Impacts of household sources on air pollution at village and regional scales in India

摘要

Approximately 3 billion people worldwide cook with solid fuels, such as wood, charcoal, and agricultural residues. These fuels, also used for residential heating, are often combusted in inefficient devices, producing carbonaceous emissions. Between 2.6 and 3.8 million premature deaths occur as a result of exposure to fine particulate matter from the resulting household air pollution (Health Effects Institute, 2018a; World Health Organization, 2018). Household air pollution also contributes to ambient air pollution; the magnitude of this contribution is uncertain. Here, we simulate the distribution of the two major health-damaging outdoor air pollutants (PM sub2.5/sub and Osub3/sub ) using state-of-the-science emissions databases and atmospheric chemical transport models to estimate the impact of household combustion on ambient air quality in India. The present study focuses on New Delhi and the SOMAARTH Demographic, Development, and Environmental Surveillance Site (DDESS) in the Palwal District of Haryana, located about 80?km south of New Delhi. The DDESS covers an approximate population of 200?000 within 52?villages. The emissions inventory used in the present study was prepared based on a national inventory in India (Sharma et al., 2015, 2016), an updated residential sector inventory prepared at the University of Illinois, updated cookstove emissions factors from Fleming et al.?(2018b), and PM sub2.5/sub speciation from cooking fires from Jayarathne et al.?(2018). Simulation of regional air quality was carried out using the US Environmental Protection Agency Community Multiscale Air Quality modeling system (CMAQ) in conjunction with the Weather Research and Forecasting modeling system (WRF) to simulate the meteorological inputs for CMAQ, and the global chemical transport model GEOS-Chem to generate concentrations on the boundary of the computational domain. Comparisons between observed and simulated Osub3/sub and PM sub2.5/sub levels are carried out to assess overall airborne levels and to estimate the contribution of household cooking emissions. Observed and predicted ozone levels over New Delhi during September 2015, December 2015, and September 2016 routinely exceeded the 8?h Indian standard of 100 μ g?m sup?3/sup , and, on occasion, exceeded 180 μ g?m sup?3/sup . PM sub2.5/sub levels are predicted over the SOMAARTH headquarters (September?2015 and September?2016), Bajada Pahari (a village in the surveillance site; September?2015, December?2015, and September?2016), and New Delhi (September?2015, December?2015, and September?2016). The predicted fractional impact of residential emissions on anthropogenic PM sub2.5/sub levels varies from about 0.27 in SOMAARTH HQ and Bajada Pahari to about 0.10 in New Delhi. The predicted secondary organic portion of PM sub2.5/sub produced by household emissions ranges from 16?% to 80?%. Predicted levels of secondary organic PM sub2.5/sub during the periods studied at the four locations averaged about 30 μ g?m sup?3/sup , representing approximately 30?% and 20?% of total PM sub2.5/sub levels in the rural and urban stations, respectively.