Seasonal abundances of primary and secondary carbonaceous aerosols at a high-altitude station in the Western Ghat Mountains, India

AbstractThe combustion-related primary and secondary carbon particles have gained more importance in the recent past due to their radiative and chemical properties. The present paper deals with the results obtained from observations on Organic Carbon (OC) and Elemental Carbon (EC) during 2019 –20 over a high-altitude location, Mahabaleshwar in the Western Ghats in peninsular India. The data is classified into summer (March to May 2019) and winter (December 2019 to February 2020). Mean OC mass was more during summer (13.6 ± 4.4 μg / m3) than winter (11.1  ± 3.2 μg / m3). However, mean EC mass was more in winter (3.6  ± 1.1 μg / m3) than in summer (2.2  ± 1.1 μg / m3). The mean annual OC/EC ratio was 7.4  ± 4.4 in summer and 3.1 ± 0.7 in winter, suggesting more presence of secondary organic carbon (SOC) during summer. Estimated SOC formed about 62% of OC in summer whereas in winter both SOC and primary organic carbon (POC) formed 50% each of OC. Together both POC and EC contributed to 46% of the total carbon (TC) in summer and 62% in winter indicating more primary fraction during winter. The effective carbon ratio (ECR) was 1.6 and 0.7 during summer and winter respectively, indicating the dominance of scattering-type secondary carbonaceous aerosols in summer. Cluster and concentrated weighted trajectory (CWT) analysis indicated high concentrations of OC and EC in continental originated trajectories. However, a high OC/EC ratio was observe...
Source: Air Quality, Atmosphere and Health - Category: Environmental Health Source Type: research