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1.
为探究威海市秋季挥发性有机物(VOCs)污染特征及来源,于2021年9月10—20日采用手工加密监测法对威海市秋季大气中VOCs进行监测,分析了气象因素对臭氧(O3)及其前体物的影响和VOCs污染特征,并利用正交矩阵因子模型(PMF)方法对VOCs来源进行了研究。结果表明,威海市温度对O3生成影响明显,尤其是高温、低湿、扩散较差气象条件下,有利于O3前体物的反应消耗,促使O3生成及累积。观测期间,威海市秋季φ(VOCs)平均值为47.84×10-9,VOCs中体积分数占比最高的为含氧挥发性有机物(OVOCs),占比为58.0%,其次为烷烃(21.6%)、卤代烃(10.2%)。O3生成潜势(OFP)平均值为393.95μg/m3,对OFP的贡献占比最高的为OVOCs(74.1%),其次为芳香烃(12.6%)、烷烃(7.0%)和烯烃(5.4%)。PMF源解析结果显示,机动车尾气排放源、工艺过程源、船舶尾气排放源和溶剂使用源是威海市秋季VOCs排放主要来源,贡献占比分别为30.4%,23.9%,21.1%,16.5%。控制机动车排放和工艺过程排放是控制威海市秋季VOCs污染的重要途径。  相似文献   

2.
利用合肥市臭氧和VOCs连续观测数据分析了合肥市臭氧及其前体物污染特征,并使用NAQPMS模型研究了合肥市不同季节臭氧来源情况。结果表明:O3已经成为影响合肥市环境质量的主要污染因子,O3高值区主要集中在5—6月和9月。合肥市大气VOCs中烷烃含量最丰富,其次是烯烃、芳香烃和炔烃;主要物种为乙烷、丙烷、乙炔、正戊烷、乙烯、环戊烷、异戊烷、正丁烷、异丁烷和甲苯。合肥市O3生成主要受VOCs控制,其中,烯烃是合肥市O3生成贡献最大的关键活性组分,乙烯的OFP贡献率居首位。合肥市不同季节O3来源差异较大,其中,本地排放是主要来源,夏季占比为50%,其余季节占比为30%~45%,O3存在跨省长距离输送特征,主导风向的变化是造成合肥市臭氧来源季节性变化的重要因素。  相似文献   

3.
2020年7月30日—10月10日对西安市某工业园区大气中的70种VOCs开展了为期73 d的VOCs手工采样监测,分析了上、下风向2个点位VOCs浓度组成特征、O3生成潜势和SOA生成潜势,并运用PMF进一步分析该区域VOCs的主要来源。结果显示:监测期间工业园区平均VOCs浓度为203.50 μg/m3,以甲醛和乙醛为主的醛酮类(148.37 μg/m3)是主要污染物,占TVOC浓度的57%~84%,其次是烷烃。通过上、下风向VOCs成分比较发现,醛酮类为高污染时段特征污染物,工业园区平均OFP为969.66 μg/m3,醛酮类对O3生成的贡献最大,占TOFP的80%~97%,其次是烯烃。工业园区平均SOAFP为0.50 μg/m3,芳香烃对SOA生成的贡献最大,占TSOAFP的48%~98%,其次是烷烃。PMF源解析得到5个因子,分别为工业源、溶剂涂料、燃烧源、移动源及其他源,贡献率分别占35.2%、20.4%、18.3%、12.8%、13.3%,解析显示该区域受到下风向电子产业影响较大。  相似文献   

4.
选取臭氧(O3)污染高发的7月为夏季典型月,采用自动观测设备,从前体物VOCs的浓度水平及O3生成潜势(OFP),前体物、气象因素与O3相关性等多方面研究了衡水市O3污染影响因素,并剖析了一次典型的O3污染过程,以期为衡水市夏季O3污染防治提供科学参考。研究结果表明:衡水市VOCs主要组分浓度占比为烷烃 > 烯烃 > 芳香烃 > 乙炔,主要组分对总OFP的贡献为烯烃 > 芳香烃 > 烷烃 > 乙炔;O3与前体物VOCs、NO2存在负相关性,与温度存在正相关性;相对湿度低于48%时,O3和相对湿度呈负相关性,相对湿度高于48%时,O3和相对湿度呈正相关性;气团中VOCs化学组成稳定性较低,平均VOCs最大增量反应活性(MIR)较低,为4.855gO3/gVOCs;衡水市7月2—4日重度污染过程受本地生成和区域传输叠加影响。  相似文献   

