Overview of VOC emissions and chemistry from PTR-TOF-MS measurements during the SusKat-ABC campaign: high acetaldehyde, isoprene and isocyanic acid in wintertime air of the Kathmandu Valley

Wintertime air pollution in the Kathmandu Valley, Nepal, is characterized by unusually high concentrations of volatile organic compounds (VOCs), with acetaldehyde (8.8 ppb), methanol (7.4 ppb), and acetone + propanal (4.2 ppb) dominating the chemical profile. The study, conducted during the SusKat-ABC campaign in 2012–2013 using a high-resolution proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS), identified 71 VOC species, including 'new' ambient compounds like formamide and acetamide, which can photochemically produce isocyanic acid—a known health hazard. Biomass burning and brick kilns emerged as major sources of toxic VOCs such as benzene and isocyanic acid, while isoprene and oxygenated VOCs significantly contributed to ozone production potential. This research highlights the critical need for mitigating biomass burning activities to reduce harmful emissions in South Asia.

Sarkar, C., Sinha, V., Kumar, V., Rupakheti, M., Panday, A., Mahata, K. S., Rupakheti, D., Kathayat, B., & Lawrence, M. G. (2016). Overview of VOC emissions and chemistry from PTR-TOF-MS measurements during the SusKat-ABC campaign: high acetaldehyde, isoprene and isocyanic acid in wintertime air of the Kathmandu Valley. Atmospheric Chemistry and Physics, 16(6), 3979–4003. https://doi.org/10.5194/acp-16-3979-2016