The complex air pollution driven by both Ozone(O_(3))and fine particulate matter(PM2.5)sig nificantly influences the air quality in the Sichuan Basin(SCB).Understanding the O_(3)for mation during autumn and winter is ...The complex air pollution driven by both Ozone(O_(3))and fine particulate matter(PM2.5)sig nificantly influences the air quality in the Sichuan Basin(SCB).Understanding the O_(3)for mation during autumn and winter is necessary to understand the atmospheric oxidative capacity.Therefore,continuous in-site field observations were carried out during the late summer,early autumn and winter of 2020 in a rural area of Chongqing.The total volatile organic compounds(VOCs)concentration reported by a Proton-Transfer-Reaction Time-of Flight Mass Spectrometry(PTR-ToF-MS)were 13.66±9.75 ppb,5.50±2.64 ppb,and 9.41±5.11 ppb in late summer,early autumn and winter,respectively.The anthropogenic VOCs(AVOCs)and biogenic VOCs(BVOCs)were 8.48±7.92 ppb and 5.18±2.99 ppb in late sum mer,3.31±1.89 ppb and 2.19±0.93 ppb in autumn,and 6.22±3.99 ppb and 3.20±1.27ppb in winter.A zero-dimensional atmospheric box model was employed to investigate the sensitivity of O_(3)-precursors by relative incremental reactivity(RIR).The RIR values of AV OCs,BVOCs,carbon monoxide(CO),and nitrogen oxides(NOx)were 0.31,0.71,0.09,and-0.36 for late summer,0.24,0.59,0.22,and-0.38 for early autumn,and 0.30,0.64,0.33 and-0.70 for winter,and the results showed that the O_(3)formation of sampling area was in the VOC-limited region,and O_(3)was most sensitive to BVOCs(with highest RIR values,>0.6)This study can be helpful in understanding O_(3)formation and interpreting the secondary formation of aerosols in the winter.展开更多
含氧挥发性有机物(OVOCs)在光化学烟雾形成过程中起到重要作用,其分析技术在近些年才有突破性发展.为了解深圳大气中含氧挥发性有机物和NMHCs的组成和浓度的演变规律与来源特征,2011年夏季在深圳利用先进的质子转移反应质谱技术对①生...含氧挥发性有机物(OVOCs)在光化学烟雾形成过程中起到重要作用,其分析技术在近些年才有突破性发展.为了解深圳大气中含氧挥发性有机物和NMHCs的组成和浓度的演变规律与来源特征,2011年夏季在深圳利用先进的质子转移反应质谱技术对①生物质燃烧示踪物、②生物源排放挥发性有机物、③芳香烃类以及④含氧挥发性有机物等4类VOCs进行了为期4个月的观测.结果显示,深圳OVOCs和NMHCs浓度水平普遍高于国外,且本地甲苯、甲醇和异戊二烯有较强排放,它们的浓度分别为(3.86±5.85)、(16.06±13.88)和(0.75±1.12)ppbv(parts per billion by volume:10-9),主要受本地的溶剂使用挥发以及夏季高温高日照的影响;不同类VOCs有不同的月际变化,但大部分VOCs浓度5月份最高,6月份最低,分析表明这是气象条件和排放源源强变化的综合作用结果;通过研究OVOCs的日变化曲线发现OVOCs不仅来源于一次源的排放,还源于NMHCs的二次转化,其中甲醇和丙酮可能还源于生物质燃烧,乙醛和MEK还受生物源排放的影响;最后结合反向轨迹发现深圳夏季源于洋面的气团对苯乙烯和C9芳香烃的传输作用较大,源于内陆的气团对MEK、乙醛和甲苯的传输作用较大,而甲醇、丙酮、苯等主要受本地源排放的控制.展开更多
利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/...利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/mol,TATP与H3O+可发生质子转移反应.在自行研制的质子转移反应质谱(Proton transfer reaction mass spectrometry,PTR-MS)装置上,研究了TATP与H3O+反应生成的特征离子.当漂移管中E/N=1.4×10-15V.cm2时,在荷质比m/z=91,75,74,59,43等处观察到了产物离子.降低E/N至0.5×10-15V.cm2后,在m/z=223处观察到了质子化产物离子([TATP+H]+),验证了计算结果;结合[TATP+H]+的构型,分析了TATP质子转移反应产物离子可能的归属及其形成过程.结合PTR-MS漂移管内E/N的改变引起m/z=223,91,43等离子的变化特征,可实现TATP的准确识别和快速定量检测,检测下限达到5.0×10-10mol/L(±50%).展开更多
