The viewer provides forecasted hourly concentrations of ground-level nitrogen dioxide (NO2) (based on satellite data processed by the Copernicus Atmosphere Monitoring Service (CAMS)).

To select the date and region of interest, click on this icon in the viewer:

To view the map in full screen mode, click on this item in the viewer:

To view a chart showing the changes in hourly ground-level NO2 concentrations over the forecast period in a given location:



Click on the map

The classification of the hourly NO2 concentrations in ambient air follows the one used by the up-to-date air quality data for Europe, where the five categories range from good (< 40 µg/m3) to very poor (> 400 µg/m3). The ambient air quality directives stipulate that to protect human health, hourly NO2 concentrations should not exceed 200 µg/m3 more than 18 times per calendar year, and mean annual concentrations should not exceed 40 µg/m3. The population Alert threshold for NO2 is set at  400 µg/m3 measured over three consecutive hours at locations representative of air quality (over at least 100 km2 or an entire zone or agglomeration, whichever is the smaller). The exceedance of this threshold triggers the dissemination of information to the public on the risks of exposure and the implementation, if appropriate, of short-term measures to reduce pollutant levels.

In 2021, the World Health Organization (WHO) published new air quality guidelines to protect human health, updating the 2005 air quality guidelines on the basis of a systematic review of the latest scientific evidence of how air pollution damages human health. According to the new WHO guidelines, the mean annual concentration should not exceed 10 µg/m3, the daily concentration should not exceed 25 µg/m3 more than 3-4 days per year, and the hourly concentrations should not exceed 200 µg/m3. The European Commission published a proposal for a revision of the Ambient Air Quality Directive in October 2022, which aligns EU air quality standards more closely with 2021 WHO recommendations, and introduces limit values for all air pollutants currently subject to target values, except for ozone. For NO2, hourly concentrations should not exceed 200 µg/m3 more than once per calendar year while daily concentrations should not exceed 50 µg/m3 more than 18 times per calendar year by 2030. For the annual mean concentration, the limit is set at 20 µg/m3.

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This translation is generated by eTranslation, a machine translation tool provided by the European Commission.