A series of emission reduction measures were conducted in Wuhan,Central China,to ensure good air quality during the 7th Military World Games(MWG)in October 2019.To better understand the implications for ozone(O_(3))po...A series of emission reduction measures were conducted in Wuhan,Central China,to ensure good air quality during the 7th Military World Games(MWG)in October 2019.To better understand the implications for ozone(O_(3))pollution control strategies,we applied integrated analysis approaches based on the de-weathered statistical model,parameterization methods,chemical box model,and positive matrix factorization model.During the MWG,concentrations of O_(3),NO_x,and volatile organic compound(VOCs),OFP(O_(3)formation potential),L_(OH)(OH radical loss rate)were 83μg/m^(3),43μg/m^(3),26 ppbv,188μg/m^(3),and 3.9 s^(-1),respectively,which were 26%,18%,3%,15%,and 13%lower than pre-MWG values and 6%,39%,30%,33%,and 50%lower than post-MWG values,respectively.After removing meteorological influence,O_(3)and its precursors during the MWG decreased largely compared with post-MWG values,and only O_(3),NO_(2),and oxygenated VOCs(OVOCs)declined compared with pre-MWG values,which revealed the emission reduction measures during the MWG played an important role for O_(3)decline.For six VOCs sources,the mass contributions of biomass burning and solvents usage during the MWG decreased largely compared with pre-MWG values.O_(3)production was sensitive to VOCs and the key species were aromatics,OVOCs,and alkenes,which originated mainly from solvents usage,biomass burning,industrial-related combustion,and vehicle exhaust.Decreasing O_(3)concentration during the strict control was mainly caused by OVOCs reduction due to biomass burning control.Generally,the O_(3)abatement strategies of Wuhan should be focused on the mitigation of high-reactivity VOCs.展开更多
Although peace was still the main theme last year, various kinds of uncertainties piled up quickly. Many of the traditional security issues were still there, while new threats like terrorism made things look even wors...Although peace was still the main theme last year, various kinds of uncertainties piled up quickly. Many of the traditional security issues were still there, while new threats like terrorism made things look even worse. Some major powers were busy to rethink their military strategies in the new century. Japan and Germany, the two "defeated countries" of World War Two, sent their troops abroad for the展开更多
The world military situation in 2016was complex,military strategies of major countries undergoing profound readjustment,contest in emerging fields increasing and a new round of populism cropping up worldwide which res...The world military situation in 2016was complex,military strategies of major countries undergoing profound readjustment,contest in emerging fields increasing and a new round of populism cropping up worldwide which resulted in'Black swan events'happening one after another,major-country contest and geopolitical conflicts piling up and local展开更多
基金supported by the National Key Research and Development Program of China (No.2022YFE0136100)the National Natural Science Foundation of China (No.41505133,41775162,and 42061130215)+1 种基金the Royal Society Newton Advanced Fellowship (No.NAFR1201354)the Beijing Major Science and Technology Project (No.Z211100004321006)。
文摘A series of emission reduction measures were conducted in Wuhan,Central China,to ensure good air quality during the 7th Military World Games(MWG)in October 2019.To better understand the implications for ozone(O_(3))pollution control strategies,we applied integrated analysis approaches based on the de-weathered statistical model,parameterization methods,chemical box model,and positive matrix factorization model.During the MWG,concentrations of O_(3),NO_x,and volatile organic compound(VOCs),OFP(O_(3)formation potential),L_(OH)(OH radical loss rate)were 83μg/m^(3),43μg/m^(3),26 ppbv,188μg/m^(3),and 3.9 s^(-1),respectively,which were 26%,18%,3%,15%,and 13%lower than pre-MWG values and 6%,39%,30%,33%,and 50%lower than post-MWG values,respectively.After removing meteorological influence,O_(3)and its precursors during the MWG decreased largely compared with post-MWG values,and only O_(3),NO_(2),and oxygenated VOCs(OVOCs)declined compared with pre-MWG values,which revealed the emission reduction measures during the MWG played an important role for O_(3)decline.For six VOCs sources,the mass contributions of biomass burning and solvents usage during the MWG decreased largely compared with pre-MWG values.O_(3)production was sensitive to VOCs and the key species were aromatics,OVOCs,and alkenes,which originated mainly from solvents usage,biomass burning,industrial-related combustion,and vehicle exhaust.Decreasing O_(3)concentration during the strict control was mainly caused by OVOCs reduction due to biomass burning control.Generally,the O_(3)abatement strategies of Wuhan should be focused on the mitigation of high-reactivity VOCs.
文摘Although peace was still the main theme last year, various kinds of uncertainties piled up quickly. Many of the traditional security issues were still there, while new threats like terrorism made things look even worse. Some major powers were busy to rethink their military strategies in the new century. Japan and Germany, the two "defeated countries" of World War Two, sent their troops abroad for the
文摘The world military situation in 2016was complex,military strategies of major countries undergoing profound readjustment,contest in emerging fields increasing and a new round of populism cropping up worldwide which resulted in'Black swan events'happening one after another,major-country contest and geopolitical conflicts piling up and local
