Previous studies have measured several pollutants in tents in Nam Co, Tibet. In a household using a simple stove without a chimney, the 24-h average concentrations of PM2.5 ranged between 1270 and 1670 mg/m3. A tent with a chimney stove had a lower 24-h average PM2.5 concentration of 97 mg/m3 (Chen et al., 2011), which was still approximately four-times higher than the WHO Air Quality Guideline (25 mg/m3, 24-h mean). While previous studies measured total PM2.5 from biomass combustion in Tibetan tents, no study quantified the BC component. Moreover, all previous studies were conducted in the summer, which is the warmest season in Tibet (monthly average temperature in August was 8.8 C in Nam Co in 2005).
During winter or spring when the temperature is much lower (monthly average temperature in March, for example, was 5.5 C in Nam Co in 2006)