In Beijing and the surrounding region, reducing household pollution emissions may have greater benefits to air quality than reducing emissions in the transportation and power sectors, according to a new paper published in the Proceedings of the National Academy of Sciences (PNAS).

China’s rapid urbanization and development over the last 30 years have left leaders facing public outcry about worsening air quality. In response, the government has imposed restrictions on key sources of pollution including power plants and vehicle use, the authors note. Yet the potential benefits of reducing emissions in the residential sector remains largely overlooked in air pollution control strategies.

COEH co-author Kirk Smith shows replacing household solid fuels with cleaner energy sources in Beijing, and in the Beijing, Tianjin, and Hebei (HTB) region, would reduce annual emissions of fine particle pollution by approximately 32 percent and sulfur dioxide by 15 percent – more than the transportation and power sectors combined and, in winter, more than the industrial sector of the economy. In this region populated by over 100 million, households burn larger quantities of coal and biomass fuels during the winter months and, therefore, contributions of the residential sector to total emissions are larger than at other times of the year, note the authors.

The Global Burden of Disease Study reports household air pollution as the single most important risk factor in many poor regions and the most important environmental risk factor globally. “In 2013, direct household exposure to air pollution from solid fuels was responsible for 0.8 million premature deaths in China, about equal to the number of premature deaths from ambient air pollution,” the researchers state in PNAS.

“You cannot have a clean outdoor environment if a large percentage of the population is burning dirty fuels in households several times a day,” Smith said in a press release. “The smoke may start indoors, but soon leaves the house and becomes a significant part of regional air pollution.”

Investigators used the Weather Research and Forecasting with Chemistry model to evaluate potential residential emission controls in Beijing, China’s capital, and the HTB region. Air pollution in Beijing receives considerable attention, but when the prevailing wind is southerly, air pollutions from Hebei, Shandong, and Henan are transported to Beijing, contributing nearly 40 percent of PM2.5 concentrations, the authors note. The study, therefore, contributes strong evidence of the value air quality management at the regional level.

“On a smaller scale, here in the Bay Area air-quality control is not only focused on San Francisco and Oakland, but also coordinates across nine Bay Area counties through a regional governing body,” Smith notes. “One might think that, because China has a powerful central government, it would be easy to coordinate regional governing bodies to fight pollution, but that is not necessarily the case.”

Smith, a professor of Global Environmental Health at UC Berkeley, co-led the investigation with Tong Zhu of Peking University and Denise Mauzerall of Princeton University. The study was supported by the National Natural Science Foundation Committee of China, the European Seventh Framework Programme Project, and the Collaborative Innovation Center for Regional Environmental Quality.

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