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The roles of heterogeneous chemical processes in the formation of an air pollution complex and gray haze

Science china Chemistry 2011年第1期54卷 145-153页

作者： ZHU Tong,SHANG Jing & ZHAO DeFeng 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

Urban and regional air pollutions are characterized by high concentrations of secondary pollutants such as photo-oxidants （mainly ozone） and fine particulate matter, which are formed through chemical reactions of the primary pollutants emitted from various sources. The accumulation of these pollutants under stagnant meteorological conditions results in the formation of gray haze, reducing visibility and causing major impacts on human health and climate. In an air pollution complex, the co- existence of high concentrations of primary and secondary gaseous and particulate pollutants provides a large amount of reac- tants for heterogeneous reactions on the surface of fine particles; these reactions change the oxidizing capacity of the atmos- phere, as well as chemical compositions along with the physicochemical and optical properties of particulate matter, thereby accelerating formation of the air pollution complex and gray haze. Using in situ technologies, such as diffuse reflectance infra- red Fourier-transform spectroscopy and single-particle Raman spectroscopy, we systematically investigated the reaction kinet- ics and mechanisms of gaseous pollutants （i.e., NO2. SO2. 03, and formaldehyde） on the surfaces of the major components of atmospheric particles such as CaCO3, kaolinite, montmorillonite, NaC1, sea salt, A12.3, and Tit2. We found that the main re- action products were sulfate, nitrate, or formate, which can change the hygroscopicity and light extinction parameters of those particles significantly. By analyzing the reaction kinetics of these heterogeneous reactions, we identified synergetic mechanisms of the three ternary reaction systems, ,i.e., NOE-particles-H2., SO2.particles-O3, and organics/SO2.particles-UV illumination. These synergetic mechanisms can provide experimental and theoretical bases for understanding the feedback mechanisms and nonlinear processes in the formation of an air pollution complex and gray haze.

关键词： fine particles secondary pollutants oxidizing capacity ternary reaction nonlinear processes

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Photocatalytic degradation of rhodamine B by dye-sensitized TiO_2.under visible-light irradiation

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Science china Chemistry 2011年第1期54卷 167-172页

作者： SHANG Jing,ZHAO FengWei,ZHU Tong & LI Jia 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

Perylene tetracarboxylic diimide (PTCDI),widely used in organic photovoltaic devices,is an n-type semiconductor with strong absorption in the visible-light *** has been almost no study of the PTCDI-sensitized TiO2.composite used to photocatalytically degrade *** this study,PTCDIand copper phthalocyanine tetrasulfonic acid (CuPcTs)-sensitized TiO2.composites were prepared using a hydrothermal *** morphologies and structures of the two composites were characterized by X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,and fluorescence *** visible-light photocatalytic activities of the composites were evaluated using the degradation of rhodamine B as a model *** showed that dye-sensitized TiO2.samples had a wider absorption spectrum range and higher visiblelight photocatalytic activity compared to TiO2.*** double dye-sensitized (or co-sensitized) TiO2.composite with efficient electron collection exhibited higher photocatalytic activity than did the single dye-sensitized TiO2.*** electron transfer processes of single and double dye-sensitized TiO2.composites were illustrated according to band theory.

关键词： copper phthalocyanine tetrasulfonic acid dye sensitization perylene tetracarboxylic diimide rhodamine B visible-lightphotocatalysis

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Small Peptide Interacting with Pollen Calmodulinand their Effects on Cellular Functions

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Chinese Chemical Letters 1999年第11期10卷 929-932页

作者： Jing SU Yan Ling SONG Min HU(college of Chemistry and Molecular Engineering, peking university, {2.)(state key laboratory of environmental simulation and pollution control,peking university. {2.) peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China peking Univ State Key Lab Environm Simulat & Pollut Control Beijing 100871 Peoples R China

The interaction between dansyl-labeled pollen calmodulin (D-pCaM) and synthesized peptides was studied in the presence of Ca2. by fluorescence spectra. It is Found that Gly/L-Ala --> D-Ala substitution in peptide chains caused great changes in their affinity for pCaM. Besides. our data provided evidence on the dissimilarity of different CaMs although they have highly-conserved structures. A preliminary study was carried out on the effects of CaM-binding peptides on cellular signal transduction, cell proliferation, showing the participation of CaM in cell functions mentioned above.

