Power generation including coal-fired power stations is responsible for much less particulate and Nox emissions but generally more SO2 emissions than mobile sources such as road traffic. Most emissions are continuing to decline. Widespread use of ESP or baghouses on coal-fired power stations have substantially reduced the mass of primary particulate emissions. However, the emitted particles are in the finer particle size range. The smallest particles are of most concern. Those equal to or less than 10 um in diameter are termed PM10 and the fine particles of diamater <2.5 ?m are PM2.5. Gaseous emissions such as SO2 and NOx are to a varying extent oxidised in the atmosphere to form secondary particulate matter. PM2.5 is a complex mixture of pollutants which, to date, is defined largely by the sampling methods and not by chemical criteria. In 1997 the US EPA promulgated a new ambient air quality standard for PM2.5. This standard has resulted in controversy, not only with respect to the stringent limit selected, but also due to the many problems associated with complying with a standard for a pollutant which is so poorly understood. The US EPA is aware of these problems and has embarked on a five-year plan of studies leading to possible revision of the standard in 2002. The issue of particulate matter is therefore complex and controversial. This report by Irene Smith and Lesley Sloss identifies major research needs as a means of ensuring that new and proposed standards for particulate matter are workable.
Title: PM10/PM2.5 – emissions and effects, CCC/08
Author(s): Irene Smith, Dr Lesley Sloss
ISBN: ISBN: 92-9029-312-8
Publication Date: 01/10/1998