不同行业减排对我国东部地区空气质量及大气温度的影响

Impact of Emission Reduction in Different Sectors on Air Quality and Atmospheric Temperature in Eastern China

未来我国减排政策更加关注对大气污染和大气增温的协同控制效果,但不同行业减排对空气质量改善和大气温度的影响不同.利用双向耦合的空气质量模型WRF-Chem,通过多组敏感性试验量化各部门人为源(工业源、居民源、交通源、火电厂和农业源)减排对2016年9月我国东部地区空气质量和大气温度的影响.结果表明,工业源、居民源、交通源、火电厂和农业源减排均能有效改善空气质量,PM_(2.5)浓度分别下降33.9%、9.6%、15.8%、10.8%和26.7%,但减弱的气溶胶-辐射相互作用使地表层获得更多能量,进而增加近地面气温0.04、0.03、0.01、0.03和0.09℃.在大气层顶,工业源、居民源、交通源和火电厂减排分别导致净辐射通量下降0.3、0.8、0.7和0.1 W·m^(-2);而农业源减排则引起大气层顶净辐射通量增加0.8 W·m^(-2).一方面,减排农业源导致散射性气溶胶下降进而引起净辐射增加;另一方面,减排农业源不会导致吸收性气溶胶(黑碳)下降,不能抵消散射性气溶胶下降引起的辐射增加.因此,减排农业源会导致大气层顶净辐射通量增加,同时近地面温度增加也最为显著.未来需要特别关注的是,尽管控制农业源排放会带来显著的空气质量改善,但同时会带来不利的显著增温后果.

China's emission reduction policy will focus on the synergistic control of air pollution and atmospheric warming in future.However,the impacts of emission reductions in different sectors on air quality and atmospheric temperature vary significantly.Using a two-way coupled air quality model(WRF-Chem),this study quantified the impacts of anthropogenic emission reductions from various sectors(industrial,residential,transportation,thermal power plants,and agricultural sectors)on air quality and atmospheric temperature in eastern China in September 2016.Emission reduction from industrial,residential,transportation,thermal power plant,and agricultural sources could effectively improve air quality,with PM_(2.5)reduction of 33.9%,9.6%,15.8%,10.8%,and 26.7%,respectively;however,the weakened aerosol-radiation interactions resulted in more energy at the surface,further increasing the near-surface air temperature by 0.04,0.03,0.01,0.03,and 0.09℃.At the top of the atmosphere,the net radiation flux decreased by 0.3,0.8,0.7,and 0.1 W·m^(-2)owing to the emission reduction from industrial,residential,traffic,and thermal power plant sectors,whereas the emission reduction from agricultural sources resulted in an increase in the net radiation flux of 0.8 W·m^(-2).On one hand,the emission reduction from agricultural sources led to a decrease in scattering aerosols and increase in the net radiation flux;contrastingly,it did not lead to a decrease in absorbing aerosols(black carbon),which could not offset the radiation increase caused by the decrease in scattering aerosols.Therefore,the emission reduction from agricultural sources led to the increase in net radiation flux at the top of the atmosphere and the most significant increase in near-surface temperature.It is noted that in the future,although emission reduction from agricultural sources will bring about significant air quality improvement,it will also consequently cause significant warming.