我国移动源主要大气污染物排放量的估算

在考虑我国移动源主要大气污染物排放标准变化的基础上,分别对我国2000—2012年道路移动源和非道路移动源主要大气污染物(CO、NOx、HC、PM2.5)的排放量进行了估算。研究表明:2000—2012年间,我国移动源主要大气污染物排放总量呈现先增后减的趋势,2005年达到最大值,为4 233万t,其中道路移动源的排放量占80%以上;各类大气污染物的排放量的差异性较大,CO和NOx的排放量较多,占排放总量的87%以上,从整体趋势上来看,CO的排放量逐年较少,NOx的排放量逐年增大,而HC和PM2.5变化不大;摩托车和重型柴油货车是道路移动源主要排放源,农业机械是非道路移动源的主要排放源;移动源排放的主要大气污染物在地区间的分布极不平衡,2012年排放量最高的5个省份依次是山东、河北、河南、广东和江苏;排放强度较大的地区主要集中在环渤海经济圈、长三角地区和珠三角地区,其中又以上海、北京、天津3个直辖市的排放强度最大。     

西安市机动车污染控制策略实施效益评估

为研究未来西安市机动车污染控制策略的实施效果,基于情景分析法,以MOVES模型为平台,预测2020年西安市机动车PM_(2.5)、PM_(10)、NO_x、总碳氢化合物(THC)、CO、SO_2排放量分别为1 531.41、1 596.33、44 159.48、14 029.62、383 200.08、5 164.63t。设置5类不同控制措施情景,分析其对机动车的减排效果。结果显示:单一措施中,淘汰"黄标车"和老旧车对污染减排效果最明显,6种污染物均有较大幅度减排;调控轻型客车保有量可明显削减THC、CO的排放,减排比例分别为13.49%、18.59%;提升燃油质量可使各车型SO_2的减排比例均达到90%以上;使用替代燃料情景的污染物减排比例相对较低,但也是一种有效的控制策略;综合控制措施的减排效果最为显著,与基准情景相比,2020年PM_(2.5)、PM_(10)、NO_x、THC、CO和SO_2减排比例分别为78.50%、78.37%、71.77%、72.47%、76.94%、98.30%。     

不同减排情景下郑州市机动车污染物排放研究

采用情景分析的方法,设置4种减排情景(包括1种基准情景和3种控制策略情景),研究适合郑州市机动车污染控制的政策,估算2013—2017年不同情景下郑州市机动车污染物排放量,并与基准情景下的排放量进行比较,分析不同控制策略情景下减排效果的年度变化。情景分析结果表明:通过提高燃油标准,减排能力在2013—2017年基本稳定,2017年CO、碳氢化合物(HC)、NO_x和颗粒物(PM)的削减率分别为8.8%、3.5%、0.4%、1.9%;通过淘汰黄标车,削减率大体随着黄标车年保有量的减少逐年下降,2017年CO、HC、NO_x和PM的削减率分别为0.6%、0.8%、0.5%、2.3%;通过推广新能源汽车,每年新增新能源汽车在大型客车、小型客车和公交车中的比例分别是10%、30%、100%,削减率逐年上升,2017年CO、HC、NO_x和PM的削减率分别为3.2%、3.3%、2.2%、2.8%。     

和田绿洲沙尘暴强度及其影响因子分析——以墨玉县为例

以和田绿洲西北部的墨玉县为研究区域,对该地区2016—2018年发生的沙尘暴天气资料以及气象因子(气温、风速、湿度、气压、水汽压、日照时数)和大气污染物(PM2.5、PM10、SO2、NO2、CO、O3)进行分析。结果表明,墨玉县沙尘暴天气主要发生在春夏季(3—8月),平均占全年发生频率的77.12%。墨玉县沙尘暴强度主要由气象因子决定,特别是气温、风速、日照时数和湿度。沙尘暴强度与大气颗粒物(PM10和PM2.5)存在着明显的间接关系,主要因为两者均受风速影响较大,沙尘暴强度越大,大气中PM10和PM2.5浓度越高。沙尘暴强度与SO2、NO2、CO、O3等大气污染物的关系非常微弱,但O3与沙尘暴的形成季节比较一致。     

成都市餐饮源大气污染物排放清单研究

为全面、准确地获得成都市餐饮源大气污染物排放清单,针对成都市社会餐饮、家庭餐饮和食堂餐饮分别选择监测对象进行细颗粒物(PM2.5)、非甲烷总烃(NMHCs)、油烟、氮氧化物(NOx)、SO2和CO 6种大气污染物排放浓度监测.分别按照用油量、就餐人次和灶头风量3种核算依据计算了6种大气污染物的排放因子,并计算成都市餐饮...     

