In this paper we present a review of atmospheric chemistry research in China over the period 2006-2010, focusing on tropospheric ozone, aerosol chemistry, and the interactions between trace gases and aerosols in the p...In this paper we present a review of atmospheric chemistry research in China over the period 2006-2010, focusing on tropospheric ozone, aerosol chemistry, and the interactions between trace gases and aerosols in the polluted areas of China. Over the past decade, China has suffered severe photochemical smog and haze pollution, especially in North China, the Yangtze River Delta, and the Pearl River Delta. Much scientific work on atmospheric chemistry and physics has been done to address this large-scale, complex environmental problem. Intensive field experiments, satellite data analyses, and model simulations have shown that air pollution is significantly changing the chemical and physical characters of the natural atmosphere over these parts of China. In addition to strong emissions of primary pollutants, photochemical and heterogeneous reactions play key roles in the formation of complex pollution. More in-depth research is recommended to reveal the formation mechanism of photochemical smog and haze pollution and their climatic effects at the urban, regional, and global scales.展开更多
Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature a...Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature and atmospheric composition.However,the existing parameters for mechanism interpretation are derived from the traditional smog chambers.To address the gap between the traditional laboratory simulations and the photochemistry in the real atmosphere,a vehicle-mounted indoor-outdoor dual-smog chamber(JNUVMDSC)was developed,which can be quickly transferred to the desired sites to simulate quasi-realistic atmosphere simultaneously in both chambers using“local air”.Multiple key parameters of the smog chamber were characterized in the study,demonstrating that JNUVMDSC meets the requirements of general atmospheric chemistry simulation studies.Additionally,the preliminary results for the photochemical simulations of quasi-realistic atmospheres in Pearl River Delta region and Nanling Mountains are consistent with literature reports on the photochemistry in this region.JNU-VMDSC provides a convenient and reliable experimental device and means to study the mechanism of atmospheric photochemical reactions to obtain near-real results,and will make a great contribution to the control of composite air pollution.展开更多
The process analysis is performed for August and December, 2002 using the process analysis tool embedded in the Community Multiscale Air Quality (CMAQ) modeling system at a fine horizontal grid resolution of 4-km over...The process analysis is performed for August and December, 2002 using the process analysis tool embedded in the Community Multiscale Air Quality (CMAQ) modeling system at a fine horizontal grid resolution of 4-km over an area in the southeastern U.S. that is centered at North Carolina. The objectives are to qunatify the contributions of major atmospheric processes to the formation of major air pollutants and provide the insights into photochemistry that governs the fate of these pollutants at a fine grid scale. The results show that emissions provide a dominant source for gases including ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) and Particulate Matter (PM) species including fine PM (PM2.5) and its composition such as sulfate, elemental carbon, primary organic aerosol, and other inorganic fine PM in both months. While transport acts as a major sink for NH3, NO, and SO2 at most sites and PM2.5 and most of PM2.5 composition at urban sites, it provides a major source for nitric acid (HNO3) and ozone (O3) at most sites in both months, and secondary PM species in August and most PM species in December at rural and remote sites. Gas-phase chemistry serves as a source for NO2 and HNO3 but a sink for O3 at urban and suburban sites and for NO and SO2 at all sites. PM processes contribute to the formation of PM2.5 and nitrate () at the urban and suburban sites and secondary organic aerosol (SOA) at most sites in December and ammonium () in both months. They reduce formation at most sites in August and at rural and remote sites in December and the formation of PM2.5 and SOA at most sites in August. Dry deposition is an important sink for all these species in both months. The total odd oxygen (Ox) production and the total hydroxyl radical (OH) reacted are much higher at urban and suburban sites than at rural sites. Significant amounts of OH are consumed by biogenic volatile organic compounds (BVOCs) in the rural and remote areas and a combination of anthropogenic VOCs (AVOCs) and BVOCs in urban and subareas areas in August and mainly by AVOCs in December. The amount of NO2 produced by the reactions of hydroperoxy radical (HO2) is similar to that of organic peroxy radical (RO2) at all sites in August but higher than that by the reactions of RO2 inDecember. The production rate of HNO3 due to the reaction of OH with NO2 dominates in both months. The ratio of the production rates of hydrogen peroxide (H2O2) and HNO3 (PH2O2/PHNO3) is a more robust photochemical indicator than the ratios of their mixing ratios (H2O2/HNO3) and the afternoon mixing ratios of NOy in both months, and it is highly sensitive to the horizontal grid resolution in August. The use of PH2O2/PHNO3 simulated at 4-km indicates a VOC-limited O3 chemistry in urban and suburban areas in August that was not captured in previous model simulations at a coarser grid resolution.展开更多
Indoor air pollutants impact human health,comfort and productivity.The method of photocatalysis has been applied mainly in flow reactors and little information is available on indoor air pollutant removal in airtight ...Indoor air pollutants impact human health,comfort and productivity.The method of photocatalysis has been applied mainly in flow reactors and little information is available on indoor air pollutant removal in airtight reactors.In the paper,experiments were carried out to remove formaldehyde(HCHO),ammonia(NH_3) and volatile organic compounds(VOCs)in the airtight and ventilated chambers.Results demonstrated that 90.4%of HCHO,92.3%of NH_3 and 57.9%of VOCs were removed in the amine adsorption process,while 67.5% (hereinbefore,these are the mass fraction)of HCHO,60.0%of NH_3,and 61.2%of VOCs were removed in the photocatalytic process.However,ozone-assisted photocatalytic process showed great potential to degrade indoor air pollutants in the ventilated chamber.Factors and mechanisms of the photocatalytic degradation of HCHO, NH_3 and VOCs were also discussed.展开更多
基金funded by the China Meteorological Administration (Grant Nos. GYHY 200706005, GYHY 201106023 and GYHY 201206015)
文摘In this paper we present a review of atmospheric chemistry research in China over the period 2006-2010, focusing on tropospheric ozone, aerosol chemistry, and the interactions between trace gases and aerosols in the polluted areas of China. Over the past decade, China has suffered severe photochemical smog and haze pollution, especially in North China, the Yangtze River Delta, and the Pearl River Delta. Much scientific work on atmospheric chemistry and physics has been done to address this large-scale, complex environmental problem. Intensive field experiments, satellite data analyses, and model simulations have shown that air pollution is significantly changing the chemical and physical characters of the natural atmosphere over these parts of China. In addition to strong emissions of primary pollutants, photochemical and heterogeneous reactions play key roles in the formation of complex pollution. More in-depth research is recommended to reveal the formation mechanism of photochemical smog and haze pollution and their climatic effects at the urban, regional, and global scales.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.41877370 and 42077190)the China Postdoctoral Science Foundation(No.2021M691229)+2 种基金the fund of Creative Research Groups of NSFC(No.42121004)the Science and Technology Planning Project of Guangdong Province of China(No.2019B121202002)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N263).
