when considering the many functions that water serves in the cities. Most European cities have grown by important waterbodies such as lakes, rivers, estuaries, and coastal waters. In all cities water is a vital economic resource in addition to its role for commercial traffic, transport and recreation. Surface water is also important as a habitat for wildlife and for its influence on the urban climate, helping to cool the air and stimulate air circulation.

Urban waterbodies in European cities are under pressure due to intensified expansion of built-up areas, uncontrolled use of land and water, and releases of pollutants. Sealing off land greatly accelerates runoff; extensive surface sealing causes cities to drain off up to 90 per cent of rainwater as opposed to 10 to 15 per cent in unbuilt areas (Miess, 1979). Following heavy rain episodes, severe contamination of the recipient waterbody can occur due to the combination of sewer overflows or by direct rain runoff through separate sewer systems. Effects can include: increasing bacterial concentrations, oxygen deficiency from the breakdown of excess organic matter, increased concentration of nutrients, heavy metals and polyaromatic hydrocarbons (PAHs), as well as general loss of aesthetic value. In spite of important progress achieved in reducing water pollution in several Western European cities, in most of Europe, especially in Eastern and Southern European countries, rivers crossing urban areas are in bad or poor condition.

The water quality of a river running through a city reflects the geological conditions and human activities taking place in the catchment upstream from the point of measurement. Depending on the location of the measurement point, the water quality reflects the pollution loads in the city itself in addition to those from activities taking place hundreds or more kilometres away from the point of measurement. Figure 10.6 summarises the water quality of 16 rivers running through some of the larger European cities. As far as possible each river monitoring site has been selected to represent the water quality of the river entering the city. Data are not available to assess the impact of cities on the river quality by, for example, comparing upstream and downstream concentrations. The quality indicators reported and the classification used have been chosen to describe river water quality in cities with respect to two widespread sources of river pollution in Europe: sewage discharge (eg, BOD, ammonium and total phosphorus) and pollution by agriculture (eg, nitrates). According to the classification adopted for Figure 10.6, it is evident that sewage pollution represents a bigger problem than does agricultural pollution. Organic matter content (BOD), ammonium and total phosphorus concentrations generally range from fair to poor, with the French river Rhone being the only notable exception having good quality. Nitrate conditions range from good to fair in the majority of rivers and concentrations are in all rivers below the maximum admissible concentration (50 mg/l) in water used for drinking water abstraction, but often exceed the threshold value for eutrophication.

Aquifers below many cities are threatened due to overexploitation and contamination of groundwater. In cities, groundwater can help to conserve the urban fabric, particularly in areas of clay and peat where buildings need stilts (piles) with foundations in deep sand layers in the soil. Most of the buildings in some historic town centres in The Netherlands, Belgium, Denmark and Germany, but also in Italy, have wooden stilt foundations conserved in groundwater. In many places drainage systems are installed in order to stabilise groundwater levels (equally important for green spaces as well as for building foundations).

In cities with high groundwater levels, sewage pipes lie below the water table. When the sewage system is old or not well maintained, sewage pipes can serve as drains, lowering the groundwater table. In other cities intensive abstraction of groundwater for industry, and for the production of piped water for households, is responsible for the lowering of the water table. This can affect the stability of urban soils. It can also lead to the deterioration of wooden foundations, which require water for their conservation. Water table lowering may affect the stability of historic city centres, as it is occurring in Amsterdam and Venice. The complex relationships between cities and water are well illustrated by the case of Venice (Box 10F).

Acoustic quality

Many Europeans experience noise, caused by road-, rail- and air-traffic, by industry and recreational activities, as the main local environmental problem (see Chapter 16). The methods that are generally used to assess the exposure to noise in European urban areas are described in Box 10G. The findings of many studies undertaken in European countries on the effects of noise point out that, to ensure desirable indoor comfort, the outdoor level should not exceed a daytime Leq of 65 dB(A) (OECD, 1991). In the case of new residential areas, the outdoor level should not exceed 55 dB(A). Urban areas with noise levels between 55 and 65 dB(A) are referred to as 'grey areas', while areas with levels in excess of 65 or 70 dB(A), which are perceived as annoying, are referred to as 'black spots'.

In large cities, the proportion of people exposed to unacceptable levels of noise is two to three times higher than the national average (OECD, 1992). It is recognised in many European countries that the percentage of population living in the 'grey areas' with noise levels between 55 and 65 dB(A) is increasing, and therefore noise has become a more significant problem than was predicted some years ago. The percentage of the urban population suffering from noise increases with the number of inhabitants. In West Germany, regular public opinion polls within the last ten years show that, in towns with up to 5000 inhabitants, 14 to 16 per cent of the population are strongly/severely annoyed by street noise. In towns with between 5000 and 20 000 inhabitants this percentage is 17 to 19 per cent, in cities with between 20 000 and 100 000 inhabitants, 19 to 25 per cent, and in cities of 100 000 and more inhabitants, 22 to 33 per cent (see, eg, UBA 1988).

Exceedances of the maximum acceptable level of 65 dB(A) occur in most cities ­ affecting between 10 and 20 per cent of inhabitants in Western Europe and up to 50 per cent in some cases in Central and Eastern Europe. The 70 dB(A) threshold, which is well beyond an acceptable level of noise, is also exceeded in 40 per cent of the cases where data were available. In Sofia 47 per cent of the urban population is exposed to more than 70 dB(A), as are 25 per cent in Budapest, 20 per cent in St Petersburg, 19 per cent in Cracow, 17 per cent in Dnepropetrovsk and 12 per cent in Bratislava. Some cities are 'better off': only 4 per cent in Copenhagen, 3.2 per cent in Kiev and 2 per cent in Amsterdam of the population are exposed to noise levels of 70 dB(A) (Figure 10.7). A larger number of people live in unacceptable acoustic conditions, if this is considered as a noise level above 65 dB(A). In Budapest this proportion is 50 per cent, in Prague 45 per cent and in Dnepropetrovsk 33 per cent. Other cities where data are available are Amsterdam (19 per cent), Oslo (16 per cent), Bergen (12 per cent) and Bilbao (10 per cent).

Data required for a systematic analysis of noise exposure are poor in most cities. However, a recent OECD/ECMT survey on the perceived severity of urban problems, shows that 25 per cent of the cities ranked noise as a severe or very severe problem, and half indicated that noise levels were increasing (OECD/ECMT, 1993). In Europe it is estimated that 113 million people are affected by noise levels of over 65 dB(A) and 450 million people by noise levels of over 55 dB(A). Road traffic is the major offending source of noise in terms of the number of people disturbed. Second and third come neighbourhood and aircraft noise (see also Chapter 16).

In urban areas, tackling the problem of ambient noise is difficult because of the combination of different sources. A number of European countries including The Netherlands, Germany and Switzerland have adopted regulations and noise zoning which establish quality standards for different landuse designation. In Switzerland cities are required to apply specific standards including planning limits, ambient limits and alarm limits for four different zones. For example, a number of measures have been adopted by the city of Zurich to achieve targets. These include: rerouting traffic, quieting vehicles, noise barriers and insulation, pedestrian zones, speed limits of 30 km/h, traffic flow control and noise-absorbent road surfaces.

