Imported Pollution: A Leading Contributor to Surface Ozone-Related Deaths in Europe

A recent study reveals that a significant portion of the surface ozone responsible for premature deaths in Europe originates from sources beyond the continent’s borders.

Conducted by researchers from the Barcelona Institute for Global Health (ISGlobal), in collaboration with the French National Institute of Health and Medical Research (Inserm) and the Barcelona Supercomputer Center, the study assessed the impact of imported ozone across 813 regions spanning 35 European countries. Their findings indicate that approximately 60 percent of ground-level ozone-related deaths stem from sources outside Europe, underscoring the transboundary nature of air pollution.

While just under 12 percent of ozone-related deaths can be attributed to domestic sources of pollution, the bulk of the harmful ozone results from the chemical reaction between pollutants emitted by vehicles and power plants, reacting with sunlight. It’s worth noting that ground-level ozone differs from the ozone layer higher in the atmosphere, which shields against the Sun’s ultraviolet radiation.

The researchers utilized numerical models to track the dispersion of precursor emissions, predominantly nitrogen oxides and volatile organic compounds, during the high ozone season from May to October over a two-year period. This modeling approach enabled them to quantify the contribution of specific countries, neighboring nations, and even atmospheric contributions from beyond Europe’s borders.

Estimating the total number of deaths between 2015 and 2017 at around 114,000, the researchers employed a methodology that assumed no safe threshold for ozone’s health impact, which led to higher mortality figures compared to estimates by the European Environment Agency (EEA).

Dr. Laurence Rouil, Director of the Copernicus Atmosphere Monitoring Service (CAMS), emphasized the significant health and ecological costs associated with ozone pollution, particularly its detrimental effects on respiratory health and crop yields. Despite stringent emission reduction policies targeting ozone precursors, there has been no observed decrease in background ozone levels at regional or global scales.

The study also identified that Europe’s most industrialized nations are contributing to ozone-related deaths in neighboring countries. For instance, ozone emissions from France impact countries like Luxembourg, Switzerland, Belgium, and Spain, while Germany’s emissions affect Luxembourg, the Czech Republic, and the Netherlands.

Moreover, wind patterns play a crucial role, with southwestern European countries being the least affected by imported surface ozone. Spain, France, and Portugal were found to have the highest levels of domestic ozone contributing to mortality compared to other European nations.

However, the study had its limitations, including not considering chronic effects and assuming a fixed link between ozone and mortality, despite potential variations in risk among populations.

In light of these findings, there is a pressing need for coordinated local and global efforts to reduce ozone concentrations, underscoring the interconnectedness of air quality and the imperative for collaborative action beyond national and regional boundaries.