This report analyses and presents changes in air pollutant emissions and their possible health or ecosystem impacts in Europe covering the period 1990–2004.
Emissions of all air pollutants fell substantially during the period 1990–2004 in the 32 EEA member countries (EEA-32), resulting in improved air quality over the region. However, ambient concentrations of particulate matter and ozone in the air have not shown any improvement since 1997, despite the decrease in emissions. This might be due to meteorological variability and growing long‑distance transport of pollutants. Fine particulate matter with a diameter size below 2.5 micrometer (PM2.5) is now generally recognised to be the main threat to human health from air pollution. As sulphur emissions have fallen, ammonia emitted from agricultural activity and nitrogen oxides from combustion processes have become the predominant acidifying and eutrophying agents affecting ecosystems.
Air pollution issues in Europe
The major classical air pollutants emitted into the atmosphere in Europe are sulphur dioxide (SO2), nitrogen oxides (NOX), ammonia (NH3), non‑methane volatile organic compounds (NMVOC) and particulate matter (PM). Air pollutants have direct and indirect effects on human health (Figure 1).
Sulphur and nitrogen compounds emitted into the air are potentially acidifying and can cause harm when deposited into sensitive terrestrial or aquatic ecosystems. Nitrogen compounds are also potentially eutrophying, i.e. can cause an oversupply of nutrient in soils and water bodies (Figure 1).
Particulate matter emissions include primary PM and secondary particulates, formed from so-called PM precursor gases (SO2, NOX, NH3, VOC and NMVOC). Primary PM is the fraction of PM that is directly emitted into the atmosphere, whereas secondary PM is the fraction of PM created in the atmosphere through oxidation of precursor gases, e.g. of SO2, NOX into sulphuric acid (liquid) and nitric acid (gaseous), respectively. Secondary organic PM can also be formed from the oxidation of volatile organic compounds (VOCs). Ozone (O3) is formed in the atmosphere by reaction between NOX and NMVOC gases in the presence of heat and sunlight. Ozone pollution is thus a major concern during the summer months. Presently, more than 2 300 air quality monitoring stations report air pollution data to the EEA. Widespread observations started to become available at the European level in 1996/1997. For 2004, 32 EEA member countries reported observations that could be used for the analyses presented in this report.
- The significant emission reductions in PM precursors are not reflected in observed PM10 concentrations, which have shown no change between 1997 (when observations became widely available) and 2004. This can be (partly) explained by meteorological variability affecting concentrations by between 15–20 % in recent years.
- 20–30 % of the European urban population lives in cities where EU air quality limit values of particulate matter (PM10) were exceeded at urban background monitoring stations between 1997 and 2004.
Small airborne particulate matter is inhaled by humans. It can shorten life expectancy and increase numbers of premature deaths, hospital admissions and emergency room visits (e.g. respiratory diseases, increased risk of heart attack). The coarse fraction of PM10 reaches the upper part of the airways and lung (PM10 = particles with a diameter up to 10 μm). The fine fraction of PM10 is more dangerous, as it penetrates more deeply into the lung (PM2.5 = particles with a diameter up to 2.5 μm). Adverse health effects occur after short-term exposure to concentration peaks, as well as longterm exposure to relatively low PM concentrations. However, the mechanism of how PM affects health still remains unclear