In a smog chamber, the photooxidation of toluene was initiated by hydroxyl radical （OH.） under different experimental conditions. The size distribution of secondary organic aerosol（SOA） particles from the above re...In a smog chamber, the photooxidation of toluene was initiated by hydroxyl radical （OH.） under different experimental conditions. The size distribution of secondary organic aerosol（SOA） particles from the above reaction was measured using aerodynamic particle sizer spectrometer. It was found from our experimental results that the number of SOA particles increased with increasing the concentration of toluene. As the reaction time prolonged, the sum of SOA particles was also increased. After a reaction time of 130 min, the concentration of secondary organic aerosol particles would be kept constant at 2300 particles/cm^3. Increasing illumination power of blacklamps could significantly induce a higher concentration of secondary organic aerosol particle. The density of SOA particles would also be increased with increasing concentration of CH30NO, however, it would be decreased as soon as the concentration of CH30NO was larger than 225.2 ppm. Nitrogen oxide with initial concentration higher than 30. 1 ppm was also found to have little effect on the formation of secondary organic aerosol.展开更多
Hydroxyl radical （.OH）-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium ...Hydroxyl radical （.OH）-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium chloride, were introduced into the chamber to assess their influence on the growth of secondary organic aerosols （SOA）. It was found that the low concentration of seed aerosols might lead to high concentration of SOA particles. Seed aerosols would promote rates of SOA formation at the start of the reaction and inhibit its formation rate with prolonging the reaction time. In the case of ca. 9000 pt/cm^3 seed aerosol load, the addition of sodium silicate induced a same effect on the SOA formation as ammonium nitrate. The influence of the four individual seed aerosols on the generation of SOA decreased in the order of calcium chloride〉sodium silicate and ammonium nitrate〉ammonium sulfate.展开更多
Secondary organic aerosol （SOA） formation from hydroxyl radical （OH.） initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using a...Secondary organic aerosol （SOA） formation from hydroxyl radical （OH.） initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for α-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light application time, the concentration, and the size of SOA particles were also increased. In addition, the factors influencing the formation of SOA were discussed. In addition, this article compared the effect of α-pinene with that of toluene, and discussed the contribution of α-pinene to SOA formation.展开更多
Anthropogenic emissions alter biogenic secondary organic aerosol(SOA)formation from naturally emitted volatileorganic compounds(BVOCs).We review the major laboratory and field findings with regard to effects of anthro...Anthropogenic emissions alter biogenic secondary organic aerosol(SOA)formation from naturally emitted volatileorganic compounds(BVOCs).We review the major laboratory and field findings with regard to effects of anthropogenicpollutants(NO_(x),anthropogenic aerosols,SO_(2),NH_(3))on biogenic SOA formation.NO_(x) participate in BVOC oxidationthrough changing the radical chemistry and oxidation capacity,leading to a complex SOA composition and yield sensitivitytowards NO_(x) level for different or even specific hydrocarbon precursors.Anthropogenic aerosols act as an importantintermedium for gas-particle partitioning and particle-phase reactions,processes of which are influenced by the particlephase state,acidity,water content and thus associated with biogenic SOA mass accumulation.SO_(2)modifies biogenic SOAformation mainly through sulfuric acid formation and accompanies new particle formation and acid-catalyzedheterogeneous reactions.Some new SO_(2)-involved mechanisms for organosulfate formation have also been proposed.NH_(3)/amines,as the most prevalent base species in the atmosphere,influence biogenic SOA composition and modify theoptical properties of SOA.The response of SOA formation behavior to these anthropogenic pollutants varies amongdifferent BVOCs precursors.Investigations on anthropogenic-biogenic interactions in some areas of China that aresimultaneously influenced by anthropogenic and biogenic emissions are summarized.Based on this review,somerecommendations are made for a more accurate assessment of controllable biogenic SOA formation and its contribution tothe total SOA budget.This study also highlights the importance of controlling anthropogenic pollutant emissions witheffective pollutant mitigation policies to reduce regional and global biogenic SOA formation.展开更多
Photooxidation of isoprene leads to the formation of secondary organic aerosol （SOA）. In this study, the chemical composition of SOA formed from OH-initiated photooxidation of isoprene has been investigated with gas...Photooxidation of isoprene leads to the formation of secondary organic aerosol （SOA）. In this study, the chemical composition of SOA formed from OH-initiated photooxidation of isoprene has been investigated with gas chromatography/mass spectrometry （GC/MS） and a home-made aerosol time-of-fiight mass spectrometer. Sampling particles generated in a home-made smog chamber. The size distribution of SOA particles was detected by a TSI 3321 aerodynamic particle size spectrometer in real time. Results showed that SOA created by isoprene photooxidation was predominantly in the form of fine particles, which have diameters less than 2.5 μm. The obtained mass spectra of individual particles show that products of the OH-initiated oxidation of isoprene contain methyl vinyl ketone, methacrolein, formaldehyde, and some other hydroxycarbonyls. The possible reaction mechanisms leading to these products were also discussed.展开更多