Green areas

City planning has increasingly recognised the importance and varied functions of green space in urban areas. Standards have been established in several European countries to determine the requirements of green space in new neighbourhoods (Table 10.9). One of the most important functions of green areas in cities is recreation for the urban population. Another is optical dispersion and urban design. But green areas perform other important functions:

Green space in European cities varies considerably in size and type as well as in distribution across the city spatial structure (Figure 10.8). Recent studies on the mental and social aspects of urban life show that the quality and accessibility of available green spaces in cities is far more important than their sizes. A walking distance of 15 minutes or less from homes to green space in urban areas is suggested as an indicator of urban environmental quality. In Brussels, Copenhagen, Glasgow, Gothenburg, Madrid, Milan and Paris, all the citizens live within 15 minutes walk from public green space. This is also the case in most smaller cities, such as Evora, Ermoupolis, Ferrara, Reggio Emilia and Valletta. In Prague and Zurich the corresponding figure is 90 per cent, in Sofia 85 per cent, in Bratislava 63 per cent, in Venice 50 per cent and in Kiev 47 per cent. In the majority of European cities, more than half of the population meet this criterion.

Size and location of green spaces in the city, together with type and frequency of their use, are important indicators of the quality of these spaces as biotopes. Large parks in the inner cities are habitats for a wide and diverse wildlife (Box 10H). The diversity of species between the countryside and the city has been attributed to the transition character of the biotopes which occur in these areas. Railway tracks and green lanes allow immigration and emigration of species across urban areas. Vacant land in the inner city is relevant for its typically urban wasteland ecosystems which include a surprisingly high diversity of species adapted to urban environmental conditions and pressures.

Biotope mapping has been carried out in a number of European cities. The municipality of Lidingö in Greater Stockholm has carried out a comprehensive project to economise use of land and water in the built-up area and achieve a better integration of natural elements in landuse planning. In addition to mapping all vegetation, 'ecological corridors' were marked to connect the various biotopes in the town with reproduction areas outside the town. Other examples in Sweden emphasise that biotope protection in cities can be achieved only if the urban infrastructure is integrated with the green infrastructure. Several other examples exist in European cities. However, no systematic monitoring is carried out to assess natural biotope loss due to increased demand for built-up areas or caused by disturbances such as air pollution and noise.

Housing

Social and economic changes which have accompanied the urbanisation process in Europe are reflected in the housing quality within European cities. During the last century, large sectors of the Western European population have experienced a general improvement in living standards reflected for example in the increase in the average living space per capita. Simultaneously with this trend, rapid demographic changes in European cities were a cause of increasing marginalisation of urban population groups and housing problems. High standard districts together with very poor housing conditions coexist in most European cities. Housing conditions of marginalised groups ­ and often entire districts ­ in many cities are poor, and particularly so during periods of economic recession. However, such groups in Western Europe are still relatively well off when compared with those in Central and Eastern Europe.

Differences in housing standards are clearly evident when comparing Western European with Central and Eastern European cities. Housing quality, measured as average available area per person, is twice as high in Western Europe as in Central and Eastern Europe (Figure 10.9). Moscow has 11.6 m2 net living space per person available, Bratislava 15.4, Prague 16.4, Kiev 17.2, Riga 18.3, Sofia 22.6 and Ljubljana 23.7 m2. Paris has 28.2, Rotterdam 32.8, Copenhagen 45.1, Oslo 47.2 and Zurich 50.6 m2 per inhabitant. The emergence of housing problems in Central and Eastern European cities is also evident when examining the number of housing units without basic services. Lack of basic sanitary requirements such as indoor piped water, flush toilet and fixed bath or shower is reported in many Eastern European countries (WHO, in press). Although rural dwellings are more likely to lack these requirements, the proportion of these dwellings in cities is still high. In Russian cities, for example, every fifth house is without running water, sewage and central heating. Even when the basic infrastructure is present, the state of housing stock in Eastern European countries is often reported to be in need of significant repair (Kosareva, 1993).

The design, layout and building materials are important elements affecting the quality of housing. Design and layout of buildings affect urban microclimate, natural elements and the urban landscape. Building technologies and materials are particularly relevant for the indoor environment. All these factors also determine buildings' environmental performance (eg, energy requirements). This latter aspect is treated further on in this chapter.

The quality of the indoor environment in cities is increasingly of great concern, as its link with human health has become evident (see Chapter 11). Public attention to indoor pollution is relatively recent, and little is known regarding the state of the indoor environment in European cities. However, it is increasingly recognised in most European countries that indoor pollution is an important area of inquiry, since the majority of the population spends most of its time indoors. Among the many pollutants found indoors are nitrogen dioxide, carbon monoxide, radon and asbestos, formaldehyde (from insulation), volatile organics, tobacco smoke and other numerous substances contained in consumer products. The concentrations of indoor pollutants are generally higher indoors than outdoors (Nero, 1988). Pollution from traffic may also have important effects on the quality of indoor air in urban areas (WHO/UNEP, 1990).

Road traffic

Cars dominate the public spaces of European cities. According to a recent OECD/ECMT study on urban travel in 132 cities, there are at least three reinforcing trends which make urban mobility one of the major environmental problems facing cities. These are: increasing levels of car ownership; modal transfer from public transport to car; and the decentralisation of population and employment from inner to outer areas (OECD/ECMT, 1993).

In addition to traffic-related air pollution and noise problems, most large European cities share growing concern for traffic congestion and accidents which are increasingly deteriorating the quality of life of urban communities. Comparable data on traffic congestion are difficult to obtain and have not been included among the indicators selected here. Data from the OECD/ECMT study provide an overview of the general trends. According to OECD estimates vehicle speeds declined by 10 per cent over last 20 years in major OECD cities. Congestion in Paris in the same period increased by 10 per cent per annum. Since 1971, inner London transport speeds have fallen to less than 18 km/h, and on all London roads the average speed is less than 26 km/h. Speeds, and spatial and time distribution in OECD cities suggest that congestion is particularly significant in the morning peak compared to the inter-peak period. Likewise, speeds are lower in the central business district (CBD) area than in the built-up area (Table 10.11) (OECD/ECMT, 1993).

Road traffic, Milan
Source: Michael St Maur Scheil

While important progress in the implementation of traffic safety measures has been achieved in European cities, traffic-related accidents remain a prominent urban concern. Over the past 20 years in EU countries alone more than a million people died in traffic accidents and more than 30 million were injured and/or permanently handicapped. This corresponds to an annual average of 55 000 people killed, 1.7 million injured and 150 000 permanently disabled due to traffic accidents. Expenditure for related health care figures prominently in public budgets.

In European countries, between a quarter and a third of casualties in built-up areas arise from accidents on residential streets. Pedestrians account for 20 to 60 per cent of victims, depending on cities and countries. In London in 1991, for example, 59 per cent of the victims were pedestrians (LRC, 1993). Children are particularly vulnerable. In Brussels, traffic accidents cause three times as many victims among the 5 to 9 age group than among the population as a whole (Région de Bruxelles Capitale, 1993).The number of people killed or injured in traffic accidents in selected cities is given in Figures 10.10 and 10.11. High figures are reported in Paris, Bordeaux, Milan and Reggio Emilia.

Improvement of public transport plays a role in reducing car use and accidents. Many Western European cities have tried to improve road safety through a variety of measures. Speed limits, improved design of road environments and traffic calming have helped considerably. In a limited number of cities in Western Europe, public transport systems are promoted. Examples are: integrated networks of rapid trams, subways, buses and trains as introduced in urban regions in Germany, Switzerland and Scandinavia. Several instances of good public transport can be found in Central and Eastern European cities; one is Prague.

In Denmark, France, Germany, Sweden and The Netherlands bicycling in cities has been promoted since the early 1970s. In relatively flat towns, over 40 per cent of journeys to work can be made by bicycle (IIUE, 1992). With appropriate safety measures, bicycling in cities can contribute to a substantial drop in the number of traffic accidents. In Sweden, for example, bicycle travel increased by one third in ten years, and at the same time the fatal casualty rate was reduced by more than 50 per cent, and the number of deaths by 40 per cent. However, bicycling still remains dangerous in cities with a large number of cars. In The Netherlands, where every citizen has one or more bicycles, a bicyclist is still five times more likely to be involved in a traffic accident than a car driver. Public transport is relatively safe. Public transport passengers have only a 10 per cent chance of being involved in an accident, compared to car drivers. The automobile causes most accidents. Compared to a bicycle, a car causes 20 times more accidents per passenger, while public transport causes only 5 times more (IIUE, 1992).

