Potential Uses of Coal Methane in China and Associated Benefits for Air Quality, Health, and Climate.

China is the world's largest producer and consumer of coal, but the country has recently set ambitious targets for cleaner energy sources. These include goals to capture and utilize methane from coal seams as a source of unconventional natural gas. We investigate the impacts of using coal methane to displace coal power plants and residential coal combustion across northern China. We compare the greenhouse gas emissions, air quality, and public health impacts of several scenarios for coal methane utilization. We find that China's existing goals would decrease the country's total carbon emissions by ∼2.3% (284 million tons CO2eq). Furthermore, these reductions are dominated by mitigated methane emissions and therefore confer a much larger climate benefit than would be expected from other forms of natural gas. Our results also indicate that the air quality and health impacts strongly depend on how the methane is utilized. Using the methane to displace coal-fired electricity would reduce annual mean ambient PM2.5 concentrations by up to >2.5 μg/m3 and prevent up to 9290 premature mortalities annually (95% confidence interval: 7862-9992). By contrast, utilizing coal methane in home heating yields smaller changes to ambient air quality (∼0.6 μg/m3), but improvements to indoor air quality could produce comparable reductions in premature mortality.