From Source Characterization to Ambient Measurements to Dissemination: An Overview of the NAMaSTE Project in the Kathmandu Valley of Nepal

PETER F. DECARLO, Benjamin Werden, Michael R. Giordano, Erin Katz, Md. Robiul Islam, Thilina Jayarathne, Tianyi Li, Elizabeth Stone, Chelsea Stockwell, Ted Christian, Robert J. Yokelson, Eri Saikawa, Donald Blake, Simone Meinardi, Isobel Simpson, Arnico Panday, Prakash Bhave, Siva Praveen Puppala, Douglas Goetz, Sagar Adhikari, Rashmi Shrestha, Johns Hopkins University

     Abstract Number: 586
     Working Group: Identifying and Addressing Disparate Health and Social Impacts of Exposure to Aerosols and Other Contaminants across Continents, Communities, and Microenvironments

Abstract
The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) was a multi-institutional effort to characterize and quantify the various sources of air pollution in the Kathmandu Valley and Indo-Gangetic Plain of Nepal. In country collaborators at the International Center for Integrated Mountain Development (ICIMOD) were critical for the successful execution of this project. Beginning in 2015, aerosol and gas-phase emissions from common South Asian sources (e.g. brick kilns, trash burning, agricultural residue burning, cookstoves) were characterized using filter collection and offline analysis, online Aerosol Mass Spectrometry (AMS), and photo-acoustic spectroscopy. Gas-phase emissions were measured with a variety of instruments including FTIR, WAS, and CRDS. Source chemical and mass spectral profiles and emission factors were generated from this portion of the project. These were then utilized in regional models and with ambient measurements to quantify the source contributions to ambient aerosol both regionally and explicitly at 4 different locations in and adjacent to the Kathmandu Valley and covering a mix of socioeconomic areas within the agglomeration. Source apportionment studies of ambient particulate matter using AMS with positive matrix factorization and filter collection with chemical mass balance agreed well and showed source differences across the study sites. Although no single source was dominant at any of the sites trash burning, traffic, biomass burning, and dust are major concerns. Results from this multi-stage effort have been used by local partners in Nepal, and international agencies to identify strategies for improving air quality in Kathmandu and more broadly in South Asia.