Methylglyoxal(CH3COCHO,MG),which is one of the most abundant α-dicarbonyl compounds in the atmosphere,has been reported as a major source of secondary organic aerosol(SOA).In this work,the reaction of MG with hydroxy...Methylglyoxal(CH3COCHO,MG),which is one of the most abundant α-dicarbonyl compounds in the atmosphere,has been reported as a major source of secondary organic aerosol(SOA).In this work,the reaction of MG with hydroxyl radicals was studied in a 500 L smog chamber at(293±3)K,atmospheric pressure,(18±2)%relative humidity,and under different NOx and SO2.Particle size distribution was measured by using a scanning mobility particle sizer(SMPS)and the results showed that the addition of SO2 can promote SOA formation,while different NOx concentrations have different influences on SOA production.High NOx suppressed the SOA formation,whereas the particle mass concentration,particle number concentration and particle geometric mean diameter increased with the increasing NOx concentration at low NOx concentration in the presence of SO2.In addition,the products of the OH-initiated oxidation of MG and the functional groups of the particle phase in the MG/OH/SO2 and MG/OH/NOx/SO2 reaction systems were detected by gas chromatography mass spectrometry(GC-MS)and attenuated total reflection fourier transformed infrared spectroscopy(ATR-FTIR)analysis.Two products,glyoxylic acid and oxalic acid,were detected by GC-MS.The mechanism of the reaction of MG and OH radicals that follows two main pathways,H atom abstraction and hydration,is proposed.Evidence is provided for the formation of organic nitrates and organic sulfate in particle phase from IR spectra.Incorporation of NOx and SO2 influence suggested that SOA formation from anthropogenic hydrocarbons may be more efficient in polluted environment.展开更多
γ-terpinene is widely used in personal care and household cleaning products.The gas-phase oxidation mechanism ofγ-terpinene is essential for understanding its influence on atmospheric chemistry and its implications ...γ-terpinene is widely used in personal care and household cleaning products.The gas-phase oxidation mechanism ofγ-terpinene is essential for understanding its influence on atmospheric chemistry and its implications for human health.Utilizing quantum chemical calculations and computational toxicology simulations,we examined the·OH-mediated atmospheric transformation and toxicological progression ofγ-terpinene in the indoor environment.The results indicate that·OH additions are the dominant pathways for the reaction of·OH+γ-terpinene.The most favorable reactive intermediates formed from the·OHaddition reactions subsequently react with O2 to form hydroxyγ-terpinene peroxy radicals(OH-γ-terp-RO2·).The formed OH-γ-terp-RO2·follows concerted peroxy radical(RO2·)and alkoxy radical(RO·)modulated autoxidation,providing a new case for such a mechanism beyond the well-known only RO2-driven autoxidation mechanism.Our findings also reveal that the transformation of OH-γ-terp-RO2·demonstrates the competitive nature of the cyclization pathway indoors,with dicarbonyl formation,a rarely observed process in hydroxy terpene RO2 reaction systems.Toxicological evaluations further indicate that a significant proportion of transformation products(TPs)display higher mutagenicity,carcinogenicity,skin sensitization,and irritation to eyes compared toγ-terpinene.The detailed mechanism for·OH-initiatedγ-terpinene advances our understanding of RO2·and RO·chemistry while also emphasizing the potential adverse effects that arise from the interaction of these chemicals in indoor environments.展开更多
基金supported by the National Natural Science Foundation of China(No.91644214)the Shandong Natural Science Fund for Distinguished Young Scholars(No.JQ201705)。
文摘Methylglyoxal(CH3COCHO,MG),which is one of the most abundant α-dicarbonyl compounds in the atmosphere,has been reported as a major source of secondary organic aerosol(SOA).In this work,the reaction of MG with hydroxyl radicals was studied in a 500 L smog chamber at(293±3)K,atmospheric pressure,(18±2)%relative humidity,and under different NOx and SO2.Particle size distribution was measured by using a scanning mobility particle sizer(SMPS)and the results showed that the addition of SO2 can promote SOA formation,while different NOx concentrations have different influences on SOA production.High NOx suppressed the SOA formation,whereas the particle mass concentration,particle number concentration and particle geometric mean diameter increased with the increasing NOx concentration at low NOx concentration in the presence of SO2.In addition,the products of the OH-initiated oxidation of MG and the functional groups of the particle phase in the MG/OH/SO2 and MG/OH/NOx/SO2 reaction systems were detected by gas chromatography mass spectrometry(GC-MS)and attenuated total reflection fourier transformed infrared spectroscopy(ATR-FTIR)analysis.Two products,glyoxylic acid and oxalic acid,were detected by GC-MS.The mechanism of the reaction of MG and OH radicals that follows two main pathways,H atom abstraction and hydration,is proposed.Evidence is provided for the formation of organic nitrates and organic sulfate in particle phase from IR spectra.Incorporation of NOx and SO2 influence suggested that SOA formation from anthropogenic hydrocarbons may be more efficient in polluted environment.
基金supported by the National Natural Science Foundation of China(22176022,22306002).
文摘γ-terpinene is widely used in personal care and household cleaning products.The gas-phase oxidation mechanism ofγ-terpinene is essential for understanding its influence on atmospheric chemistry and its implications for human health.Utilizing quantum chemical calculations and computational toxicology simulations,we examined the·OH-mediated atmospheric transformation and toxicological progression ofγ-terpinene in the indoor environment.The results indicate that·OH additions are the dominant pathways for the reaction of·OH+γ-terpinene.The most favorable reactive intermediates formed from the·OHaddition reactions subsequently react with O2 to form hydroxyγ-terpinene peroxy radicals(OH-γ-terp-RO2·).The formed OH-γ-terp-RO2·follows concerted peroxy radical(RO2·)and alkoxy radical(RO·)modulated autoxidation,providing a new case for such a mechanism beyond the well-known only RO2-driven autoxidation mechanism.Our findings also reveal that the transformation of OH-γ-terp-RO2·demonstrates the competitive nature of the cyclization pathway indoors,with dicarbonyl formation,a rarely observed process in hydroxy terpene RO2 reaction systems.Toxicological evaluations further indicate that a significant proportion of transformation products(TPs)display higher mutagenicity,carcinogenicity,skin sensitization,and irritation to eyes compared toγ-terpinene.The detailed mechanism for·OH-initiatedγ-terpinene advances our understanding of RO2·and RO·chemistry while also emphasizing the potential adverse effects that arise from the interaction of these chemicals in indoor environments.
