10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Black Carbon Source Apportionment In Delhi during Winter
UMESH C. DUMKA, Suresh Tiwari, D.G. Kaskaoutis, S.D. Attri, Vijay Kumar Soni, P.D. Safai, Narendra Singh, N. Mihalopoulos, ARIES Nainital
Abstract Number: 1126 Working Group: Carbonaceous Aerosol
Abstract Urban areas in the developing countries are major sources of carbonaceous aerosols, especially for black carbon (BC) that constitutes the most efficient absorbing aerosol, pointing out the need for detailed assessment of the levels and source apportionment close to the source. In the current work, we present a multi-instrument research campaign which was performed in Delhi, India during December 2015 – February 2016 aiming at exploring the pollution levels and the BC source apportionment due to fossil-fuel (BCff) and wood burning (BCwb) using the “Aethalometer model” approach. The database consists of continuous measurements of BC mass concentrations, scattering, absorption, and extinction aerosol coefficients, along with the intensive aerosol properties like single scattering albedo (SSA), extinction and absorption Ångström exponents (SAE and AAE, respectively), air pollutants (CO, NOx, O3) and meteorological observations.
The results show very high pollution (PM10, PM2.5, CO, NOx, and O3) levels, while the daily-mean BC mass concentration ranging from 3.2 μg m−3 to 59.9 μg m−3. The very weak winds along with the shallow boundary layer favor the accumulation of the pollutants near the ground resulting in high BC mass concentrations. The daily-averaged Absorption Ångström Exponent (AAE), the BCff/BC and BCff/BCwb ratios varied between 1.1 – 1.5, 0.5 – 0.9, and 1.1 – 9.9, respectively due to changes in the BC emission rates, variations in the relative emissions from fossil-fuel and wood-burning sources and the mixing processes in the atmosphere. The mean BCwb contribution to total BC mass was estimated at 28% at 880 nm, while at 370 nm, the BCwb accounts for the 44% of the BC emissions, highlighting an important biomass-burning component within the urban environment. The BCff and BCwb components also exhibit remarkable diurnal patterns with maximum concentrations in the morning and evening/night hours and lower around noon primarily driven by the boundary-layer dynamics. The BCff/BC fraction maximizes during the late night-to-morning hours, while the BCwb exhibits higher contribution in the evening hours, pointing out increased emissions from wood and waste-material burning for heating purposes.