### Seasonal inhomogeneity of soot particles over the central Indo-Gangetic Plains, India: Influence of meteorologySeasonal inhomogeneity of soot particles over the central Indo-Gangetic Plains, India: Influence of meteorology

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 Author Singh, B. P. ♦ Tiwari, S. ♦ Hopke, Philip K. ♦ Singh, R. S. ♦ Bisht, D. S. ♦ Srivastava, A. K. ♦ Singh, R. K. ♦ Dumka, U. C. ♦ Singh, A. K. ♦ Rai, B. N. ♦ Srivastava, Manoj K. Source SpringerLink Content type Text Publisher The Chinese Meteorological Society File Format PDF Copyright Year ©2015 Language English
 Subject Domain (in DDC) Natural sciences & mathematics ♦ Earth sciences Subject Keyword black carbon ♦ Indo-Gangetic Plains ♦ absorption Ångström exponent ♦ biomass ♦ fossil fuel ♦ Atmospheric Sciences ♦ Meteorology ♦ Geophysics and Environmental Physics ♦ Atmospheric Protection/Air Quality Control/Air Pollution Abstract Black carbon (BC) particles play a unique and important role in earth’s climate system. BC was measured (in-situ) in the central part of the Indo-Gangetic Plains (IGP) at Varanasi, which is a highly populated and polluted region due to its topography and extensive emission sources. The annual mean BC mass concentration was 8.92 ± 7.0 µg m $^{-3}$, with 34% of samples exceeding the average value. Seasonally, BC was highest during the post-monsoon and winter periods (approximately 18 µg m $^{-3}$) and lower in the premonsoon/ monsoon seasons (approximately 6 µg m $^{-3}$). The highest frequency (approximately 46%) observed for BC mass was in the interval from 5 to 10 µg m $^{-3}$. However, during the post-monsoon season, the most common values (approximately 23%) were between 20 and 25 µg m $^{-3}$. The nighttime concentrations of BC were approximately twice as much as the daytime values because of lower boundary layer heights at nighttime. The Ångström exponent was significantly positively correlated (0.55) with ground-level BC concentrations, indicating the impact of BC on the columnar aerosol properties. The estimated mean absorption Ångström exponent was 1.02 ± 0.08 µg m $^{-3}$, indicating that the major source of BC was from fossil fuel combustion. Significant negative correlations between BC mass and meteorological parameters indicate a pronounced effect of atmospheric dynamics on the BC mass in this region. The highest mean BC mass concentration (18.1 ± 6.9 µg m $^{-3}$) as a function of wind speed was under calm wind conditions (38% of the time). ISSN 20956037 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 2016-01-09 Publisher Place Beijing e-ISSN 21980934 Journal Journal of Meteorological Research Volume Number 29 Issue Number 6 Page Count 15 Starting Page 935 Ending Page 949