A Comparison of Particulate Matter from Biomass-Burning Rural and Non-Biomass-Burning Urban Households in Northeastern China

BACKGROUND: Biomass fuel is the primary source of domestic fuel in much of rural China. Previous studies have not characterized particle exposure through time–activity diaries or personal monitoring in mainland China. OBJECTIVES: In this study we characterized indoor and personal particle exposure in six households in northeastern China (three urban, three rural) and explored differences by location, cooking status, activity, and fuel type. Rural homes used biomass. Urban homes used a combination of electricity and natural gas. METHODS: Stationary monitors measured hourly indoor particulate matter (PM) with an aerodynamic diameter ≤ 10 μm (PM(10)) for rural and urban kitchens, urban sitting rooms, and outdoors. Personal monitors for PM with an aerodynamic diameter ≤ 2.5 μm (PM(2.5)) were employed for 10 participants. Time–activity patterns in 30-min intervals were recorded by researchers for each participant. RESULTS: Stationary monitoring results indicate that rural kitchen PM(10) levels are three times higher than those in urban kitchens during cooking. PM(10) was 6.1 times higher during cooking periods than during noncooking periods for rural kitchens. Personal PM(2.5) levels for rural cooks were 2.8–3.6 times higher than for all other participant categories. The highest PM(2.5) exposures occurred during cooking periods for urban and rural cooks. However, rural cooks had 5.4 times higher PM(2.5) levels during cooking than did urban cooks. Rural cooks spent 2.5 times more hours per day cooking than did their urban counterparts. CONCLUSIONS: These findings indicate that biomass burning for cooking contributes substantially to indoor particulate levels and that this exposure is particularly elevated for cooks. Second-by-second personal PM(2.5) exposures revealed differences in exposures by population group and strong temporal heterogeneity that would be obscured by aggregate metrics.