Headline: Near-road sampling of PM2. 5, BC, and fine-particle chemical components in Kathmandu Valley, Nepal

Semicontinuous PM2. 5 and black carbon (BC) concentrations, and 24 h integrated PM2. 5 filter samples were collected near roadways in the Kathmandu Valley, Nepal. Instruments were carried by a group of volunteer traffic police officers in the vicinity of six major roadway intersections in the Kathmandu Valley across two sampling periods in 2014. Daily PM2. 5 filter samples were analyzed for water-soluble inorganic ions, elemental carbon (EC) and organic carbon (OC), and 24 elements. Mean PM2. 5 and BC concentrations were 124.76 µg m−3 and 16.74 µgC m−3 during the drier spring sampling period, and 45.92 µg m−3 and 13.46 µgC m−3 during monsoonal sampling. Despite the lower monsoonal PM2. 5 concentrations, BC and several elements were not significantly lower during the monsoon, which indicates an important contribution of vehicle-related emissions throughout both seasons in this region. During the monsoon, there was an enhanced contribution of chemical species (elements and water-soluble inorganic ions), except secondary inorganic ions, and BC to PM2. 5 (crustal elements: 19 %; heavy metals: 5 %; and BC: 39 %) compared to those in spring (crustal elements: 9 %; heavy metals: 1 %; and BC: 18 %). Silica, calcium, aluminum, and iron were the most abundant elements during both spring and the monsoon, with total concentrations of 12.13 and 8.85 µg m−3, respectively. PM2. 5 and BC showed less spatial variation compared to that for individual chemical species.

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Academic Articles

Shakya, K. M., Rupakheti, M., Shahi, A., Maskey, R., Pradhan, B., Panday, A., Puppala, S. P., Lawrence, M. G., & Peltier, R. E. (2017). Near-road sampling of PM2. 5, BC, and fine-particle chemical components in Kathmandu Valley, Nepal. Atmospheric Chemistry and Physics, 17(10), 6503-6516. doi:10.5194/acp-17-6503-2017.

10.5194/acp-17-6503-2017 10.5194/acp-17-6503-2017-supplement
https://publications.rifs-potsdam.de/rest/items/item_2305891_10/component/file_… https://publications.rifs-potsdam.de/rest/items/item_2305891_10/component/file_…
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A Sustainable Atmosphere for the Kathmandu Valley (SusKat)