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Biogenic Isoprene Emission Mechanism from ^(13)CO_2.Exposure Experiments

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Chinese Chemical Letters 2002年第9期13卷 897-900页

作者： Min SHAO state joint {2. laboratory of environmental simulation and pollution control, Center for environmental Sciences, peking university, beijing 100871 state joint {2. laboratory of environmental simulation and pollution control Center for Environmental Sciences Peking University Beijing 100871 China

Biogenic isoprene emissions have been believed to be from only photosynthesis processes in plant. However nocturnal isoprene emission from pine is detected. And by feeding 13CO2.to plants, it is found that both photos... 详细信息

关键词： Emissions volatile organic compounds (VOCs) 13C labeling isoprene.

Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation

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Journal of environmental Sciences 2010年第4期22卷 570-574页

作者： Daoming Huang,Zhongming Chen The state key {2. of environmental simulation and pollution control,college of environmental Sciences and Engineering,peking university,beijing 100871,china. [a] The state key {2. of environmental simulation pollution control College of Environmental Sciences Engineering Peking University Beijing 100871 China

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx （OH and HO2. radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry＇s law constant （KH）, significantly influences its role in atmospheric processes. Large discrepancies between the KH values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of （0.960 ± 0.013） atm （1 atm = 1.0132. × 10^5 Pa）. The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van＇t Hoff equation form, expressed as lnKH = a/T - b, and a = -△H/R, where KH is in M/atm （M is mol/L）, T is in degrees Kelvin, R is the ideal gas constant, and AH is the standard heat of solution. For acidity dependence, results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level （from pH 7 to pH 1）. Combining the dependence of both temperature and acidity, the obtained a and b were 702. ± 138 and 11.97 ± 0.48, respectively, AH was （58.40 ± 1.15） kJ/（***）, and the uncertainties represent σ. Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.

关键词： hydrogen peroxide Henry's law constant atmosphere acidity

Heterogeneous reactions of gaseous methanesulfonic acid with calcium carbonate and kaolinite particles

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Science china Chemistry 2010年第12期53卷 2657-2662页

作者： TANG MingJin,LI MengQiu & ZHU Tong state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering,peking university,beijing 100871,{12. 1. state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering Peking University Beijing 100871 China

Heterogeneous reactions of gaseous methanesulfonic acid (MSA) with calcium carbonate (CaCO3) and kaolinite particles at room temperature were investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC).Methanesulfonate (MS-) was identified as the product in the condensed phase,in accordance with the product of the reaction of gaseous MSA with NaCl and sea salt *** the concentration of gaseous MSA was 1.34 × 10-13 molecules cm-3,the uptake coefficient was (1.2. ± 0.06) × 10-8 (1) for the reaction of gaseous MSA with CaCO3 and (4.10 ± 0.65) × 10 10 (1) for the reaction with *** uptake coefficients were significantly smaller than those of the reactions of gaseous MSA with NaCl and sea salt particles.

关键词： gaseous MSA heterogeneous reaction calcium carbonate kaolinite

Heterogeneous reaction of SO_2.on TiO_2.particles

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Science china Chemistry 2010年第12期53卷 2637-2643页

作者： SHANG Jing,LI Jia & ZHU Tong state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering,peking university,beijing 100871,{12. 1. state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering Peking University Beijing 100871 China

The heterogeneous reaction of SO2.on TiO2.particles was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).The influences of the oxygen concentration,relative humidity (RH),and ultraviolet (UV) light illumination (λ=365 nm) intensity on the reaction were *** main product of the heterogeneous reaction of SO2.on TiO2.particles was sulfate with UV illumination and sulfite without *** production of sulfate was promoted significantly with UV illumination or water,and there was a synergistic effect when both were *** the dry system without UV,the heterogeneous reaction of SO2.on TiO2.particles was found to be second-order for SO2.and the initial uptake coefficient,BET,was determined to be 1.94 × *** UV and RH=40%,the reaction order was first-order and the initial uptake coefficient was 1.35 × 10-5.

关键词： SO2 TiO2 DRIFTS heterogeneous oxidation

Influence of fuel quality on vehicular NOx emissions

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Journal of environmental Sciences 2001年第3期13卷 265-271页

作者： WANG Shao xia, SHAO Min, ZHANG Yuan hang (state joint {2. laboratory of environmental simulation and pollution control, Center for environmental Sciences, peking university, beijing 100871, china. state joint {2. laboratory of environmental simulation and pollution control Center for Environmental Sciences Peking University Beijing 100871 China.

The quality of gasoline and diesel fuel affects pollutant emissions from vehicles. By applying the COMPLEX model, developed by the US EPA and industry to relate fuel composition to vehicle emissions, this paper estimates the influence of improvements in gasoline quality to lower vehicular NOx emissions. A case study is performed for Guangzhou City that has NOx concentrations significantly above the national ambient air quality standards (NAAQS). The paper discusses the potential for reducing NOx in Guangzhou by improving the quality of gasoline.

关键词： Air quality Automotive fuels Gasoline

pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

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Science china Chemistry 2006年第5期49卷 466-474页

作者： NIU Yuwen1,2.HE Lingyan1,2.HU Min2.ZHANG Jing2.& ZHAO Yunliang2.1. Shenzhen Graduate School of peking university,Shenzhen 518055,china {2.,college of environmental Sciences,peking university,beijing 100871,china 1. Shenzhen Graduate School of peking university Shenzhen 518055 China 2. state joint key laboratory of environmental simulation and pollution control College of Environmental Sciences Peking University Beijing 100871 China

Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2.04. Totally 30 sets of 2. h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal varia- tions and secondary pollution characteristics of fine particles during the sampling periods were dis-cussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respec-tively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol compo-nents in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South china Sea in summer, and the air quality was good. The prevailing wind in winter was from china's Mainland to the north, and the polluted air mass led to poor air quality.

