Study finds that Europe’s air quality has shown significant improvement over the past 20 years

Research led by the Barcelona Institute for Global Health (ISGlobal) consistently estimates daily ambient concentrations of PM._2.5,afternoon_Tenno₂ And O₃ Based on machine learning techniques, it was conducted across a large ensemble in the European region from 2003 to 2019. The aim was to assess the occurrence of so-called “air pollution days” when one or more pollutants exceed the World Health Organization’s (WHO) 2021 guidelines.

The research team analyzed pollution levels in more than 1,400 regions (543 million people) in 35 European countries. Result is, nature communicationsoverall suspended particulate matter (PM_2.5 and the prime minister_Ten) and nitrogen dioxide (NO₂) Levels have fallen in most parts of Europe.

Especially PM_Ten The largest decrease during the study period was NO, followed by NO.₂ and the prime minister_2.5, decreased by 2.72%, 2.45%, and 1.72% annually, respectively. On the other hand, O₃ In southern Europe, levels increased by 0.58% annually and the number of days with dirty air increased almost fourfold.

The study also looked at the number of days when limits for two or more pollutants were exceeded at the same time, a confluence known as “compound poor air days.” Despite overall improvements, 86.3% of the European population still experienced at least one combined unclean day and PM outbreak per year during the study period._2.5-no₂ and the prime minister_2.5-O₃ has emerged as the most common compound combination.

The results highlighted significant improvements in air quality and subsequent reductions in PM in Europe._Ten and no₂during PM_2.5 And O₃ Concentrations continue to exceed WHO guidelines in many regions, resulting in more people being exposed to unclean air levels.

“Targeted efforts are needed to address PM.”_2.5 And O₃ This level and associated combined unclean days are remarkable, especially in the context of rapidly increasing threats from climate change in Europe,” said Zhao-Yue Chen, researcher at ISGlobal and lead author of the study. says Mr.

“Our consistent estimates of population exposure to complex air pollution events provide a solid foundation for future research and policy development to address air quality management and public health concerns across Europe. ” points out Carlos Pérez García Pando, ICREA and AXA Research Professor. BSC-CNS.

Uneven geographical distribution

The research team developed a machine learning model to estimate high-resolution daily concentrations of major air pollutants such as PM._2.5,afternoon_Tenno₂ And O₃. This data-driven approach creates a comprehensive daily air quality picture for the European continent, going beyond sparsely distributed monitoring stations.

The model collects data from multiple sources, including satellite-based aerosol estimates, existing atmospheric and climate data, and land use information. By analyzing these air pollution estimates, the research team calculated the average number of days per year exceeding the WHO’s daily limits for one or more air pollutants.

Despite improvements in air quality, 98.10%, 80.15% and 86.34% of the European population live in areas where annual levels of PM exceed the WHO recommended levels._2.5,afternoon_Ten and no₂, Each. These results are broadly in line with the European Environment Agency’s (EEA) estimates for the EU-27 countries, which use data only from urban observatories.

Moreover, no country had ever encountered ozone (O₃) Annual basis for peak seasons from 2003 to 2019. Looking at short-term exposure, more than 90.16% of the European population and 82.55% of her lived in areas that exceeded the WHO daily guideline for PM by at least 4 days._2.5 And O₃ The numbers for 2019 are NO₂ and the prime minister_Ten They were 55.05% and 26.25%.

During the research period, PM_2.5 and the prime minister_Ten Levels were highest in northern Italy and eastern Europe, but PM_Ten Levels were highest in southern Europe. High NO₂ These levels were mainly observed in northern Italy and some parts of Western Europe, including southern England, Belgium, and the Netherlands.

Similarly, O₃ Southern Europe saw an increase of 0.58%, while the rest of the continent showed a decreasing or non-significant trend. On the other hand, the most significant decrease in PM was_2.5 and the prime minister_Ten was observed in central Europe, but for NO.₂ They were mainly found in urban areas of Western Europe.

Complex management of ozone

Average PM exposure time and population exposed to unclean air_2.5 And O₃ much higher than the other two pollutants. According to the research team, this highlights the urgency of strengthening the management of these pollutants and the importance of addressing rising trends and impacts of O2.₃ exposure.

terrestrial or tropospheric O₃ It is considered a secondary pollutant because it exists in the lower layers of the atmosphere, is not emitted directly into the atmosphere, and is formed from certain precursors such as volatile organic compounds (VOCs), carbon monoxide (CO), and nitrogen oxides. It is considered.no_X) – produced primarily in combustion processes in transportation and industry. High concentrations of ozone can harm human health, vegetation, and ecosystems.

“Ozone management is complicated by its secondary formation pathways. Traditional air pollution control strategies that focus on reducing emissions of primary pollutants are not sufficient to effectively mitigate the ozone layer. There may not be.₃ Joan Ballester Claramund, a researcher at ISGlobal and lead author of the study, said: “Excesses and associated unclean days are occurring. “Addressing climate change that impacts the environment is critical to long-term ozone management and protection.” of public health. ”

Challenge to complex episodes

Despite improvements in air pollution, over 86% of Europeans experienced at least one combined air pollution event each year between 2012 and 2019 where multiple pollutants exceeded WHO limits at the same time. The research team reported that.

Among those compound days, PM’s contribution is_2.5-O₃ Composite days increased from 4.43% in 2004 to 35.23% in 2019, making them the second most common type in Europe and showing an alarming trend. These mainly occur at low latitudes during the warm season and are probably related to the complex interaction between climate change and PM._2.5 And O₃.

In summer, temperatures are high and sunlight is strong, leading to an increase in O.₃ Formed by chemical reactions.Then the level of O will be higher₃ Promotes the oxidation of organic compounds in the air. This oxidation process results in the condensation of certain oxidized compounds and the formation of new PM._2.5 particle.

Additionally, climate change will increase the likelihood of wildfires, further increasing both O and O.₃ and the prime minister_2.5 level. “This complex interaction creates a harmful loop and highlights the urgent need to tackle climate change and air pollution simultaneously,” explains Ballester Claramund.