The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM 2.5 showed an increasing trend. To understand pollution characteristics of PM 2.5 and its relationship...The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM 2.5 showed an increasing trend. To understand pollution characteristics of PM 2.5 and its relationship with the meteorological conditions in Beijing, a one-year monitoring of PM 2.5 mass concentration and correspondent meteorological parameters was performed in Beijing in 2001. The PM 2.5 levels in Beijing were very high, the annual average PM 2.5 concentration in 2001 was 7 times of the National Ambient Air Quality Standards proposed by US EPA. The major chemical compositions were organics, sulfate, crustals and nitrate. It was found that the mass concentrations of PM 2.5 were influenced by meteorological conditions. The correlation between the mass concentrations of PM 2.5 and the relative humidity was found. And the correlation became closer at higher relative humidity. And the mass concentrations of PM 2.5 were negtive-correlated to wind speeds, but the correlation between the mass concentration of PM 2.5 and wind speed was not good at stronger wind.展开更多
Atmospheric oxidizing capacity is the essen- tial feature of urban and regional air. And OH and HO2 radicals are the key species indicating atmospheric oxidizing capacity. Using Guangzhou City as a case, this work has...Atmospheric oxidizing capacity is the essen- tial feature of urban and regional air. And OH and HO2 radicals are the key species indicating atmospheric oxidizing capacity. Using Guangzhou City as a case, this work has conducted field measurements of photochemistry relevant pollutants including O3, NOx, VOCs, H2O2, HNO2 and CO, SO2. The concentrations of OH radical are measured simul- taneously by impregnated filter trapping and HPLC (IFT- HPLC) method. The factors influencing OH levels are as- sessed. Based on understanding of OH and HO2 air chemis- try, the production and removal rates of these 2 radicals are calculated. The results show that the budget of OH and HO2 can generally be closed, the radical transformation between OH and HO2 dominates the sources and sinks of them, and also the photolysis of HNO2 and HCHO is the significant source of OH and HO2 respectively.展开更多
文摘The recent year's monitor results of Beijing indicated that the pollution level of fine particles PM 2.5 showed an increasing trend. To understand pollution characteristics of PM 2.5 and its relationship with the meteorological conditions in Beijing, a one-year monitoring of PM 2.5 mass concentration and correspondent meteorological parameters was performed in Beijing in 2001. The PM 2.5 levels in Beijing were very high, the annual average PM 2.5 concentration in 2001 was 7 times of the National Ambient Air Quality Standards proposed by US EPA. The major chemical compositions were organics, sulfate, crustals and nitrate. It was found that the mass concentrations of PM 2.5 were influenced by meteorological conditions. The correlation between the mass concentrations of PM 2.5 and the relative humidity was found. And the correlation became closer at higher relative humidity. And the mass concentrations of PM 2.5 were negtive-correlated to wind speeds, but the correlation between the mass concentration of PM 2.5 and wind speed was not good at stronger wind.
文摘Atmospheric oxidizing capacity is the essen- tial feature of urban and regional air. And OH and HO2 radicals are the key species indicating atmospheric oxidizing capacity. Using Guangzhou City as a case, this work has conducted field measurements of photochemistry relevant pollutants including O3, NOx, VOCs, H2O2, HNO2 and CO, SO2. The concentrations of OH radical are measured simul- taneously by impregnated filter trapping and HPLC (IFT- HPLC) method. The factors influencing OH levels are as- sessed. Based on understanding of OH and HO2 air chemis- try, the production and removal rates of these 2 radicals are calculated. The results show that the budget of OH and HO2 can generally be closed, the radical transformation between OH and HO2 dominates the sources and sinks of them, and also the photolysis of HNO2 and HCHO is the significant source of OH and HO2 respectively.