Due to the increasing numbers of cars, the effect of measures to promote traffic safety remains limited. Some cities in Europe are anticipating more drastic solutions, for instance by promoting 'Cities without cars'. A 'car-free cities' network promoted by the European Commission has been created recently in Europe to exchange experience and undertake common actions to reduce the use of cars in cities (Car Free Cities Charter, 1994).

Cityscapes

Cityscapes are the visual scenery of urban life. They consist of the architecture and archaeology of built-up areas, but also of the building design, layout and the presence and integration of natural elements into built-up and open areas. They are shaped by the cultural and historical development of individual cities and by their social and economic developments. Planning plays a critical role. Cityscapes are affected by urban density, land-use and infrastructure, and by the degree of integration or separation of urban activities in the various districts. These elements have created unique environments in European cities with their own image and identity. Urban change has affected the visual scene of European cities during rapid growth and decline, suburbanisation and reurbanisation. Loss of historical and natural values, as a result of uncontrolled urbanisation and redevelopment in European cities, is an increasing concern. Although many European countries have systems for listing historical buildings, quantification of the loss of the historical fabric in cities at the European scale is difficult due to different listing systems and criteria.

Perhaps the key elements that contribute to cityscape are the impact of buildings beyond the 'human-scale' and the impact of infrastructure, especially that brought about by the private car. In many cases, there are management responses to preserve certain components of cityscapes: traffic management schemes are probably the most widespread. Reducing car traffic in towns through traffic calming, pedestrian zones and encouraging public transport, have brought tremendous benefits to town centres (eg, improved environmental quality, reduced social stress, improved commercial turnover and so on) (Friends of the Earth, 1992). Another example has been the development of strategic planning guidelines for protecting skylines in several European cities (such as London, Liverpool, Paris and Munich). In London, for example, ten strategic views of the skyline of central London (including St Paul's Cathedral and the Palace of Westminster) are safeguarded: this may be increased to 12 views in the near future (LPAC, 1993a, 1993b).

URBAN FLOWS

The impact of cities on the global environment can be described by analysing the flows of natural resources that support their activities. Cities import vast quantities of oxygen, water and organic matter (in the form of fossil fuels and food), and release corresponding quantities of emissions and waste. The land surface required to support any given city and to absorb its waste is many times greater than the city itself. The concept of a city's 'ecological footprint' on the Earth has been proposed to measure the aggregated land area required to support various urban communities (Rees, 1992). The total energy, water and materials which enter a city and the amount of emissions and waste released to the environment depend on city size and average living standards of its inhabitants, but also on the capacity of cities to exploit economies of scale provided by urban concentrations.

Battersea and Albert Bridges, London
Source: H Girardet

Three indicators of urban flows are given in Table 10.13. Particular caution should be exercised when analysing this information due to comparability problems (Table 10.4). Several case studies have been used, as indicated in the following sections, to compensate for the lack of data and to confirm the interpretation of available information. Energy, water and material flows are treated separately in the following sections by examining their impacts and options for an efficient management. As an example, a more comprehensive picture of urban flows in the city of Prague is provided in Box 10I.

Few comparable data on energy consumption are available at the urban scale. It is even more difficult to obtain disaggregation by fuel type or end use. Electricity consumption per capita in cities where data are available average 5700 kWh per year, ranging from 500 to 23 000 (see Statistical Compendium). The data show that electricity consumption per capita is clearly influenced by climate patterns, but provide some indication of better performance (eg, for Helsinki). The lack of data on wastewater, waste composition and waste disposal facilities have led to the omission of these indicators from Table 10.13. Except in a few cases (Bergen, Milan, Oslo, and Reykjavík), water consumption per capita is clearly higher in Central and Eastern European cities. The large variation from the range of 100 to 400 litres per capita per day may be due to differences in measurements, rather than reflecting major differences in consumption levels. One third of European cities produce annually more than 600 kg of waste per capita.

Energy flows

The main source of energy entering the city is the sun, but cities have still very limited technological capability to capture and transform it so that people and machinery can use it. A large part of the solar energy is immediately radiated out of cities. Only a small part is captured by urban vegetation or absorbed in soils and green spaces. Taking Barcelona as an illustration, the relative proportions of energy flows into the city can be measured (Pares et al, 1985). In Barcelona one third (31.6 x 1012 kcal/year) of the total solar energy entering the city is absorbed by vegetation. About two thirds falls on buildings (71.4 x 1012 kcal/year), where it is absorbed in cool periods and/or radiated out into the air in warmer times. In addition to natural energy radiation, 15 x 1012 kcal of combusted fuels and 3 x 1012 kcal of energy in the form of food are imported each year into Barcelona. Human-induced energy in Barcelona accounts for about one fifth of the total quantity of the solar energy flux.

Primary sources of energy used in European cities are fossil fuels, including petroleum products, gas and coal. Electricity is mainly derived from fossil fuels or produced by nuclear installations and hydropower plants; in rare cases it is generated also from geothermal power. Some small settlements use biomass from natural systems in the immediate vicinity. In some cities, advanced systems are in use to derive energy from waste: gas from waste dumps or through fermentation in waste installations; heat from incineration. The use of wind and sun energy (active through solar panels and photovoltaic cells or passive through appropriate architecture and urban design) is still very limited.

Energy consumption in cities varies with differences in climate, degree of urbanisation and industrial structure. Recent studies have explored the relationships between per capita energy consumption and patterns of landuse, transportation modes, building technologies and lifestyle. Compared with North American cities, European and Japanese cities are much more energy-efficient (Lowe, 1991), often explained by their more compact urban system and density. However, important differences can be also observed between European cities. Although comparable data on energy consumption by sectors and by fuels are not generally available, a number of cities, such as Berlin, Bologna, Brussels, Copenhagen, London, Helsinki and Hanover, have charted urban energy flows and their environmental impact (Table 10.12). As an example, the energy flow of London is illustrated in Figure 10.12. From the examples of these cities, consistent patterns and trends emerge. The domestic sector is the largest consumer of energy (from 48 per cent in Copenhagen to 28 per cent in Hanover ­ see Table 10.12). This is in large part due to heating and cooling of residential buildings. A main area of growth in domestic energy consumption is appliances, such as driers and dishwashers. Transport is the second most important sector in terms of urban energy consumption, even if considerable variations can be found between European cities. Commercial and industrial energy consumption vary considerably according to the predominance of economic activities.

Total energy consumption in cities has increased following the general trend in European countries (see Chapter 19). However, different patterns can be analysed according to different sectors. Industrial use of energy in Western European cities has declined considerably in the last 30 years, due to urban de-industrialisation and an increase in efficiency. In London, for example, the industrial sector accounts for 11 per cent of total energy consumption, which is 15 points lower than it was in 1965 (26 per cent) (Figure 10.13). In contrast to this trend is the increasing importance of transport; in the group of cities mentioned above this accounts for 20 to 33 per cent of total energy consumption. Transport in London accounts for 29 per cent of energy use, which represents 11 points growth from 1965 (18 per cent). This is particularly due to greater mobility of citizens and the increased use of cars (LRC, 1993).

Energy efficiency in cities requires the proper allocation of energy supply to the various end uses. District heating or cogeneration (combined heat and power) are important means to improve the urban environmental energy balance, but this potential for energy saving is not yet fully exploited in Europe. Rapid progress is being made in Belgium, Denmark, Finland, Germany and The Netherlands. Cogeneration contributes significantly to the improved energy efficiency in Helsinki (Box 10J). In Copenhagen, the district heating network covers two thirds of the heating requirements in the municipality and it is planned to achieve 95 per cent by the year 2002. However, the proportion of district heating in European cities varies considerably (Nijkamp and Perrels, 1989).

