Abstract View
Black Carbon Source Apportionment and Fluxes in Delhi Measured Using a Single Particle Soot Photometer (SP2)
Rutambhara Joshi, JAMES ALLAN, Ernesto Reyes Villegas, Dantong Liu, Eiko Nemitz, Ben Langford, James Cash, Neil Mullinger, Drysdale Will, James Lee, Chiara Di Marco, Shivani Shivani, Ranu Gadi, Hugh Coe, University of Manchester
Abstract Number: 376
Working Group: Carbonaceous Aerosol
Abstract
Black carbon (BC) plays a significant role in climate, human health and the environment. Indian cities, especially its capital Delhi is known to emit a large amount of BC aerosol, and their emissions have been rising due to continuing rapid growth in population. However, the precise emissions from different sources are currently uncertain, which are critical for making effective policies for mitigation. In this study, we measure BC using a Single Particle Soot Photometer (SP2) at an urban location near Old Delhi’s Kashmere Gate, at Indira Gandhi Delhi Technical University for Women, measuring both ambient concentrations and also fluxes using the eddy covariance (EC) technique. During pre-Monsoon (25th May - 2nd June) and post-Monsoon (12th Oct - 23rd Nov) of 2018, which included the Diwali festival (known for lighting fireworks) and is a period associated with crop residue burning across the region. The measurements were made as part of large UK–India fieldwork, part of Air Pollution and Human Health (APHH) programme. We focus on characterising BC properties for pre-monsoon and post-monsoon periods, particularly its mixing state, through analysis of the size and coating content of individual particles. This allows us to attribute individual particles to potential sources. In the last two weeks of the post-monsoon period, we additionally include BC flux measurements from a 33 m tower. BC emission fluxes were calculated over flux footprints of up to ~ 1 km. Very high levels of BC concentrations were observed with half-hourly averaged concentrations routinely above 10 mg m-3 during both seasons. The campaign wide mean BC concentrations were 4.2 mg m-3 (Pre-monsoon) and 10.7 mg m-3 (Post-monsoon), and mean BC mass flux was 16 ng m-2 s-1.