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GEO Year Book 2004/5  
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Theme: URBAN AREAS

Issue: Urban air quality
Indicators: Concentrations of lead, particulate matter (PM) sulphur dioxide (SO2) and nitrogen dioxide (NO2) in air

Urban air quality

The air in cities may be severely polluted not only by transport but also by the burning of fossil fuels in power plants, factories, office buildings, and homes and by the incineration of garbage. There are no up-to-date and comprehensive data on city air quality for most regions of the world. However, selected data collected by OECD indicates that lead is becoming less of a problem in developed regions and its levels are now well below the WHO guideline value (WHO 2000) (Figure 17). In many of the cities the concentrations of particulate matter and sulphur dioxide are also decreasing (Figures 18 and 19), while nitrogen dioxide levels are still high (Figure 20) (OECD 2002). The decrease in pollutant levels has usually been brought about through controls on emissions and changing fuel use patterns.

Figure 17: Concentrations of lead (µg/m3) in air in selected cities, 1985–99

Source: GEO Data Portal, compiled from OECD Environmental Data Compendium 2002


Figure 18: Concentrations of PM (µg/m3) in air in selected cities, 1985–2000

Source: GEO Data Portal, compiled from OECD Environmental Data Compendium 2002


Figure 19: Concentrations of SO2 (µg/m3) in air in selected cities, 1985–2000

Source: GEO Data Portal, compiled from OECD Environmental Data Compendium 2002


Figure 20: Concentrations of NO2 (µg/m3) in air in selected cities, 1985–2000

Source: GEO Data Portal, compiled from OECD Environmental Data Compendium 2002

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