基于电力结构调整的上海市电力行业大气污染物排放总量研究

基于上海市能源与电力统计数据,参考政府间气候变化专门委员会(IPCC)及国内发电企业污染物排放相关研究报告,设定不同发电方式的装机比例,分析核算不同装机比例下SO2、NOX以及CO2的排放量与减排量。结果表明,装机比例提升10.0%,相比煤电装机,天然气装机的SO2、NOX及CO2的排放量分别降低90.2%、91.3%与99.9%,减排效果显著。新能源装机比例由5.0%提升至10.0%,SO2、NOX及CO2分别削减3.0×103、3.8×103、3.6×107 t。     

河谷型城市一次大气持续重污染特征及其原因分析 —— 以宝鸡市为例

利用2016年冬季12月16—22日监测的宝鸡市6种大气污染物及主要气象要素,分污染前、重污染期、污染结束3个过程分析了污染物的变化特征,探讨了大气污染物时间变化与气象要素关系。结果表明:(1)大气重污染过程中主要污染物为PM_(10)和PM_(2.5),重污染期最大值比污染前增加113%、93%,比污染结束高出268%、190%,浓度均超过《环境空气质量标准》(GB 3095—2012)中24h平均二级限值。SO_2、CO、NO_2、O_3重污染期最大值比污染前增加7%、33%、54%、18%,比污染结束高出36%、33%、58%、57%,但浓度均未超过GB 3095—2012中1h平均二级限值。日变化总体表现为PM_(2.5)、PM_(10)、CO出现两个峰值,SO_2、NO_2、O_3出现一个峰值;3个过程峰值点出现时间基本一致;重污染期PM_(2.5)、PM_(10)较高,但振幅比污染前后的振幅减小。(2)PM_(10)、PM_(2.5)与相对湿度、风速关系密切,与气温关系较差。(3)河谷地形、气象条件及大气环流场相互作用形成污染物持续的集聚是导致宝鸡市重污染发生的重要因素,并对污染物的扩散和清除具有滞后作用。     

乌昌石区域的非金属矿物制品业大气污染物排放清单研究

建立了乌昌石区域非金属矿物制品业CO、NO_x、SO_2、PM_(2.5)和PM_(10) 5种大气污染物的排放清单,并进行了时空分布特征分析,初步探究了估算的不确定性。结果显示,乌昌石区域非金属矿物制品业CO、NO_x、SO_2、PM_(2.5)和PM_(10)总排放量分别为3.71×10~4、2.76×10~4、3.10×10~4、3.04×10~4、1.29×10~5 t。熟石膏行业是CO的主要排放源;水泥(干法)行业是NO_x、SO_2、PM_(2.5)和PM_(10)的主要排放源。乌鲁木齐市是CO、NO_x和SO_2排放量的最大贡献源;石河子市是PM_(2.5)和PM_(10)排放量的最大贡献源。乌昌石区域5月至9月是一年中污染物排放的高峰期,11:00至20:00是一天中污染物排放的高峰期。空间上,乌昌石区域的污染物排放主要分布在乌鲁木齐市中部、西南部以及石河子市。     

秸秆成型燃料锅炉污染物排放规律试验研究

根据锅炉烟尘测试方法(GB 5468-91)及锅炉大气污染物排放标准(GB 13271-2001),在不同风门的工况下,分别对设计的双层炉排秸秆成型燃料锅炉污染物排放规律进行试验.试验表明,在较好工况下,双层炉排锅炉排烟中CO等中间产物及烟尘含量低于单层炉排锅炉,其排烟中CO、NOx、SO2和烟尘浓度等指标远远低于燃煤锅炉,符合国家关于工业锅炉大气污染物排放标准要求,有较好环保效益.     

