Scientists from the Australian Nuclear Science Technology Organisation (ANSTO) have established how to pinpoint the source of fine airborne particles known to exacerbate respiratory disease, sometimes with serious consequences.
The research, led by Dr David Cohen of ANSTOs Physics Division, is helping governments develop monitoring protocols and mitigation strategies for the particles, responsible for particulate haze in big cities.
The work is also helping to answer big questions about the greenhouse effect as the particles, which measure less than 2.5 microns (2.5 millionths of a metre) in diameter, have a cooling effect on the planet.
Health risks posed by fine particle pollution are prompting many governments to put in place measures to control it. These small sized particles may penetrate deep into the lungs and are believed responsible for up to 60,000 deaths in the USA and 10,000 deaths in the United Kingdom each year.
Studies in NSW indicate excess deaths and morbidity when fine particle pollution levels are high. The number of resultant fatalities in Australia each year may even be comparable with the national road toll.
The US Environmental Protection Agency has introduced an annual average goal of 15 micrograms (15 millionths of a gram) per cubic metre for fine particles. Australia currently has no goal for fine particles less than 2.5 microns but it has an annual average goal of 50 micrograms per cubic metre for coarser particles of less than 10 microns in diameter. Both natural and man-made particles form the airborne pollution, which varies in its constituents between and within cities, and with season.
Sources include motor vehicle exhaust, industrial plants, wind-blown soil and sea spray. The picture is complicated by secondary particles produced in the atmosphere by the photochemical oxidation of precursor gases.
The ANSTO scientists used advanced nuclear analysis methods combined with routine statistical techniques to find correlations between many different chemical species, and devise unique source fingerprints. A correlation between arsenic, selenium, elemental carbon and sulfur, for example, is a signature of coal burning.
Australian cities had average annual fine particle levels ranging from 10 to 20 micrograms per cubic
metre, against the US target of 15. In Sydney, the average annual level in 1999 was around 9
micrograms per cubic metre. The main contributors were motor vehicles and industry. The
contribution from motor vehicles was significantly higher in the winter and lower in the summer. The
reverse was the case for the contribution from industry.