The field observation of 54 non-methane hydrocarbon compounds(NMHCs)was conducted from September 1 to October 20 in 2020 during autumn in Haidian District,Beijing.The mean concentration of total NMHCs was 29.81±1...The field observation of 54 non-methane hydrocarbon compounds(NMHCs)was conducted from September 1 to October 20 in 2020 during autumn in Haidian District,Beijing.The mean concentration of total NMHCs was 29.81±11.39 ppbv during this period,and alkanes were the major components.There were typical festival effects of NMHCs with lower concentration during the National Day.Alkenes and aromatics were the dominant groups in ozone formation potential(OFP)and OH radical loss rate(L_(OH)).The positive matrix factorization(PMF)running results revealed that vehicular exhaust became the biggest source in urban areas,followed by liquefied petroleum gas(LPG)usage,solvent usage,and fuel evaporation.The box model coupled with master chemical mechanism(MCM)was applied to study the impacts of different NMHCs sources on ozone(O_(3))formation in an O_(3)episode.The simulation results indicated that reducing NMHCs concentration could effectively suppress O_(3)formation.Moreover,reducing traffic-related emissions of NMHCs was an effective way to control O_(3)pollution at an urban site in Beijing.展开更多
The concentration variation of C3-C11 non-methane hydrocarbons(NMHCs)collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ioniza...The concentration variation of C3-C11 non-methane hydrocarbons(NMHCs)collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ionization detector(GC-FID)system.The per-centage loss of each NMHC in the polyvinyl fluoride(PVF)bags was less than 5%during a 7-hr storage period;significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags.The thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95%at 300℃,and the loss of NMHCs in the adsorption tubes during 20-days storage at 4℃was less than 8%.The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve SⅢabsorbents was less than 40%at 300℃,and pyrolysis of the absorbents at 330℃interfered significantly with the measurements of some alkenes.The loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at-90℃in the presence of O3 for the online NMHC measurements,and negligible for enrichment us-ing adsorption tubes at 25℃.Although O_(3)scrubbers have been widely used to eliminate the influence of O_(3)on NMHC measurements,the loss of NMHCs with carbon numbers greater than 8 was more than 10%.Therefore,PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.展开更多
The concentrations of 56 hydrocarbons from C2 to C12 were measured simultaneously in the southbound bore,the northbound bore and the exhaust air shafts of the Hsuehshan tunnel near Yilan,Taiwan for 12 days during 2007...The concentrations of 56 hydrocarbons from C2 to C12 were measured simultaneously in the southbound bore,the northbound bore and the exhaust air shafts of the Hsuehshan tunnel near Yilan,Taiwan for 12 days during 2007 and 2008.A total of 60 integrated air samples were collected using stainless steel canisters and analyzed using GC/FID and GC/MS.The five most abundant species in all samples were ethylene,acetylene,isopentane,propylene and toluene.The exit/entrance ratios of total non-methane hydrocarbons（NMHC） concentration were 7.8 and 4.8 for the southbound and northbound bores,respectively.Furthermore,the exhaust from the vertical shafts a？ects air quality in the neighborhood.The most abundant species of emission rate（ER） was toluene（21.93-42.89 mg/sec）,followed by isopentane,ethylene,propylene and 1-butene,with ER ranging from 2.50 to 9.31 mg/sec.The species in the three exhaust air shafts showed that the reactivities of these emissions are similar to those of vehicle emissions.Notably,the control of emissions in the vertical shafts of the vehicle tunnel will be important in the future.展开更多
