Impact of ice-free oases on particulate matter over the East Antarctic: Inferences from the carbonaceous, water-soluble species and trace metals

Abstract

The present study reports on carbonaceous, water-soluble species and trace metals in PM10 aerosols collected at Bharati station during the austral summer (December 17, 2016 to February 2, 2017) over East Antarctica. Organic matter was the predominant among all measured species followed by nss-Ca2+ and nss-SO42-. Two distinct air masses that arrive from high-altitude-troposphere (HTAs) and low-altitude-troposphere (LTAs) regions which clearly showed significant differences in concentrations of measured chemical and metal species as inferred from the air mass backward trajectory analysis and mixed layer height variations. Based on significant positive correlations among chemical species, aerosol liquid water content (ALWC), and PM10 mass, we confirmed that the aqueous-phase formation of secondary aerosols followed by atmospheric processing are possible sources in HTAs while primary emissions associated with soil/dust from ice-free regions and in-situ emissions are major sources in LTAs. This result further supported by significant (p < 0.05) higher concentrations of specific trace metals (for example, Fe, Ti, and Pb) in LTAs. Moreover, higher cation-to-anion (Σ+/Σ−) ratios suggesting the alkaline nature of aerosols at Bharati. The present study demonstrates that ice-free regions over East Antarctica may act as major sources of particulate matter, thus significant implications toward climate change over the global environment.