Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China.

The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation in the rural counties of Xuanwei and Fuyuan, in Yunnan Province, China, which have among the highest lung cancer rates in the nation, a total of 163 participants in 30 selected villages were enrolled. Indoor 24-h NO2 and SO2 samples were collected in each household over two consecutive days. Compared to smoky coal, smokeless coal use was associated with higher NO2 concentrations [geometric mean (GM) = 132 µg/m(3) for smokeless coal and 111 µg/m(3) for smoky coal, P = 0.065] and SO2 [limit of detection = 24 µg/m(3) ; percentage detected (%Detect) = 86% for smokeless coal and 40% for smoky coal, P < 0.001]. Among smoky coal users, significant variation of NO2 and SO2 air concentrations was observed across different stove designs and smoky coal sources in both counties. Model construction indicated that the measurements of both pollutants were influenced by stove design. This exposure assessment study has identified high levels of NO2 and SO2 as a result of burning solid fuels for cooking and heating.

Outdoor, indoor, and personal black carbon exposure from cookstoves burning solid fuels.

Black carbon (BC) emissions from solid fuel combustion are associated with increased morbidity and mortality and are important drivers of climate change. We studied BC measurements, approximated by particulate matter (PM2.5 ) absorbance, in rural Yunnan province, China, whose residents use a variety of solid fuels for cooking and heating including bituminous and anthracite coal, and wood. Measurements were taken over two consecutive 24-h periods from 163 households in 30 villages. PM2.5 absorbance (PMabs ) was measured using an EEL 043 Smoke Stain Reflectometer. PMabs measurements were higher in wood burning households (16.3 × 10(-5) /m) than bituminous and anthracite coal households (12 and 5.1 × 10(-5) /m, respectively). Among bituminous coal users, measurements varied by a factor of two depending on the coal source. Portable stoves (which are lit outdoors and brought indoors for use) were associated with reduced PMabs levels, but no other impact of stove design was observed. Outdoor measurements were positively correlated with and approximately half the level of indoor measurements (r = 0.49, P < 0.01). Measurements of BC (as approximated by PMabs ) in this population are modulated by fuel type and source. This provides valuable insight into potential morbidity, mortality, and climate change contributions of domestic usage of solid fuels.