BACKGROUND Type 1 diabetes originates from gene-environment interactions,with increasing incidence over time.AIM To identify correlates of childhood type 1 diabetes in European countries using an ecological approach.S...BACKGROUND Type 1 diabetes originates from gene-environment interactions,with increasing incidence over time.AIM To identify correlates of childhood type 1 diabetes in European countries using an ecological approach.Several environmental variables potentially influencing the onset of type 1 diabetes have been previously evaluated.However,the relationships between epidemiologic data and exposure to toxic airborne molecules are scarcely studied.METHODS We employed an ecological model to explore,in a wide time period(1990-2018),associations between type 1 diabetes incidence in 19 European countries(systematic literature review)and the nationwide production of five widely diffused air pollutants:particulate matter<10μm(PM10),nitrogen oxides(NO),non-methane volatile organic compounds(VOCs),sulphur oxide(SO2),and ammonia.RESULTS Data confirm a raising incidence of type 1 diabetes in 18 out of 19 explored countries.The average difference(last vs first report,all countries)was+6.9×100000/year,with values ranging from-1.4(Germany)to+16.6(Sweden)per 100000/year.Although the overall production of pollutants decreased progressively from 1990 to 2018,type 1 diabetes incidence was positively associated with the nationwide emissions of PM10,VOCs,and NO but not with those of SO2 and ammonia.Type 1 diabetes incidence was significantly higher in countries with high emissions than in those with low emissions of PM10(27.5±2.4 vs 14.6±2.4×100000 residents,respectively),VOCs(24.5±4.4 vs 13.2±1.7×100000 residents,respectively),and NO(26.6±3 vs 13.4±2.4×100000 residents,respectively),but not of SO2 or ammonia.CONCLUSION Evidence justify further studies to explore better links between long-term air quality and type 1 diabetes onset at the individual level,which should include exposures during pregnancy.In this respect,type 1 diabetes could be,at least in part,a preventable condition.Thus,primary prevention policies acting through a marked abatement of pollutant emissions might attenuate future type 1 diabetes incidence throughout Europe.展开更多
The capture of trace amounts of non-methane hydrocarbons(NMHCs)from air due to the toxicity of volatile organic compounds is a significant challenge.A total of 31399 hydrophobic metal–organic frameworks(MOFs)were fir...The capture of trace amounts of non-methane hydrocarbons(NMHCs)from air due to the toxicity of volatile organic compounds is a significant challenge.A total of 31399 hydrophobic metal–organic frameworks(MOFs)were first screened from 137953 hypothetical MOFs using high-throughput computational screening(HTCS),and their performance indices(adsorption capacity and selectivity)for the adsorption of NMHCs(C_(3)–C_(6))were obtained by molecular simulations.The discovery of a“second peak”near twice the kinetic diameter of the corresponding NMHC provided more choices for excellent MOFs that adsorb NMHCs.Four machine learning(ML)classification and regression algorithms predicted the performance of MOFs,and the relative importance values of the six descriptors were determined.The combination of the Random Forests algorithm and Molecular ACCess Systems molecular fingerprint(MF)had an excellent predictive ability for MOFs.According to the performance,the fingerprint commonalities of the 100 top-performing MOFs were counted,and the excellent bits(EBs)that could promote the performance were defined.Finally,new substructures containing all of the EBs were designed for each NMHC to build a new MOF database.This work combined the HTCS,ML,and MF to provide a detailed insight into the design of efficient MOFs for adsorbing NMHCs.展开更多
In order to study the variation characteristics of concentration of the atmospheric non-methane hydrocarbons （NMHCs） in background area of China, the atmospheric concentrations of NMHCs were measured at Lin＇an （LA...In order to study the variation characteristics of concentration of the atmospheric non-methane hydrocarbons （NMHCs） in background area of China, the atmospheric concentrations of NMHCs were measured at Lin＇an （LA） regional GAW （Global Atmosphere Watch） Station （30°25＇N, 119°44＇E; 132.0 m ASL） and Shangdianzi （SDZ） regional GAW Station （40°19＇N, 117°07＇E; 286.5 m ASL） with the sorbent sorption/thermal desorption/gas chromatographic method. Totally 145 samples were collected during the period of October 2003 and July 2004. Among the 52 NMHC species of C2-C10 detected there were 26 alkanes, 17 alkenes, and 9 aromatics. The average concentrations of total NMHCs （TNMHCs） at LA and SDZ were （238.5±126.0） ×10^-9C and （278.7±185.5）×10^-9C, respectively. The results showed the ambient concentrations of TNMHCs at LA regional GAW Station increased notably over the last decade. The compositions of NMHCs at SDZ and LA were relatively similar. The proportions of alkanes, alkenes, and aromatics for SDZ and LA were in ranges of （27.3±4.0）%, （10.3±3.5）%, and （62.5±4.8）%, respectively, with features of vehicle exhaust emissions. The concentrations of NMHCs at the two sites showed obvious diurnal and seasonal variations. The TNMHC concentrations in October-November were high at the two sites, and relatively low in April and July. The diurnal variation patterns at the sites were different. The high TNMHC concentrations at SDZ normally appeared in evening and night, but appeared in morning at LA. The TNMHCs concentrations at the two sites were significantly influenced by the meteorological condition. The high TNMHC concentration associated with the local wind from the urban areas or traffic in upper reaches.展开更多
