However, some major Parisian highways pass below this threshold for the first time.

  

However, some major Parisian highways pass below this threshold for the first time. In 2019, around 500,000 inhabitants of Ile-de-France are potentially exposed to exceeding the annual limit value of NO2. In Paris, it is 1 in 10 inhabitant. The fall in NO2 levels in the Paris conurbation continued in 2019.For PM10 particles, the trend has also improved in recent years, but the daily and annual limit values are still exceeded very locally. For fine PM2.5 particles, French and European regulations are respected, with the exception of the quality objective.(As a reminder, France is in dispute with the European Commission, concerning NO2 and PM10, for non-compliance with limit values and insufficient measures taken.)For ozone (O3), in 2019, the health protection threshold (target value) was exceeded in Île-de-France. 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.