关键词： PM2.5, mass concentration, secondary pollution, seasonal variation, Shenzhen.

Heterogeneous reaction of formaldehyde on the surface of TiO_2.particles

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Science china Chemistry 2010年第12期53卷 2644-2651页

作者： XU BingYe 1,2.ZHU Tong 1,TANG XiaoYan 1 & SHANG Jing 1 1 state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering,peking university,beijing 100871,{12. 2.Zhejiang Province environmental Monitoring Center,Hangzhou 310012.{12. 1. state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering Peking University Beijing 100871 China2. Zhejiang Province Environmental Monitoring Center Hangzhou 310012 China

The heterogeneous reaction of formaldehyde (HCHO) on the surface of titanium dioxide (TiO2. was investigated in situ using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) combined with ion chromatography (IC),X-ray diffraction (XRD),and transmission electron microscopy (TEM).Formate,dioxymethylene,methoxy,and polyoxymethylene were observed in the infrared spectra of TiO2.particles during the *** the surface of TiO2.the adsorbed HCHO was first oxidized to dioxymethylene and further oxidized to *** effects of temperature and ultraviolet radiation (UV) on the reaction products and reactive uptake coefficients were studied,and the results indicate that the reaction rate can be accelerated at increasing temperatures as well as under *** heterogeneous reaction mechanisms of HCHO on the surface of TiO2.in the dark and under UV irradiation are *** measurements show that formate formation on TiO2.is second order in HCHO concentration and the initial reactive uptake coefficients at room temperature calculated with the Brunauer-EmmettTeller specific surface area are (0.5-5) × 10-8 ([HCHO]:1 × 1013-2.× 10 14 molecules/cm3).A linear function relationship exists between the uptake coefficient and the *** apparent activation energy of the reaction was also determined.

关键词： DRIFTS formaldehyde heterogeneous reaction reactive uptake coefficient TiO2

Estimation methods of eco-environmental water requirements: Case study

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Science china Earth Sciences 2005年第8期48卷 1280-1292页

作者： YANG Zhifeng1,2. CUI Baoshan1 & LIU Jingling 1. School of Environment, beijing Normal university, beijing 100875, china 2. state key joint laboratory of environmental simulation and pollution control, beijing 100875, china 1. School of Environment Beijing Normal University 100875 Beijing China 2. state key {2. laboratory of environmental simulation and pollution control 100875 Beijing China

Supplying water to the ecological environment with certain quantity and quality is significant for the protection of diversity and the realization of sustainable development. The conception and connotation of eco-environmental water requirements, including the definition of the conception, the composition and characteristics of eco-environmental water requirements, are evaluated in this paper. The classification and estimation methods of eco-environmental water requirements are then proposed. On the basis of the study on the Huang-Huai-Hai Area, the present water use, the minimum and suitable water requirement are estimated and the cor-responding water shortage is also calculated. According to the interrelated programs, the eco-environmental water requirements in the coming years (2.10, 2.30, 2.50) are estimated. The result indicates that the minimum and suitable eco-environmental water requirements fluc-tuate with the differences of function setting and the referential standard of water resources, and so as the water shortage. Moreover, the study indicates that the minimum eco-environmental water requirement of the study area ranges from 2.84×1010m3 to 1.02.1011m3, the suitable water requirement ranges from 6.45×1010m3 to 1.78×1011m3, the water shortage ranges from 9.1×109m3 to 2.16×1010m3 under the minimum water requirement, and it is from 3.07×1010m3 to 7.53×1010m3 under the suitable water requirement. According to the different values of the water shortage, the water priority can be allocated. The ranges of the eco-environmental water re-quirements in the three coming years (2.10, 2.30, 2.50) are 4.49×1010m3?1.73×1011m3, 5.99×10m3?2.09×1011m3, and 7.44×1010m3?2.52.1011m3, respectively.

关键词： eco-environmental water requirements, assessment methods, Huang-Huai-Hai area.

Heterogeneous reactions of SO_2.on ZnO particle surfaces

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Science china Chemistry 2011年第1期54卷 161-166页

作者： LI Jia,SHANG Jing & ZHU Tong state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering,peking university,beijing 100871,{12. 1. state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering Peking University Beijing 100871 China

Heterogeneous reactions of SO2.on ZnO particle surfaces were studied using in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）. The influences of relative humidity （RH） and UV radiation （2. 365 nm） were investigated. In the absence of UV radiation, sulfite was the prominent product on the particle surfaces, and a negative relationship between RH and sulfite production was observed. In the presence of UV radiation, infrared （IR） absorption of sulfite and sulfate was evident in the spectra. With increasing RH or UV intensity, sulfite was gradually transformed into sulfate. UV intensity and RH exhibited a synergistic effect on the heterogeneous oxidation of SO2.on ZnO. On dry particles and with no UV radiation, the reaction order of SO2.on ZnO particles was 1.6. The initial uptake coefficient for the formation of sulfite, using the Brunauer-Emmett-Teller （BET） area as the reactive surface area of SO2. was 4.87 × 10^-6. At 40% RH and with UV radiation, the reaction order was 0.91, and the initial uptake coefficient was 2.2. ×10^-5.

关键词： SO2 ZnO DRIFTS heterogeneous oxidation UV radiation