5.
利用数值天气预报模式和嵌套网格空气质量预报系统的来源解析模块(WRF NAQPMS/OSAM)对中山市2019年9月1次臭氧(O3)污染过程进行了模拟分析,并对O3来源进行了解析。结果表明,WRF-NAQPMS/OSAM模型能较好地模拟出该时段的O3浓度。此次污染过程区域传输对中山市O3浓度贡献显著,平均贡献比例为82.9%,本地平均贡献比例为17.1%,对中山市O3贡献最大的2个来源分别是溶剂源和交通源,平均贡献占比分别为43.0%和42.7%。另外,工业源的贡献也不可忽略,平均贡献占比为11.0%。中山市O3总体上处于挥发性有机物(VOCs)控制区,结合臭氧生成潜势(OFP)分析和源解析结果,溶剂源、交通源和工业源排放的甲苯、间/对二甲苯、邻二甲苯、1,2,3-三甲苯、正丁烷和异戊烷对O3形成贡献显著,是中山市O3污染治理应注意的重要前体物。建议中山市建立以VOCs控制为主导,VOCs和氮氧化物(NOX)协同控制的长期O3防控策略。  相似文献   

6.
工业化与城镇化交替演进使珠三角及其周边地区土地利用类型较为复杂。快速的城市化进程使城市建成区与大量村镇工业园区互相交错。这种变化势必会增加挥发性有机物(VOCs)在组分构成和空间分布上的复杂性,并对臭氧(O3)污染的时空变化产生影响。为厘清这种排放的空间异质性特征及其对O3污染分布的影响,分别选取可以代表清远市典型工业园区和城市建成区的站点开展观测研究。结果表明:工业园区和城市建成区VOCs浓度水平和污染特征有较大的空间差异,其中代表村镇工业园区的龙塘站VOCs日均浓度为30.42×10-9,高于代表城市建成区的技师学院站(17.32×10-9)。龙塘站二甲苯和甲苯的臭氧生成潜势(OFP)比技师学院站高57.6×10-9,且该值相当于技师学院站排名前10位物种OFP的总和。气象分析表明:2个站点之间并非彼此的上、下风向,而是共同受到局地气团的影响。源解析结果表明:源排放是造成这种空间异质性的内因,其中交通源对技师学院的贡献更高,而工业相关排放源对龙塘的贡献更高。该研究进一步比较了周边站点O3时间序列的一致性,并模拟2个站点的O3生成速率。研究发现O3在局地范围内变化较小,高VOCs排放的地点对局地O3有较高的贡献,局地内不同地点的O3生成过程也存在较大差异。据此,笔者提出O3污染防控建议:短期内可通过技术手段和观测数据发现O3污染的重要贡献点,并进行针对性的"散乱污"清理整治和涉VOCs行业综合整治,长期看应科学合理规划城市发展布局和产业布局,预留城市通风廊道,以有效减少O3污染。  相似文献   

7.
2018年4月至2019年3月对杭州市城区大气中117种挥发性有机物(VOCs)开展了为期一年的手工采样观测,分析了VOCs各组分的浓度特征、臭氧生成潜势(OFP)和二次有机气溶胶(SOA)生成潜势。结果显示,观测期杭州市大气VOCs体积分数均值为(56.72±29.56)×10-9,含氧挥发性有机物(OVOCs)、烷烃和卤代烃是其主要组分,分别占33.86%、30.70%、15.73%。VOCs体积分数前10位的物种为丙烷、甲醛、异丁烷、乙烷、乙酸乙酯、二氯甲烷、正丁烷、丙酮、甲苯和1,2-二氯乙烷。杭州市VOCs的OFP为135.18×10-9,各VOCs组分的OFP贡献为OVOCs(45%) > 芳香烃(22%) > 烯烃和炔烃(21%) > 烷烃(11%) > 卤代烃(1%),其中甲醛、乙烯和乙醛是OFP主要贡献者。SOA生成潜势为1.64 μg/m3,芳香烃是最重要的SOA前体物。SOA生成潜势最大的5种VOCs物种为甲苯、对/间二甲苯、乙苯、邻二甲苯和苯,因此控制来自机动车尾气和溶剂使用过程中产生的VOCs可有效降低SOA的生成。通过甲苯与苯体积分数比分析发现,杭州市城区芳香烃除了来自机动车尾气以外,在春、夏季和秋、冬季还分别受到生物质燃烧和涂料溶剂的影响;分析了乙烷与乙炔体积分数比、乙炔与CO体积分数比,发现杭州市气团的老化程度呈现整体较高的特点。  相似文献   

