空气污染控制背景下未来中国和印度热浪、PM_2.5和臭氧污染共发频率的持续升高

热浪和空气污染极端事件是全球两大主要的健康风险来源,且在中国和印度尤为严重。高温和污染密切相关,通常由持续性高压系统驱动,该系统下强烈的太阳辐射、低降水和低风速有利于热量和污染物的积累。越来越多的证据表明,在热浪与空气污染事件期间,复杂的相互作用和反馈机制可能会导致健康影响的放大,其效应远超单一因素的简单叠加。然而目前对于未来这类共发事件的长期预测仍然不足。本研究基于先进的区域耦合气象-化学模型WRF-Chem及偏差订正后的CMIP6多模式集合,分析了本世纪末中国和印度热浪与空气污染(颗粒物和臭氧)极端事件的未来共同发生趋势。我们比较了2010年代(2010-2014年)与2100年代(2096-2100年)在中等排放情景(SSP245,包含适度气候缓解措施)和高排放情景(SSP585,强调高强度化石能源开发)下,中国与印度热浪及空气污染极端事件的单独发生与共发情况。我们预测,至21世纪末,中国和印度的热浪极端事件在发生频率、持续时间及强度方面将显著增加,导致人群暴露水平大幅提升。未来,在SSP245和SSP585情景下,中国东部及印度整体将呈现明显升温趋势。同时,热浪的平均持续时间和相对强度也将同步上升,且在高排放情景下更为显著。空气质量方面,预计两国主要污染物排放将在21世纪末均有所下降,两国人口加权平均PM2.5和臭氧浓度均大幅降低。关于热浪与空气污染极端事件的共发,当前高频区主要位于中国东部和印度恒河平原,印度三重共发频率约为华北平原的四倍。未来在SSP245情景下,恒河平原热浪与PM2.5共发频率增长超过600%,华北平原增长近440%。由于中国NOx和VOCs排放大幅减少,而印度减幅较小,导致印度热浪与臭氧共发频率上升,中国则下降。SSP585情景下,华北平原热浪与臭氧共发频率由6.8天/年增至20.3天/年,印度的共发增强更显著。三重共发频率在恒河平原和北京分别增长382%和729%。综上所述,尽管空气污染控制措施显著改善了空气质量,但热浪与空气污染极端事件的共发趋势仍将加剧。这表明全球温室气体积累引发的持续变暖将加剧复合极端事件,并且带来更复杂的公共健康风险,进一步凸显了制定综合应对策略、强化地方适应措施的紧迫性。

Heat waves and air pollution extreme events are two major sources of health risks in the world, especially in China and India. High temperature is closely related to pollution and is usually driven by a continuous high-pressure system, under which strong solar radiation, low precipitation and low wind speed are conducive to the accumulation of heat and pollutants. There is increasing evidence that complex interactions and feedback mechanisms during heat waves and air pollution events may lead to the amplification of health effects, which far outweigh the simple superposition of single factors. However, the long-term prediction of such co-occurrence events in the future is still insufficient. Based on the advanced regional coupled meteorological-chemical model WRF-Chem and the bias-corrected CMIP6 multi-model ensemble, this study analyzes the future co-occurrence trends of heat waves and air pollution ( particulate matter and ozone ) extreme events in China and India at the end of this century. We compare the individual and co-occurrence of extreme events of heat waves and air pollution in China and India in the 2010s ( 2010-2014 ) and the 2100s ( 2096-2100 ) under the medium-emission scenario ( SSP245, including moderate climate mitigation measures ) and the high-emission scenario ( SSP585, emphasizing high-intensity fossil energy development ). We predict that by the end of the 21 st century, extreme heat wave events in China and India will increase significantly in terms of frequency, duration and intensity, resulting in a significant increase in population exposure levels. In the future, under the SSP245 and SSP585 scenarios, eastern China and India as a whole will show a significant warming trend. At the same time, the average duration and relative intensity of heat waves will also increase simultaneously, and will be more significant under high emission scenarios. In terms of air quality, major pollutant emissions in both countries are expected to decline by the end of the 21 st century, and the population-weighted average PM2.5 and ozone concentrations in both countries are expected to decrease significantly. Regarding the co-occurrence of extreme events of heat waves and air pollution, the current high-frequency areas are mainly located in eastern China and the Ganges Plain in India. The frequency of triple co-occurrence in India is about four times that of the North China Plain. In the future, under the SSP245 scenario, the frequency of heat waves and PM2.5 in the Ganges Plain will increase by more than 600 %, and the North China Plain will increase by nearly 440 %. Due to the significant reduction of NOx and VOCs emissions in China and the smaller reduction in India, the frequency of heat wave and ozone co-occurrence in India has increased, while that in China has decreased. Under the SSP585 scenario, the frequency of heat wave and ozone co-occurrence in the North China Plain increased from 6.8 days / year to 20.3 days / year, and the co-occurrence enhancement in India was more significant. The triple co-occurrence frequency increased by 382 % and 729 % in the Ganges Plain and Beijing, respectively. In summary, although air pollution control measures have significantly improved air quality, the co-occurrence trend of heat waves and air pollution extreme events will continue to intensify. This indicates that the continuous warming caused by global greenhouse gas accumulation will aggravate compound extreme events and bring more complex public health risks, further highlighting the urgency of formulating comprehensive response strategies and strengthening local adaptation measures.