Environmental impacts

The impact of urban energy flows on the local, regional and global environment depends on the total energy demand from various activities, and also on fuel mix and end uses. This can be seen by examining the energy flows in London according to different emissions of air pollutants and end uses (Figure 10.15). Different fuels emit very different amounts of pollutants, so that the fuel mix may offset lower levels of energy consumption when comparing energy flow impacts between different cities. Lower levels of energy consumption per capita in some cities do not necessarily mean that these cities release fewer pollutants into the air. Likewise, the environmental impacts of various urban activities are dependent on the allocation of energy supply.

Local impacts of urban air emissions from urban energy production and consumption for domestic heating have been significantly reduced in most European cities as a result of switching fuels and the introduction of more efficient technologies. In most Central and Eastern European cities, however, power plants and domestic heating are still major causes of local problems. In addition, increasing production of nitrogen oxides as a consequence of increased car use in both Western and Eastern countries is now a major concern because of local and regional impacts (see Chapters 4, 31 and 32).

Cities produce a considerable amount of greenhouse gases which contribute to climate change. An overview of carbon dioxide (CO2) emissions by sectors in a number of European cities is given in Figure 10.16. Major contributions derive from road transport. Second and third rank the residential and commercial sectors. Emission of CO2 per capita in European cities is relatively low compared to North American cities. This is explained by the higher population densities and the increasing use of district heating in Europe. However, the difference in the level of CO2 emissions per capita in European and North American cities is not as large as one would expect by the difference in energy use per capita. This could be explained by the higher CO2 intensity of the fuels used in European cities (ICLEI, 1993). This suggests that considerable room for reduction in CO2 emissions exists even at the same level of energy consumption.

Options for efficient urban energy management

Cities provide a wide range of opportunities for improving energy efficiency and reducing the impacts of their energy consumption. Some energy management measures apply specifically to cities because of their high concentration of activities. They include:

Water flows

Urban water flows consist of natural flows (surface water, groundwater, precipitation and evaporation) and artificial flows (piped water and drained water). Cities rely on piped water for their water supply. The average per capita water supply in European cities is 320 litres per day, ranging in most cities between 100 and 400 litres per day (Figure 10.17). However, in several cities, especially in Central and Eastern Europe, including Prague, Moscow, Zagreb and Warsaw, reported figures are much higher. Higher values are also reported in Nordic cities such as Oslo (663), Reykjavík (580), and Bergen (584). However, high figures in several cities suggest uses for purposes other than domestic supply (eg, for industry).

The use of groundwater for drinking water purposes generally exceeds other sectoral uses. For Europe as a whole, groundwater supplies on average 65 per cent of drinking water. In recent years a tendency towards more intensive use of surface water for drinking water supplies has been observed. This is partly due to the easier accessibility of surface water and partly to the widespread deterioration of groundwater reservoirs (see Chapter 5).

During the International Drinking Water and Sanitation Decade (the 1980s) an analysis was made of the public water supply in 32 European countries. The finding revealed that more than 16 million people in urban areas, and 27 million in rural areas, still rely on public fountains for their daily water supply. In the slum districts of a few urban agglomerations, 1.6 million people do not yet have adequate water supplies. Twenty-two of the countries involved offer a full network service to their urban citizens. Full network supply to homes does not, however, guarantee that water will be available when it is needed. There are many reports about shortages, either seasonally (mainly due to low precipitation) or during the day (mainly due to variation in consumption or technical insufficiency).

On a European scale it seems that drinking water resources now and in the foreseeable future are sufficient. However, as shown in Chapter 5, the resources may not always be present where and when they are needed.

Lack of drinking water resources in many places is also due to lack of proper resource and supply management or to insufficient maintenance of the distribution system. In many cities there are no individual water meters, which leads to reduced awareness of water consumption. In Moscow and Bratislava, but also in several Western and Southern European cities, a large amount of water is lost because of leaking pipes before it reaches the user. Leakages as high as 30 to 50 per cent are frequently reported.

Comparable data on the quality of drinking water are not available, but many countries report failure of compliance with standards; in some countries as many as 40 to 50 per cent of samples do not comply. Two pollutants, nitrates and pesticides, are repeatedly mentioned as causing problems. In many places special treatments to remove nitrates have to be implemented to achieve compliance. Other contaminants occasionally causing problems are heavy metals (particularly lead), aluminium, manganese, sulphate, microbiological pollutants and organic matter. (For further information see WHO, in press.)

Environmental impacts

Urban water flows are controlled to a certain degree, and losses of water occur during transportation and use. Figure 10.18 depicts the flows of water to, through and out of Barcelona. Between the points of abstraction and delivery, about one fifth of the water (50 million m3 per year) is lost in leakage and inadequate processing. After use in households (105 million m3 per year), industries (65 million m3 per year) and other public utilities (15 million m3 per year), the water evaporates (19.6 million m3 per year), runs in drains (30.4 million m3 per year), or vanishes in groundwater (4.7 million m3 per year). Urban water flows catch atmospheric deposits (wet and dry), pollutants in runoff from roofs, streets, roads, parks and gardens, and pollutants from traffic, households and industries.

Urban water use

Until a few decades ago, in many cities, requirements for piped water could be met from natural resources such as rivers, lakes and aquifers. Today, water resources used to prepare drinking water are collected in large reservoirs outside the city. The need to look for clean water sources has led to the extraction of deep groundwater around cities. In Germany, this has caused irreversible changes of heathland around cities, and in The Netherlands to drying out of nature conservation areas. Water consumption in Europe in the domestic sector generally increases with living standards. In most European countries the consumption of piped water in households has increased over the past 15 years from 30 to 45 per cent, with the exception of Sweden and Switzerland (countries where policies to limit end use of water have been implemented). Urban industries have reduced their use of water.

The provision of drinking water for household purposes is often not the most efficient way to allocate a valuable resource. For example, it has been estimated in both Switzerland and The Netherlands that only 5 per cent of all piped water used in houses is for drinking and cooking, nearly two thirds is for bathing and washing clothes and dishes, while nearly one third is to flush toilets and clean houses and streets. It has been demonstrated that more than 60 per cent of the drinkable water could be substituted by 'grey' water (upgraded wastewater to be used in toilets), and rainwater (for bathing and washing). Pilot projects in Berlin and other German cities have tested new systems for re-use of wastewater and use of rainwater.

Urban water supply systems require basins for storage in order to meet consumption peaks. In such basins water can evaporate or leak away. In long, hot, dry periods the water levels in basins can drop dramatically, as was the case in Genoa, Italy in 1991, resulting in rationing of the available piped water. Systems can become inoperative; for instance, the water supply of cities along the Rhine is frequently threatened by pollution from upstream industries, and in certain periods no water is taken for the preparation of drinking water. For many cities piped water has to be transported over great distances, which reduces the efficiency of piped water systems. As distances increase, more transformation stations and pumps are needed, requiring more energy and materials. Longer distances imply more risks and losses, especially when the water transportation infrastructure is not well maintained.

Sewage systems and wastewater treatment plants

In several European cities the wastewater from users is collected together with rain water in sewers and discharged to seas, lakes and rivers without any purification. A very few cities in Europe have installed costly 'separate systems', with one system of channels combining domestic and industrial wastewater and one system for rainwater. Since the rainwater drain is not usually connected to purification installations (in contrast to the channel for wastewater), street dirt (including pollutants from traffic) flows with rainwater into lakes, seas and rivers.

