People are still exposed to unsafe levels of air pollution in 60% of OECD regions. While air quality has improved across OECD countries since 2000s, PM 2.5 has started to grow again in recent years, particularly in Italy, Japan, Korea and Slovenia.
The exposure to air pollution in regions and cities is greatly associated with the industry located in the territory, its level of urbanisation and its transportation system. Fine particulate matters (PM2.5) are generally emitted from the combustion of liquid and solid fuels for industrial and housing energy production, vehicles and biomass burning in agriculture.
In 2015, in 60% of the OECD regions, people were on average exposed to levels of air pollution that were higher than those recommended by the World Health Organization (pollution concentration level of 10 μg/m3), although this was down from 74% in 2000. Italy and Korea were the countries where the highest regional concentrations of air pollution were observed in OECD countries. In the regions of Lombardy (Italy) and the Capital Region (Korea), pollution levels were above 30 PM2.5 per person ( 2.18). In contrast, people in all regions in Canada, Australia, New Zealand, Estonia, Norway, Ireland and Finland were exposed to low levels of air pollution (below 10 μg/m3).