Abstract View
Contributions of Cooking and Biomass Burning to Primary Organic Aerosol in Delhi
SAHIL BHANDARI, Gazala Habib, Joshua Apte, Lea Hildebrandt Ruiz, University of Texas at Austin
Abstract Number: 562
Working Group: Urban Aerosols
Abstract
Delhi, India experiences extremely high concentrations of primary organic aerosol (POA). No prior source apportionment study has captured the influence of biomass burning (BBOA) and cooking (COA) on POA. Here, we quantify the contributions of BBOA, COA, and hydrocarbon-like organic aerosol (HOA) by applying positive matrix factorization (PMF) on mass spectrometer data resolved by the time of day (six 4-hour segments) over two seasonal periods. We utilized the Multilinear Engine (ME-2) based EPA PMF tool and conducted detailed uncertainty analysis for statistical validation of our results. In addition to HOA, COA is found to be a major constituent of POA in monsoon and BBOA is found to be a major constituent of POA in the winter. Neither COA nor BBOA was resolved in the seasonal (not time-resolved) analysis. The COA mass spectral profiles (MS) are consistent with reference profiles from around the world, particularly resembling MS of heated cooking oils with a high m/z 41. The BBOA MS have a very prominent m/z 29 in addition to the characteristic peak at m/z 60, consistent with previous MS observed from wood burning. In addition to separating the POA, our technique also captures changes in MS profiles with the time of day, a unique feature among source apportionment tools available. In addition to the primary factors, we separate 2–3 OOA components. When all factors are recombined to total POA and OOA, our results are consistent with seasonal PMF analysis conducted using IGOR PET and EPA PMF. Results from this work can be used to better design policies that target primary sources of organic aerosols in Delhi.