基金supported by the National Key Research and Development Program of China(No.2017YFC0210001)National Natural Science Foundation of China(Nos.42022039,21671089)+2 种基金the Scientific Research Fund of Liaoning Provincial Education Department(No.L2020002)Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202011)the Youth Innovation Promotion Association CAS(No.2017042)
文摘The field observation of 54 non-methane hydrocarbon compounds(NMHCs)was conducted from September 1 to October 20 in 2020 during autumn in Haidian District,Beijing.The mean concentration of total NMHCs was 29.81±11.39 ppbv during this period,and alkanes were the major components.There were typical festival effects of NMHCs with lower concentration during the National Day.Alkenes and aromatics were the dominant groups in ozone formation potential(OFP)and OH radical loss rate(L_(OH)).The positive matrix factorization(PMF)running results revealed that vehicular exhaust became the biggest source in urban areas,followed by liquefied petroleum gas(LPG)usage,solvent usage,and fuel evaporation.The box model coupled with master chemical mechanism(MCM)was applied to study the impacts of different NMHCs sources on ozone(O_(3))formation in an O_(3)episode.The simulation results indicated that reducing NMHCs concentration could effectively suppress O_(3)formation.Moreover,reducing traffic-related emissions of NMHCs was an effective way to control O_(3)pollution at an urban site in Beijing.
基金This work was supported by the National Natural Science Foundation of China(Nos.21976190,21707151,22076202,41727805,41975164,21876186,41931287,and 41905109).
文摘The concentration variation of C3-C11 non-methane hydrocarbons(NMHCs)collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ionization detector(GC-FID)system.The per-centage loss of each NMHC in the polyvinyl fluoride(PVF)bags was less than 5%during a 7-hr storage period;significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags.The thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95%at 300℃,and the loss of NMHCs in the adsorption tubes during 20-days storage at 4℃was less than 8%.The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve SⅢabsorbents was less than 40%at 300℃,and pyrolysis of the absorbents at 330℃interfered significantly with the measurements of some alkenes.The loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at-90℃in the presence of O3 for the online NMHC measurements,and negligible for enrichment us-ing adsorption tubes at 25℃.Although O_(3)scrubbers have been widely used to eliminate the influence of O_(3)on NMHC measurements,the loss of NMHCs with carbon numbers greater than 8 was more than 10%.Therefore,PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.
基金supported by the Science Council in Taiwan supported this work under the grant NSC 96-2221-E-166-005-MY2 and CTU 99-P-12
文摘The concentrations of 56 hydrocarbons from C2 to C12 were measured simultaneously in the southbound bore,the northbound bore and the exhaust air shafts of the Hsuehshan tunnel near Yilan,Taiwan for 12 days during 2007 and 2008.A total of 60 integrated air samples were collected using stainless steel canisters and analyzed using GC/FID and GC/MS.The five most abundant species in all samples were ethylene,acetylene,isopentane,propylene and toluene.The exit/entrance ratios of total non-methane hydrocarbons（NMHC） concentration were 7.8 and 4.8 for the southbound and northbound bores,respectively.Furthermore,the exhaust from the vertical shafts a？ects air quality in the neighborhood.The most abundant species of emission rate（ER） was toluene（21.93-42.89 mg/sec）,followed by isopentane,ethylene,propylene and 1-butene,with ER ranging from 2.50 to 9.31 mg/sec.The species in the three exhaust air shafts showed that the reactivities of these emissions are similar to those of vehicle emissions.Notably,the control of emissions in the vertical shafts of the vehicle tunnel will be important in the future.
