共查询到20条相似文献，搜索用时 31 毫秒
1.
Alvin C. K. Lai 《Water, air, and soil pollution》2006,175(1-4):323-334
Accurate modeling indoor aerosol deposition and decay is an important step for exposure assessment. High deposition rate reduces indoor pollutant concentration and results in lower inhalation exposure. Many of indoor surfaces have random roughness protrusion scales up to several millimeters which it may significantly affect the deposition loss rate. Aerosols deposition onto most indoor surfaces can be considered as “rough’ surface deposition. However, particle deposition from anleaflong indoor environment is frequently modeled by assuming that surfaces are smooth. In this work, experimental results for deposition velocity onto drywall surfaces for supermicron particles from 1 to 7 μm are presented. Deposition velocity is significantly higher than that predicted by a previous published model. To illustrative the influence of particle deposition on exposure, two hypothetical room sizes and two air exchange rates were considered. Inhalation transfer factor was adopted as a risk exposure index. Taking into account of high deposition velocity onto drywall surfaces, inhalation transfer factors are 8 to 35% lower than that predicted by the model and this significant difference is important to the exposure assessment. 相似文献
2.
3.
M. A. Leal M. Joppert M. V. Licínio H. Evangelista J. Maldonado K. C. Dalia C. Lima C. V. Barros Leite S. M. Correa Geiza Medeiros K. Dias da Cunha 《Water, air, and soil pollution》2008,188(1-4):67-80
The aim of the present work is to characterize the local atmospheric emissions levels and compare them to the component derived from global pollution in a remote site at South Hemisphere (Admiralty Bay located at King George Island in Antarctic Peninsula). Airborne particles, snow and soil/sediments samples were analyzed. Local-produced atmospheric aerosol dispersion was estimated for metals originated by fossil fuel burning from the permanent scientific stations using a simplified Gaussian model. Validation of atmospheric dispersion was established by in situ measurements. Soluble and insoluble particles deposited in freshly snow and airborne particles were analyzed by PIXE (Particle Induced X-Ray Emission) for the determination of the elemental mass concentration and to obtain the Mass Median Aerodynamic Diameter (MMAD). The results showed significant correlation between the concentration of atmospheric aerosol and the freshly deposited particles in the snow, and permitted an estimate of the atmospheric snow deposition factor for K, Cu, Zn, Fe, Pb, and Ti. Results of long-term aerosol data compilation suggest that besides the local aerosol sources, the continental atmospheric transport of airborne particles is not significantly affected by the airborne particles produced by local human impacts at King George Island. 相似文献
4.
Maeda Y. Morioka J. Tsujino Y. Satoh Y. Zhang Xiaodan Mizoguchi T. Hatakeyama S. 《Water, air, and soil pollution》2001,130(1-4):141-150
Atmospheric and laboratory corrosion tests were carried out to assess the intensity of air pollution in East Asia. Qualitative and quantitative atmospheric corrosion was estimated from the damage caused to bronze, copper, steel, marble, cedar, cypress and urushi (Japanese lacquer) plates, exposed to outdoor and indoor airs in some cities of East Asia. Brochantite and cuprite were formed on copper at sites where the sulfur dioxide concentrations were high, and basic cupric nitrate and cuprite at sites where nitrogen dioxide concentrations were high. Gypsum was formed on marble pieces exposed to indoor air at all sites but was not found on pieces exposed to outdoor air. Numerous fine spots (0.2–0.3 mm in diameter) were observed on surfaces of urushi plates exposed at foggy cities such as Chongqing, China and Taejon, Korea. The effects of atmospheric and meteorological factors on the damage to copper and marble plates in several cities in East Asia were estimated using regression analysis. The results indicate that sulfur dioxide is the most destructive of materials especially in China and South Korea. In Japan copper plates may be damaged under natural conditions and by sea salt. Copper may also be damaged by surface deposition of sulfur and chlorine. Marble may be substantially degraded by gaseous sulfur dioxide but sulfate ions in rain had no effect. The analysis of air pollution from the point of view of material damage was very useful in evaluating and visualizing the intensity of air pollution in East Asia. 相似文献
5.
室内空气质量受复杂交互因子的影响,它是多种影响因素和过程相互作用的结果,因此清晰辨别理解各因素对室内空气质量的影响和作用方式,是制定正确的改善空气质量措施的基础。本文针对农村室内空气质量污染的特点,对影响农村室内空气质量的主要因素房屋建筑与通风进行研究和分析。在开门关窗、开门开窗两种通风方式进行室内CO浓度测试,开门开窗工况下,室内CO浓度超标时间较开门关窗工况下减少了8 m in,而且CO浓度峰值也由开门关窗工况下的17.3m g/m3降为开门开窗工况下的13.9 m g/m3。对CO浓度和空气换气率进行相关性分析,发现两者之间有较强的负相关关系。 相似文献
6.