关键词： pollen calmodulin affinity cellular signal transduction cell proliferation

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Degradation of 4-chlorophenol in aqueous solution by γ-radiation and ozone oxidation

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Science china Chemistry 2006年第2期49卷 186-192页

作者： HU Jun1, WANG Jianlong1,2.& CHEN Rong1 1. laboratory of environmental Technology, Institute of Nuclear Energy Technology, Tsinghua {2., beijing 100084, china 2. state key joint laboratory of environmental simulation and pollution {12., Tsinghua {2., beijing 100084, china Correspondence should be addressed to Wang Jianlong 1. laboratory of environmental Technology Institute of Nuclear Energy Technology Tsinghua University Beijing 100084 China 2. state key {2. laboratory of environmental simulation and pollution control Tsinghua University Beijing 100084 China

The degradation of 4-chlorophenol (4-CP) by using gamma rays generated by a 60Co source in the presence of O3 was investigated. The radiolysis of 4-CP and the kinetics of 4-CP min-eralization were analyzed based on the determination of total organic carbon (TOC). The influence of initial 4-CP concentration and the free radicals scavengers (such as NaHCO3 and t-butanol) on the 4-CP degradation was also studied. The results showed that when the radiation rate was 336 Gy·min?1, 4-chlorophenol at concentration of 10 mg·L?1 could be completely degraded at the radiation dose of 2.kGy. The degradation of 4-chlorophenol could be described by a first-order reaction model, the rate constant of 4-CP degradation by combined ozonation and radiation was 0.1016 min?1, which was 2.4 times higher than the sum of radiation (0.02.4 min?1) and ozonation (0.0137 min?1). It re-vealed that the combination of radiation and ozonation resulted in synergistic effect, which can re-markably increase the degradation efficiency of 4-CP.

关键词： radiolysis, 4-chlorophenol, priority pollutant, degradation, O3, synergistic effect, kinetics.

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Hydroxyl radicals induced by quartz particles in lung alveolar macrophages: the role of surface iron

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Progress in Natural Science:Materials International 2006年第10期16卷 1038-1044页

作者： LI Yi, ZHU Tong, GUO Xinbiao and SHANG Yu ( state key {2. laboratory for environmental simulation & pollution control, peking university, beijing 100871, china Occupational & environmental Health Sciences, School of Public Health, peking university Health Science Center, beijing 100083, china) [a]state key {2. laboratory for environmental simulation & pollution control Peking University Beijing China [b]Occupational & environmental Health Sciences School of Public Health Peking University Health Science Center Beijing China

Previous studies have shown that hydroxyl radical generation is a key step in the mechanism of pathogenic process caused by airborne particles to the lung. However, there is no direct evidence for dose-response relationship between airborne particles and hydroxyl radical generation. In this study, hydroxyl radicals generated in lung alveolar macrophages exposed to quartz particles were measured using a highly sensitive capillary electrophoresis-fluorescence detection method. The results demonstrated that quartz particles induced the generation of hydroxyl radical in a dose-dependent manner, and the amount of the hydroxyl radicals was 10-10 mol/10 cells. The viability of alveolar macrophages exposed to quartz particles decreased with the increase of quartz concentration, showing a clear dose-response relationship. Hydroxyl radical scavenger mannitol could increase the viability of quartz-treated cells, suggesting that hydroxyl radical contributed directly to cell death. In this study this contribution accounted for about 5%-2.% of cell death. The hydroxyl radical generating potential was found to be related to surface iron content of the quartz particles.

关键词： inhalable quartz hydroxyl radical capillary electrophoresis dose-response relationship iron.