8.
2019年7-8月在四川省遂宁市实验学校、遂宁中学、金鱼小学、石溪浩4个点位同步开展为期20d的挥发性有机物(VOCs)离线观测,分析了遂宁市VOCs浓度时空分布特征、臭氧生成潜势(OFP)和VOCs主要来源。遂宁市TVOC体积浓度为39.4×10-9,占比较高的组分为OVOCs和烷烃,体积浓度分别为15.6×10-9和13.3×10-9,占比分别为39.5%和33.6%。遂宁中学、金鱼小学、石溪浩24 h平均体积浓度分别为29.8 ×10-9、58.4 ×10-9、30.0×10-9;加密点实验学校的小时平均浓度为22.9×10-9。遂宁市总OFP为166.7 μg/m3,占比最大的为烯烃(33.1%)。实验学校、遂宁中学、金鱼小学、石溪浩OFP浓度分别为101.2、134.4、243.6、122.1 μg/m3。金鱼小学采样点位于工业园区下风向,受工业园区企业排放源影响,VOCs浓度和OFP值均明显高于其他点位。PMF模型源解析结果表明:遂宁市VOCs来源占比最大的为工业排放源,达32%;其次为机动车尾气源、燃烧源,占比均达17%;油气挥发源、天然源、溶剂使用源分别占13%、11%、10%。工业源、机动车尾气来源占比最高的均是金鱼小学,分别为39%、30%;天然源占比较高的是实验学校(13%)和石溪浩(10%)。  相似文献   

9.
2020年4—9月通过离线采样研究了盐城市城区大气中的挥发性有机物(VOCs)浓度水平及组成特征、臭氧生成潜势、二次有机气溶胶生成潜势以及毒性效应等多效应评估和来源贡献。结果表明:盐城市城区VOCs平均体积浓度为35.09×10-9,盐塘湖公园站点浓度最高;盐城市VOCs主要组分为含氧有机物(OVOCs)和烷烃。通过挥发性有机物多效应评估发现,关键物种为乙醛、对二乙苯、丙酮、甲苯和间/对二甲苯等。采样期间对VOCs浓度的主要贡献来源为二次生成、工业排放和交通排放。  相似文献   

10.
利用2020年3月28日—5月3日南京某典型化工园区挥发性有机物(VOCs)离线监测数据,分析了园区内VOCs污染特征及臭氧生成潜势(OFP)。结果表明,春季园区φ(VOCs)范围为22.3×10-9 ~892.6×10-9,82.1%频率的φ(VOCs)<100×10-9;VOCs组分占比表现为:烷烃>含氧挥发性有机物(OVOCs)>烯烃>卤代烃>芳香烃>炔烃>有机硫。高体积分数VOCs中烷烃和烯烃占比高于低体积分数VOCs,受园区内部储罐存储、运输、转运等过程产生的油气挥发及石油化工原料、合成材料的生产影响显著。不同时刻φ(VOCs)表现为夜间最高、早晨其次、下午最低的变化特征,这与园区内部VOCs排放累积、大气边界层抬升和大气光化学反应等因素有关。OFP值范围为166.2~6 920.9 ,μg/m3,56.0%频率的OFP<500。  相似文献   

11.
微波消解-原子吸收光度法测定土壤中铜锌铅镉镍铬   总被引:24,自引:5,他引:24       下载免费PDF全文
用微波消解-原子吸收光度法测定土壤中铜,锌,铅,镉,镍和铬。通过硝酸-氢氟酸-过氧化氢体系消解液对土壤样品消解,选择出微波最佳消解条件。对硝酸-盐酸-过氧化氢体系消解液和硝酸-氢氟酸-过氧化氢体系消解液进行消解对比试验,发现前者不能将土壤样品完全消解,后者能将样品消解完全,但需将消解液中剩余的酸赶尽,否则测定结果将明显偏低。微波消解土壤与传统电热消解相比,操作简便快速,可提高工作效率。  相似文献   