In the majority of cities more than 95 per cent of city dwellings are connected to a sewage system. In Amsterdam, Barcelona, Bergen, Copenhagen, Madrid, Moscow, Paris, Rotterdam, Oslo and Valletta all city dwellings are now connected. In Evora, Helsinki, Liverpool, Ljiubljana, Rennes and Reykjavík less than 1 per cent of all houses are excluded. However, in Southern and Eastern European cities, and also in several cities in Western Europe, lack of wastewater treatment is still a major problem (eg, Brussels and Venice have no treatment plant).

Wastewater plants were rapidly built in the 1960s and 1970s, particularly in Northern and Western European cities. Between 70 and 100 per cent of the wastewater of Denmark, Finland, Germany, Luxembourg, Sweden, The Netherlands and the UK is now treated in sewage plants and up to 90 per cent with chemical or biological treatment (see Chapter 14).

Options for water management

The flows of water in cities are influenced by urban landuse patterns and by the design and management of infrastructures for piped water and drained sewage water. Spatial planning and management of water flows in relation to infrastructure development have become necessities to reduce adverse environmental impacts. A few cities in Europe have integrated water management systems based on careful analysis of the various possible options, their environmental costs and benefits. However, most cities suffer from poor water management and old infrastructures.

The most advanced examples for the management of water flows include:

Material flows

Cities import a wide range of raw and elaborated materials, semi-finished products and end products. Materials brought into cities are transformed into other materials or products, distributed, used and re-used and exported as products or in the form of wastes. All the activities involved, from extraction to production, transport into cities, use and disposal, are potential causes of environmental impacts. The amount and quality of materials imported and exported are therefore a measure of the burden that cities place on the local, regional and global environment.

Building materials are one major component of this flow. Sands, stone and gravel are prime constituents of buildings and road construction. Other building materials used in cities are wood, aluminium, steel, iron, glass and rubble. Enormous quantities of these materials end up as demolition waste which contributes approximately 20 per cent of the total waste produced in cities (where data are available). Cities also import vast quantities of food. In London, for example, 2.4 million tonnes of food were imported in 1990, including milk products (83 000 tonnes), meat products (353 000 tonnes), fish (52 000 tonnes), fruits and vegetables (1 150 000 tonnes), grains (536 000 tonnes), eggs (24 000 tonnes) and beverages (26 000 tonnes) (UK MAFF, 1990). In Europe, the balance of imports and exports varies considerably among cities according to local economic structure and consumption patterns. At European level, few comparable data are available in cities which allow a comparison of imported and exported goods. The assessment of environmental impacts of material flows can be partially made on the basis of urban waste.

Environmental impacts

Materials and products that enter cities are exported as products or transformed into waste. Municipal waste consists of organic substances, paper, metals, textiles, glass, synthetic materials and a large variety of small quantities of toxic substances. In Europe, between 150 and 600 kg of municipal waste are produced per person each year. On average each European produces more than 500 kg of waste per annum or 1.5 kg of waste each day. An assessment of municipal waste in Europe is presented in Chapter 15.

Waste production in selected cities is presented in Figure 10.19. The majority of Western European cities, including Amsterdam, Brussels, Copenhagen, Glasgow, London, Paris and Rotterdam, produce between 300 and 600 kg per capita per year. The same level is reported also in Southern European cities, including Barcelona, Ferrara, Madrid, Milan and Reggio Emilia. In general, Eastern European cities produce annually less than 400 kg of solid waste per capita. These include Budapest, Kiev, Ljubljana, Odessa, Prague, Sofia, Tirana and Warsaw. Some exceptions such as Gda´nsk, Cracow, Riga and St Petersburg, but also Bratislava and Moscow, suggest that reported quantities include waste other than generally classified as municipal. Greater amounts of waste per capita are reported in most Northern European cities such as Bergen, Helsinki, Oslo and Reykjavík.

Although historical data on municipal waste production at the European scale are incomplete, estimates provided by the OECD for Western Europe indicate an increase in production of municipal waste at a rate of 3 per cent per annum between 1985 and 1990 (OECD, 1993e). In addition, a major shift is occurring in the composition of municipal waste with the increase in plastic and packaging materials. The introduction of Western consumer products in to Eastern European markets will extend this effect to these countries.

Municipal waste is generally collected in most European cities, although in deteriorating neighbourhoods removal systems do not always work adequately, due to lack of public funding. A large proportion of municipal waste (60 per cent in OECD Europe) from cities is taken to landfills. Tipping, which is the most common method of disposing of urban wastes in landfills in Europe, is not always controlled. Building and demolition waste are often re-used. Demolition waste is sometimes used for landscaping of recreational areas outside cities. Toxic substances which may be found in those materials are an increasing concern (see Chapter 15).

Incineration of municipal waste in Western Europe is used on average for 20 per cent of waste produced (OECD, 1993c). A few cities compost and ferment their household waste (only 4 per cent of all municipal waste in OECD countries). This requires selective collection of waste to ensure that toxic or non-biodegradable substances do not contaminate the resulting compost. Special handling procedures for toxic and hazardous waste from industrial waste and hospitals do not apply to the increasing amount of the so-called small quantities of hazardous waste produced by households, including paints and inks, batteries, medicinal products and pesticides. This has raised concern for the potential risk they pose in both waste disposal and recycling.

Options for waste reduction and recycling

Efforts are undertaken now in many cities in Europe to set examples of good practice. The flows of materials in several European cities are being remodelled, according to the waste avoidance concept. The aim is to reduce the unnecessary import of materials and to reduce the volume of wastes leaving the city. Recycling in cities is an important way to achieve a better balance between the import and export of materials. This requires selective collection, which means a more differential organisation and management of flows of materials. A number of cities have started differentiated collection programmes and have achieved up to 50 per cent recycling of municipal waste. In Copenhagen, for example, a waste management plan adopted in 1990 has increased the share of recycled waste from 17 per cent in 1988 to 48 per cent in 1993.

Reported levels of recycling achieved in different cities are often not comparable, since they refer to different components of waste materials. Out of the total volume of urban waste, Reggio Emilia now recycles 5 per cent, Moscow recycles 15 per cent of its municipal waste and 54 per cent of its industrial waste, St Petersburg recycles 15 per cent, Oslo 21 per cent and Bratislava 23 per cent.

URBAN PATTERNS

The changes in the quality of the environment in European cities are correlated with changes in production and consumption processes which have occurred in the last decades. The decline in sulphur dioxide air concentrations, for example, is explained by the fuel switch in domestic heating and the increases achieved in energy efficiency. The increased importance of nitrogen oxides in urban air pollution is clearly linked to increased urban traffic. However, the way these patterns are linked together with the changes in the urban structure is often not fully appreciated. Density and location of urban activities influence mobility. Public transportation infrastructure affects people's choice of mode of transport. Changes in the quality of the environment and in the environmental performance of European cities can be explained by examining the changes in urban patterns as a result of socio-economic developments.

Table 10.15 gives an overview of urban size and density patterns in the sample of cities examined. Cross-comparisons should be made with extreme caution since measurements of urban density are particularly sensitive to urban boundary definitions. Administrative city boundaries usually do not respect the actual limits of the built-up areas; they either go beyond them or exclude significant portions. Consequently, estimated densities will often misrepresent the true urban densities of particular cities. Differences in boundary definitions are a major constraint in the attempt to establish correlations between density patterns and urban quality or urban flows. Other important indicators selected to describe European urban patterns such as landuse and mobility patterns (number of trips, trip length and modal share) are not available or comparable for the majority of the cities and are not included in the table.

