Low cost, rapid method for ambient particulate matter speciation in specific environments

Chemical speciation of ambient particulate matter (PM) is important for understanding the health effects of this most ubiquitous air pollutant. Many studies in India have reported significant contribution of road dust to ambient PM, in some cases as high as 70%. This study presents a quick and affordable method for knowing the approximate chemical composition of the atmospheric PM from the chemical analysis of sediment deposits from ground surface. Sediment from street surface was collected and segregated into different size fractions using sieves. Chemical characterization was done separately for each size fraction, and from the results the composition of dust particles of size less than 10µm was obtained. Ambient PM was monitored using MiniLAS, which is a real time PM monitoring instrument that measures PM in 24 different size channels. Using size as criteria, the fraction of road dust in ambient PM was determined. Now, combining the results of ambient PM monitoring and chemical characterization of street dust, the chemical composition of atmospheric PM was calculated. To confirm the results, PM collected in a high-volume air sampler deployed at the place was analyzed for chemical composition. The results matched with the calculated composition indicating the possibility of adopting this method for environments polluted with resuspended dust, which is very often the case in developing countries.