汾渭平原采暖期与非采暖期大气环境质量时空变化特征研究

采暖期重污染天气频发,成为大气环境质量改善的难点。汾渭平原刚被划为中国环境治理的重点区域,大气污染形势十分严峻。基于2014—2018年PM2.5、SO_2、NO_2、O_3和CO等污染物监测数据及空气质量指数,分析了汾渭平原采暖期和非采暖期大气环境质量的时空变化特征。结果表明:(1)采暖期PM_(2.5)、SO_2、NO_2和CO浓度均高于非采暖期,非采暖期PM_(2.5)相比采暖期低42%～54%,采暖期SO_2、NO_2和CO的平均浓度分别是非采暖期的2.7、1.5、1.6倍,而非采暖期O_3平均浓度是采暖期的2.2倍;(2)PM_(2.5)和SO_2为采暖期首要污染物,O_3为非采暖期首要污染物;(3)采暖期和非采暖期三省交界处和临汾的PM2.5浓度均较高,采暖期气态污染物的空间分布与非采暖期基本相似,其中SO_2浓度的空间分布为山西境内河南境内陕西境内;(4)采暖期PM_(2.5)与SO_2、NO_2、CO浓度均呈正相关,与O_3呈负相关,非采暖期SO_2、NO_2和CO随PM_(2.5)浓度呈一致变化趋势,均先上升后下降,与采暖期的变化趋势并不相同;(5)采暖对PM_(2.5)和SO_2的年平均贡献率分别为34.9%和42.1%。     

The binding of three PCB congeners to dissolved organic carbon in freshwaters

The binding of three polychlorinated biphenyl (PCB) congeners to natural levels of dissolved organic carbon (DOC) was measured in 12 lakes and streams using Sep-Pak C₁₈ columns. The association coefficients calculated on the basis of DOC (i.e. K_DOC mL/g C), varied by over an order of magnitude among the different freshwaters and ranged between 2.05 × 10² and 8.86 × 10³ mL/g C for PCB 52 and 1.03 × 10⁴ and 1.70 × 10⁵ mL/g C for PCB 153. In general, there were no significant correlations (p > 0.05) between the K_DOC values and various chemical parameters in the study lakes and streams.

A relationship was derived between the fraction of bound PCB and the octanol-water partition coefficient. While this relationship explained almost 50% of the variation in the observed data, it is apparent that other factors influence K_DOC values and that in natural freshwaters, only a small fraction of the DOC is involved in the binding of PCBs and other hydrophobic pollutants.     

Cold season CH4, CO2 and N2O fluxes from freshwater marshes in northeast China

Cold season (winter and thaw) CH₄, CO₂ and N₂O fluxes from freshwater marshes (47°35′N, 133°31′E, Northeast China) were measured, using the static chamber method. The mean CH₄ and CO₂ fluxes from Carex lasiocarpa (Cl) were 0.5 ± 0.19 and 6.23 ± 1.36 mg C m⁻² h⁻¹, respectively, and those from Deyeuxia angustifoli (Da) were 0.18 ± 0.15 and 5.22 ± 2.48 mg C m⁻² h⁻¹, respectively in winter. There was no significant difference between Cl and Da (p > 0.05). The contributions of winter CH₄ fluxes were about 5.5% and 3% in the Cl and Da, respectively. Marshes are an important potential N₂O sink in winter season in northeast China. During thaw, the CH₄ and CO₂ emissions rapidly increased, 4.5–6 times of winter emissions. Wetland became a source of N₂O. Cold season gases flux from northern wetlands play an important role in the seasonal gas exchange.     

Determination of trichloroacetic acid in environmental studies using carbon 14 and chlorine 36

Radioisotopes carbon 14 and chlorine 36 were used to elucidate the environmental role of trichloroacetic acid (TCA) formerly taken to be a herbicide and a secondary air pollutant with phytotoxic effects. However, use of ¹⁴C-labeling posed again known analytical problems, especially in TCA extraction from the sample matrix. Therefore—after evaluation of available methods—a new procedure using decarboxylation of [1,2-¹⁴C]TCA combined with extraction of the resultant ¹⁴C-chloroform with a non-polar solvent and its subsequent radiometric measurement was developed. The method solves previous difficulties and permits an easy determination of amounts between 0.4 and 20 kBq (10–500 ng g⁻¹) of carrier-less [1,2-¹⁴C]TCA in samples from environmental investigations. The procedure is, however, not suitable for direct [³⁶Cl]TCA determination in chlorination studies with ³⁶Cl. Because TCA might be microbially degraded in soil during extraction and sample storage and its extraction from soil or needles is never complete, the decarboxylation method—i.e. 2 h TCA decomposition to chloroform and CO₂ in aqueous solution or suspension in closed vial at 90 °C and pH 4.6 with subsequent CHCl₃ extraction—is recommended here, estimated V < 7%. Moreover, the influence of pH and temperature on the decarboxylation of TCA in aqueous solution was studied in a broad range and its environmental relevance is shown in the case of TCA decarboxylation in spruce needles which takes place also at ambient temperatures and might amount more than 10–20% after a growing season. A study of TCA distribution in spruce needles after below-ground uptake shows the highest uptake rate into current needles which have, however, a lower TCA content than older needle-year classes, TCA biodegradation in forest soil leads predominatingly to CO₂.     

