The air pollution phenomenon in Athens is known as 'the nefos' (the cloud), a name which underlines its visible character. Visibility impairment during pollution episodes is due to high burdens of aerosol particles, and the yellowish-brown colour of the cloud is due to nitrogen dioxide. The local monitoring stations measure concentrations of suspended particles by two methods: the black-smoke method, capturing carbonaceous particles mainly emitted by diesel vehicles and heating, and the 'total suspended particulates' (TSP) method taking into account both black and non-black (ie non-carbonaceous) particles. The latter are generated by industrial activities as primary aerosols, including dust, or formed in the atmosphere as secondary aerosols by chemical conversion of gaseous pollutants. These secondary non-black aerosols have the greatest effect on visibility reduction through scattering mechanisms. Satellite multispectral images provide a general view of how the nefos spreads over the Athens basin and help explain the spatial distribution of particulate pollution at a single point in time. Such images illustrate that, during a typical autumn episode in the city, the main burden of non-black suspended particles is confined to the industrial district west of the city centre. Figure 10.5 shows the relative concentration levels of the different particles monitored at two representative stations: in the city centre (Station V) and in the industrial area (Station R). Black-smoke concentrations are three times higher in the city centre, while TSP concentrations are slightly higher in the industrial area. This is because non-black and/or dust concentrations are much higher in the industrial area. The trends show that there has been a decline in black-smoke levels in recent years at both stations thanks to the control measures applied to vehicles and domestic heating. Such measures have little effect, however, on non-black particulate concentrations, which is why TSP levels are relatively stable. Source: N Sifakis Data sources: EURIMAGE, PERPA-Athens Figure 10.5 - Athens: the nefos
The local monitoring stations measure concentrations of suspended particles by two methods: the black-smoke method, capturing carbonaceous particles mainly emitted by diesel vehicles and heating, and the 'total suspended particulates' (TSP) method taking into account both black and non-black (ie non-carbonaceous) particles. The latter are generated by industrial activities as primary aerosols, including dust, or formed in the atmosphere as secondary aerosols by chemical conversion of gaseous pollutants. These secondary non-black aerosols have the greatest effect on visibility reduction through scattering mechanisms. Satellite multispectral images provide a general view of how the nefos spreads over the Athens basin and help explain the spatial distribution of particulate pollution at a single point in time. Such images illustrate that, during a typical autumn episode in the city, the main burden of non-black suspended particles is confined to the industrial district west of the city centre. Figure 10.5 shows the relative concentration levels of the different particles monitored at two representative stations: in the city centre (Station V) and in the industrial area (Station R). Black-smoke concentrations are three times higher in the city centre, while TSP concentrations are slightly higher in the industrial area. This is because non-black and/or dust concentrations are much higher in the industrial area. The trends show that there has been a decline in black-smoke levels in recent years at both stations thanks to the control measures applied to vehicles and domestic heating. Such measures have little effect, however, on non-black particulate concentrations, which is why TSP levels are relatively stable. Source: N Sifakis Data sources: EURIMAGE, PERPA-Athens Figure 10.5 - Athens: the nefos
Satellite multispectral images provide a general view of how the nefos spreads over the Athens basin and help explain the spatial distribution of particulate pollution at a single point in time. Such images illustrate that, during a typical autumn episode in the city, the main burden of non-black suspended particles is confined to the industrial district west of the city centre. Figure 10.5 shows the relative concentration levels of the different particles monitored at two representative stations: in the city centre (Station V) and in the industrial area (Station R). Black-smoke concentrations are three times higher in the city centre, while TSP concentrations are slightly higher in the industrial area. This is because non-black and/or dust concentrations are much higher in the industrial area. The trends show that there has been a decline in black-smoke levels in recent years at both stations thanks to the control measures applied to vehicles and domestic heating. Such measures have little effect, however, on non-black particulate concentrations, which is why TSP levels are relatively stable. Source: N Sifakis Data sources: EURIMAGE, PERPA-Athens Figure 10.5 - Athens: the nefos
Figure 10.5 shows the relative concentration levels of the different particles monitored at two representative stations: in the city centre (Station V) and in the industrial area (Station R). Black-smoke concentrations are three times higher in the city centre, while TSP concentrations are slightly higher in the industrial area. This is because non-black and/or dust concentrations are much higher in the industrial area. The trends show that there has been a decline in black-smoke levels in recent years at both stations thanks to the control measures applied to vehicles and domestic heating. Such measures have little effect, however, on non-black particulate concentrations, which is why TSP levels are relatively stable. Source: N Sifakis Data sources: EURIMAGE, PERPA-Athens Figure 10.5 - Athens: the nefos
Source: N Sifakis
Data sources: EURIMAGE, PERPA-Athens