Exposure to indoor air pollution from household energyuse depends on fuel, stove, housing characteristics,
andstove use behavior. We monitored three important indoor airpollutants-respirable particles (RPM), carbon monoxide(CO),
and sulfur dioxide (SO
2)-for a total of 457 household-days in four poor provinces in China (Gansu, 129 household-days; Guizhou, 127 household-days; Inner Mongolia, 65household-days;
and Shaanxi, 136 household-days), in twotime intervals during the heating season to investigatespatial
and temporal patterns of pollution. The two provinceswhere biomass is the primary fuel (Inner Mongolia
andGansu) had the highest RPM concentrations (719
g/m
3 inthe single cooking/living/bedroom in Inner Mongolia inDecember
and 351-661
g/m
3 in different rooms
and monthsin Gansu); lower RPM concentration were observed inthe primarily coal-burning provinces of Guizhou
and Shaanxi(202-352
g/m
3 and 187-361
g/m
3 in different rooms
and months in Guizhou
and Shaanxi, respectively). InnerMongolia
and Gansu also had higher CO concentrations (7.4ppm in the single cooking/living/bedroom in Inner Mongoliain December
and 4.8-11.3 ppm in different rooms
andmonths in Gansu). Among the two primarily coal-burningprovinces, Guizhou had lower concentrations of CO thanShaanxi (1.2-1.8 ppm in Guizhou vs 2.0-13.3 ppm in differentrooms
and months in Shaanxi). In the two coal-burningprovinces, SO
2 concentrations were substantially higher inShaanxi than in Guizhou. Relative concentrations indifferent rooms
and provinces indicate that in the northernprovinces heating is an important source of exposure toindoor pollutants from energy use. Day-to-day variability ofconcentrations within individual households, althoughsubstantial, was smaller than variation across households.The implications of the findings for designing environmentalhealth interventions in each province are discussed.