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Residential contribution to air pollution–associated health impacts is critical, but inadequately addressed because of data gaps. Here, we fully model the effects of residential energy use on emissions, outdoor and indoor PM2.5 concentrations, exposure, and premature deaths using updated energy data. We show that the residential sector contributed only 7.5% of total energy consumption but contributed 27% of primary PM2.5 emissions; 23 and 71% of the outdoor and indoor PM2.5 concentrations, respectively; 68% of PM2.5 exposure; and 67% of PM2.5-induced premature deaths in 2014 in China, with a progressive order of magnitude increase from sources to receptors. Biomass fuels and coal provided similar contributions to health impacts. These findings are particularly true for rural populations, which contribute more to emissions and face higher premature death risks than urban populations. The impacts of both residential and nonresidential emissions are interconnected, and efforts are necessary to simultaneously mitigate both emission types.

Household energy use is an important aspect of environmental pollution and sustainable development. From a nationwide residential energy survey, this study revealed that household fuel “stacking”-mixed use of multiple fuels-is becoming noticeable over the 20 years from 1992 to 2012, particularly in northern China where space heating is needed in the winter. Approximately 28% of rural households used only one single energy type in 1992, whereas the percentage declined to merely 11% in 2012. The number of energy types correlated positively with the heating degree days and negatively with the household income in areas with limited or no heating requirements. Combined use of biomass and fossil fuels may lead to extra energy use, up to 40% for cooking and 20% for heating. Some fuels, as supplementary ones, are used more often than others, and the energy consumption of coal and honeycomb briquette could be underestimated by 34% and 22% if only the primary energy was accounted for. Generally, household energy is shifting from solid fuels to cleaner ones, such as electricity or gas for both cooking and heating, but with different patterns and transition rates. Transition pathways varied extensively from one region to another due to the imbalanced development. Clean transitions initially occur in well-developed provinces and megacities and then extend to inland provinces approximately 5–10 years later. Rapid energy transitions and urbanization have led to nearly 50% reduction in residential energy consumption over these two decades, consequently resulting in significant declines in emissions of most air pollutants. The updated residential emission of primary PM2.5 was 3100 Gg in 2014. Extensively fuel stacking and rapid energy transitions have led to complex circumstances in energy use.

The presence of sulfur dioxide (SO2) in the air is a global concern because of its severe environmental and public health impacts. Recent evidence from satellite observations shows fast changes in the spatial distribution of global SO2 emissions, but such features are generally missing in global emission inventories that use a bottom-up method due to the lack of up-to-date information, especially in developing countries.Here, we rely on the latest data available on emission activities, control measures, and emission factors to estimate global SO2 emissions for the period 1960-2014 on a 0.1° × 0.1° spatial resolution. We design two counterfactual scenarios to isolate the contributions of emission activity growth and control measure deployment on historical SO2 emission changes. We find that activity growth has been the major factor driving global SO2 emission changes overall, but control measure deployment is playing an increasingly important role. With effective control measures deployed in developed countries, the predominant emission contributor has shifted from developed countries in the early 1960s (61%) to developing countries at present (83%). Developing countries show divergency in mitigation strategies and thus in SO2 emission trends.Stringent controls in China are driving the recent decline in global emissions. A further reduction in SO2 emissions would come from a large number of developing nations that currently lack effective SO2 emission controls.