The impact of biomass burning on total suspended particulate matter in the southeastern Tibetan Plateau

Abstract

To investigate the impact of biomass burning (BB) emissions on total suspended particulate (TSP) in the southeastern Tibetan Plateau (TP), BB tracers (including levoglucosan, mannosan, and galactosan) were measured at Lulang (a remote site, ∼3300 m above sea level) during the period 2015–2016. The concentrations of levoglucosan and mannosan showed large variability of more than 8-fold (range: 0.029–0.253 μg m−3) and 6-fold (range: 0.01–0.061 μg m−3), respectively. The highest seasonal average concentrations of levoglucosan (0.131 ± 0.073 μg m−3) and mannosan (0.028 ± 0.019 μg m−3) were observed during the winter season. The BB contributions to the TSP organic carbon (OC) and TSP mass were estimated with positive matrix factorization (PMF) by using BB tracers, inorganic ions, elements, OC, and EC. The BB contributions to the TSP OC and TSP mass were quite substantial in winter with 26% and 14%, respectively. The results evidenced a major contribution of BB to the aerosol OC during winter season. Major potential source distributions of BB were identified, which included the pollution bands along the Indo-Gangetic Plain, the Yarlung Tsangpo River Valley and the interior of the TP. In addition to the long-range transport of BB, the sources of anthropogenic emissions (residential BB for cooking and heating) in the TP may be an important contributor. The results facilitated understanding of the characteristics and effects of BB in the TP.