Effect of boiler operation and RDF feedstock on emissions of dioxins and furans from an RDF fired sp reader-stoker system in Albany, NY

The data on dioxin and furan emissions revealed, based on individual analysis for 2,3,7,8-TCDD, TCDD, 2,3,7,8-TCDF and TCDF for the six test periods and the operation of the two RDF-fired boilers, that there is no apparent consistent relationship between the dioxin and furan emissions and the individual or combined (averaged) boiler steam flow, total flue gas flow, sidewall furnace temperature, furnace temperature at 2-second residence time, or total furnace residence time at this plant. Only RDF feeder balance begins to show a correlation. However, there was a difference between RDF-natural gas firing and RDF-only firing; the RDF-only firing had lower PCDD and PCDF emissions while consistently operating at lower excess air.

The dioxin and furan emissions from this testing are comparable to the low end of the range of these emissions measured by the U.S. EPA at resource recovery plants in the past 4 years. This may be due in part to the calculated average furnace retention of 4 to 5 seconds during Tests #4–6, with average furnace temperatures at 2-second residence time from 1650°F to 1750°F. However, there was no correlation between dioxin and furan emissions in the stack and individual boiler operation, as judged by the average concentrations of O₂, CO, CO₂, 1-CO/CO₂), NO_x, HCl, SO₂, or TSP, and furnace upset conditions versus normal operation as judged by instantaneous steam flow, sidewall furnace temperature, O₂, CO, NO_x, or SO₂.     

Emissions from RDF/coal blended fuel combustion

The significant volume and weight reduction along with the energy potential of MSW, in the form of refuse derived fuel (RDF), has made its incineration an attractive alternative. However, the gaseous emissions such as, CO₂, CO, NO_x and SO₂, which are the byproduct of the combustion process pose serious environmental problems. These problems are compounded by the presence of certain highly regulated hazardous wastes such as, dioxins and furans in the exhaust stream. In the present investigation, different compositions of RDF/Coal blends were examined and the gaseous emissions from the combustion of the briquetted fuel were measured. Also, a direct comparison of emissions from RDF/coal blend incineration with coal combustion is presented in this paper. The potential for recovery of ferrous and non- ferrous metals provides an additional economic motivation for the use of RDF/Coal blended briquettes.     

Modelling the environmental degradation of water contaminants. Kinetics and mechanism of the riboflavin-sensitised-photooxidation of phenolic compounds

The aerobic visible-light-photosensitised irradiation of methanolic solutions of either of the phenolic-type contaminants model compounds (ArOH) p-phenylphenol (PP), p-nitrophenol (NP) and phenol (Ph), and for two additional phenolic derivatives, namely p-chlorophenol (ClP) and p-methoxyphenol (MeOP), used in some experiments, was carried out. Employing the natural pigment riboflavin (Rf) as a sensitiser, the degradation of both the ArOH and the very sensitiser was observed. A complex mechanism, common for all the ArOH studied, operates. It involves superoxide radical anion (O₂^√−) and singlet molecular oxygen (O₂(¹Δ_g)) reactions. Maintaining Rf in sensitising concentrations levels (≈0.02 mM), the mechanism is highly dependent on the concentration of the ArOH. Kinetic experiments of oxygen and substrate consumption, static fluorescence, laser flash photolysis and time-resolved phosophorescence detection of O₂(¹Δ_g) demonstrate that at ArOH concentrations in the order of 10 mM, no chemical transformation occurs due to the complete quenching of Rf singlet excited state. When ArOH is present in concentrations in the order of mM or lower, O₂^√− is generated from the corresponding Rf radical anion, which is produced by electron transfer reaction from the ArOH to triplet excited Rf. The determined reaction rate constants for this step show a fairly good correlation with the electron-donor capabilities for Ph, PP, NP, ClP and MeOP. In this context, the main oxidative species is O₂^√−, since O₂(¹Δ_g) is quenched in an exclusive physical fashion by the ArOH. The production of O₂^√− regenerates Rf impeding the total degradation of the sensitiser. This kinetic scheme could partially model the fate of ArOH in aquatic media containing natural photosensitisers, under environmental conditions.     