Elucidating the effects of anthropogenic pollutants on the photooxidation of biogenic volatile organic compounds is crucial to understanding the fundamental mechanisms of secondary organic aerosol(SOA)formation.Here,t...Elucidating the effects of anthropogenic pollutants on the photooxidation of biogenic volatile organic compounds is crucial to understanding the fundamental mechanisms of secondary organic aerosol(SOA)formation.Here,the impacts of NO_(2)and SO_(2)on SOA formation from the photooxidation of a representative monoterpene,β-pinene,were investigated by a number of laboratory studies.The results indicated NO_(2)enhanced the SOA mass concentrations and particle number concentrations under both low and highβ-pinene conditions.This could be rationalized that the increased O_(3)concentrations upon the NO_(x)photolysis was helpful for the generation of more amounts of O_(3)-oxidized products,which accelerated the SOA nucleation and growth.Combing with NO_(2),the promotion of the SOA yield by SO_(2)was mainly reflected in the increase of mass concentration,which might be due to the elimination of the newly formed particles by the initially formed particles.The observed low oxidation degree of SOA might be attributed to the fast growth of SOA,resulting in the uptake of less oxygenated gas-phase species onto the particle phase.The present findings have important implications for SOA formation affected by anthropogenic–biogenic interactions in the ambient atmosphere.展开更多
An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limi...An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limited experiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments and recorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particle sizer ...展开更多
Aerosol liquid water content(ALWC)plays an important role in secondary aerosol formation.In this study,a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021.ALWC estimated by ISORR...Aerosol liquid water content(ALWC)plays an important role in secondary aerosol formation.In this study,a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021.ALWC estimated by ISORROPIA-Ⅱ was then investigated to explore its characteristics and relationship with secondary aerosols.ALWC exhibited a highest value in spring(66.38μg/m^(3)),followed by winter(45.08μg/m^(3)),summer(41.64μg/m^(3)),and autumn(35.01μg/m^(3)),respectively.It was supposed that the secondary inorganic aerosols(SIA)were facilitated under higher ALWC conditions(RH>80%),while the secondary organic species tended to form under lower ALWC levels.Higher RH(>80%)promoted the NO_(3)^(-)formation via gas-particle partitioning,while SO_(4)^(2-)was generated at a relative lower RH(>50%).The ALWC was more sensitive to NO_(3)^(-)(R=0.94)than SO_(4)^(2-)(R=0.90).Thus,the self-amplifying processes between the ALWC and SIA enhanced the particle mass growth.The sensitivity of ALWC and OX(NO_(2)+O_(3))to secondary organic carbon(SOC)varied in different seasons at Shanxi,more sensitive to aqueous-phase reactions(daytime R=0.84;nighttime R=0.54)than photochemical oxidation(daytime R=0.23;nighttime R=0.41)in wintertime with a high level of OX(daytime:130-140μg/m^(3);nighttime:100-140μg/m^(3)).The self-amplifying process of ALWC and SIA and the aqueous-phase formation of SOC will enhance aerosol formation,contributing to air pollution and reduction of visibility.展开更多
The formation and aging mechanism of secondary organic aerosol(SOA)and its influencing factors have attracted increasing attention in recent years because of their effects on climate change,atmospheric quality and hum...The formation and aging mechanism of secondary organic aerosol(SOA)and its influencing factors have attracted increasing attention in recent years because of their effects on climate change,atmospheric quality and human health.However,there are still large errors between air quality model simulation results and field observations.The currently undetected components during the formation and aging of SOA due to the limitation of current monitoring techniques and the interactions among multiple SOA formation influencing factors might be the main reasons for the differences.In this paper,we present a detailed review of the complex dynamic physical and chemical processes and the corresponding influencing factors involved in SOA formation and aging.And all these results were mainly based the studies of photochemical smog chamber simulation.Although the properties of precursor volatile organic compounds(VOCs),oxidants(such as OH radicals),and atmospheric environmental factors(such as NOx,SO2,NH3,light intensity,temperature,humidity and seed aerosols)jointly influence the products and yield of SOA,the nucleation and vapor pressure of these products were found to be the most fundamental aspects when interpreting the dynamics of the SOA formation and aging process.The development of techniques for measuring intermediate species in SOA generation processes and the study of SOA generation and aging mechanism in complex systems should be important topics of future SOA research.展开更多
文摘In a smog chamber, the photooxidation of toluene was initiated by hydroxyl radical （OH.） under different experimental conditions. The size distribution of secondary organic aerosol（SOA） particles from the above reaction was measured using aerodynamic particle sizer spectrometer. It was found from our experimental results that the number of SOA particles increased with increasing the concentration of toluene. As the reaction time prolonged, the sum of SOA particles was also increased. After a reaction time of 130 min, the concentration of secondary organic aerosol particles would be kept constant at 2300 particles/cm^3. Increasing illumination power of blacklamps could significantly induce a higher concentration of secondary organic aerosol particle. The density of SOA particles would also be increased with increasing concentration of CH30NO, however, it would be decreased as soon as the concentration of CH30NO was larger than 225.2 ppm. Nitrogen oxide with initial concentration higher than 30. 1 ppm was also found to have little effect on the formation of secondary organic aerosol.
