10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Aerosol Chemistry at an Urban Site of Delhi: During Winter Fog Campaign
DEEWAN S. BISHT, Atul K. Srivastava, Sachin Ghude, Dilip Chate, P.D. Safai, P. Rao, R. Kulkarni, Suresh Tiwari, Indian Institute of Tropical Meteorology
Abstract Number: 1213 Working Group: Aerosol Chemistry
Abstract During the foggy period (December 2015 to February 2016), the fine particulate matter (PM: diameter less than 2.5 micro meter) during the day and night time samples were collected at the Indira Gandhi International Airport New Delhi. The samples were weighted for mass concentrations and analyzed in the laboratory for chemical profiles of nine water-soluble inorganic ions (K+, NH4+, Na+, Ca2+,Mg2+, F−, Cl−, NO3- and SO42-), however, the carbon fractions (OC: organic carbon and EC: elemental carbon) is in progress. The concentrations of PM2.5 and its major chemical species were found large variability in their physical and chemical characteristics during the study period, which is due to the impact of meteorological conditions. The average concentration of PM2.5 was 230.9±185.9 µg m−3 which is 100 % of sampling days exceeding with the national ambient standard (40 µg m−3) and USEPA standard (12 µg m−3) which is seriousness for the regional atmosphere. The analysed chemical components in PM were 75.6 µg m−3 which is about 33% of the total mass concentrations. The concentration of total water-soluble inorganic species (PM2.5: 71.4 µg m-3and 79.7 µg m-3) during winter season was recorded higher day and nighttime respectively. A significant correlation was found between NH4+ and Clֿ, SO42-, NO3- of PM2.5, which indicates the presence of ammonium salts (NH4Cl, (NH4)2SO4, NH4HSO4 and NH4NO3) and also indicates NH4+ as the major cation species for the neutralization of acidic components in the winter season. Whereas, in summer season Ca2+, Mg2+, Na+ and K+ were the alkaline species responsible for the neutralization of acidic components in the PM2.5 samples. In winter season the advection of air masses over the continental landmasses of Southern Afghanistan and Western region of Pakistan (winter season), and adjoining states of Delhi and could be the cause of higher PM2.5 aerosol over the studied region.