Chemical characterization of submicron particulate matter (PM1) and its source apportionment using positive matrix factorization

Abstract

The present study was conducted to address four key questions: (i) What are the levels of submicron particulate matter at the study area?, (ii) which are the major contributing sources of these particles?, and (iii) is there any seasonal changes in the levels of pollutants at the study site? Thus, the study was conducted at an urban residential site of Jaipur City, India, to determine the elemental and ionic composition of toxic elements associated with PM₁ using inductively coupled plasma optical emission spectroscopy and ion chromatography to reveal specific sources. Monitoring was done for a period of 8 months between October 2020 and May 2021 considering three seasons: winter (December–February), pre-monsoon (March–May), and post-monsoon (October–November). PM₁ samples were found to be highly enriched with Ag, Cd, B, Ni, and Zn. PM₁ mass concentrations were observed to be greater in winter (104.13 ± 30.16 µg m⁻³) and lower in the pre-monsoon season (83.62 ± 19.40 µg m⁻³). Ion concentrations (Cl⁻, NO₃²⁻, and SO₄²⁻) followed a similar pattern to PM₁ concentrations. Source apportionment by positive matrix factorization at the study site revealed six major sources of pollutants (soil dust, agro-based industry, automobile industry, salt aerosols, industrial activities, and biomass burning).