Indoor Nitrogen Dioxide And Sulfur Dioxide Exposures From Burning Solid Fuels For Cooking And Heating In Yunnan Province, China

Abstract

Background: Little information is available regarding household exposure to NO2 and SO2 due to burning solid fuels such as coal and biomass in China. We characterized indoor NO2 and SO2 levels in relation to solid fuel use and stove ventilation in Yunnan, China, where a variety of solid fuels, including smoky (bituminous) coal, smokeless (anthracite) coal, and wood is used. Methods: Thirty villages were selected and 163 participants were enrolled in Xuanwei and Fuyuan Counties. Indoor 24-hour NO2 and SO2 samples were collected in each household over two consecutive days. Tukey's honest significant difference and analysis of variance tests were used to compare indoor NO2 levels (continuous) and logistic regression and Fisher's exact tests were used to compare indoor SO2 levels (detected or non-detected) among different fuel types and stove designs. Linear and logistic mixed models were used to identify determinants of indoor NO2 and SO2 respectively. Results: Compared to smoky coal, smokeless coal was associated with higher NO2 (geometric mean=132.1µg/m3 for smokeless coal and 111.2µg/m3 for smoky coal, P=0.065) and SO2 (percentage detected=85.7% for smokeless coal and 38.9% for smoky coal, P