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Electricity production is a significant source of air pollution. Various factors, including electricity demand, generation efficiency, energy mix, and end-of-pipe control measures, are responsible for the emission changes during electricity generation. Although electricity production more than doubled from 1990 to 2017, air pollutant emissions showed a moderate increase or decrease, which was attributed to mitigating drivers such as increased clean energy use, improved power generation efficiency, and widespread installation of end-of-pipe control facilities. The absence of these mitigating drivers would have increased CO2, fine particulate matter (PM2.5), black carbon, SO2, and NOx emissions in 2017 by 165 %, 403 %, 1070 %, 614 %, and 274 % than their actual levels, respectively. The improved electricity generation efficiency reduced potential CO2, PM2.5, SO2, and NOx emissions by 30 %, 295 %, 119 %, and 52 % compared to actual emissions, respectively. Meanwhile, the installation of end-of-pipe facilities reduced potential SO2 and PM2.5 emissions by 34.7 and 4.0 Tg, respectively. Considerable differences in emissions among countries were found to be attributable to their differences in electricity demand and the implementation of local mitigating polices.

Abstract Following a series of actions in China, the annual mean fine particle (PM2.5) concentrations have considerably reduced since 2013. However, in some cities, the PM2.5 concentrations exceed the national ambient air quality standard of 35 μg/m3. Herein, we evaluated the historical trends of PM2.5 from 2014 to 2022 in mainland China and found continuously declining trends. However, the annual decline rates decreased despite increasing investments on pollution control, showing considerably diminishing marginal effects of these investments. Accumulative reduction in PM2.5 concentrations is linearly dependent on the log‐transformed accumulative investment in air pollution control. The standard of 35 μg/m3 can be achieved by 2035 if the current efforts continue at the same pace. However, the standard of 35 μg/m3 can weaken the momentum of future actions in cities where the standard has already been implemented. We proposed and tested two tiers with four or six levels of specific regional standards based on the regression model predictions from the historical data and demonstrated that more rigorous standards for regions where the current standard is already attained could provide more momentum for strengthening abatement efforts. The results show that both tiers are feasible if the level of abatement endeavor is maintained even with marginal effects. We also demonstrate that additional 135,000 or 384,000 deaths can be avoided by applying the regional standards. Health benefits are monetized and compared with the control costs, suggesting that compared to Tier‐2, Tier‐1 is more cost‐effective and balanced across the mainland China.

Abstract Marine plastic pollution poses a potential threat to the ecosystem, but the sources and their magnitudes remain largely unclear. Existing bottom-up emission inventories vary among studies for two to three orders of magnitudes (OMs). Here, we adopt a top-down approach that uses observed dataset of sea surface plastic concentrations and an ensemble of ocean transport models to reduce the uncertainty of global plastic discharge. The optimal estimation of plastic emissions in this study varies about 1.5 OMs: 0.70 (0.13–3.8 as a 95% confidence interval) million metric tons yr−1 at the present day. We find that the variability of surface plastic abundance caused by different emission inventories is higher than that caused by model parameters. We suggest that more accurate emission inventories, more data for the abundance in the seawater and other compartments, and more accurate model parameters are required to further reduce the uncertainty of our estimate.

Chinese cooking features several unique processes, e.g., stir-frying and pan-frying, which represent important sources of household air pollution. However, factors affecting household air pollution and the vertical variations of indoor pollutants during Chinese cooking are less clear. Here, using low-cost sensors with high time resolutions, we measured concentrations of five gas species and particulate matter (PM) in three different sizes at multiple heights in a kitchen during eighteen different Chinese cooking events. We found indoor gas species were elevated by 21%–106% during cooking, compared to the background, and PMs were elevated by 44%–159%. Vertically, the pollutants concentrations were highly variable during cooking periods. Gas species generally showed a monotonic increase with height, while PMs changed more diversely depending on the cooking activity's intensity. Intense cooking, e.g., stir-frying, pan-frying, or cooking on high heat, tended to shoot PMs to the upper layers, while moderate ones left PMs within the breathing zone. Individuals with different heights would be subject to different levels of household air pollution exposure during cooking. The high vertical variability challenges the current indoor standard that presumes a uniform pollution level within the breathing zone and thus has important implications for public health and policy making.