Journal article
Pre-monsoon submicron aerosol composition and source contribution in the Kathmandu Valley, Nepal
Environmental science: atmospheres, Vol.2(5), pp.978-999
09/15/2022
DOI: 10.1039/d2ea00008c
Abstract
The Kathmandu Valley in Nepal suffers from unhealthy air quality, with mean pre-monsoon submicron particulate matter concentration (PM1) of 40 mu g m(-3) and daily peaks over 75 mu g m(-3). A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) measured ambient non-refractory submicron PM (NR-PM1) in a Kathmandu suburb in April 2015. The mean NR-PM1 composition was 15.8 mu g m(-3) (39.7%) organic aerosol (OA), 10.5 mu g m(-3) (25.0%) BC, 8.4 mu g m(-3) (21.1%) SO42-, 2.96 mu g m(-3) (7.4%) NH4+, 1.22 mu g m(-3) (3.1%) NO3-, and 0.92 mu g m(-3) (2.3%) Cl-. NR-PM1 exhibited a diurnal pattern with concentration maxima at 08:00 local standard time. Afternoon winds and an elevated planetary boundary layer then mitigated NR-PM1. Positive matrix factorization (PMF) of OA mass spectral data identified four primary source components: hydrocarbon-like OA (HOA, 15%), biomass burning OA (BBOA, 15%), trash burning OA (TBOA, 11%), a local sulfur-containing OA (sLOA, 7%), and three oxidized OA (OOA, 50%) factors. sLOA contains the ion C3HSO+, associated with emissions from coal used in brick kilns. Secondary aerosols account for 50% of all OA mass within the valley. Gas-phase carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O-3), methane (CH4), and black and brown carbon (BC, BrC) measurements also characterized pollution in the valley. Composition, concentration, and source analysis from AMS-PMF and filter-based chemical mass balance measurements agree well (OC slope = 1.05, R-2 = 0.47). This work identifies and quantifies significant sources of PM1 in the Kathmandu Valley and provides insight into the impact of these sources on overall air quality throughout South Asia.
Details
- Title: Subtitle
- Pre-monsoon submicron aerosol composition and source contribution in the Kathmandu Valley, Nepal
- Creators
- Benjamin S. Werden - Drexel UniversityMichael R. Giordano - Drexel UniversityJ. Douglas Goetz - Drexel UniversityMd Robiul Islam - University of IowaPrakash Bhave - Int Ctr Integrated Mt Dev, Lalitpur, NepalSiva Praveen Puppala - International Centre for Integrated Mountain DevelopmentMaheswar Rupakheti - Inst Adv Sustainabil Studies, Potsdam, GermanyEri Saikawa - Emory UniversityArnico K. Panday - International Centre for Integrated Mountain DevelopmentRobert J. Yokelson - University of MontanaElizabeth A Stone - University of Iowa, ChemistryPeter F. DeCarlo - Johns Hopkins University
- Resource Type
- Journal article
- Publication Details
- Environmental science: atmospheres, Vol.2(5), pp.978-999
- DOI
- 10.1039/d2ea00008c
- ISSN
- 2634-3606
- eISSN
- 2634-3606
- Publisher
- Royal Soc Chemistry
- Number of pages
- 22
- Grant note
- DOI: 10.13039/100000001, name: National Science Foundation, award: AGS0003865, AGS1349976, AGS1350021, AGS1351616, AGS1461458; DOI: 10.13039/100008211, name: Drexel University; DOI: 10.13039/100008893, name: University of Iowa; DOI: 10.13039/100008457, name: University of Virginia; DOI: 10.13039/100008524, name: University of Montana; DOI: 10.13039/100006939, name: Emory University; DOI: 10.13039/501100004581, name: Brandenburger Staatsministerium für Wissenschaft, Forschung und Kultur; DOI: 10.13039/501100007190, name: Sveriges Regering; DOI: 10.13039/501100002347, name: Bundesministerium für Bildung und Forschung
- Language
- English
- Date published
- 09/15/2022
- Academic Unit
- Chemistry; Chemical and Biochemical Engineering
- Record Identifier
- 9984460056202771
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