Air pollutant emissions from Chinese households: A major and underappreciated ambient pollution source

As part of the 12th Five-Year Plan, the Chinese government has developed air pollution prevention and control plans for key regions with a focus on the power, transport, and industrial sectors. Here, we investigate the contribution of residential emissions to regional air pollution in highly polluted eastern China during the heating season, and find that dramatic improvements in air quality would also result from reduction in residential emissions. We use the Weather Research and Forecasting model coupled with Chemistry to evaluate potential residential emission controls in Beijing and in the Beijing, Tianjin, and Hebei (BTH) region. In January and February 2010, relative to the base case, eliminating residential emissions in Beijing reduced daily average surface PM_2.5 (particulate mater with aerodynamic diameter equal or smaller than 2.5 micrometer) concentrations by 14 ± 7 μg·m^-3 (22 ± 6% of a baseline concentration of 67 ± 41 μg·m^-3; mean ± SD). Eliminating residential emissions in the BTH region reduced concentrations by 28 ± 19 μg·m^-3 (40 ± 9% of 67 ± 41 μg·m^-3), 44 ± 27 μg·m^-3 (43 ± 10% of 99 ± 54 μg·m^-3), and 25 ± 14 μg·m^-3 (35 ± 8% of 70 ± 35 μg·m^-3) in Beijing, Tianjin, and Hebei provinces, respectively. Annually, elimination of residential sources in the BTH region reduced emissions of primary PM_2.5 by 32%, compared with 5%, 6%, and 58% achieved by eliminating emissions from the transportation, power, and industry sectors, respectively. We also find air quality in Beijing would benefit substantially from reductions in residential emissions from regional controls in Tianjin and Hebei, indicating the value of policies at the regional level.