The majority of cities examined have a density between 2000 and 5000 inhabitants per km2. Population densities greater than 5000 inhabitants per km2 occur in 20 per cent of the cities selected. Paris ranks the highest with more than 20 000 inhabitants/km2. The intensity of built-up area averages 50 per cent of total city areas, ranging from 11 per cent in Dubrovnik and Reggio Emilia up to more than 90 per cent in Amsterdam. Except for Paris and Barcelona, where high built-up density as well as high density of transportation network, correspond to high density of the city population, in the majority of other cases these variables show mixed patterns. Built-up density is influenced by the city form and location. More compact cities such as Amsterdam have developed according to scarce availability of space. In other cases, the spread of the city and lower population densities play a role in the greater density of the transportation network.

The influences of urban patterns on the state of the environment are still poorly understood. The lack of comparable environmental information at the urban scale does not allow general conclusions to be derived. Notwithstanding, the findings of the current analysis together with several thematic studies provide new evidence of the impact of alternative urban patterns on environmental problems. The importance of variables such as population density, landuse, structure and infrastructure, but also mobility and lifestyles, shows that urban environmental problems will be resolved only if serious attention is given to the patterns of urban development.

Urban change

Urban population change in European cities shows mixed patterns. While Southern and Eastern European cities are growing faster, most Western European cities have reached stabilisation and a number of them are experiencing a phase of decline (Figure 10.20). Nevertheless, the proportion of people living in urban areas in Southern and Eastern European countries remains in most cases below that in Northern countries. Recent trends suggest that European urban systems have become more balanced in population size: larger cities have stopped growing in favour of smaller and medium-sized cities. However, increased imbalance exists between cities as to the levels of economic development and quality of life.

Different urban patterns in Europe reflect different stages in the economic transition of various European countries, but are also dependent on the economic and institutional capacity of each individual city to respond to these transformations. Accordingly, different priorities of environmental problems between European cities reflect regional differences in urban development. Northern and Western European cities are facing issues related to shifts in activities and specialisation. These changes are expected to bring increased congestion and stress if environmental implications are not fully understood and addressed. Disregard for environmental implications during rapid urban growth has placed heavy demands on local ecosystems. More recently, urban decline and the loss of functions in urban areas as a result of a decline in traditional industrial sectors have left derelict and contaminated sites. The process of suburbanisation in the last decades has raised major concerns for the local and global impacts of increased demand for land and the increased commuting distance to work of the urban population.

Most Southern and Eastern European cities are facing the pressure of increased demand of housing and infrastructure to support increased economic activities and migration of population from rural areas. Several Southern European cities and particularly Eastern European cities find it difficult to meet acceptable environmental standards for large sectors of their populations. Those cities are also now facing problems of air, water and soil contamination as a result of poor environmental practices in the past.

Density and landuse

Urban growth has direct impacts on the use of land. According to recent estimates, in Europe 2 per cent of agricultural land is lost to urbanisation every ten years. In addition to urban population growth, the expansion of urban areas is the result of increased demand for urban land per capita. During the last century, the surface of urban land per capita in Europe has increased tenfold (Hahn and Simonis, 1991). Even when the city population has not increased, suburbanisation and urban sprawl have induced increased demand for land.

A recent OECD/ECMT survey of 132 cities shows that whether a city is growing or declining, there is a consistent trend towards decentralisation (from inner to outer areas) of both people and jobs in the majority of cities (OECD/ECMT, 1993). This trend is particularly characteristic of the largest cities in Northern and Western European countries, such as Brussels, Copenhagen and Paris. Decentralisation of the urban structure is accompanied by increased separation of urban landuses as a result of urban economic restructuring. Important factors affecting the location of activities (eg, communication and transportation) have changed, reinforcing the tendency to separate home from work and both (home and work) from commercial and recreation areas.

Density patterns vary considerably between European cities, as illustrated in Maps 10.4 to 10.11. Low densities in city centres occur in cities where depopulation is linked to the rise in the Central Business District (Vandermotten, 1994). Examples are Brussels and Copenhagen, where the core districts have less then 5000 inhabitants per km2. In contrast, high densities in the central city core are characteristic of most Mediterranean cities such as Rome and Madrid, with densities higher than 10 000 inhabitants per km2. However, high densities may also be found in several Northern and Western European cities as a result of particular land-forms and very strict landuse regulation and planning, for example, Amsterdam and Rotterdam. Central and Eastern European countries have the highest population densities in the core built-up areas, reflecting the centralised spatial planning of the former centrally planned economies. Examples are Bratislava, Cracow, Warsaw and Moscow.

Different settlement and landuse patterns have been analysed in relation to the pressure on the local and global environment generated by selected cities worldwide (ICLEI, 1993; Lowe, 1991; Newman and Kenworthy, 1989). A city's form and landuse may determine the efficient use of energy, materials, water and space. Dense settlement patterns together with mixed landuses which are generally associated with European cities are considered more efficient in the use of natural resources. The density and location of urban activities as well as the provision of infrastructure also affect travel patterns and petrol consumption and hence the level of emissions from urban transport. Research conducted by the UK government (ECOTEC, 1993) suggests that landuse policies could reduce projected transport emissions by 16 per cent over 20 years. More compact cities, when appropriately planned, reduce travel needs and provide many opportunities for efficient public transport and other forms of energy saving.

However, density alone is not a measure of better environmental performance. Other factors such as centralisation, location of activities and degree of landuse mix play an important role. For example, when combined with the separation of activities in different urban districts, high concentration of activities generates increased mobility and hence increased energy consumption and traffic congestion. In addition, the infrastructure is also crucial. In high density districts, such as the historical cores of several European cities, increased pressure of urban activities combined with the old structure and infrastructure inevitably produces congestion and environmental degradation. The structure of these districts cannot accommodate the increased volume of motorised traffic. The infrastructure for water and energy can be adapted to contemporary demands only at great cost.

Mobility and transport

The increases in mobility and in car ownership and use, as indicated in a recent study of 132 cities in OECD countries (OECD/ECMT, 1993) are consistent with the trend of declining population living in the city core in favour of the suburbs. This study includes 93 cities located in 15 European countries and thus does not provide a complete overview of urban travel trends in all cities selected for this report. However, it does provide the most up-to-date base of comparative information on urban travel in a wide spectrum of cities. Travel distances have increased over time with a shift in trip length from the 5 to 10 km to the 10 to 15 km band. Modal split in the majority of the cities is increasingly dominated by the private car. Table 10.16 shows a marked increase in car ownership, with 45 per cent of the cities having almost one car for every two people in 1990, compared to only 9 per cent in 1970.

Construction site for the
Olympic Games, Barcelona, 1992

Source: Frank Spooner Pictures

Travel demand and modal split are influenced by settlement size, urban density and structure. A recent joint study by the UK Departments of Environment and Transport (UK DoE/DoT, 1993) indicates that higher residential densities are likely to be associated with a relatively lower demand for travel and a higher efficiency in the mode of transport. Travel demand in UK cities is seen to rise markedly as density falls below 15 inhabitants per hectare, and falls as density reaches the threshold of 50 inhabitants per hectare. The relationship between settlement size and emissions-efficient transport is more complex. It is however evident that both the dispersal of population from major city centres and smaller settlement sizes are typically accompanied by higher car use. More centralised urban structures have the effect of increasing journey length, but, according to the UK study, they also increase the use of public transport.

The location of urban activities, especially the location of workplaces, as well as the provision of infrastructure, is crucial to the choice of mode of transport. In Copenhagen, a study of seven districts (Jorgensen, 1993) shows that only 7 per cent of workers actually work in their home district and 18 per cent in the neighbouring district. Consequently, only one quarter of the employed residents work in a range of 5 km from their homes. Another study in Copenhagen shows that the relocation of a large office from the city centre to a suburban location increased the proportion of car-use by the employees from 26 to 54 per cent, while the average travel distance remained the same. A similar study extended to four large offices shows that car use is between 10 and 15 per cent higher in offices located more than 500 metres from an underground station.

