Characteristics and Sources of Carbonaceous, Ionic, and Isotopic Species of Wintertime Atmospheric Aerosols in Kathmandu Valley, Nepal

Aerosol pollution in Kathmandu Valley during winter is dominated by local emissions, with secondary organic carbon (SOC) contributing 31% to organic carbon (OC). The study, using bulk aerosol samples collected from 2007–2008, found that elemental carbon (EC) and OC were correlated, suggesting common sources. Water-soluble organic carbon (WSOC) accounted for half of OC, with SOC strongly correlating with WSOC, indicating water solubility in both primary and secondary forms. Carbon isotope analysis confirmed anthropogenic fossil fuel combustion as a consistent source, while nitrogen isotopes suggested limited biomass burning influence. Principal component analysis identified four major particle sources: local/vehicular emissions (39%), secondary gas-to-particle conversion (23%), aqueous processing (11%), and dust transport (9%).

Shakya, K. M., Ziemba, L. D., & Griffin, R. J. (2010). Characteristics and Sources of Carbonaceous, Ionic, and Isotopic Species of Wintertime Atmospheric Aerosols in Kathmandu Valley, Nepal. Aerosol and Air Quality Research, 10(3), 219–230. https://doi.org/10.4209/aaqr.2009.10.0068