Coal combustion by power plants and industry pollutes the air, causing many governments to implement mitigation actions and encourage cleaner forms of energy. Now, a new study in ACS’ Environmental Science & Technology indicates that in China, indoor air pollution from residential coal burning causes a disproportionate number of premature deaths from exposure to tiny, inhalable pollutants known as PM2.5.
In China, coal is still the largest source of energy, although recent mitigation actions have replaced some coal-fired power plants with petroleum- or natural gas-powered plants. Also, many coal-fired power plants and industrial boilers have installed equipment that reduces emissions. However, some households continue to use coal for heating and cooking, especially in rural areas, and the health impacts of this indoor PM2.5 exposure compared with other forms of indoor and outdoor exposure are largely unknown. Therefore, Shu Tao and colleagues wanted to quantify health risks of exposure to indoor and outdoor PM2.5 from coal used in the power, industrial and residential sectors in China from 1974 to 2014.
The researchers compiled data on coal consumption by power plants, industry, and rural and urban residences over the 40-year period. Using atmospheric chemical transport and statistical models, they calculated outdoor and indoor PM2.5 levels. Then, the team used exposure response functions — mathematical relationships that calculate health effects resulting from specific exposures — to estimate premature deaths caused by five diseases associated with PM2.5, including lung cancer and heart disease. From 1974 to 2014, the contribution of indoor residential coal use to overall PM2.5 exposure decreased in urban populations but remained steady in rural populations. The researchers calculated that in 2014, residential coal accounted for 2.9% of total energy use in China but 34% of premature deaths associated with PM2.5. The number of premature deaths caused by unit coal consumption in the residential sector was 40 times higher than that in the power and industrial sectors. These results indicate that efforts to reduce residential coal use should be a key focus of future air pollution mitigation actions in China, the researchers say.
The authors acknowledge funding from the Chinese Academy of Sciences and the National Natural Science Foundation of China.
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