基金supported by the National Natural Science Foundation of China(No.42075109)the National Key Research and Development Program of China(No.2018YFC0214001)。
文摘The complex air pollution driven by both Ozone(O_(3))and fine particulate matter(PM2.5)sig nificantly influences the air quality in the Sichuan Basin(SCB).Understanding the O_(3)for mation during autumn and winter is necessary to understand the atmospheric oxidative capacity.Therefore,continuous in-site field observations were carried out during the late summer,early autumn and winter of 2020 in a rural area of Chongqing.The total volatile organic compounds(VOCs)concentration reported by a Proton-Transfer-Reaction Time-of Flight Mass Spectrometry(PTR-ToF-MS)were 13.66±9.75 ppb,5.50±2.64 ppb,and 9.41±5.11 ppb in late summer,early autumn and winter,respectively.The anthropogenic VOCs(AVOCs)and biogenic VOCs(BVOCs)were 8.48±7.92 ppb and 5.18±2.99 ppb in late sum mer,3.31±1.89 ppb and 2.19±0.93 ppb in autumn,and 6.22±3.99 ppb and 3.20±1.27ppb in winter.A zero-dimensional atmospheric box model was employed to investigate the sensitivity of O_(3)-precursors by relative incremental reactivity(RIR).The RIR values of AV OCs,BVOCs,carbon monoxide(CO),and nitrogen oxides(NOx)were 0.31,0.71,0.09,and-0.36 for late summer,0.24,0.59,0.22,and-0.38 for early autumn,and 0.30,0.64,0.33 and-0.70 for winter,and the results showed that the O_(3)formation of sampling area was in the VOC-limited region,and O_(3)was most sensitive to BVOCs(with highest RIR values,>0.6)This study can be helpful in understanding O_(3)formation and interpreting the secondary formation of aerosols in the winter.
文摘含氧挥发性有机物(OVOCs)在光化学烟雾形成过程中起到重要作用,其分析技术在近些年才有突破性发展.为了解深圳大气中含氧挥发性有机物和NMHCs的组成和浓度的演变规律与来源特征,2011年夏季在深圳利用先进的质子转移反应质谱技术对①生物质燃烧示踪物、②生物源排放挥发性有机物、③芳香烃类以及④含氧挥发性有机物等4类VOCs进行了为期4个月的观测.结果显示,深圳OVOCs和NMHCs浓度水平普遍高于国外,且本地甲苯、甲醇和异戊二烯有较强排放,它们的浓度分别为(3.86±5.85)、(16.06±13.88)和(0.75±1.12)ppbv(parts per billion by volume:10-9),主要受本地的溶剂使用挥发以及夏季高温高日照的影响;不同类VOCs有不同的月际变化,但大部分VOCs浓度5月份最高,6月份最低,分析表明这是气象条件和排放源源强变化的综合作用结果;通过研究OVOCs的日变化曲线发现OVOCs不仅来源于一次源的排放,还源于NMHCs的二次转化,其中甲醇和丙酮可能还源于生物质燃烧,乙醛和MEK还受生物源排放的影响;最后结合反向轨迹发现深圳夏季源于洋面的气团对苯乙烯和C9芳香烃的传输作用较大,源于内陆的气团对MEK、乙醛和甲苯的传输作用较大,而甲醇、丙酮、苯等主要受本地源排放的控制.
文摘利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/mol,TATP与H3O+可发生质子转移反应.在自行研制的质子转移反应质谱(Proton transfer reaction mass spectrometry,PTR-MS)装置上,研究了TATP与H3O+反应生成的特征离子.当漂移管中E/N=1.4×10-15V.cm2时,在荷质比m/z=91,75,74,59,43等处观察到了产物离子.降低E/N至0.5×10-15V.cm2后,在m/z=223处观察到了质子化产物离子([TATP+H]+),验证了计算结果;结合[TATP+H]+的构型,分析了TATP质子转移反应产物离子可能的归属及其形成过程.结合PTR-MS漂移管内E/N的改变引起m/z=223,91,43等离子的变化特征,可实现TATP的准确识别和快速定量检测,检测下限达到5.0×10-10mol/L(±50%).
