Viviamo troppi “unclean air days”

At a European level, the study “Population exposure to multiple air pollutants and its compound episodes in Europe” published last month in Nature Communications by an international team of researchers led by the Institut de Salut Global de Barcelona (ISGlobal), finally gives us a good news claiming that air pollution in more than 1,400 regions of 35 European countries is improving and “Overall levels of suspended particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO2) have decreased in most of the ‘Europe”. Starting from an estimate of daily ambient concentrations of PM2.5, PM10, NO2 and O3 between 2003 and 2019, with the aim of evaluating the occurrence of days that exceed the 2021 World Health Organization (WHO) guidelines for one or more pollutants (the “unclean air days”), the research team analyzed the pollution levels that affect the lives of 543 million people. The results elaborated by the Catalan Institute demonstrate, in particular, that “PM10 levels decreased the most during the study period, followed by NO2 and PM2.5, with annual decreases of 2.72%, 2.45% and respectively. 1.72%”. Is everything okay then? Not really because “In contrast, O3 levels increased annually by 0.58% in Southern Europe, leading to an almost 4-fold increase in unclean air days.” The study also examined the number of days in which the limits for two or more pollutants were simultaneously exceeded (the “compound unclean air days”) and here too the result is not comforting: “Despite the overall improvements, during the study, 86.3% of the European population still experienced at least one unclean air day per year, with PM2.5 – NO2 and PM2.5 – O3 emerging as the most common combinations of compounds”.

The results therefore highlight “Significant improvements in air quality in Europe followed by decreases in PM10 and NO2, while PM2.5 and O3 levels did not follow a similar positive trend, resulting in an increase in the number of people exposed to levels of impure air.” For this reason, according to the study’s lead author, Zhao-Yue Chen of ISGlobal, “Targeted efforts are needed to address PM2.5 and O3 levels and related unclean air days, especially in the context of rapidly increasing threats resulting from changes climate change in Europe”. In the Po Valley, however, this trend is particularly critical, even when talking about PM10. In fact, in February the European Space Agency created a video showing the hourly concentrations of PM10 in the Po Valley from 1 to 31 January 2024. For the Space Agency’s researchers, PM10 in particular plays a fundamental role in the dynamics of air quality of the Po Valley, because here the unique topography and weather conditions contribute to its accumulation, particularly during stagnant weather periods. Currently, according to European Union directives and legal standards, PM10 concentrations above 50 μg/m³ are considered dangerous and this threshold should not be exceeded for any location for a specific number of days per year, generally set in 35. However, the levels of these hourly concentrations indicate that in the Po Valley only in January 2024 there were multiple cases in which this critical threshold was significantly exceeded, highlighting a constant and worrying trend in the fluctuations of the Po Valley air quality in the winter months .

Unfortunately, the Po Valley seems to remind us that despite this general positive trend, certified by particularly in-depth monitoring that ISGlobal has conducted, going beyond just the sparsely distributed monitoring stations and collecting data from multiple sources, “Including satellite-based aerosol estimates, existing atmospheric and climate data and land use information”, the situation remains critical. By analyzing these air pollution estimates, the team calculated the average annual number of days on which the WHO daily limit for one or more air pollutants is exceeded and found that “Despite improvements in air quality, 98.10%, 80.15% and 86.34% of the European population live in areas that exceed the annual levels recommended by the WHO for PM2.5, PM10 and NO2 respectively”. The Study notes that “Furthermore, no country met the annual ozone (O3) standard from 2003 to 2019. Considering short-term exposure, over 90.16% and 82.55% of the European population lived in areas with at least 4 days more than the daily value foreseen by the WHO guidelines for PM2.5 and O3 in 2019″. The study’s senior author, Joan Ballester Claramunt, highlights that despite improvements in air pollution, “Between 2012 and 2019, more than 86%

of Europeans experienced at least one day a year with composite air pollution events, where multiple pollutants exceeded WHO limits at the same time. Among these composite days, the contribution of PM2.5 -O3 composite days increased from 4.43% in 2004 to 35.23% in 2019, becoming the second most common type in Europe, and indicating a worrying trend.”

Meanwhile, on March 14th the European Commission sent a letter of formal notice pursuant to art. 260 TFEU to Italy “For the persistent failure to implement the sentence of the Court of Justice of the EU of 10 November 2020 (case C-644/18)”. In the ruling, the Court of Justice challenged Italy for its unimplemented obligations under the Ambient Air Quality Directive (Directive 2008/50/EC). The European Commission reminded the Meloni government that “The European Green Deal, which aims at the “zero pollution” objective, requires the full implementation of air quality standards to effectively protect human health and safeguard the environment natural. The Ambient Air Quality Directive obliges Member States to keep concentrations of specific pollutants in the air, such as PM10 particulate matter, below certain levels. When these maximum values are exceeded, Member States are required to take measures to reduce as much as possible the duration of the period of exceeding the limits. Although Italy has adopted some measures since the date of the ruling, in 2022 daily limit values were still exceeded in 24 zones, while one area reported annual limit values exceeded.” The Bel Paese (which doesn’t look so beautiful) now has another month to respond and remedy the shortcomings reported by the Commission. In the absence of a satisfactory response, the Commission may decide to refer Italy to the Court, with a request to provide financial sanctions. For the general director of Legambiente Giorgio Zampetti “The opening of the infringement procedure initiated by the European Commission against Italy is a clear alarm bell of how little our country is doing in terms of air quality. In particular, the smog emergency is now increasingly chronic starting from the Po Valley which represents one of the most vulnerable areas of the country. What we ask is that air quality truly becomes a priority issue on the political agenda again.” We would need to start a technical but also regulatory table at a national level, involving the Government, Regions and local administrations, to plan rapid and structured interventions in the long term that can no longer be postponed. A priority which, however, does not seem to worry the Meloni Government, at least until the fine becomes official.

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