EU legislation has led to significant improvements in air quality. The percentage of urban citizens exposed to pollutant levels above EU legal standards set to protect human health fell between 2000 and 2021, in particular for fine particulate matter and nitrogen dioxide (due to road transport and households emissions reductions). For these air pollutants, less than 1% of citizens were exposed to levels above EU legal standards in 2021. However, poor air quality remains a problem: in 2021, 10% of EU citizens were exposed to ozone and particulate matter PM10 levels above EU standards.

Figure 1. Urban population exposed to air pollutant concentrations above selected EU air quality standards, EU-27


More than 70% of EU citizens live in urban areas, where high population densities and economic activities cause high levels of air pollution. Such exposure is linked to adverse health effects, such as respiratory and heart problems, and cancer. Particulate matter (PM), ozone (O3), nitrogen dioxide (NO2),  sulphur dioxide (SO2) and benzo[α]pyrene (BaP) are associated with serious health problems . The EU Ambient Air Quality Directives aim to protect human health, vegetation and natural ecosystems by setting limit and target values for, among others, those air pollutants (and long-term objectives for O3).

The European Green Deal’s Zero Pollution Action Plan has a vision of reducing by 2050 air pollution to levels no longer considered harmful to health and natural ecosystems, that respect the boundaries with which our planet can cope, thereby creating a toxic-free environment. It also set the 2030 health-related goal of reducing the number of premature deaths caused by fine particulate matter (PM2.5) by at least 55% compared with 2005 levels.

The European Green Deal also proposed to revise the EU air quality standards to align them more closely with the World Health Organization (WHO) recommendations. Subsequently, the Commission published a proposal for a revised Directive of ambient air quality and cleaner air for Europe on 26 October 2022. The levels recommended in the latest edition of the WHO air quality guidelines from 2021, based on the latest scientific evidence, are much stricter than the current EU air quality standards.

For most pollutants, especially fine particulate matter (PM2.5) and NO2, the percentage of urban population exposed to levels above EU standards has decreased since 2000. In 2021, less than 1% of the urban population lived in zones exceeding the EU annual limit values for PM2.5 and NO2.

For SO2, the percentage exposed to levels above the daily limit value decreased between 2000 and 2021: from a maximum of 2% in 2006 to less than 0.1% in all the years in the period 2010-2021. Therefore, these values are not shown in Figure 1.

However, levels above other EU standards are still recorded in many areas. For instance, in 2021, 10% of urban citizens were still exposed to PM with a diameter of 10µm or less (PM10) above the EU daily limit value. Nevertheless, this value is the minimum in the series and much lower than the 51% peak in 2000.

O3 is a secondary pollutant formed from other pollutants in the presence of solar light. Its levels are determined by emissions and meteorology. The proportion of the urban population exposed to O3 above EU target levels has fluctuated from a 64% peak in 2003 to 9% in 2014. Since this low value, the urban population exposure has been fluctuating to reach the second lowest value of 10% in 2021.

As there are relatively few reported measurements of BaP and these were not considered to be homogeneous across Europe until 2008, the values are not shown in Figure 1. Considering data reported after that year, the portion of the urban population exposed to concentrations above the BaP target value has halved from 31% stabilising around 16% in the period 2017-2020, before reaching a minimum of 14% in 2021.

Figure 2. Urban population exposed to air pollutant concentrations above 2021 WHO air quality guidelines, EU-27


For the reasons mentioned above, BaP values are also not shown in Figure 2. When considering the estimated ‘reference level’ for BaP, the portion of the urban population exposed has decreased from around 90%, in 2009, to 64% in 2021, the lowest value in the period 2008-2021. 

The results for SO2 show that the portion of the urban population exposed to concentrations above the daily WHO guideline level reached a minimum of 1% in 2019 and 2020 and fell below this 1% in 2021. Therefore, these values are also not shown in Figure 2.

The 2021 WHO air quality guidance levels are much lower than previous values (except for SO2) and therefore little progress can be seen when calculating the exposure retrospectively, except for PM10. The proportion of the EU urban population exposed to concentrations above the 2021 WHO annual guideline level for PM10 decreased from 97% in 2000 to 71% in 2020 and rebounded to 76% in 2021. For NO2, the decrease for exposure above the 2021 WHO annual guideline level was from 100% to 90%. For O3, the proportion of the urban population exposed to concentrations above the 2021 WHO short-term guideline level fluctuated between 93% and 98% in the period 2013-2021, with a value of 94% in 2021 and no decreasing trend over time. The same is true for PM2.5, for which the share of the urban population exposed to annual averages above 5 µg/m3 (the WHO annual guideline level) ranged from 96% to 100% (and took a value of 97% in 2021).