Source Apportionment of Ambient Fine Particle Size Distribution Using Positive Matrix Factorisation and Conditional Bivariate Probability Function in a Coastal Urban Area

Considering the adverse effect of fine particulate matter (PM) on human health, the number concentration of PM is considered superior to the mass concentration. CO, NO, NO2, SO2, O3, and size segregated PM number concentration were collected during May 2018-July 2018 in Chennai city to examine the possible sources of fine particles. A total of 8640 number concentration samples covering different particle sizes ranging from 0.265 to 2.75 µm and gaseous species were analysed using positive matrix factorization (PMF) model. Additional analyses such as determining the directional locations of the factors using conditional bivariate probability function (CBPF) and examining the diurnal variations of the factor’s contribution were performed to aid the interpretations of the sources. Three major sources were identified at the study site which includes local traffic, regional traffic, and secondary nitrate. Nearly one-half of the total number concentrations at the study site were attributed to local traffic (36%) and regional traffic (21%) emissions. © 2023, The Institution of Engineers (India).