Individual exposure to particulate matter in urban and rural Chinese households: estimation of exposure concentrations in indoor and outdoor environments

According to the World Health Report, an estimated 540,000 people in China died prematurely due to indoor air pollution in 2009. The major source of indoor air pollution is the burning of solid fuels, such as coal and biomass, for household heating and cooking. To understand the current state of indoor air pollution in China, we quantified the total domestic energy consumption and exposure concentrations of pollutants in indoor environments. We investigated domestic energy consumption by fuel type and energy use in both urban and rural areas in 31 provinces in China and modified a microenvironmental exposure model to estimate the exposure concentrations of particulate matter with a diameter of less than 2.5 mu m (PM2.5). Our results revealed that in urban areas, the main source of indoor PM2.5 pollution was inflow from outdoor pollution sources. In contrast, the main source of indoor pollution in rural areas was the combustion of coal and biomass. Men who spent more time in heated indoor environments were exposed to higher PM2.5 concentrations than women. However, in rural areas, women were exposed to twice the PM2.5 concentrations than men, as they spent more time cooking and heating water.