WHO ambient air quality database, 2022 update: status report

The document describes the latest WHO database on ambient air quality. The guidelines recommend new air quality levels to protect the health of populations. Moreover reducing the levels of key air pollutants will also contribute to slowing climate change. Pollutants for which new guidelines for annual mean values have been set are PM2.5, with a guideline value half the previous one, PM10, which is decreased by 25 %, and that for nitrogen dioxide (NO2), which is four times lower than the previous guideline.