Serious air quality problems in Europe
Between 80 and 90 per cent of the EU urban population is exposed to levels of harmful particulate matter (PM10) exceeding the air quality guideline set by the World Health Organization, and more than 95 per cent is exposed to ozone exceeding this level.
Air quality in Europe has improved over the last twenty years, as emissions of most air pollutants have fallen, according to a new report from the European Environment Agency (EEA). But even though emissions have fallen, this has not always led to a corresponding drop in pollutant concentrations in the air.
This is particularly the case for particulate matter (PM) and ground-level ozone, which have complex relationships between emissions and air quality, and concentration levels of these two pollutants have remained relatively stable over recent years despite efforts to improve air quality.
Ozone and PM are also the most problematic pollutants for health. Epidemiological studies show that the most severe health damage from exposure to air pollution is associated with particulate matter and, to a lesser extent, ozone. Both pollutants can cause or aggravate cardiovascular and lung diseases and lead to premature death.
Eutrophication, an oversupply of nutrient nitrogen in terrestrial and aquatic ecosystems, is another major problem caused by air pollutants. Ammonia (NH3) from agriculture and nitrogen oxides (NOx) from combustion processes are a main cause of eutrophication. They are now also the main acidifying air pollutants, as emissions of sulphur dioxide (SO2) have fallen significantly over the last two decades. Projections for 2010 have shown that 69 per cent of the total sensitive ecosystem area in the EU was at risk of eutrophication and 11 per cent was at risk of acidification.
Twenty per cent of the EU urban population lives in areas where the EU air quality 24-hour limit value for PM10 concentration was exceeded in 2009. For the 32 member countries of the EEA, the estimate is 39 per cent. However, 80-90 per cent of the EU urban population was exposed to levels of PM10 which exceed the more stringent World Health Organization (WHO) air quality guideline of 20µg/m3 as an annual mean. This situation does not seem to be improving.
Particulate matter in the atmosphere originates both from direct emissions (primary particles) and as a product of oxidation (secondary particles) of so-called PM precursor gases, namely SO2, NOx, NH3 and volatile organic compounds (VOCs). PM precursor emissions decreased between 1999 and 2009 in the EU: SO2 by 56 per cent, NOx by 28 per cent, and NH3 by 11 per cent. Emissions of primary PM10 and PM2.5 decreased by 16 and 21 per cent respectively in the same period.
Although man-made emissions of many of the precursors to ozone formation have declined, ozone levels did not fall significantly between 1999 and 2009. Approximately 17 per cent of European citizens live in areas where the EU health-related target level for ozone concentration was exceeded in 2009. If ambient ozone levels are compared to the more stringent WHO guidelines, more than 95 per cent of the EU urban population was exposed to ozone exceeding this level. Moreover, about one third of the total arable land in the 32 EEA member countries was exposed to levels of ozone above the EU vegetation-related target level.
Ozone is not directly emitted into the atmosphere but formed from a chain of photochemical reactions following emissions of the precursor pollutants NOx, VOCs, carbon monoxide (CO) and methane (CH4).
Very few EU urban citizens are exposed to levels of SO2 above the EU limit value, although 68-85 per cent of the EU urban population is potentially exposed to levels above the WHO guidelines. Concentrations of NO2 have declined slightly in recent years, and exceedances of EU air quality limits usually occur at hotspots, such as main roads. Twelve per cent of the European urban population live in areas with urban background (non-traffic) concentrations of NO2 exceeding EU and WHO levels.
Atmospheric levels of arsenic, cadmium, lead and nickel are generally low in Europe. However, heavy metal levels can build up in soils, sediments and organisms. Despite considerable cuts in emissions of heavy metals since 1990 in the EU, a significant share of the ecosystem area is still at risk of heavy metal contamination. Exceedances of mercury critical loads were projected to occur in 54 per cent of sensitive ecosystems areas in 2010 under current legislation, while for lead the projected exceedance area is 12 per cent of sensitive ecosystem areas.
The links between air quality and other policy areas are mentioned in the report, and it is noted that measures aimed at combating climate change or noise may contribute substantially to reducing air pollution, while some climate measures may worsen air quality. Likewise, air quality measures can have both positive and negative climate change impacts.
"Europe's air quality is generally getting better, but concentrations of some pollutants are still endangering people's health," Jacqueline McGlade, EEA Executive Director, said. "To improve air quality further, we need to use many different kinds of policies and measures. These could include reducing emissions levels at source, better urban planning to reduce people's exposure and lifestyle changes at the individual level."
Air quality in Europe – 2011 report. EEA Technical report No 12/2011. Published 9 November 2011. Available at: http://www.eea.europa.eu/publications/air-quality-in-europe-2011
Figure 1. Major air pollutants in Europe, clustered according to impacts on human health, ecosystems and the climate.
Figure 2. EU emissions of primary PM and of PM and ozone precursor gases 1990–2009
Table. Percentage of the urban population in the EU exposed to air pollutant concentrations above the EU and WHO reference levels
Note: The reference levels included comprise EU limit or target levels and WHO air quality guidelines (AQG). The averaging period is shown and the reference levels in brackets are in μg/m3 except for CO which is in mg/m3. For some pollutants EU legislation allows a limited number of exceedances. This aspect is considered in the compilation of exposure in relation to EU air quality limit and target values. The comparison is made for the most stringent EU limit or target values set for the protection of human health. For PM10 the most stringent standard is for 24-hour mean concentration. This estimate refers to a recent three-year period (2006–2008) and includes variations due to meteorology, as dispersion and atmospheric conditions differ from year to year.