10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Aerosol Characteristics during Intense Crop Residue Burning: A Case Study Over Indo-Gangetic Plain
NANDITA SINGH, Vishnu Murari, Rajesh Kumar Mall, R.S. Singh, Tirthankar Banerjee, Institute of Environment and Sustainable Development, BHU
Abstract Number: 1396 Working Group: Aerosol Chemistry
Abstract The Indo-Gangetic Plain (IGP), South Asia experiences frequent haze events during post-monsoon (October-November), especially influenced by burning of agricultural residues over upper IGP, and additionally instigate by regional boundary conditions. To understand the effects of biomass burning on regional aerosol characteristics, size-segregated airborne particulates were collected in Varanasi during October to November 2016. Aerosol samples were analyzed for both biomass burning tracers (levoglucosan, K+, and NH4+) and water-soluble ions in coarse mode (PM>2.1), finer mode (PM1.1-2.1) and accumulation mode (PM<1.1). The concentration of fine particles (PM2.1) was found to continuously increase during the period (PM2.1/PM>2.1: 0.2-1.5), while fine particles especially dominated during later phase. Biomass burning tracers like levoglucosan were found highest in accumulation mode, followed by fine and coarse mode, and temporal analysis showed the gradual increasing trend similar to particle ratio. The secondary inorganic ions (NH4+, NO3- and SO42-) constituted the major proportion of water-soluble ions and were found highest in PM<1.1. A positive correlation was also noted between levoglucosan with K+ (0.86) and NH4+ (0.93) for PM<1.1 referring common emission sources. The significant change in fine-mode particle concentration, biomass burning tracers, and secondary inorganic ions in accumulation mode indicate the influence of biomass-burning on fine-mode particulates. MODIS fire count and air-mass back trajectories also indicate possible advection pathways of aerosol from upper to lower Gangetic plain.