基金Project supported by the National Natural Science Foundation of China(No.20477043)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-SW-H08).*
文摘Hydroxyl radical （.OH）-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium chloride, were introduced into the chamber to assess their influence on the growth of secondary organic aerosols （SOA）. It was found that the low concentration of seed aerosols might lead to high concentration of SOA particles. Seed aerosols would promote rates of SOA formation at the start of the reaction and inhibit its formation rate with prolonging the reaction time. In the case of ca. 9000 pt/cm^3 seed aerosol load, the addition of sodium silicate induced a same effect on the SOA formation as ammonium nitrate. The influence of the four individual seed aerosols on the generation of SOA decreased in the order of calcium chloride〉sodium silicate and ammonium nitrate〉ammonium sulfate.
基金supported by the Knowledge Innovation Foundation of Chinese Academy of Sciences (No.KJCX2-YW-N24)
文摘Secondary organic aerosol （SOA） formation from hydroxyl radical （OH.） initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for α-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light application time, the concentration, and the size of SOA particles were also increased. In addition, the factors influencing the formation of SOA were discussed. In addition, this article compared the effect of α-pinene with that of toluene, and discussed the contribution of α-pinene to SOA formation.
基金This work was supported by National Natural Science Foundation of China(Grant No.91644214)Youth Innovation Program of Universities in Shandong Province(Grant No.2019KJD007)Fundamental Research Fund of Shandong University(Grant No.2020QNQT012).
文摘Anthropogenic emissions alter biogenic secondary organic aerosol(SOA)formation from naturally emitted volatileorganic compounds(BVOCs).We review the major laboratory and field findings with regard to effects of anthropogenicpollutants(NO_(x),anthropogenic aerosols,SO_(2),NH_(3))on biogenic SOA formation.NO_(x) participate in BVOC oxidationthrough changing the radical chemistry and oxidation capacity,leading to a complex SOA composition and yield sensitivitytowards NO_(x) level for different or even specific hydrocarbon precursors.Anthropogenic aerosols act as an importantintermedium for gas-particle partitioning and particle-phase reactions,processes of which are influenced by the particlephase state,acidity,water content and thus associated with biogenic SOA mass accumulation.SO_(2)modifies biogenic SOAformation mainly through sulfuric acid formation and accompanies new particle formation and acid-catalyzedheterogeneous reactions.Some new SO_(2)-involved mechanisms for organosulfate formation have also been proposed.NH_(3)/amines,as the most prevalent base species in the atmosphere,influence biogenic SOA composition and modify theoptical properties of SOA.The response of SOA formation behavior to these anthropogenic pollutants varies amongdifferent BVOCs precursors.Investigations on anthropogenic-biogenic interactions in some areas of China that aresimultaneously influenced by anthropogenic and biogenic emissions are summarized.Based on this review,somerecommendations are made for a more accurate assessment of controllable biogenic SOA formation and its contribution tothe total SOA budget.This study also highlights the importance of controlling anthropogenic pollutant emissions witheffective pollutant mitigation policies to reduce regional and global biogenic SOA formation.
基金supported by the Knowledge Innovation Foundation of Chinese Academy of Sciences (No. KJCX2-YW-N24)
文摘Photooxidation of isoprene leads to the formation of secondary organic aerosol （SOA）. In this study, the chemical composition of SOA formed from OH-initiated photooxidation of isoprene has been investigated with gas chromatography/mass spectrometry （GC/MS） and a home-made aerosol time-of-fiight mass spectrometer. Sampling particles generated in a home-made smog chamber. The size distribution of SOA particles was detected by a TSI 3321 aerodynamic particle size spectrometer in real time. Results showed that SOA created by isoprene photooxidation was predominantly in the form of fine particles, which have diameters less than 2.5 μm. The obtained mass spectra of individual particles show that products of the OH-initiated oxidation of isoprene contain methyl vinyl ketone, methacrolein, formaldehyde, and some other hydroxycarbonyls. The possible reaction mechanisms leading to these products were also discussed.