PM2.5 chemical source profiles for vehicle exhaust, vegetative burning, geological material, and coal burning in Northwestern Colorado during 1995

PM_2.5 (particles with aerodynamic diameters less than 2.5 μm) chemical source profiles applicable to speciated emissions inventories and receptor model source apportionment are reported for geological material, motor vehicle exhaust, residential coal (RCC) and wood combustion (RWC), forest fires, geothermal hot springs; and coal-fired power generation units from northwestern Colorado during 1995. Fuels and combustion conditions are similar to those of other communities of the inland western US. Coal-fired power station profiles differed substantially between different units using similar coals, with the major difference being lack of selenium in emissions from the only unit that was equipped with a dry limestone sulfur dioxide (SO₂) scrubber. SO₂ abundances relative to fine particle mass emissions in power plant emissions were seven to nine times higher than hydrogen sulfide (H₂S) abundances from geothermal springs, and one to two orders of magnitude higher than SO₂ abundances in RCC emissions, implying that the SO₂ abundance is an important marker for primary particle contributions of non-aged coal-fired power station contributions. The sum of organic and elemental carbon ranged from 1% to 10% of fine particle mass in coal-fired power plant emissions, from 5% to 10% in geological material, >50% in forest fire emissions, >60% in RWC emissions, and >95% in RCC and vehicle exhaust emissions. Water-soluble potassium (K⁺) was most abundant in vegetative burning profiles. K⁺/K ratios ranged from 0.1 in geological material profiles to 0.9 in vegetative burning emissions, confirming previous observations that soluble potassium is a good marker for vegetative burning.     

As(V) adsorption on amorphous iron oxide: Triple layer modelling

The adsorption of As(V) by amorphous iron oxide was investigated at 25°C, 0.01 M NaNO₃ background electrolyte as a function of solution pH(4–10) at three initial As(V) concentrations and two Fe(III) concentrations. As(V) adsorption increased with decreasing pH. A modified Langmuir isotherm has been used for describing an equilibrium partition existing between solid and liquid phases. The triple-layer model was used for simulating As(V) adsorption on iron oxide surface. This model was able to describe As(V) adsorption over the pH range 4–10, all at the concentrations of As(V) and Fe(III) studied. =Fe(H₂AsO₄)⁰, = Fe(HAsO₄)⁻ and = Fe(AsO₄)²⁻ have been shown through simulation with inner-sphere complexation products to be more consistent with experimental adsorption observations than complexation with other surface species.     

Relationship between electron donor and microorganism on the dechlorination of carbon tetrachloride by an anaerobic enrichment culture

An investigation involving the supplement of different concentrations of substrates and microorganisms was carried out under anaerobic condition to assess the feasibility of bioremediation of carbon tetrachloride (CCl₄) with the amendment of low concentrations of auxiliary substrate and microorganisms. The concentrations of substrate and microorganisms ranged from 10 to 100 mg/l and from 3.7 × 10⁴ to 3.7 × 10⁶ cell/ml, respectively. The biotransformation rate of CCl₄ increased progressively with the increase in the concentrations of the substrate and microorganisms. In the low biomass-amended system (3.7 × 10⁴cells/ml), 28–71% and 57–96% of CCl₄ removals were exhibited when 10–100 mg/l of acetate or glucose was supplemented, respectively, whereas nearly complete degradation of CCl₄ was observed in the heavily inoculated systems (3.7 × 10⁶ cells/ml). An addition of electron donor in the low microbial activity batches enhanced greater efficiency in dechlorination than in the high microbial activity batches. The second-order rate constants ranged from 0.0059 to 0.0092 l/mg/day in high biomass input system, while a two- to four-fold increase in rate constant was obtained in the low microbial activity system. This study indicates that biomass was the more important environmental parameter than substrate affecting the fate of CCl₄. The addition of auxiliary substrates was effective only in low biomass-amended batches (0.56 mg-VSS/l) and diminished inversely with the increase of microbial concentration.