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Raman micro-spectrometry as a technique for investigating heterogeneous reactions on individual atmospheric particles

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Science china Chemistry 2011年第1期54卷 154-160页

作者： ZHAO DeFeng,ZHU Tong,CHEN Qi,LIU YingJun & ZHANG ZeFeng 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

Investigating the heterogeneous reaction on individual atmospheric particles is important because it approximates actual atmospheric conditions and can aid in reducing artifacts in elucidating real mechanisms and processes,and determining real kinetic parameters of the atmosphere *** study developed a Raman microspectrometry method to investigate heterogeneous reactions on individual *** method was applied to the reaction of NO2.with individual CaCO3 *** was demonstrated that Raman microspectrometry can obtain information on both chemical composition and microscopic morphology at the same time,as well as information on chemical characteristics,such as the phase,which is useful for studying reaction *** spectra of individual particles deposited on a substrate showed no interference by morphological resonance,which is helpful for obtaining high-quality ***,Raman microspectrometry was compared with other methods for investigating heterogeneous reactions on individual particles and was found to have several advantageous characteristics.

关键词： Raman microspectrometry individual atmospheric particle heterogeneous reaction

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Heterogeneous reactions on the surface of fine particles in the atmosphere

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Chinese Science Bulletin 2003年第21期48卷 2267-2276页

作者： DING Jie & ZHU Tong state key {2. laboratory of environmental simulation and pollution control, college of environmental Sciences, peking university, beijing 100871, {12. Correspondence should be addressed to Zhu Tong (e-mail:tzhu@ ***) state key {2. laboratory of environmental simulation and pollution control College of Environmental Sciences Peking University China

Fine particles play an important role in the atmosphere. Research on heterogeneous reactions on the surface of fine particles is one of the frontier areas of atmospheric science. In this paper, physical and chemical characteristics of fine particles in the atmosphere and the interactions between trace gases and fine particles are described, methods used in heterogeneous reactions research are discussed in detail, progress in the study of heterogeneous reactions on the surface of fine particles in the atmosphere is summarized, existing important questions are pointed out and future research directions are suggested.

关键词：细微颗粒大气科学多相反应空气动力学

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Heterogeneous reaction of NO_2.with sea salt particles

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Science china Chemistry 2010年第12期53卷 2652-2656页

作者： YE ChunXiang 1,LI HongJun 1,ZHU Tong 1,SHANG Jing 1,ZHANG ZeFeng 1,2.& ZHAO DeFeng 1 1 state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering,peking university,beijing 100871,{12. 2.college of Atmospheric Physics,Nanjing university of Information Science and Technology,Nanjing 2.0044,{12. 1. state key {2. laboratory of environmental simulation and pollution control college of environmental Sciences and Engineering Peking University Beijing 100871 China2. College of Atmospheric Physics Nanjing University of Information Science and Technology Nanjing 210044 China

To understand how NO2.reacts with sea salt particles in the atmosphere of Mega-cities in coastal zones,the heterogeneous reaction of NO2.on the surface of wet sea salt was investigated with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC).Kinetic measurements indicated that nitrate formation on sea salt was second order in NO 2.concentration and reactive uptake coefficients were (5.51 ± 0.19) × 10-7 and 1.2. × 10-6 respectively under 0% and 2.% relative humidity (RH) at NO 2.molecular concentration of 1.96 × 1015 mol/*** results showed that liquid water was formed at the site of MgCl2.6H2.,CaCl2.2.2. on the surface of sea salt and made the reaction more sustainable by releasing hydrated water and absorbing water from air even under a low RH (30%).Therefore,pure NaCl particles should not be used to represent sea salt in studies of the heterogeneous reaction with NO2.