Dias da Cunha K. Lipsztein J. L. Azeredo A. M. Melo D. Julião L. M. Q. C. Lamego F. F. Santos M. Barros Leite C. V. 《Water, air, and soil pollution》2002,137(1-4):45-61
The aim of this study is to evaluate worker’s exposure to particles, with special attention to thorium, uranium and niobiumbearing particles. A cascade impactor (CI) with six stages was used to collect particles with aerodynamic diameter in the rangeof 0.64 to 19.4 μm. The elemental mass concentrations impacted in each stage of the CI were determined using the PIXE(Particle Induced X-ray Emission) technique. The Mass Median Aerodynamic Diameter (MMAD) and elemental mass concentration in the fine fraction of aerosol (0.5 to 2.5 μm) were determined.Personal air samplers were used by workers to collect fine particles of aerosol. The concentrations of 232Th and 228Th in these air samplers were measured by the alpha spectrometry technique. Faeces and urine samples from the workersand their wives were analyzed to determine the thorium, uranium and niobium mass concentration (mass spectrometry) and 232Th, 228Th, 238U and 234U concentrations (α spectrometry) and then compared to inhabitants of regions with low metal concentrations. The analysis of thefaecesand urine samples from workers and their wives indicated that themain pathway of thorium, uranium and niobium incorporation was byingestion. The observed concentrations of niobium and uranium inurine samples from workers showed a systemic incorporation of niobium and uranium. 相似文献
7.
B. B. Hicks 《Water, air, and soil pollution》1986,30(1-2):75-90
The exchange process known as dry deposition encompasses the dynamic exchange of trace gases and aerosol particles, and the gravitational settling of large particles. Except for particles large enough that their sedimentation velocity exceeds turbulent velocities, the rate of deposition is mostly determined by surface properties, such as roughness, stickiness, and wetness, and by atmospheric stability. Thus, it is difficult to interpret results obtained using collection devices having surfaces different from those of nature. Other methods for measuring dry deposition exist, mostly micrometeorological, but these are sufficiently complicated that routine application as in a monitoring network is not yet feasible. For some chemical species and in some locations, inferential methods offer considerable promise. These methods measure atmospheric concentrations (C) of the relevant chemical species, and derive relevant deposition velocities (vd) on a site-specific, species-dependent, and time-evolving basis. The dry deposition rates of interest are then evaluated as the product vd.C. A major goal of current research programs is to provide the knowledge necessary to evaluate vd. Experimental methods are reviewed, and potential sources of error are examined, for both the research methods and the “concentration monitoring” methodologies presently being advocated for use in numerical models as well as for routine monitoring. 相似文献
8.
Schönbuchner Heiko Guggenberger Georg Peters Klaus Bergmann Hans Zech Wolfgang 《Water, air, and soil pollution》2001,128(3-4):355-367
The aim of the present study was to elucidate thedistribution of particulate polycyclic aromatichydrocarbons (PAH) in the air of a remote Norwayspruce (Picea abies (L.) karst.) stand.The study encompassed a total of twenty differentcongeners. Particles in ambient air were alternativelycollected by two different Berner cascade impactors atthe field site in Northern Bavaria over a 14-weeksperiod from the end of April through to the end ofJuly 1994 and subsequently analyzed for their PAHcontent. The concentrations of total suspendedparticulate matter (TSP) ranged from 9–31 μg m-3,suggesting that the field site is an area with a lowlevel of airborne particles. There was a negativerelationship of total particle concentrations with theamount of canopy precipitation due to particle washout at precipitation events. The distribution of theparticle masses on the different size fractions witha maximum in the 1-μm range is typical for remoteareas and indicates a medium-range transport. Theaerosol-bound PAH load decreased from spring sampleswith 2–4 ng m-3 to values <1 ng m-3 in the summersamples. Concurrently, the proportion of low molecularweight congeners in the total PAH load declined.Frequently, the highest PAH concentrations (referringto the air) were found in the 0.1–3 μm sizeseparates (accumulation mode). The results suggestthat apart from PAH input to the soil with litter, dryand wet deposition of aerosol particles is animportant pathway of PAH contamination of acid forestsoils in the Fichtelgebirge mountain range. 相似文献
9.