The growth in urban mobility and the predominance of road traffic are among the principal causes of urban air pollution, congestion and noise (see Chapters 21 and 37).

Buildings and infrastructure

The urban structure influences also the efficiency of resources use and the opportunities for implementing ecologically efficient solutions through its buildings and infrastructure. Recent studies by the European Commission (DG XVIII PERU programme) and by OECD (1993a, b, c) have examined the influence of urban structure on energy requirements. In European cities, different levels of efficiency can be generally associated with the typology of buildings in the various city districts. Building design (eg, layout and orientation), density and materials are important factors influencing, for example, the capacity to save energy for space heating and cooling. Detached houses have a greater heat loss compared with flats because of their greater surface/volume ratio. Smaller housing units, both terraced housing and low-rise flats, have the advantage of maximising passive solar gains. In addition, attention to microclimate in building design can save at least 5 per cent in energy requirements (OECD, 1993b).

Other important factors influencing the environmental efficiency of buildings are age, maintenance and tenure of building stocks. The structure of old buildings in the historical centres of many European cities imposes severe constraints in the implementation of energy-saving measures. Most of these buildings were built before or at the beginning of the century and hence do not respond to the energy-related building standards (eg, insulation) progressively introduced in most countries. However, the new system-built apartment buildings erected during the 1960s and 1970s, as well as most of the most recent high-rise buildings erected to accommodate business offices or housing, often disregard the minimum microclimate and other environment-related considerations.

Incorporating environmental considerations into the design of the infrastructure which supplies a city with water, energy, food and transportation can be even more critical to prevent and minimise environmental problems. The quality and maintenance of urban supply systems influence the volume of flows of resources and services necessary to the functioning of the city as well as the level of environmental impacts generated. Urban renewal projects implemented in a number of European cities (eg, Berlin, Copenhagen, and Helsinki) have proved that upgrading the urban infrastructure may save energy and water. The provision of a diversified transportation infrastructure and efficient public transportation system is even more important. In Copenhagen, Zurich, Bordeaux, Oslo, Bergen and Stockholm, measures adopted to improve access to public transportation together with alternative infrastructures (eg, bicycling pathways) have been proved to encourage energy-efficient choices in the mode of transport used, and hence to reduce pollution and congestion. In the majority of Western European countries, up to 70 per cent of national investments in the building sector are being channelled into urban renewal and restoration. Urban redevelopment projects are being implemented not only to restore old areas of major urban centres, but are also being increasingly carried out in the districts of more recent suburban development or former industrial zones. These projects provide important opportunities for achieving more livable urban districts while increasing the efficiency of resource use.

Urban lifestyles

The root cause of many urban environmental problems is ultimately unsustainable production and consumption patterns. Consumption of water, energy and materials and production of waste are general concerns of the sustainability of national economies, and not exclusively an urban concern (see Chapter 12). They become an urban concern since the majority of population and economic activities are concentrated in cities. Urbanisation and increased economic affluence undoubtedly have an influence on lifestyles. Cities attract people because of their increased opportunities for economic activities and social interactions. Increase in income has an important influence on the ability of people to choose. The combination of these factors therefore gives urban communities a critical role in achieving better environmental performance.

Changes in lifestyles are examined in detail in Chapter 26, which describes current trends in households and their environmental implications. In cities, mixed patterns emerge. On the one hand, change in the household structure (average household size) and the number of households together with increased household income and the availability of goods, have resulted in increased consumption. On the other hand, recent years have seen a raised awareness of the problems involved, largely as a result of concerned pressure groups influencing consumer behaviour.

While plans and policies may be framed at the national, regional and local levels, the actual test of their effectiveness is whether they are taken up in modified urban lifestyles. Opportunities in cities are greater. In some cases the possibility of personal choice is controlled, or at least guided, by encouraging environmentally friendly behaviour (eg, traffic management schemes) or by providing the necessary infrastructure and information to make better choices. However, increasingly, the role of the individual in promoting environmental improvement has become vital given the increased reliance on voluntary actions (eg, for recycling). This suggests that the implementation of measures to improve the quality of the urban environment and cities' environmental performance can be achieved only by increasing individual and collective awareness, together with promoting citizens' participation in the design of such measures.

TOWARDS SUSTAINABLE EUROPEAN CITIES

Urban environmental problems

Europe is a highly urbanised continent with more than twothirds of the total population living in urban areas. The state of the environment in cities is consequently of great importance to most Europeans. On the other hand, environmental problems, from local to global, are often rooted in increasing urban activities and their pressure on natural resources. The level of ecological awareness in designing and managing cities is thus a crucial test for achieving sustainable development in Europe.

The urban environmental indicators which have been selected to describe European cities provide a basis for identifying major urban environmental problems and assessing regional differences and priorities. From the assessment of 51 European cities, the environmental quality of urban areas emerges as a major concern for Europe (see Chapter 37). However, the importance and severity of various problems vary widely between European cities and regions. Three interconnected areas of concerns are: air quality, noise and road traffic. Despite the achievements in the reduction of traditional emissions (SO2 and particulate matter) the majority of cities still exceed short-term WHO AQGs. Compared with Eastern and Southern European cities, Northern and Western cities are better off in terms of long-term exposure to SO2, but are now faced with other types of threats (eg, NOx and VOCs). Even for strictly regulated air pollutants, there is an enormous variation in the level of implementation of standards and guidelines between European cities. Poor acoustic quality is also of increasing concern, particularly in urban areas. Between 30 and 40 per cent of cities indicate that more than 10 per cent of the residents are exposed to unacceptable levels of noise (above 70 dB). Furthermore, increased traffic congestion and accidents are other dominant characteristics of most European urban centres.

Greater variations can be detected when examining the quality of urban space and housing. Land availability varies according to geographic location and land form. However, economic and political factors play a decisive role in resolving the tension between different landuses in cities. Thus, landuse regulations in Europe have been vital to balancing urban development with the need to satisfy urban quality criteria and the protection of natural areas and historical centres. More recently, under increased economic pressure, most municipalities have found it increasingly difficult to protect and maintain open space and green areas, as well as to prevent the replacement of historical buildings and sites. Different patterns of housing quality and capacity are clearly linked to regional differences. Housing problems are more relevant in Eastern European countries, where basic standards for housing are not met for a considerable proportion of urban residents. However, high-standard districts together with very poor housing conditions coexist in most European cities.

While all European cities are faced with increasing environmental pressures and deterioration, the causes are often diverse. One important example is given by the uneven contribution of various activities to urban air pollution problems across Western and Eastern Europe. Since the early 1970s, sulphur dioxide air concentrations in Western European cities have considerably decreased as a result of reduced coal burning for domestic heating. Instead, increased concentrations of nitrogen oxides, carbon monoxide and carbon dioxide show that increased traffic volumes are a major cause of urban air pollution. Different patterns of air pollutant concentrations in Central and Eastern European cities show that heavy industrial activities and energy production plants are relatively more important as sources of air pollution in the city.

A measure of the contribution of European cities to regional and global environmental problems is the amount of energy and water consumed as well as the per capita production of emissions and waste. Most Western European cities have achieved important results in energy efficiency as well as reducing the amount of emitted pollutants per unit of product and service provided. However, the total amount of natural resources used by urban activities has increased as a consequence of changes in lifestyle and living standards. Furthermore the total amounts of waste have increased. On the other hand, in many Southern and Eastern European cities, limited economic resources are a major constraint in the process of replacing highly polluting and inefficient technologies which still place enormous burdens on the local and global environment.

Root causes of urban degradation and poor environmental performance of cities are often the result of inadequate environmental consideration in landuse planning and urban management. The deterioration of the urban environment accelerates particularly in periods of rapid change. Both urban growth and decline in Europe have caused increased pressure on the urban environment. Current trends towards the decentralisation of urban structure and increased mobility dependent on the private car are likely to exacerbate current environmental problems in the major European cities.

