Particulate Matter (aerosols, or PM) is important in the atmosphere for at least four reasons. It provides a sink for reactive gases, e.g. particulate matter contains sulphate and nitrate from oxidation of SO2 and NO2. It provides a surface for chemical reactions, the chemistry of Antarctic ozone depletion attests to that. Particles can carry toxic chemicals such as PAHs and metals to remote areas, many of the toxic chemicals found in the Arctic get there this way. Particles can penetrate into the bronchial tract and the lungs causing human health problems such as bronchitis and pneumonia, there is now overwhelming evidence relating mortality to particulate levels.
Updated on August 28th, 2017.