关键词： sea salt particles diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) hydrated water absorbed water reactive uptake coefficient

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Identification of secondary organic aerosols based on aerosol mass spectrometry

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中国科学：化学英文版 2010年第12期53卷 2593-2599页

作者： HUANG XiaoFeng 1,ZHAO QianBiao 1,2.HE LingYan 1,HU Min 2.BIAN QiJing 3,XUE Lian 1 & ZHANG YuanHang 2.1 key laboratory for Urban Habitat {2. Science and Technology School of Environment and Energy,peking university Shenzhen Graduate School,Shenzhen 518055,china 2.state key joint laboratory of {2. simulation and pollution {12. college of {2. Sciences and Engineering,peking university,beijing 100871,china 3 Division of Environment,Hong Kong university of Science & Technology,Hong Kong,china 1. key laboratory for Urban Habitat {2. Science and Technology School of Environment and Energy Peking University Shenzhen Graduate School Shenzhen 518055 China2. State Key Joint Laboratory of Environmental Simulation and Pollution Control college of environmental Sciences and Engineering Peking University Beijing 100871 China3. Division of Environment Hong Kong University of Science & Technology Hong Kong China

Secondary organic aerosol (SOA) is one of the major components of aerosols in the atmosphere and has not been well understood so *** to the complex chemical composition of organic aerosols,the identification of SOA has been a hotspot and difficult issue in the field of aerosol *** study attempts to quantitatively identify SOA in winter of Shenzhen based on positive matrix factorization (PMF) *** sources were resolved and SOA was identified subsequently according to the characteristic ion fragments measured by highly time-resolved aerosol mass spectrometer *** showed that in the winter of Shenzhen the average SOA concentration was 9.41±6.33 g/m 3,accounting for 39.9±2..8% of the total organic *** with primary organic aerosol (POA),the SOA concentrations had no large variation,suggestive of characteristics of regional secondary *** ratio of SOA/BC had pronounced diurnal variation,similar to that of O x (O3+NO2.,indicating SOA formation was significantly controlled by activity of photochemistry in the *** most effective period for SOA formation was from 9 am～3 pm since the SOA/BC ratio increased by 12.% during this *** study provides a new technical method and a new idea for SOA investigation.

关键词： secondary organic aerosol aerosol mass spectrometry positive matrix factorization (PMF)

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High time resolution observation and statistical analysis of atmospheric light extinction properties and the chemical speciation of fine particulates

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Science china Chemistry 2010年第8期53卷 1801-1808页

作者： YAO TingTing1,HUANG XiaoFeng1,HE LingYan1,HU Min2.SUN TianLe1,XUE Lian1,LIN Yun1,ZENG LiWu1 & ZHANG YuanHang2.1key laboratory for Urban Habitat {2. Science and Technology,School of Environment and Energy,peking university Shenzhen Graduate School,Shenzhen 518055,china 2.5} key joint laboratory of {2. simulation and pollution {12. college of {2. Sciences and Engineering,peking university,beijing 100871,china 1. key laboratory for Urban Habitat {2. Science and Technology School of Environment and Energy Peking University Shenzhen Graduate School Shenzhen 518055 China2. State Key Joint Laboratory of Environmental Simulation and Pollution Control college of environmental Sciences and Engineering Peking University Beijing 100871 China

In recent years,the visibility deterioration caused by regional fine particulate pollution becomes one of the crucial air pollution problems in the urban areas of our *** rapid variation of visibility and fine particulates make it difficult to estimate the relationship between them precisely and accurately unless high time resolution observation data can be *** study aims to fill this gap in the field of atmospheric science by establishing a formula using multiple linear *** fitting goodness (R2.0.913,n=3167) was obtained using 10 min average of high-resolution real-time light scattering coefficients,light absorption coefficients,main chemical speciation concentration in PM1 and some meteorological parameters from 17 Jan to 16 Feb,*** shows that the average light extinction coefficient during the observation in the winter of Shenzhen was measured to be 2.0 ± 183 Mm?1,consisting of 72. of light scattering and 2.% of *** terms of the percentage contribution of PM1 chemical species to the total light extinction,the organic matter was estimated to be most with an average of 45%,followed by ammonium sulfate with an average of 2.%.The contributions of black carbon and ammonium nitrate were 17% and 12.,***,the diurnal variation of light extinction was investigated as well in this study.

关键词： light extinction PM1 chemical speciation high time resolution multiple linear regressions

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