文摘BACKGROUND Type 1 diabetes originates from gene-environment interactions,with increasing incidence over time.AIM To identify correlates of childhood type 1 diabetes in European countries using an ecological approach.Several environmental variables potentially influencing the onset of type 1 diabetes have been previously evaluated.However,the relationships between epidemiologic data and exposure to toxic airborne molecules are scarcely studied.METHODS We employed an ecological model to explore,in a wide time period(1990-2018),associations between type 1 diabetes incidence in 19 European countries(systematic literature review)and the nationwide production of five widely diffused air pollutants:particulate matter<10μm(PM10),nitrogen oxides(NO),non-methane volatile organic compounds(VOCs),sulphur oxide(SO2),and ammonia.RESULTS Data confirm a raising incidence of type 1 diabetes in 18 out of 19 explored countries.The average difference(last vs first report,all countries)was+6.9×100000/year,with values ranging from-1.4(Germany)to+16.6(Sweden)per 100000/year.Although the overall production of pollutants decreased progressively from 1990 to 2018,type 1 diabetes incidence was positively associated with the nationwide emissions of PM10,VOCs,and NO but not with those of SO2 and ammonia.Type 1 diabetes incidence was significantly higher in countries with high emissions than in those with low emissions of PM10(27.5±2.4 vs 14.6±2.4×100000 residents,respectively),VOCs(24.5±4.4 vs 13.2±1.7×100000 residents,respectively),and NO(26.6±3 vs 13.4±2.4×100000 residents,respectively),but not of SO2 or ammonia.CONCLUSION Evidence justify further studies to explore better links between long-term air quality and type 1 diabetes onset at the individual level,which should include exposures during pregnancy.In this respect,type 1 diabetes could be,at least in part,a preventable condition.Thus,primary prevention policies acting through a marked abatement of pollutant emissions might attenuate future type 1 diabetes incidence throughout Europe.
基金National Natural Science Foundation of China(Nos.21978058 and 21676094)the Pearl River Talent Recruitment Program,China(No.2019QN01L255)+1 种基金the Natural Science Foundation of Guangdong Province,China(No.2020A1515010800)the Guangzhou Municipal Science and Technology Project,China(No.202102020875)for the financial support.
文摘The capture of trace amounts of non-methane hydrocarbons(NMHCs)from air due to the toxicity of volatile organic compounds is a significant challenge.A total of 31399 hydrophobic metal–organic frameworks(MOFs)were first screened from 137953 hypothetical MOFs using high-throughput computational screening(HTCS),and their performance indices(adsorption capacity and selectivity)for the adsorption of NMHCs(C_(3)–C_(6))were obtained by molecular simulations.The discovery of a“second peak”near twice the kinetic diameter of the corresponding NMHC provided more choices for excellent MOFs that adsorb NMHCs.Four machine learning(ML)classification and regression algorithms predicted the performance of MOFs,and the relative importance values of the six descriptors were determined.The combination of the Random Forests algorithm and Molecular ACCess Systems molecular fingerprint(MF)had an excellent predictive ability for MOFs.According to the performance,the fingerprint commonalities of the 100 top-performing MOFs were counted,and the excellent bits(EBs)that could promote the performance were defined.Finally,new substructures containing all of the EBs were designed for each NMHC to build a new MOF database.This work combined the HTCS,ML,and MF to provide a detailed insight into the design of efficient MOFs for adsorbing NMHCs.
基金Ministry of Science and Technology(Project No.2001DIA10009).
文摘In order to study the variation characteristics of concentration of the atmospheric non-methane hydrocarbons （NMHCs） in background area of China, the atmospheric concentrations of NMHCs were measured at Lin＇an （LA） regional GAW （Global Atmosphere Watch） Station （30°25＇N, 119°44＇E; 132.0 m ASL） and Shangdianzi （SDZ） regional GAW Station （40°19＇N, 117°07＇E; 286.5 m ASL） with the sorbent sorption/thermal desorption/gas chromatographic method. Totally 145 samples were collected during the period of October 2003 and July 2004. Among the 52 NMHC species of C2-C10 detected there were 26 alkanes, 17 alkenes, and 9 aromatics. The average concentrations of total NMHCs （TNMHCs） at LA and SDZ were （238.5±126.0） ×10^-9C and （278.7±185.5）×10^-9C, respectively. The results showed the ambient concentrations of TNMHCs at LA regional GAW Station increased notably over the last decade. The compositions of NMHCs at SDZ and LA were relatively similar. The proportions of alkanes, alkenes, and aromatics for SDZ and LA were in ranges of （27.3±4.0）%, （10.3±3.5）%, and （62.5±4.8）%, respectively, with features of vehicle exhaust emissions. The concentrations of NMHCs at the two sites showed obvious diurnal and seasonal variations. The TNMHC concentrations in October-November were high at the two sites, and relatively low in April and July. The diurnal variation patterns at the sites were different. The high TNMHC concentrations at SDZ normally appeared in evening and night, but appeared in morning at LA. The TNMHCs concentrations at the two sites were significantly influenced by the meteorological condition. The high TNMHC concentration associated with the local wind from the urban areas or traffic in upper reaches.
