While wood and to some extent charcoal are the most common solid fuels used in developing countries, China and Mongolia have high household prevalence of coal, especially for heating in open portable space heaters, some with and some without chimney. Mestl et al. (2006), based on data from the China 2000 Population Census, report that about 60 percent of rural households used biomass as primary cooking fuel. Nearly 30 percent of rural households used coal as the primary fuel. Mestl et al model annual average population weighted exposure (PWE) to indoor air pollution by.
