Carbon isotope‐constrained seasonality of carbonaceous aerosol sources from an urban location (Kanpur) in the Indo‐Gangetic Plain

摘要: The Indo-Gangetic Plain (IGP) in northern India, Pakistan, and Bangladesh is a major source of carbonaceous aerosols South Asia. However, poorly constrained seasonality their sources over the IGP leads to large uncertainty climate health effects. Here we present first data set for year-round radiocarbon (Δ14C) stable carbon (δ13C)-based apportionment total (TC) ambient PM10 (n = 17) collected from an urban site (Kanpur: 26.5°N, 80.3°E) during January 2007 2008. 14C-based fraction biomass (fbio-TC) estimate at Kanpur averages ~77 ± 7% emphasizes impact burning emissions (BBEs). highest fbio-TC (%) observed fall season (October–November, 85 ± 6%) followed by winter (December–February, 80 ± 4%) spring (March–May, 75 ± 8%), while lowest values are found summer (June–September, 69 ± 2%). Since biomass/coal combustion vehicular mostly contribute IGP, predict δ13CTC (δ13Cpred) using known δ13C signatures measured Δ14C value each sample. seasonal variability δ13Cobs − δ13Cpred versus Δ14CTC together with air mass back trajectories Moderate Resolution Imaging Spectroradiometer fire count reveal that winter/fall significantly influenced atmospheric aging (downwind transport crop residue burning/wood IGP), local (wheat combustion/vehicular emissions) dominate spring/summer. Given temporal emission strength TC constraints are, thus, crucial reducing uncertainties aerosol budgets models.