Application of size distribution of particulate matter as a forensic tool for source apportionment

Particulate Matter (PM) is a major pollutant in ambient air emitted from a wide range of sources causing various adverse effects on the environment. Identifying the sources contributing PM into the ambient atmosphere is important to understand their impact on the environment and to implement appropriate control measures to reduce their emissions. Conventional methods used to apportion PM mostly relay on chemical speciation and are time-consuming and expensive. Thus an efficient and cost-effective method is required to have a preliminary understanding of sources and to suggest quick remedies. In this study, the particle size distribution of PM from different sources is studied to analyze the signature of each source based on the pattern of the size distribution. The sources studied include vehicular emission (petrol and diesel), resuspension dust, wood burning, paper burning, coal industry emission, and incineration. Real-time PM measuring instrument GRIMM MiniLAS was used to collect the data where particles ranging from 0.23 to 10µm were divided into 24 size channels. The particle size distribution of each source showed significant differences in their size distribution patterns, thereby giving a signature of the source from where it is emitted. Sources like petrol combustion emit particles of relatively higher size range compared to lower size particles from diesel fuel burning. Further, the size distribution of re-suspended dust showed a pattern distinct from fuel emissions. Conclusively, the particle size distribution pattern-based source apportionment has a potential application in identifying the sources as a preliminary, cost-effective method to take quick countermeasures.