PM.sub.1 composition and source apportionment at two sites in Delhi, India, across multiple seasons

• Published in: Atmospheric chemistry and physics 2021-08, Vol.21 (15), p.11655
• Main Authors: Reyes-Villegas, Ernesto, Panda, Upasana, Darbyshire, Eoghan, Cash, James M, Joshi, Rutambhara, Langford, Ben, Di Marco, Chiara F, Mullinger, Neil J, Alam, Mohammed S, Crilley, Leigh R, Rooney, Daniel J, Acton, W. Joe F, Drysdale, Will, Nemitz, Eiko, Flynn, Michael, Voliotis, Aristeidis, McFiggans, Gordon, Coe, Hugh, Lee, James, Hewitt, C. Nicholas, Heal, Mathew R, Gunthe, Sachin S, Mandal, Tuhin K, Gurjar, Bhola R, Shivani, Gadi, Ranu, Singh, Siddhartha, Soni, Vijay, Allan, James D
• Format: Article
• Language: English
• Subjects: Air pollution; Air quality; Air quality management; Analysis; Sulfates; Volatile organic compounds
• ISSN: 1680-7316; 1680-7324

Air pollution in urban environments has been shown to have a negative impact on air quality and human health, particularly in megacities. Over recent decades, Delhi, India, has suffered high atmospheric pollution, with significant particulate matter (PM) concentrations as a result of anthropogenic activities. Organic aerosols (OAs) are composed of thousands of different chemical species and are one of the main constituents of submicron particles. However, quantitative knowledge of OA composition, their sources and their processes in urban environments is still limited. This is important particularly in India, as Delhi is a massive, inhomogeneous conurbation, where we would expect the apportionment and concentrations to vary depending on where in Delhi the measurements/source apportionment is performed, indicating the need for multisite measurements. This study presents the first multisite analysis carried out in India over different seasons, with a focus on identifying OA sources. The measurements were taken during 2018 at two sites in Delhi, India. One site was located at the India Meteorological Department, New Delhi (ND). The other site was located at the Indira Gandhi Delhi Technical University for Women, Old Delhi (OD). Non-refractory submicron aerosol (NR-PM.sub.1) concentrations (ammonium, nitrate, sulfate, chloride and organic aerosols) of four aerosol mass spectrometers were analysed. Collocated measurements of volatile organic compounds, black carbon, NO.sub.x and CO were performed. Positive matrix factorisation (PMF) analysis was performed to separate the organic fraction, identifying a number of conventional factors: hydrocarbon-like OAs (HOAs) related to traffic emissions, biomass burning OAs (BBOAs), cooking OAs (COAs) and secondary OAs (SOAs).