The need for an integrated approach

Urban environmental problems can be tackled by reducing the pressure of urban activities through landuse planning, and the efficient management of the flows of resources as well as through measures directed towards protecting the quality of the urban environment. Addressing the causes of urban environmental problems instead of focusing on their symptoms is a necessary condition for success. Moreover, the interrelated nature of urban environmental problems requires that the actions undertaken at the various levels should be part of an integrated approach. The need for integration was acknowledged in an OECD report (OECD, 1990) which examined the organisational and institutional implications. At the EU level this was recognised in the Green Paper on the Urban Environment, 1990 (CEC, 1990). Both reports emphasised the importance of a specifically urban approach if environmental problems are to be effectively addressed and resolved. The options and examples illustrated below show the wide scope for change that an adequate consideration of environmental concerns in urban planning and management can provide.

Changing urban patterns

Landuse planning and space management are powerful tools to improve the condition of the urban environment. Through ecological management of the urban space, the demand for mobility can be reduced and access to essential public services increased. Urban renewal and re-use of old industrial sites in urban areas provide the opportunity for creating open spaces and ecological restructuring of urban centres (Box 10K). Also the replacement or rehabilitation of inadequate urban infrastructure can improve access to urban areas and services and reduce the pressure of urban travel.

The shift from private to public transportation in urban areas is highly dependent on the urban structure and integration of urban activities. It also depends on the level of accessibility of public facilities. While landuse planning is one of the most efficient tools for reducing the need of people to move, an integrated public transportation system together with proper traffic management can influence the choice of transportation mode (Boxes 10L and 10M). In particular the provision of differentiated infrastructure for public transportation, bicycles and pedestrians in urban centres is important to satisfy a differentiated demand for urban mobility (Box 10N).

Managing urban flows

The flows of energy, materials and water in the urban system can be reduced by improved management and up-to-date technologies. Considerable opportunities for energy and water savings as well as material recycling are available at the urban level. However, if urban ecological cycles are to be made more efficient, there will have to be active integration of the technical and green infrastructures. As one of the first national reports on the state of the urban environment produced by Sweden, Ecocycles (SEAC, 1992), pointed out, in order to improve the urban environment, supply systems need to be adapted to environmental cycles, and the cycles must be made visible in the cities. Successful examples of eco-restructuring and implementation of small-scale ecological infrastructures have been developed in Northern and Western European cities (Box 10 O). Important efforts are also being made in Central and Eastern European cities. These experiences constitute an important base of information for exploring new and creative solutions.

Improving urban environmental quality

Although important progress has been achieved in establishing air pollution standards for cities, their implementation is still a major problem in several European countries. Improved monitoring of air quality is a priority in most Eastern European cities. New mechanisms, such as local taxation and permitting systems need to be developed to achieve effective implementation of established standards. Comparable standards for water resources, soil and noise still remain to be established to protect the health of people living in urban areas.

Setting urban sustainability targets

The World Conference on Environment and Development (UNCED, 1992), recognised the crucial role of cities and local authorities in achieving sustainable development. Chapter 28 of Agenda 21 highlights that:

local authorities construct, operate and maintain economic, social and environmental infrastructure, oversee planning processes, establish local environmental policies and regulations, and assist in implementing national and subnational environmental policies. As the level of governance closest to the people, they play a vital role in educating, mobilising and responding to the public to promote sustainable development.

Among the other objectives, Chapter 28 establishes that by 1996:

local authorities in each country should have undertaken a consultative process with their population and achieved a consensus on a Local Agenda 21 for the community.

A starting point for developing local Agenda 21 in European cities is to achieve a better understanding of what a sustainable city looks like. Ideally, local Agenda 21 should be designed to ensure compliance with sustainability limits. In practical terms, there is vast uncertainty on the exact limits of local and global ecosystems to accommodate increasing demands of environmental goods and services. Notwithstanding, the evidence that current urban patterns have reached critical thresholds in such areas as air pollution and energy consumption is already an important basis for setting targets to move in the direction of sustainability. Progressive improvements of these targets and the means to achieve them will be possible only with the improvement of our understanding of what sustainability entails and of different priorities to achieve sustainable targets in each local context.

The design of local Agenda 21 should also help in balancing the local and global perspective. Considering the various scales of urban environmental problems, including district, city and metropolitan, as well as their interactions with the regional and global scales, will help clarify problem areas where different perspectives (eg, local and global) may conflict. Cross-national cooperation of local authorities and international programmes is being pursued to accomplish this task (Box 10P). This will help improve the institutional framework to address urban environmental problems.

Building institutional capacity

Important progress achieved in understanding the nature of urban environmental problems has led to relevant changes in urban planning and management in Europe.

Local authorities in several European cities are rearranging their functions and setting new mechanisms to achieve the necessary integration between departments and across different sectors of activities. In these attempts, cities have discovered that the scope for integrating environmental considerations into urban decision making is vast and needs to be fully exploited if measurable improvements in the quality of European cities are to be achieved. Eco-auditing and environmental accounting at the municipal level could help to establish feedback mechanisms in order to ensure that progress is being made in all sectors of urban activities that affect environmental quality and performance. Increased attention is placed on economic instruments to achieve better internalisation of environmental costs and to encourage less polluting behaviours. In addition, full compliance with ambient quality and emission standards for the outdoor and indoor environment is to be ensured. The need for better integration and coordination across the various levels of government is also required.

New forms of cooperation with all sectors of the urban community have proved crucial to the success of programmes of urban renewal and environmental improvement in several European cities. Amsterdam, Berlin, Copenhagen, London and Manchester have successfully established partnerships between private and public sectors in urban redevelopment projects. A similar approach is now being considered in a larger number of cities.

Monitoring urban environmental change

One major challenge for the orientation of future urban environmental programmes is building the necessary technical and institutional capacity for monitoring urban environmental change. As anticipated in the introduction to this chapter, the improvement of environmental information at the urban scale is a priority for sound environmental action. Important progress is being made at the municipal level in most European countries to establish systematic monitoring and reporting on the state of the urban environment. For the present analysis, outstanding efforts have been made by the selected cities to provide the information presented in this chapter. This is an effort which needs building upon if future monitoring and reporting on the urban environment is to be improved.

An important distinction must be drawn between the comparability and availability of information. Obtaining comparable information on the state of the urban environment at the European scale has gained increased importance as countries have recognised the European dimension of most urban environmental problems. However, environmental information is often not available or adequate in the first place. Indeed, in many cities environmental monitoring activities are still limited in scope. Furthermore, most environmental statistics are not collected at the municipal level. The sectoral organisation of data collection across various agencies usually does not allow for cross-sectoral analyses and comparisons because of different classification systems and accuracy.

The influence of different urban patterns on the quality of the urban environment can be understood only when quantitative links between landuses, transport, energy use and emissions can be established. The improvement of environmental monitoring at the urban scale and its integration with other urban statistics is crucial to interpret changes in environmental quality and assess the effects of urban policies and programmes. There are several advanced examples of cities in European countries such as France, Finland, Germany, Switzerland and Sweden where systematic monitoring of urban environmental quality is effectively integrated with emission inventories and dispersion modelling. These experiences could provide a useful framework for integrating and harmonising urban monitoring across European cities.

Obtaining objective and comparable information on the state of the urban environment also requires comparable urban environmental indicators to monitor progress and assess the effectiveness of programmes and measures designed to improve the state of European urban environments. The experimental indicators used in this chapter demonstrate the benefits of this approach, but considerable improvements are required to obtain a more accurate picture. Existing networks of cities may play an important role in this process.