Ambient (outdoor) air pollution in cities database 2014 (WHO study on urban air quality)
The database contains results of ambient (outdoor) air pollution monitoring from almost 1600 cities in 91 countries. Air quality is represented by annual mean concentration of fine particulate matter (PM10 and PM2.5, i.e. particles smaller than 10 or 2.5 microns).
The database covers the period from 2008 to 2013, with the majority of values for the years 2011 and 2012. The database aims to be representative for human exposure, and therefore primarily captures measurements from monitoring stations located in urban background, residential, commercial and mixed areas. The world's average PM10 levels by region range from 26 to 208 ug/m3, with a world's average of 71 ug/m3.