Air quality in Europe has improved considerably over the last two decades. It’s quite a paradox. We breathe increasingly cleaner air, but this does not prevent us from being far from the levels that would be desirable taking into account the recommendations established by the WHO. This is why, despite everything, 86% of the European population lives in areas that exceed the annual limits recommended by the WHO for nitrogen dioxide (NO2), a pollutant mainly caused by traffic.
The improvement in air quality has been confirmed in a study by the Global Health Institute of Barcelona (ISGlobal), a center promoted by Fundació La Caixa, and the Barcelona Supercomputing Center. They analyzed pollution levels in 35 European countries (543 million people) between 2003 and 2019.
The results show a decrease in the levels of both nitrogen dioxide (NO2), a pollutant caused mainly by exhaust pipes, and the suspended particles PM2.5 and PM10 (with maximum diameters of 2.5 and 10 microns), from very diverse (and of domestic, agricultural, industrial, transport or natural origin).
Specifically, the levels of PM10 particles decreased the most during the study period, followed by NO2 and PM2.5, with annual decreases of 2.72%, 2.45% and 1.72 %, respectively. In contrast, levels of ozone (O3), a secondary pollutant, increased by 0.58% annually in southern Europe, which almost quadrupled the number of days with poor air quality. These results largely agree with the estimates of the European Environment Agency for the 27 EU countries.
Xavier Querol, CSIC researcher (who did not participate in this study), believes that there are four factors that explain this improvement in air quality. The first is the implementation of Euro5 regulations for vehicles, which includes particle filters. The second is the entry into force of the directive on industrial emissions and large combustion facilities, which has led to drastic reductions in coal emissions, for example. The third is better planning of public works, which allows to reduce dust and particles. And the fourth is the extension of low-emission zones in cities, which restricts the most polluting traffic.
Carlos Bravo, an expert in public policies, also points to a decrease in pollution from ports in the North Sea and the Baltic.
Querol recalls that the European Environment Agency estimated in 2018 that the number of premature deaths caused by pollution was one million in 1990, a figure that a 2023 study reduced to 238,000 deaths in the EU27 in 2021
Despite everything, 98.10% of the European population suffers from excessive levels – according to the WHO – of suspended particles PM2.5, which are very dangerous, since they enter the bloodstream through the alveoli. And in the case of the largest particle size (PM10) the percentage reaches 80.15%. The study results highlight, therefore, significant improvements in air quality with respect to NO2 (which are caused by traffic) and larger particles, while it is lower in the case of ultrafine particles.
The most favorable evolution achieved by traffic emissions occurred mainly in the urban areas of Western Europe, while the decrease in particles was seen more in Central Europe. But most worrying is the fact that no country meets the annual guidelines for tropospheric ozone (O3), a pollutant that is not emitted directly into the atmosphere, but is formed from certain precursors, such as organic compounds volatiles and nitrogen oxides, under certain conditions of solar radiation. In high concentrations, ozone can harm human health, vegetation and ecosystems.
“Targeted efforts are needed to address PM2.5 levels and the associated [multi-pollutant impact] compound pollution days, especially in the context of rapidly increasing climate change threats in Europe,” says Zhao-yue Chen, ISGlobal researcher and lead author of the study.
The highest particulate matter levels were measured in northern Italy and eastern Europe. Similarly, high levels of NO2 were observed in northern Italy and in areas of Western Europe, such as the south of the United Kingdom, Belgium and the Netherlands.
