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 2022. Less than 1% of citizens were exposed to levels above EU standards in 2022 for fine pariculate matter and nitrogen dioxide. Poor air quality remains a problem: 19% and 9% of EU citizens were exposed, respectively, to ozone and particulate matter PM 10 levels above EU standards. More than 83% of urban citizens are exposed above safe levels for all pollutants, except SO2, according to 2021 World Health Organization air quality guideline values.

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. Particulate matter (PM), ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2) and benzo[α]pyrene (BaP) are associated with serious health problems. Exposure is linked to adverse health effects, such as respiratory and heart problems, and cancer.

The EU Ambient Air Quality Directives aim to protect human health, vegetation and natural ecosystems by setting limit and target values for, among others, these air pollutants (and also long-term objectives for O3). The World Health Organization (WHO) has also set air quality guideline levels to protect human health. The latest WHO guideline levels from 2021 are stricter than the current EU air quality standards and consider the latest scientific evidence.

The European Green Deal’s Zero Pollution Action Plan has a 2050 vision of achieving pollution levels which are no longer harmful to health and natural ecosystems. It also set the 2030 health-related interim 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 proposed to revise the EU air quality standards to align them more closely with the 2021 WHO guidelines. The Commission published a proposal for a revised Directive on ambient air quality and cleaner air for Europe on 26 October 2022. In February 2024 co-legislators agreed to set out enhanced EU air quality standards for 2030 closer to the WHO guideline levels and be regularly reviewed.

Analysis of Individual Pollutants

For most pollutants, especially fine particulate matter (PM2.5) and NO2, percentages of urban population exposed to levels above EU standards has decreased since 2000. In 2022, less than 1% of the urban population was exposed to concentrations above the EU annual limit values for PM2.5 and NO2.

The percentage exposed to concentrations of SO2 above the daily limit value decreased between 2000 and 2022: from a maximum of 2% in 2006 to below 0.1% in all years during 2010-2022. Hence, these values are not shown in Figure 1.

Concentrations above other EU standards are still measured in many areas. In 2022, 9% of urban citizens were still exposed to PM with a diameter of 10µm or less (PM10) above the EU daily limit value. 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 reactions. Its levels are determined by precursors emissions, mainly NOx and volatile organic compounds (including methane, another potent greenhouse gas), and meteorology. The proportion of the urban population exposed to O3 above the EU target value threshold for human protection has fluctuated from a 64% peak in 2003 to 9% in 2014. Since this low value, the urban population exposure has been fluctuating, reaching 19% in 2022. The higher values in 2022 could be related to the meteorological influence on O3 formation, since, according to Copernicus, it was the fifth warmest year on record globally and the second warmest year in Europe on record. The warmest summer in Europe on record was also in 2022.

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 of BaP above 1.0ng/m3 has halved from 31% stabilising in 2017-2022, reaching a minimum of 13% in 2022.

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

The 2021 WHO air quality guideline levels are much lower than previous values (except for SO2) and 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 (15mg/m3) decreased from 97% in 2000 to a minimum of 71% in 2020 and rebounded to 83% in 2022. For NO2, exposure above the 2021 WHO annual guideline level of 10mg/m3 was 100% in the first years of the 2000’s reducing to 88% in 2022. For O3, the proportion of the urban population exposed to concentrations above the 2021 WHO short-term guideline of 100mg/m3 level fluctuated between 93% and 98% in the period 2013-2022, with a value of 94% over the last three years. For PM2.5, the share of the urban population exposed to annual averages above 5µg/m3 (WHO annual guideline level) ranged from 96% to 100% (96% for 2022).

For the reasons mentioned above in relation to Figure 1, BaP values are also not shown in Figure 2. When considering the estimated ‘reference level’ for BaP (0.12ng/m3), the percentage of the urban population exposed has decreased from around 90%, in 2009, to 65% in 2022.

The results for SO2 show that the percentage of the urban population exposed to concentrations above the daily WHO guideline level, 40mg/m3, have been below 1% since 2019. Therefore, these values are not shown in Figure 2.