Molecular characterization of organic aerosols in the Kathmandu Valley, Nepal: insights into primary and secondary sources

A year-long molecular characterization of organic aerosols in the Kathmandu Valley revealed that biomass burning (BB) is the dominant contributor to organic carbon (OC), accounting for 24.9% annually and peaking at 36.3% during the post-monsoon season. The study, conducted from April 2013 to April 2014, identified levoglucosan as the most abundant tracer, with significant seasonal variations in other tracers like isoprene-SOA (I-SOA), phenolic compounds, and resin acids. Anthropogenic and biogenic secondary organic aerosols also contributed notably, while fungal spores and plant debris had smaller but seasonally variable impacts. These findings highlight BB and anthropogenic activities as primary sources of air pollution in the region, offering critical insights for mitigation strategies.

Wan, X., Kang, S., Rupakheti, M., Zhang, Q., Tripathee, L., Guo, J., Chen, P., Rupakheti, D., Panday, A. K., Lawrence, M. G., Kawamura, K., & Cong, Z. (2019). Molecular characterization of organic aerosols in the Kathmandu Valley, Nepal: insights into primary and secondary sources. Atmospheric Chemistry and Physics, 19(5), 2725–2747. https://doi.org/10.5194/acp-19-2725-2019