Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions(CAMx),has been used to simulate a hea...Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions(CAMx),has been used to simulate a heavy O3 pollution episode in Beijing during June 26―July 2,2000.Ozone Source Apportionment Technology(OSAT) and Geographic Ozone Assessment Technology(GOAT) were applied to quantify the contributions of the precursor emissions from different regions to O3 concentrations in Beijing,to identify the relative importance of different ways by which regional sources affected the O3 levels in Beijing urban areas,and to investigate the sensitivity of O3 formation to the precursors during the episode.The O3 pollution in Beijing showed a significant spatial distribution with strong regional contribution.The results suggested that the plume originating from Beijing urban areas greatly affected the O3 concentrations at the Dingling site,accounting for 55% of elevated O3 there,while O3 pollution in the Beijing urban areas resulted from both local emissions and those from Tianjin and the south of Hebei Province.Transport of O3 was responsible for about 70% of the regional O3 contribution to Beijing urban areas,while transport of O3 precursors accounted for the remainder.The formation of O3 was limited by volatile organic compounds(VOCs) in the urban areas of Beijing,while being more sensitive to NOx levels in the suburban and more remote areas.Therefore,it is necessary to consider a large number of factors,including impacts of emissions from different regions,the two modes of regional contribution as well as the sensitivity of O3 formation to precursors,in the design of emissions control strategies for O3 reduction in Beijing.展开更多
Based on the official statistics,locally measured emission factors,and the vehicular emission factor model most suitable for China,we developed a black carbon(BC)emission inventory for 2008 in China and at a spatial r...Based on the official statistics,locally measured emission factors,and the vehicular emission factor model most suitable for China,we developed a black carbon(BC)emission inventory for 2008 in China and at a spatial resolution of 0.5°×0.5°.In 2008,the total BC emissions in China were 1604.94 Gg.Industry and the residential sector were the dominant contributors,estimated at 695.03Gg and 636.02 Gg of BC,respectively.Together,these two source types contributed 82.9% of the total emissions.Emissions from transportation were 194.63 Gg,accounting for 12.1% of the total.Since emission contributions from different sectors showed significant spatial diversity among the 31 administrative districts,we divided the districts into four categories:industry contribution district,residential contribution district,industry and residential contribution district,and transportation contribution district.As for energy consumption,coal and biofuel contributed 51.0% and 32.2%,respectively,of the total emissions.Spatially,BC emissions in China were unevenly distributed,higher in the east and lower in the west,corresponding to regional economic development and rural population density.High emission districts,covering 5.7% of the territory,contributed 41.2% of the total emissions.Shanxi,Hebei,Shandong,Henan,and Sichuan were the largest contributors to national BC emissions.展开更多
An intensive field campaign was conducted in Chongqing during the summer of 2015 to explore the formation mechanisms of ozone pollution. The sources of ozone, the local production rates, and the controlling factors, a...An intensive field campaign was conducted in Chongqing during the summer of 2015 to explore the formation mechanisms of ozone pollution. The sources of ozone, the local production rates, and the controlling factors, as well as key species of volatile organic compounds(VOCs), were quantified by integrating a local ozone budget analysis, calculations of the relative incremental reactivity, and an empirical kinetic model approach. It was found that the potential for rapid local ozone formation exists in Chongqing. During ozone pollution episodes, the ozone production rates were found to be high at the upwind station Nan Quan, the urban station Chao Zhan, and the downwind station Jin-Yun Shan. The average local ozone production rate was 30×10^(-9) V/V h^(-1) and the daily integration of the produced ozone was greater than 180×10^(-9) V/V. High ozone concentrations were associated with urban and downwind air masses. At most sites, the local ozone production was VOC-limited and the key species were aromatics and alkene, which originated mainly from vehicles and solvent usage. In addition, the air masses at the northwestern rural sites were NO_x-limited and the local ozone production rates were significantly higher during the pollution episodes due to the increased NOx concentrations. In summary, the ozone abatement strategies of Chongqing should be focused on the mitigation of VOCs. Nevertheless, a reduction in NO_x is also beneficial for reducing the regional ozone peak values in Chongqing and the surrounding areas.展开更多
