Search

The effectiveness of national policies for air pollution control has been demonstrated, but the relative effectiveness of short-term emission reduction measures in comparison with national policies has not. Here we show that short-term abatement measures during important international events substantially reduced PM2.5 concentrations, but air quality rebounded to pre-event levels after the measures ceased. Long-term adherence to strict emission reduction policies led to successful decreases of 54% in PM2.5 concentrations in Beijing, and 23% in atmospheric nitrogen deposition in China from 2012 to 2020. Incentivized by "blue skies" type campaigns, economic development and reactive nitrogen pollution are quickly decoupled, showing that a combination of inspiring but aggressive short-term measures and effective but durable long-term policies delivers sustainable air quality improvement. However, increased ammonia concentrations, transboundary pollutant flows, and the complexity to achieving reduction targets under climate change scenarios, underscore the need for the synergistic control of multiple pollutants and inter-regional action. In response to the rebound of air pollution during large events in China, the authors propose that a combination of ambitious short-term measures and enduring long-term pollution control policies is a sustainable solution for improving air quality. [ABSTRACT FROM AUTHOR]

Setting nitrogen (N) emission targets for agricultural systems is crucial to prevent to air and groundwater pollution, yet such targets are rarely defined at the county level. In this study, we employed a forecasting-and-back casting approach to establish human health-based nitrogen targets for air and groundwater quality in Quzhou county, located in the North China Plain. By adopting the World Health Organization (WHO) phase I standard for PM 2.5 concentration (35 μg m−3) and a standard of 11.3 mg NO 3 −-N L−1 for nitrate in drinking water, we found that ammonia (NH 3) emissions from the entire county must be reduced by at least 3.2 kilotons year−1 in 2050 to meet the WHO's PM 2.5 phase I standard. Additionally, controlling other pollutants such as sulfur dioxide (SO 2) and nitrogen oxides (NO x) is necessary, with required reductions ranging from 16% to 64% during 2017–2050. Furthermore, to meet the groundwater quality standard, nitrate nitrogen (NO 3 −-N) leaching to groundwater should not exceed 0.8 kilotons year-1 by 2050. Achieving this target would require a 50% reduction in NH 3 emissions and a 21% reduction in NO 3 −-N leaching from agriculture in Quzhou in 2050 compared to their respective levels in 2017 (5.0 and 2.1 kilotons, respectively). Our developed method and the resulting N emission targets can support the development of environmentally-friendly agriculture by facilitating the design of control strategies to minimize agricultural N losses. • A novel method was developed for establishing human-health-oriented nitrogen targets. • This approach was implemented in Quzhou County, the North China Plain. • Reducing agricultural ammonia emissions by at least 50% can meet PM 2.5 standard. • Decreasing nitrate leaching by at least 21% can meet water quality standards. • It provides a way to optimize regional agricultural nitrogen management. [ABSTRACT FROM AUTHOR]