Tellus: Series B, Chemical and Physical Meteorology (Jul 2016)

Chemical characterisation and source apportionment of PM1 during massive loading at an urban location in Indo-Gangetic Plain: impact of local sources and long-range transport

  • Prashant Rajput,
  • Anil Mandaria,
  • Lokesh Kachawa,
  • Dharmendra Kumar Singh,
  • Amit Kumar Singh,
  • Tarun Gupta

DOI
https://doi.org/10.3402/tellusb.v68.30659
Journal volume & issue
Vol. 68, no. 0
pp. 1 – 10

Abstract

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This study assesses temporal variability and source contributions of PM1 (particles with aerodynamic diameter ≤ 1.0 µm) samples (n=51; November 2009–February 2010) from an urban location at Kanpur (26.30°N; 80.13°E; 142 m above mean sea-level) in the Indo-Gangetic Plain (IGP). A study period from November to February is preferred owing to massive loading of particulate matter in entire IGP. PM1 varies from 18 to 348 (Avg±SD: 113±72) µg m−3 in this study. A total of 11 trace metals, five major elements and four water-soluble inorganic species (WSIS) have been measured. Mass fraction of total metals (∑metals=trace+major) centres at 18±14 %, of which nearly 15 % is contributed by major elements. Furthermore, ∑WSIS contributes about 26 % to PM1 mass concentration. Abundance pattern among assessed WSIS in this study follows the order: ≈> > Cl−. The K-to-PM1 mass fraction (Avg: 2 %) in conjunction with air-mass back trajectories (AMBT) indicates that the prevailing north-westerly winds transport biomass burning derived pollutants from upwind IGP. A recent version of positive matrix factorisation (PMF 5.0) has been utilised to quantify the contribution of fine-mode aerosols from various sources. The contribution from each source is highly variable and shows a strong dependence on AMBT. Events with predominant contribution from biomass burning emission (>70 %) indicate origin of air-masses from source region upwind in IGP. One of the most interesting features of our study relates to the observation that secondary aerosols (contributing as high as ~60 % to PM1 loading) are predominantly derived from stationary combustion sources (/ ratio: 0.30±0.23). Thus, our study highlights a high concentration of PM1 loading and atmospheric fog prevalent during wintertime can have a severe impact on atmospheric chemistry in the air-shed of IGP.

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