Source apportionment of PM10 by using positive matrix factorization at an urban site of Delhi, India

Abstract

In the present study, source apportionment of PM10 has been done using positive matrix factorization at an urban site of Delhi, India based on the chemical compositions of PM10 collected during January 2010 to December 2011. The concentration of PM10 and its chemical components including organic carbon (OC), elemental carbon (EC), water soluble inorganic ionic components (WSIC) and major and trace elements showed strong seasonal cycle with maxima during winter (PM10: 241.4±50.5μgm-3; OC: 34.7±10.2μgm-3; EC: 10.9±3.0μgm-3) and minima during monsoon (PM10: 140.1±43.9μgm-3; OC: 15.5±7.5μgm-3; EC: 4.9±2.3μgm-3). In this process, chemical composition of the PM10 mass was reconstructed using IMPROVE equation from the observed elemental composition. The highest contribution comes from particulate organic matter (24%) to the estimated average values of PM10 apart from other components e.g., soil/crustal matter (16%), ammonium sulphate (7%), ammonium nitrate (6%), aged sea salt (5%) and light absorbing carbon (4%). Positive Matrix Factorization (PMF) analysis quantified the sector wise contribution from the secondary aerosols (21.7%), soil dust (20.7%), fossil fuel combustion (17.4%), vehicle emissions (16.8%), and biomass burning (13.4%) to PM10 mass at the observational site of Delhi.