Organic speciation of fine aerosol to assess sources in Mumbai city

Increasing ambient levels of fine particles due to anthropogenic activities are leading to adverse effects on human health and climate change. The present study on PM2.5 carbonaceous characterization for different land use patterns attempts to improve spatial understanding of sources in Mumbai city. The average of PM2.5 mass concentrations at Control (C), Kerb (K), Residential (R) and Industrial (I) site were 69±20, 84±31, 89±33, and 95±36.01 μg/m3 respectively. The average OC contributions at C, K, R and I sites were 30, 34, 35 and 31%, respectively and EC contributions were 7, 11,9 and 8%, respectively. Organic marker contains useful information of the sources especially of combustion origin. About 40 PAHs, 24 alkanes, 18 hopanes, 12 sterane, 2 methyl alkanes, 3 branched alkanes, 5 cycloalkanes and 1 alkene were identified and quantified from each category. The Carbon Preference Index for alkanes between C25 and C33 was greater than one and less than three, indicating anthropogenic sources like petroleum hydrocarbons. The H+S/EC ratio at C, K, R and I were 0.0022, 0.0011, 0.0083 and 0.0027 respectively, suggesting contribution from diesel exhaust emission. Levoglucosan . at all the sites indicates presence of biomass burning as an important source to fine particles. In the present study, detailed chemical analysis of particulate matter samples provides data useful in pinpointing sources of pollution as also in predicting potential health effects.