基金Supported by the National High Technology Research and Development Program of China (Grant No. 2006AA06A306)the National Basic Research Program of China (Grant No. 2005CB422204)
文摘Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions(CAMx),has been used to simulate a heavy O3 pollution episode in Beijing during June 26―July 2,2000.Ozone Source Apportionment Technology(OSAT) and Geographic Ozone Assessment Technology(GOAT) were applied to quantify the contributions of the precursor emissions from different regions to O3 concentrations in Beijing,to identify the relative importance of different ways by which regional sources affected the O3 levels in Beijing urban areas,and to investigate the sensitivity of O3 formation to the precursors during the episode.The O3 pollution in Beijing showed a significant spatial distribution with strong regional contribution.The results suggested that the plume originating from Beijing urban areas greatly affected the O3 concentrations at the Dingling site,accounting for 55% of elevated O3 there,while O3 pollution in the Beijing urban areas resulted from both local emissions and those from Tianjin and the south of Hebei Province.Transport of O3 was responsible for about 70% of the regional O3 contribution to Beijing urban areas,while transport of O3 precursors accounted for the remainder.The formation of O3 was limited by volatile organic compounds(VOCs) in the urban areas of Beijing,while being more sensitive to NOx levels in the suburban and more remote areas.Therefore,it is necessary to consider a large number of factors,including impacts of emissions from different regions,the two modes of regional contribution as well as the sensitivity of O3 formation to precursors,in the design of emissions control strategies for O3 reduction in Beijing.
基金supported by the National Basic Research Program of China(2010CB955608)
文摘Based on the official statistics,locally measured emission factors,and the vehicular emission factor model most suitable for China,we developed a black carbon(BC)emission inventory for 2008 in China and at a spatial resolution of 0.5°×0.5°.In 2008,the total BC emissions in China were 1604.94 Gg.Industry and the residential sector were the dominant contributors,estimated at 695.03Gg and 636.02 Gg of BC,respectively.Together,these two source types contributed 82.9% of the total emissions.Emissions from transportation were 194.63 Gg,accounting for 12.1% of the total.Since emission contributions from different sectors showed significant spatial diversity among the 31 administrative districts,we divided the districts into four categories:industry contribution district,residential contribution district,industry and residential contribution district,and transportation contribution district.As for energy consumption,coal and biofuel contributed 51.0% and 32.2%,respectively,of the total emissions.Spatially,BC emissions in China were unevenly distributed,higher in the east and lower in the west,corresponding to regional economic development and rural population density.High emission districts,covering 5.7% of the territory,contributed 41.2% of the total emissions.Shanxi,Hebei,Shandong,Henan,and Sichuan were the largest contributors to national BC emissions.
基金supportted by the Environmental Public Welfare Industry in China (Grant No. 201509001)the National Science and Technology Supporting Plan (Grant No. 2014BAC21B01)the Chongqing Project of the Ozone Source Appointment
文摘An intensive field campaign was conducted in Chongqing during the summer of 2015 to explore the formation mechanisms of ozone pollution. The sources of ozone, the local production rates, and the controlling factors, as well as key species of volatile organic compounds(VOCs), were quantified by integrating a local ozone budget analysis, calculations of the relative incremental reactivity, and an empirical kinetic model approach. It was found that the potential for rapid local ozone formation exists in Chongqing. During ozone pollution episodes, the ozone production rates were found to be high at the upwind station Nan Quan, the urban station Chao Zhan, and the downwind station Jin-Yun Shan. The average local ozone production rate was 30×10^(-9) V/V h^(-1) and the daily integration of the produced ozone was greater than 180×10^(-9) V/V. High ozone concentrations were associated with urban and downwind air masses. At most sites, the local ozone production was VOC-limited and the key species were aromatics and alkene, which originated mainly from vehicles and solvent usage. In addition, the air masses at the northwestern rural sites were NO_x-limited and the local ozone production rates were significantly higher during the pollution episodes due to the increased NOx concentrations. In summary, the ozone abatement strategies of Chongqing should be focused on the mitigation of VOCs. Nevertheless, a reduction in NO_x is also beneficial for reducing the regional ozone peak values in Chongqing and the surrounding areas.
