2024-03-13 10:00:47
A study led by the Barcelona Institute for Global Health (ISGlobal) and the National Supercomputing Center (BSC-CNS) has estimated the daily ambient concentrations of PM2.5, PM10, NO2 and O3 in a broad set of European regions between 2003 and 2019 based on machine learning techniques. The goal was to evaluate the number of days exceeding the 2021 World Health Organization (WHO) guidelines for one or more contaminants.
The research team analyzed pollution levels in more than 1,400 regions from 35 European countries, which represents 543 million people. The results, published in Nature Communicationsshow that global levels of suspended particles (PM2.5 and PM10) and nitrogen dioxide (NO2) have decreased in most of Europe. Specifically, PM10 levels 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, O3 levels increased annually by 0.58% in southern Europe, which almost quadrupled the number of days with poor air quality.
The study also analyzed the number of days in which simultaneously exceeded limits for two or more pollutantsa confluence known as a “compound pollution day.”
Specific efforts are needed to address PM2.5 and O3 levels and associated composite pollution days
Zhao-Yue Chen, researcher at ISGlobal
The results highlight the significant air quality improvements in Europe regarding PM10 and NO2, while PM2.5 and O3 levels continue to exceed WHO guidelines in many regions, resulting in more people exposed to unclean air levels.
“Specific efforts are needed to address PM2.5 and O3 levels and associated composite pollution days, especially in the context of rapidly increasing climate change threats in Europe,” says Zhao-Yue ChenISGlobal researcher and lead author of the study.
“Our estimate of population exposure to composite air pollution events provides a solid basis for future research and policy development to address air quality management and public health concerns across Europe,” notes Carlos Pérez García-PandoICREA and AXA Research Professor at the BSC-CNS.
Heterogeneous geographic distribution
The research team has developed machine learning models to estimate high-resolution daily concentrations of major air pollutants, such as PM2.5, PM10, NO2 and O3. This data-driven approach creates a complete daily picture of air quality on the European continent, going beyond sparsely distributed monitoring stations.
Our estimate provides a solid foundation for future research and policy development to address air quality and public health management.
Carlos Pérez García-Pando, ICREA
The models collect data from multiple sources, such as satellite aerosol estimates, existing atmospheric and climate data, and land use information. Analyzing these air pollution estimates, the team calculated the annual average number of days on which the WHO daily limit for one or more air pollutants is exceeded.
The analysis shows that around 98.10%, 80.15% and 86.34% of the European population lived during the study period in areas that exceed the annual levels recommended by the WHO of PM2.5, PM10 and NO2, respectively. These results are largely in line with estimates by the European Environment Agency (EEA) for the 27 EU countries using only urban station data.
No country met the annual ozone (O3) guidelines during the peak season from 2003 to 2019. Regarding short-term exposure, more than 90.16% and 82.55% of the European population lived in areas with at least 4 days exceeding the WHO daily guidelines for PM2.5 and O3 in 2019, while the figures for NO2 and PM10 were 55.05% and 26.25%.
No country met annual ozone guidelines during the 2003-2019 peak season
During the study period, PM2.5 and PM10 levels were highest in northern Italy and eastern Europe, while PM10 levels were highest in southern Europe. Elevated NO2 levels were observed mainly in northern Italy and in some areas of Western Europe, such as the south of the United Kingdom, Belgium and the Netherlands.
Similarly, O3 increased by 0.58% in southern Europe, while it decreased or showed a non-significant trend in the rest of the continent. On the other hand, the most significant reductions in PM2.5 and PM10 were observed in Central Europe, while in the case of NO2 they occurred mainly in urban areas of Western Europe.
The complex management of ozone
The average exposure time and the population exposed to days with PM2.5 and O3 pollution is much greater than in the case of the other two pollutants. According to the research team, this highlights the urgency of greater control of these contaminants, as well as the importance of addressing the increasing trend and impact of O3 exposure.
Ozone management presents a complex challenge due to its secondary training path
Joan Ballester Claramunt, ISGlobal researcher
Tropospheric O3 is found in the lower layers of the atmosphere and is considered a secondary pollutant because it is not emitted directly into the atmosphere, but is formed from certain precursors – such as volatile organic compounds (VOCs), carbon monoxide (CO) and nitrogen oxides (NOx) – which are produced in combustion processes, mainly in transportation and industry. At high concentrations, ozone can harm human health, vegetation and ecosystems.
“Ozone management presents a complex challenge due to its secondary formation pathway. Conventional air pollution control strategies, which focus on reducing emissions of primary pollutants, may not be sufficient to effectively mitigate high levels. of O3 and the days with associated composite pollution,” says Joan Ballester Claramuntresearcher at ISGlobal and senior author of the study.
However, addressing the climate changewhich influences the formation of ozone through increased sunlight and increased temperatures, is crucial for the Long-term ozone management and public health protection“he concludes.
Reference:
Ballester, J. et al. “Population exposure to multiple air pollutants and its compound episodes in Europe”, Nature Communications.
#Air #quality #Europe #improved #decades