Airborne suspended particulate matter (PM) can be either primary or secondary in nature. Primary particles are emitted directly into the atmosphere either by natural or anthropogenic processes, whereas secondary particles have a predominantly man made origin and are formed in the atmosphere from the oxidation and subsequent reactions of sulphur dioxide, nitrogen oxides and VOCs. In most European countries, industrialisation and high volumes of traffic mean that anthropogenic sources predominate, especially in urban areas, and sources of anthropogenic particles are similar throughout Europe. The most significant of these are traffic, power plants, combustion sources (industrial and residential), industrial fugitive dust, loading/unloading of bulk goods, mining activities,.