文摘Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature and atmospheric composition.However,the existing parameters for mechanism interpretation are derived from the traditional smog chambers.To address the gap between the traditional laboratory simulations and the photochemistry in the real atmosphere,a vehicle-mounted indoor-outdoor dual-smog chamber(JNUVMDSC)was developed,which can be quickly transferred to the desired sites to simulate quasi-realistic atmosphere simultaneously in both chambers using“local air”.Multiple key parameters of the smog chamber were characterized in the study,demonstrating that JNUVMDSC meets the requirements of general atmospheric chemistry simulation studies.Additionally,the preliminary results for the photochemical simulations of quasi-realistic atmospheres in Pearl River Delta region and Nanling Mountains are consistent with literature reports on the photochemistry in this region.JNU-VMDSC provides a convenient and reliable experimental device and means to study the mechanism of atmospheric photochemical reactions to obtain near-real results,and will make a great contribution to the control of composite air pollution.
文摘The process analysis is performed for August and December, 2002 using the process analysis tool embedded in the Community Multiscale Air Quality (CMAQ) modeling system at a fine horizontal grid resolution of 4-km over an area in the southeastern U.S. that is centered at North Carolina. The objectives are to qunatify the contributions of major atmospheric processes to the formation of major air pollutants and provide the insights into photochemistry that governs the fate of these pollutants at a fine grid scale. The results show that emissions provide a dominant source for gases including ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) and Particulate Matter (PM) species including fine PM (PM2.5) and its composition such as sulfate, elemental carbon, primary organic aerosol, and other inorganic fine PM in both months. While transport acts as a major sink for NH3, NO, and SO2 at most sites and PM2.5 and most of PM2.5 composition at urban sites, it provides a major source for nitric acid (HNO3) and ozone (O3) at most sites in both months, and secondary PM species in August and most PM species in December at rural and remote sites. Gas-phase chemistry serves as a source for NO2 and HNO3 but a sink for O3 at urban and suburban sites and for NO and SO2 at all sites. PM processes contribute to the formation of PM2.5 and nitrate () at the urban and suburban sites and secondary organic aerosol (SOA) at most sites in December and ammonium () in both months. They reduce formation at most sites in August and at rural and remote sites in December and the formation of PM2.5 and SOA at most sites in August. Dry deposition is an important sink for all these species in both months. The total odd oxygen (Ox) production and the total hydroxyl radical (OH) reacted are much higher at urban and suburban sites than at rural sites. Significant amounts of OH are consumed by biogenic volatile organic compounds (BVOCs) in the rural and remote areas and a combination of anthropogenic VOCs (AVOCs) and BVOCs in urban and subareas areas in August and mainly by AVOCs in December. The amount of NO2 produced by the reactions of hydroperoxy radical (HO2) is similar to that of organic peroxy radical (RO2) at all sites in August but higher than that by the reactions of RO2 inDecember. The production rate of HNO3 due to the reaction of OH with NO2 dominates in both months. The ratio of the production rates of hydrogen peroxide (H2O2) and HNO3 (PH2O2/PHNO3) is a more robust photochemical indicator than the ratios of their mixing ratios (H2O2/HNO3) and the afternoon mixing ratios of NOy in both months, and it is highly sensitive to the horizontal grid resolution in August. The use of PH2O2/PHNO3 simulated at 4-km indicates a VOC-limited O3 chemistry in urban and suburban areas in August that was not captured in previous model simulations at a coarser grid resolution.
基金the National Natural Science Foundation of China(No.21177087)the Shanghai Environmental Protection Bureau(SEPB)Program(No.09-26)
文摘Indoor air pollutants impact human health,comfort and productivity.The method of photocatalysis has been applied mainly in flow reactors and little information is available on indoor air pollutant removal in airtight reactors.In the paper,experiments were carried out to remove formaldehyde(HCHO),ammonia(NH_3) and volatile organic compounds(VOCs)in the airtight and ventilated chambers.Results demonstrated that 90.4%of HCHO,92.3%of NH_3 and 57.9%of VOCs were removed in the amine adsorption process,while 67.5% (hereinbefore,these are the mass fraction)of HCHO,60.0%of NH_3,and 61.2%of VOCs were removed in the photocatalytic process.However,ozone-assisted photocatalytic process showed great potential to degrade indoor air pollutants in the ventilated chamber.Factors and mechanisms of the photocatalytic degradation of HCHO, NH_3 and VOCs were also discussed.