12.
Material Disposal Area G is the primary low-levelradioactive waste disposal site at Los Alamos NationalLaboratory, New Mexico, and is adjacent to Pueblo of SanIldefonso lands. Pueblo residents and Los Alamos scientists areconcerned about radiological doses resulting from uptake of AreaG radionuclides by mule deer (Odocoileus hemionus) andRocky Mountain elk (Cervus elaphus), then consumption ofdeer and elk meat by humans. Tissue samples were collected fromdeer and elk accidentally killed near Area G and were analyzedfor 3H, 90Sr, total U, 238Pu, 239, 240Pu,241Am, and 137Cs. These data were used to estimatehuman doses based on meat consumption of 23 kg y-1. Humandoses were also modeled using RESRAD, and dose rates to deer andelk were estimated with a screening model. Dose estimates tohumans from tissue consumption were 2.9 × 10-3 mSv y-1and 1.6 × 10-3 mSv y-1 from deer and elk, respectively,and RESRAD dose estimates were of the same order of magnitude. Estimated dose rates to deer and elk were 2.1 × 10-4 mGyd-1 and 4.7 × 10-4 mGy d-1, respectively. Allestimated doses were significantly less than established exposurelimits or guidelines.  相似文献   

13.
An important research area in life sciences is devoted to modeling, prediction, and dynamics of gene-expression patterns. As clearly understood in these days, this enterprise cannot become satisfactory without acknowledging the role of the environment. To a representation of past, present, and most likely future states, we also encounter measurement errors and uncertainties. This paper surveys and improves recent advances in understanding the foundations and interdisciplinary implications of the newly introduced gene–environment networks, and it integrates the important theme of carbon dioxide emission reduction into the networks and dynamics. We also introduce some operational and managerial issues of practical working and decision making, expressed in terms of sliding windows, quadrants (modules) of parametric effects, and navigating (controlling) between such effects and directing them. Given data from DNA microarray experiments and environmental records, we extract nonlinear ordinary differential equations that contain parameters that have to be determined. For this, we employ modern (Chebychevian) approximation and (generalized semi-infinite) optimization. After this is provided, time- discretized dynamical systems are studied. A combinatorial algorithm with polyhedra sequences allows to detect the region of parametric stability. Finally, we analyze the topological landscape of gene–environment networks with its structural (in)stability. By embedding as a module and investigating CO2 emission control and figuring out game theoretical aspects, we conclude. This pioneering work is theoretically elaborated, practically devoted to health care, medicine, education, living conditions, and environmental protection, and it invites the readers to future research.   相似文献   

14.
The aim of the study was to determine the extent of heavy metal pollution in the vicinity of a lead battery manufacturing plant in the Czech Republic, both in the general environment and within homes. Topsoils (0–5 cm) were sampled from 100 sites along 4 transects which crossed the battery factory, the town centre and outlying rural areas. Housedust samples were collected from 15 plant-workers' homes and 15 non plant-workers' homes located at various distances from the factory. Samples were analysed for levels of Pb, Zn, Cd, Cu, As and Sb, using ICP-AES. Soil concentrations of Pb, Cd, As and Sb peaked at the perimeter fence of the battery factory with Pb levels of up to 12 650 g g> -1. Concentrations of these metals decreased exponentially within 500 m of the plant. Whilst the battery factory does appear to be a source of all the metals with the exception of Zn, emissions do not appear to be transported to any great extent over distances of more than 0.5 km. Topsoil and housedust concentrations of Pb, Zn, Cd, Cu, As and Sb in the general Mlada Boleslav area do not appear to be significantly different from those recorded in a large scale survey of urban soils in the United Kingdom. A comparison of housedust Pb concentrations in homes of plant workers and non-plant workers suggests that there may be a small input of Pb into the home environment by battery plant employees.  相似文献   

