In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 an...In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 and its precursors,as well as H2O2 and meteorological data were obtained from the urban site(Yanchang,YC),suburban(Zhengzhou University,ZZU)and background sites(Ganglishuiku,GLSK).Result showed that the rates of O3 concentration exceeded Chinese National Air Quality Standard GradeⅡ(93.3 ppbv)were 59.0%,52.5%,and 55.7%at the above three sites with good consistency,respectively,indicating that O3 pollution is a regional problem in Zhengzhou.The daily peak O3 appeared at 15:00-16:00,which was opposite to VOCs,NOx,and CO and consistent with H2O2.The exhaustive statistical analysis of meteorological factors and chemical effects on O3 formation at YC was advanced.The high concentration of precursors,high temperature,low relative humidity,and moderately high wind speed together with the wind direction dominated by south and southeast wind contribute to urban O3 episodes in Zhengzhou.O3 formation analysis showed that reactive alkenes such as isoprene and cis-2-butene contributed most to O3 formation.The VOCs/NOx ratio and smog production model were used to determine O3-VOC-NOx sensitivity.The O3 formation in Zhengzhou during early summer was mainly under VOC-limited and transition regions alternately,which implies that the simultaneous emission reduction of alkenes and NOx is effective in reducing O3 pollution in Zhengzhou.展开更多
Increasing attention has been paid to the air pollution more recently. Smog chamber has been proved as a necessary and effective tool to study atmospheric processes, including photochemical smog and haze formation. A ...Increasing attention has been paid to the air pollution more recently. Smog chamber has been proved as a necessary and effective tool to study atmospheric processes, including photochemical smog and haze formation. A novel smog chamber was designed to study the atmospheric photochemical reaction mechanism of typical volatile organic compounds(VOCs) as well as the aging of aerosols. The smog chamber system includes an enclosure equipped with black lights as the light source, two parallel reactors(2 m^3 of each) with separate control of light source and temperature, with a series of coupled instruments for online monitoring of gas phase and particle phase reactants and products. Chamber characterization, including air source stability, effective light intensity, temperature stability, as well as gas phase and particle phase wall losses, were carried out before further research. The results showed that our smog chamber systems developed by other domestic and international groups. It was also observed that the wall loss of aromatic VOCs varied with different functional groups as well as the isomerism. The results of preliminary simulation experiment from styrene-NO_x demonstrated that the chamber can be well utilized to simulate gas-particle conversion progresses in the atmosphere.展开更多
Icing of wires is a product of rain, fog, and freezing rain, and is a common meteorological disaster in winter in Guizhou Province of China. It is extremely harmful to facilities such as power transmission and communi...Icing of wires is a product of rain, fog, and freezing rain, and is a common meteorological disaster in winter in Guizhou Province of China. It is extremely harmful to facilities such as power transmission and communication lines, and has caused huge economic loss up to 48.9566 billion dollars a year. Based on the meteorological records of Guizhou from 1967, we analyze the meteorological characteristics during the icing of wires, and obtain the temperature, wind speed and direction conditions of the ice accident. The icing of wires is carried out by supercooling raindrops, freezing of the clouds, freezing and spreading on the wires. Different types of supercooled raindrops and cloud freezing and freezing processes will form different types of ice accretion;wind direction and wind speed will affect the growth of ice accretion by changing the speed of sub-cooling raindrops and cloud falling. The weight of rain-type ice accretion is between 24 and 152 g, and the weight of smog-type ice is between 40 - 76 g. The average ice density of these two places can be calculated to be 0.2 - 0.5 g/cm3. The longer the icing of wires, the higher the ice disaster rate.展开更多
利用气象与化学模块在线耦合的模式WRF-Chem V3. 5(Weather Research and Forecasting Model coupled to Chemistry Version 3. 5)对2016年11月3-6日的一次京津冀污染过程展开了数值模拟,设计进行了包含人为排放源的实验,运用有效的模...利用气象与化学模块在线耦合的模式WRF-Chem V3. 5(Weather Research and Forecasting Model coupled to Chemistry Version 3. 5)对2016年11月3-6日的一次京津冀污染过程展开了数值模拟,设计进行了包含人为排放源的实验,运用有效的模拟结果对过程进行分析。结果表明:大气稳定度指数能有效量化反映污染过程中的大气稳定状况,且K指数和TT指数相较其他两种指数的指示效果更为准确,是讨论雾霾发生发展原因的有力依据。本次污染高值中心有三个,分别为北京天津一带、河北东北部以及河北南部。PM2. 5、PM10以及SO2污染物水平分布有明显日变化特征,CO和NO2则变化不明显,污染从3日开始发展至6日结束,除NO2外各项污染物都明显受到冷空气的影响,在6日浓度骤降。北京和天津地区的污染是主要来源于河北南部的工业和交通排放的外源型污染,而河北东北部和河北南部的污染则是主要受本地排放影响的内源型污染。污染物主要化学成分为CO,污染物颗粒PM2. 5和PM10量级相当且浓度差别不大,均对本次污染有较大贡献。展开更多
基金the National Key Research and Development Program of China(No.2017YFC0212403)。
文摘In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 and its precursors,as well as H2O2 and meteorological data were obtained from the urban site(Yanchang,YC),suburban(Zhengzhou University,ZZU)and background sites(Ganglishuiku,GLSK).Result showed that the rates of O3 concentration exceeded Chinese National Air Quality Standard GradeⅡ(93.3 ppbv)were 59.0%,52.5%,and 55.7%at the above three sites with good consistency,respectively,indicating that O3 pollution is a regional problem in Zhengzhou.The daily peak O3 appeared at 15:00-16:00,which was opposite to VOCs,NOx,and CO and consistent with H2O2.The exhaustive statistical analysis of meteorological factors and chemical effects on O3 formation at YC was advanced.The high concentration of precursors,high temperature,low relative humidity,and moderately high wind speed together with the wind direction dominated by south and southeast wind contribute to urban O3 episodes in Zhengzhou.O3 formation analysis showed that reactive alkenes such as isoprene and cis-2-butene contributed most to O3 formation.The VOCs/NOx ratio and smog production model were used to determine O3-VOC-NOx sensitivity.The O3 formation in Zhengzhou during early summer was mainly under VOC-limited and transition regions alternately,which implies that the simultaneous emission reduction of alkenes and NOx is effective in reducing O3 pollution in Zhengzhou.