基金National Natural Science Foundation of China (Nos.22125303,92061203,and 22288201)the National Key Research and Development Program of China (No.2021YFA1400501)+3 种基金Innovation Program for Quantum Science and Technology (No.2021ZD0303304)Dalian Institute of Chemical Physics (No.DICP DCLS201702)Chinese Academy of Sciences (No.GJJSTD20220001)K.C.Wong Education Foundation (No.GJTD-2018-06)。
文摘Elucidating the effects of anthropogenic pollutants on the photooxidation of biogenic volatile organic compounds is crucial to understanding the fundamental mechanisms of secondary organic aerosol(SOA)formation.Here,the impacts of NO_(2)and SO_(2)on SOA formation from the photooxidation of a representative monoterpene,β-pinene,were investigated by a number of laboratory studies.The results indicated NO_(2)enhanced the SOA mass concentrations and particle number concentrations under both low and highβ-pinene conditions.This could be rationalized that the increased O_(3)concentrations upon the NO_(x)photolysis was helpful for the generation of more amounts of O_(3)-oxidized products,which accelerated the SOA nucleation and growth.Combing with NO_(2),the promotion of the SOA yield by SO_(2)was mainly reflected in the increase of mass concentration,which might be due to the elimination of the newly formed particles by the initially formed particles.The observed low oxidation degree of SOA might be attributed to the fast growth of SOA,resulting in the uptake of less oxygenated gas-phase species onto the particle phase.The present findings have important implications for SOA formation affected by anthropogenic–biogenic interactions in the ambient atmosphere.
基金the National Natural ScienceFundation of China (No. 20637001)
文摘An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limited experiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments and recorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particle sizer ...
基金supported by the National Natural Science Foundation of China(Nos.91844301 and 42005087)the support from State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex,Shanghai Academy of Environment Sciences(No.CX2020080581)。
文摘Aerosol liquid water content(ALWC)plays an important role in secondary aerosol formation.In this study,a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021.ALWC estimated by ISORROPIA-Ⅱ was then investigated to explore its characteristics and relationship with secondary aerosols.ALWC exhibited a highest value in spring(66.38μg/m^(3)),followed by winter(45.08μg/m^(3)),summer(41.64μg/m^(3)),and autumn(35.01μg/m^(3)),respectively.It was supposed that the secondary inorganic aerosols(SIA)were facilitated under higher ALWC conditions(RH>80%),while the secondary organic species tended to form under lower ALWC levels.Higher RH(>80%)promoted the NO_(3)^(-)formation via gas-particle partitioning,while SO_(4)^(2-)was generated at a relative lower RH(>50%).The ALWC was more sensitive to NO_(3)^(-)(R=0.94)than SO_(4)^(2-)(R=0.90).Thus,the self-amplifying processes between the ALWC and SIA enhanced the particle mass growth.The sensitivity of ALWC and OX(NO_(2)+O_(3))to secondary organic carbon(SOC)varied in different seasons at Shanxi,more sensitive to aqueous-phase reactions(daytime R=0.84;nighttime R=0.54)than photochemical oxidation(daytime R=0.23;nighttime R=0.41)in wintertime with a high level of OX(daytime:130-140μg/m^(3);nighttime:100-140μg/m^(3)).The self-amplifying process of ALWC and SIA and the aqueous-phase formation of SOC will enhance aerosol formation,contributing to air pollution and reduction of visibility.
基金supported by the Central Level,Scientific Research Institutes for Basic R&D Special Fund Business,China(No.2021-JY-16)the National Natural Science Foundation of China(Nos.42075182 and 2130721)+1 种基金the National Research Program for Key Issue in Air Pollution Control(No.DQGG2021101)the National Key Research and Development Program of China(No.2019YFC0214800)。
文摘The formation and aging mechanism of secondary organic aerosol(SOA)and its influencing factors have attracted increasing attention in recent years because of their effects on climate change,atmospheric quality and human health.However,there are still large errors between air quality model simulation results and field observations.The currently undetected components during the formation and aging of SOA due to the limitation of current monitoring techniques and the interactions among multiple SOA formation influencing factors might be the main reasons for the differences.In this paper,we present a detailed review of the complex dynamic physical and chemical processes and the corresponding influencing factors involved in SOA formation and aging.And all these results were mainly based the studies of photochemical smog chamber simulation.Although the properties of precursor volatile organic compounds(VOCs),oxidants(such as OH radicals),and atmospheric environmental factors(such as NOx,SO2,NH3,light intensity,temperature,humidity and seed aerosols)jointly influence the products and yield of SOA,the nucleation and vapor pressure of these products were found to be the most fundamental aspects when interpreting the dynamics of the SOA formation and aging process.The development of techniques for measuring intermediate species in SOA generation processes and the study of SOA generation and aging mechanism in complex systems should be important topics of future SOA research.