15.
The San Francisco Estuary Regional Monitoring Program for Trace Substances (RMP) began in 1993 and is sponsored by 74 local, state, and federal agencies and companies through their discharge or Bay use permits. The RMP monitors water, sediment, toxicity, and bivalve bioaccumulation at 25 sites in the Bay that are considered to represent "background" conditions. Several major environmental issues have been identified by the RMP. Polychlorinated biphenyls and mercury were often above water quality guidelines, and often occurred in fish tissues above U.S. Environmental Protection Agency (U.S. EPA) screening values. Concentrations do not appear to be decreasing, suggesting continuing inputs. Episodes of aquatic toxicity often occurred following runoff events that transport contaminants into the Bay from urbanized and agricultural portions of the watershed. Sediment toxicity occurred throughout the Bay, and has been correlated with concentrations of specific contaminants (chlordanes, polynuclear aromatic hydrocarbons) at some locations; mixtures of contaminants were probably also important. Since the RMP does not monitor all ecosystem components, assessments of the overall condition of the Bay cannot be made. However, in terms of contamination, the RMP samples suggest that the South Bay, and North Bay sites are moderately contaminated.  相似文献   

16.
This paper gives mathematical details and sample applications of SWAGMAN Farm (SWAGMAN, Salt Water and Groundwater Management), a farm-scale hydrologic economic model that integrates agronomic, climatic, irrigation, hydrogeological and economic aspects of irrigated agriculture. The model is capable of determining optimum mix of land use to keep watertable and soil salinity within acceptable limits while maximising the economic returns. Alternatively, the model can simulate water and salt balance and economics of a given cropping preference. Web-based and Geographic Information Systems versions of the model are available for integration with the environmental reporting systems of the irrigation areas.  相似文献   

17.
A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in westernOregon was studied in 1993. The study was designed to determinecontaminant concentrations in eggs, contaminant concentrationsin fish species predominant in the Ospreys diet, andBiomagnification Factors (BMFs) of contaminants from fish specieseaten to Osprey eggs. Ten Osprey eggs and 25 composite samplesof fish (3 species) were used to evaluate organochlorine (OC)pesticides, polychlorinated biphenyls (PCBs), polychlorinateddibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans(PCDFs). Mercury was also analyzed in fish. Geometric meanresidues in Osprey eggs were judged low, e.g., DDE 2.3 g g-1 wet weight (ww), PCBs 0.69 g g-1, 2,3,7,8-TCDD 2.3 ng kg-1, and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presentedby River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggsfrom the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the CascadeMountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and NorthernPikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fishbiomass in the Osprey diet sampled for contaminants (and fisheaten by Ospreys similar in size to those chemically analyzed),and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the largeseries of contaminants. BMFs ranged from no biomagnification(0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for themigratory Osprey were compared to BMFs for the resident HerringGull (Larus argentatus), and differences are discussed. Webelieve a BMF approach provides some basic understanding ofrelationships between contaminant burdens in prey species offish-eating birds and contaminants incorporated into their eggs,and may prove useful in understanding sources of contaminants inmigratory species although additional studies are needed.  相似文献   

18.
The draft of the German guideline to calculate automobile exhaust dispersion is explained. It contains a two-stage-system: For first quick estimates the guideline contains the simple models MLuS and STREET. In case these models are not applicable or their results shows concentration levels close to the air quality standards, the more complex models PROKAS_V and MISKAM are recommended. PROKAS_V is a Gaussian plume model, MISKAM is a 3-dimensional microscale non hydrostatic flow model for built-up areas with an Eulerian dispersion model. The guideline comprises cases in rural areas without or with few adjacent buildings as well as urban areas with buildings near the roads. The contribution gives information about the models, typical results and some of the problems showing up presently.  相似文献   

19.
The population counts of hydrocarbon-utilising yeasts weremonitored at six sampling stations in the Benin City municipalarea over a four-week period. Although the population countswere relatively constant in each locality, the highest countsoccurred in areas heavily polluted by domestic and industrialeffluents. A total of thirty-five hydrocarbon-degrading yeastswere isolated from soil at the sampling stations usingn-hexadecane as sole carbon source. The isolates were identifiedas belonging to the genera Candida (27 strains), Endomycopsis (4 strains). All the organisms grew on long-chainn-alkane, kerosene, diesel oil and crude oil but failed to growon short-chain n-alkane, aromatic and alicyclic hydrocarbons.Measurement of growth attributes of the isolates usingn-hexadecane, diesel oil and crude oil as substrates showed thatthe Candida species were better utilizers of hydrocarbonsubstrates relative to Endomycopsis and Schizosaccharomyces species.  相似文献   

20.
The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ 15N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ 15N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ 15N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ 15N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas, the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ 15N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R 2 = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ 15N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ 15N of Spartina relates with the integrated, watershed-sea nitrogen inputs.  相似文献   

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