The WHO air quality database compiles data on ground measurements of annual mean concentrations of nitrogen dioxide (NO2), particulate matter of a diameter equal or smaller than 10 μm (PM10) or equal or smaller than 2.5 μm (PM2.5) which aim at representing an average for the city or town as a whole, rather than for individual stations. Both groups of pollutants originate mainly from human activities related to fossil fuel combustion.

Released in the lead-up to World Health Day, which this year celebrates the theme Our planet, our health, the 2022 update of the World Health Organization’s air quality database introduces, for the first time, ground measurements of annual mean concentrations of nitrogen dioxide (NO2), a common urban pollutant and precursor of particulate matter and ozone. It also includes measurements of particulate matter with diameters equal or smaller than 10 μm (PM10) or 2.5 μm (PM2.5).  Both groups of pollutants originate mainly from human activities related to fossil fuel combustion.

The database is updated regularly every 2-3 years since 2011 and this is the fifth update. The data compiled in this database is used as input to derive the Sustainable Development Goal Indicator 11.6.2, Air quality in cities, for which WHO is custodial agency.

Source: Billions of people still breathe unhealthy air: new WHO data