Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China,in contrast to the fact that an increase in emissions of non-methane hydrocarbons(NMHCs)has b...Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China,in contrast to the fact that an increase in emissions of non-methane hydrocarbons(NMHCs)has been reported.This study employed seven years continuous NMHCsmeasurements and the related activities data of Shanghai,a megacity in China,to explore evolution of emissions and effectiveness of air pollution control measures.The mixing ratio of NMHCs showed no statistical interannual changes,of which their compositions exhibited marked changes.This resulted in a decreasing trend of ozone formation potential by 3.8%/year(p<0.05,the same below),which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime.Observed alkanes,aromatics and acetylene changed by+3.7%/year,-5.9%/year and-7.4%/year,respectively,and alkenes showed no apparent trend.NMHCs sources were apportioned by a positive matrix factorization model.Accordingly,vehicular emissions(-5.9%/year)and petrochemical industry emissions(-7.1%/year)decreased significantly,but the decrease slowed down;significant reduction in solvent usage(-9.0%/year)appeared after 2010;however,emissions of natural gas(+12.6%/year)and fuel evaporation(with an increasing fraction)became more important.The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions,emphasizing the need for further validation in NMHCs emission inventory.Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions,which provided new insights into future air policies in polluted region.展开更多
In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility imp...In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility impairment were also studied. Our research indicates that the major components of PM2.5 in Shanghai are water-soluble inorganic ions and carbonaceous aerosol, accounting for about 60% and 30% respectively. Higher concentrations of sulfate (SO42-) and organic carbon (OC) in PM2.s occurred in fall and summer, while higher concentrations of nitrate (NO3-) were observed in winter and spring. The mass concentrations of Cl- and K+ were higher in winter. Moreover, NO3- increased significantly during PM2.s pollution episodes. The high values observed for the sulfate oxidizing rate (SOR), nitrate oxidizing rate (NOR) and secondary organic carbon (SOC) in OC indicate that photochemical reactions were quite active in Shanghai. The IMPROVE (Interagency Monitoring of Protected Visual Environments) formula was used in this study to investigate the contributions of individual PM2.5 chemical components to the light extinction efficient in Shanghai. Both NH4NO3 and (NH4)aSO4 had close relationships with visibility impairment in Shanghai. Our results show that the reduction of anthropogenic SO2, NOx and NH3 would have a significant effect on the improvement of air qualitv and visibility in Shanghai.展开更多
ATSI Model 3800 aerosol time-of-flight mass spectrometer(ATOFMS)was deployed for single-particle analysis in Shanghai during theWorld Exposition(EXPO),2010.Measurements on two extreme cases:polluted day(1st May)and cl...ATSI Model 3800 aerosol time-of-flight mass spectrometer(ATOFMS)was deployed for single-particle analysis in Shanghai during theWorld Exposition(EXPO),2010.Measurements on two extreme cases:polluted day(1st May)and clean day(25th September)were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols.Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods.The ART-2a neural network algorithm was applied to sort the collected particles.Seven major classes of particles were obtained:dust,sea salt,industrial,biomass burning,organic carbon(OC),elementary carbon(EC),and NH4-rich particles.Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation.The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories.Number fraction of biomass burning particles(43.3%)during polluted episode was much higher than that(21.6%)of clean time.Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically(13.3%).The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission.Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time.Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.展开更多
基金supported by the National Key Research and Development Program of China (No. 2018YFC0209800, 2017YFC1501405)the Shanghai Science and Technology Commission of the Shanghai Municipality (No. 20ZR1447800)the National Natural Science Foundation of China (No. 41775129)
文摘Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China,in contrast to the fact that an increase in emissions of non-methane hydrocarbons(NMHCs)has been reported.This study employed seven years continuous NMHCsmeasurements and the related activities data of Shanghai,a megacity in China,to explore evolution of emissions and effectiveness of air pollution control measures.The mixing ratio of NMHCs showed no statistical interannual changes,of which their compositions exhibited marked changes.This resulted in a decreasing trend of ozone formation potential by 3.8%/year(p<0.05,the same below),which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime.Observed alkanes,aromatics and acetylene changed by+3.7%/year,-5.9%/year and-7.4%/year,respectively,and alkenes showed no apparent trend.NMHCs sources were apportioned by a positive matrix factorization model.Accordingly,vehicular emissions(-5.9%/year)and petrochemical industry emissions(-7.1%/year)decreased significantly,but the decrease slowed down;significant reduction in solvent usage(-9.0%/year)appeared after 2010;however,emissions of natural gas(+12.6%/year)and fuel evaporation(with an increasing fraction)became more important.The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions,emphasizing the need for further validation in NMHCs emission inventory.Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions,which provided new insights into future air policies in polluted region.
基金supported by the “Chinese National Key Technology R&D Program” (No. 2014BAC22B03)the “Chinese National Non-profit Scientific Research Program” (No. 201409008)the Key Research Project from the Science and Technology Commission of Shanghai Municipality Fund Project (No. 14DZ1202905)
文摘In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility impairment were also studied. Our research indicates that the major components of PM2.5 in Shanghai are water-soluble inorganic ions and carbonaceous aerosol, accounting for about 60% and 30% respectively. Higher concentrations of sulfate (SO42-) and organic carbon (OC) in PM2.s occurred in fall and summer, while higher concentrations of nitrate (NO3-) were observed in winter and spring. The mass concentrations of Cl- and K+ were higher in winter. Moreover, NO3- increased significantly during PM2.s pollution episodes. The high values observed for the sulfate oxidizing rate (SOR), nitrate oxidizing rate (NOR) and secondary organic carbon (SOC) in OC indicate that photochemical reactions were quite active in Shanghai. The IMPROVE (Interagency Monitoring of Protected Visual Environments) formula was used in this study to investigate the contributions of individual PM2.5 chemical components to the light extinction efficient in Shanghai. Both NH4NO3 and (NH4)aSO4 had close relationships with visibility impairment in Shanghai. Our results show that the reduction of anthropogenic SO2, NOx and NH3 would have a significant effect on the improvement of air qualitv and visibility in Shanghai.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20937001 and 40875074)Science&Technology Commission of Shanghai Municipality(10JC1402000).
文摘ATSI Model 3800 aerosol time-of-flight mass spectrometer(ATOFMS)was deployed for single-particle analysis in Shanghai during theWorld Exposition(EXPO),2010.Measurements on two extreme cases:polluted day(1st May)and clean day(25th September)were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols.Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods.The ART-2a neural network algorithm was applied to sort the collected particles.Seven major classes of particles were obtained:dust,sea salt,industrial,biomass burning,organic carbon(OC),elementary carbon(EC),and NH4-rich particles.Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation.The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories.Number fraction of biomass burning particles(43.3%)during polluted episode was much higher than that(21.6%)of clean time.Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically(13.3%).The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission.Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time.Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.