Concentration of Indoor Particulate Matter and Carbon Monoxide among Households Using Biomass Fuels in Sarlahi, Nepal: the Effect of Cooking, Fuel Type, and Season

Abstract

Concentration of Indoor Particulate Matter and Carbon Monoxide among Households Using Biomass Fuels in Sarlahi, Nepal: the Effect of Cooking, Fuel Type, and SeasonAbstract Number:3018 Patrick N Breysse*, James M Tielsch, Chen Chen, Joanne Katz, Scott L Zeger, Frank C Curriero, Subarna K Khatry, Laxman Shrestha, and Steven C LeClerq Patrick N Breysse* Search for more papers by this author , James M Tielsch Search for more papers by this author , Chen Chen Search for more papers by this author , Joanne Katz Search for more papers by this author , Scott L Zeger Search for more papers by this author , Frank C Curriero Search for more papers by this author , Subarna K Khatry Search for more papers by this author , Laxman Shrestha Search for more papers by this author , and Steven C LeClerq Search for more papers by this author AbstractPurpose: A large (n=3129) cookstove intervention trial is underway in the Sarlahi district of Nepal. The purpose of this paper is to summarize baseline 24-hour indoor particulate matter (PM) and carbon monoxide (CO) concentrations.Methods: 24-hour continuous PM and CO samples were collected in 2871 households (92%) from March 2010 to September 2011. PM was measured passively using the pDR-1000. PM concentration values were humidity corrected and adjusted to PM2.5 equivalents using a subset of co-located gravimetric samples. CO was measured using a LASCAR data-logging CO monitor. Cooking events were identified based on empirical assessment of temporal trends in PM concentration. Regression models were utilized to evaluate the association of PM and CO concentration with cooking, fuel type, season, and household characteristics.Results: The median of daily average PM concentrations was 1334?g/m^3^ (IQR, 1279), median 95th percentile of PM concentration was 4625?g/m^3^ (IQR, 4878), and mean of time above 500?g/m^3^ was 11.04h (95% CI, 10.86—11.22). The median of daily average CO concentrations was 8.2ppm (IQR, 9.2), and median 95th percentile of CO concentration was 36.5ppm (IQR, 56.5). The mean cooking time per day was 5.63h (95% CI, 5.55—5.72), and median difference of average PM concentration between cooking and non-cooking time was 3140?g/m^3^ (IQR, 4093). All PM concentration metrics peaked in the dry season and dipped in the rainy season, while no significant seasonal variation was identified in CO concentration. PM concentration and CO concentration were weakly associated, which varied by fuel type and season. Among major biomass fuels used in Nepal, wood generated the lowest PM concentrations, and crop waste generated the lowest CO concentrations.Conclusions: Baseline PM and CO concentrations are extremely high in the Nepal cookstove trial study homes. PM demonstrated significant variability associated with season and fuel type.