The intensity of this overrun is clearly marked in 2019, given the summer heat waves

  

The intensity of this overrun is clearly marked in 2019, given the summer heat waves. Ozone formation is in fact very dependent on summer weather conditions, in particular temperature and sunshine. Ozone is the only pollutant for which annual trends do not show improvement.As for the recommendations of the World Health Organization, they are largely exceeded in Île-de-France. For ozone and fine particles PM2.5, exceeding these recommendations concerns all residents of Ile-de-France and the whole of Ile-de-France. For fine particles, the exceedance is very severe: observations can be ten times higher than the most stringent recommendation.17 days of pollution episodes in 2019:The year 2019 was marked by 17 days of pollution episodes due to either particles (PM10) or ozone (O3). For PM10 particles, ten days of episodes were recorded in 2019. Episodes are mainly observed in winter (in February and at the end of December) due to a gradual accumulation, under the effect of persistent high pressure conditions, of pollutants emitted mainly by sources(road traffic, wood heating). The summer of 2019 was marked by eight episodes of ozone (O3) pollution, linked to the scorching conditions that occurred between June and August 2019. Eleven days of ozone pollution episodes were observed during the heat waves from 2018.The number of pollution episodes per year strongly depends on weather conditions. It is therefore difficult to identify an absolute trend. However, extreme weather events, such as heat waves, are more and more common with global warming. This raises fears of a potential increase in the number of pollution episodes, especially ozone. On the other hand, the intensity of the ozone episodes recorded in 2019 was rather less compared to the scorching heat of 2003, with maximum temperatures however higher and a record of 43 ° C in Paris. This situation is explained by the drop in emissions of ozone precursors (nitrogen oxides and volatile organic compounds) under the effect of French and European regulations.(All my research was found on this site https://www.airparif.asso.fr/etat-air/bilan-annuel)