基金supported by the Local Innovative and Research Team Project of Guangdong Pearl River Talents Program (No. 2017BT01Z032)the National Natural Science Foundation of China (Nos. 41731279 and 41425015 )+2 种基金the Key-Area Research and Development Program of Guangdong Province (No. 2019B110206002)The Innovation Team Project of Guangdong Provincial Department of Education (No. 2017KCXTD012)Guangdong Special Branch Plan of Science and Technology for Innovation leading scientists (2016TX03Z094)。
文摘Increasing attention has been paid to the air pollution more recently. Smog chamber has been proved as a necessary and effective tool to study atmospheric processes, including photochemical smog and haze formation. A novel smog chamber was designed to study the atmospheric photochemical reaction mechanism of typical volatile organic compounds(VOCs) as well as the aging of aerosols. The smog chamber system includes an enclosure equipped with black lights as the light source, two parallel reactors(2 m^3 of each) with separate control of light source and temperature, with a series of coupled instruments for online monitoring of gas phase and particle phase reactants and products. Chamber characterization, including air source stability, effective light intensity, temperature stability, as well as gas phase and particle phase wall losses, were carried out before further research. The results showed that our smog chamber systems developed by other domestic and international groups. It was also observed that the wall loss of aromatic VOCs varied with different functional groups as well as the isomerism. The results of preliminary simulation experiment from styrene-NO_x demonstrated that the chamber can be well utilized to simulate gas-particle conversion progresses in the atmosphere.
文摘Icing of wires is a product of rain, fog, and freezing rain, and is a common meteorological disaster in winter in Guizhou Province of China. It is extremely harmful to facilities such as power transmission and communication lines, and has caused huge economic loss up to 48.9566 billion dollars a year. Based on the meteorological records of Guizhou from 1967, we analyze the meteorological characteristics during the icing of wires, and obtain the temperature, wind speed and direction conditions of the ice accident. The icing of wires is carried out by supercooling raindrops, freezing of the clouds, freezing and spreading on the wires. Different types of supercooled raindrops and cloud freezing and freezing processes will form different types of ice accretion;wind direction and wind speed will affect the growth of ice accretion by changing the speed of sub-cooling raindrops and cloud falling. The weight of rain-type ice accretion is between 24 and 152 g, and the weight of smog-type ice is between 40 - 76 g. The average ice density of these two places can be calculated to be 0.2 - 0.5 g/cm3. The longer the icing of wires, the higher the ice disaster rate.
文摘利用气象与化学模块在线耦合的模式WRF-Chem V3. 5(Weather Research and Forecasting Model coupled to Chemistry Version 3. 5)对2016年11月3-6日的一次京津冀污染过程展开了数值模拟,设计进行了包含人为排放源的实验,运用有效的模拟结果对过程进行分析。结果表明:大气稳定度指数能有效量化反映污染过程中的大气稳定状况,且K指数和TT指数相较其他两种指数的指示效果更为准确,是讨论雾霾发生发展原因的有力依据。本次污染高值中心有三个,分别为北京天津一带、河北东北部以及河北南部。PM2. 5、PM10以及SO2污染物水平分布有明显日变化特征,CO和NO2则变化不明显,污染从3日开始发展至6日结束,除NO2外各项污染物都明显受到冷空气的影响,在6日浓度骤降。北京和天津地区的污染是主要来源于河北南部的工业和交通排放的外源型污染,而河北东北部和河北南部的污染则是主要受本地排放影响的内源型污染。污染物主要化学成分为CO,污染物颗粒PM2. 5和PM10量级相当且浓度差别不大,均对本次污染有较大贡献。