Human health hazards can exist in swine confinement buildings due to poor indoor air quality (IAQ). During this study, airborne dust and ammonia concentrations were monitored within a working farrowing facility as indicators of IAQ. The purposes of this study were to assess the temporal variability of the airborne dust and ammonia levels over both a daily and seasonal basis, and to determine the accuracy of real-time sensors relative to actively sampled data. An ammonia sensor, aerosol photometer, indoor relative humidity sensor, and datalogger containing an indoor temperature sensor were mounted on a board 180 cm above the floor in the center of a room in the facility. Sensor readings were taken once every 4 minutes during animal occupancy (3-week intervals). Measurements of total and respirable dust concentrations by standard method, aerosol size distribution, and ammonia concentrations were taken once per week, in addition to temperature and relative humidity measurements using a thermometer and sling psychrometer, respectively. Samples were taken between September 1999 and August 2000. Diurnal variations in airborne dust revealed an inverse relationship with changes in indoor temperature and, by association, changes in airflow rate. Ammonia levels changed despite relatively stable internal temperatures. This change may be related to both changes in flow rates and in volatility rates. As expected, contaminant concentrations increased during the cold weather months, but these differences were not significantly different from other seasons. However, total dust concentrations were very low (geometric mean = 0.8 mg/m3) throughout the year. Likewise, ammonia concentrations averaged only 3.6 ppm in the well-maintained study site. 相似文献
10.
Human exposure to volatile organic compounds (VOCs) and residential indoor and outdoor VOC levels had hitherto not been investigated in Turkey. This study details investigations of indoor, outdoor, and personal exposure to VOCs conducted simultaneously in 15 homes, 10 offices and 3 schools in Kocaeli during the summer of 2006 and the winter of 2006–2007. All VOC concentrations were collected by passive sampling over a 24-h period and analyzed using thermal desorption (TD) and a gas chromatography/flame ionization detector (GC/FID). Fifteen target VOCs were investigated and included benzene, toluene, m/p-xylene, o-xylene, ethylbenzene, styrene, cyclohexane, 1,2,4-trimethylbenzene, n-heptane, n-hexane, n-decane, n-nonane, n-octane and n-undecane. Toluene levels were the highest in terms of indoor, outdoor, and personal exposure, followed by m/p-xylene, o-xylene, ethylbenzene, styrene, benzene and n-hexane. In general, personal exposure concentrations appeared to be slightly higher than indoor air concentrations. Both personal exposure and indoor concentrations were generally markedly higher than those observed outdoors. Indoor target compound concentrations were generally more strongly correlated with outdoor concentrations in the summer than in winter. Indoor/outdoor ratios of target compounds were generally greater than unity, and ranged from 0.42 to 3.03 and 0.93 to 6.12 in the summer and winter, respectively. Factor analysis, correlation analyses, indoor/outdoor ratios, microenvironment characteristics, responses to questionnaires and time activity information suggested that industry, and smoking represent the main emission sources of the VOCs investigated. Compared with the findings of earlier studies, the level of target analytes in indoor air were higher for several target VOCs, indicating a possible trend toward increased inhalation exposure to these chemicals in residential environments. 相似文献
11.
Gerhard Lammel Friedhelm Schneider Erika Brüggemann Thomas Gnauk Andreas Röhrl Paul Wieser 《Water, air, and soil pollution》2004,154(1-4):313-330
We studied the atmospheric aerosol of a farm directly on farm, downwind, and in the background with the aim to characterize the aerosol source of livestock farming physically and chemically. The farm hosted chicken, cattle and pig.The farm was found to be a source of primary and secondary particles. Super-μm particles of various types were emitted from the stables and adjacent facilities related to farming activities. On farm elevated concentrations of ammonia, particulate ammonium and nitrate were observed. The significant emission of condensation nuclei and large, 2 μm-sized particles (droplets) was observed under humid conditions in plumes which most likely originated from open manure pits at least in one case. It is suggested that this aerosol mode consisted of ammonium haze droplets formed by saturation of advected air with ammonia within a few minutes. In one night, a mass uptake of Δm > 5.4 μg m-3 in the super-μm mode was observed along with a loss of Δm = —1.0 μg m-3 in the sub-μm mode based on differential sampling upwind and downwind of the farm. The particulate matter mass median diameter was correspondingly shifted from 1.32 to 3.39 μm. About one third of the mass increase was due to organic carbon. Furthermore, differential sampling showed particulate calcium and nitrate/nitric acid to be emitted from the farm, too. The study encourages to systematically characterize the aerosol emitted from livestock raising in future studies of similar kind. 相似文献
12.
There is continuing concern over the health threat posed by theinhalation of ambient, transition-metal-containing particulatematter. Here, we report on the collection of two types ofanthropogenic, airborne particles, composed of iron with vanadiumand chromium (FeVCr) and iron with the rare earth metals ceriumand lanthanum (FeCeLa), respectively. Bi-weekly deposition platesamples were collected on indoor window sills of residentiallocations in inner-city Syracuse, NY. Sampling was continuous ateach location for two months during the spring of 1999. Themetal-bearing particles were identified, analyzed, and sizedin situ on each deposition plate using computer controlledscanning electron microscopy (CCSEM). Approximately 17% of thoseanalyzed by CCSEM fell into the inhalable size fraction. Particle loading varied between locations and changed over time.This was probably a function of various factors affectingparticle deposition rates. Notwithstanding, the plate loadingsfor the FeVCr-bearing particles tended to peak during the middleof the sampling period, suggesting that a single source/processwas operating to produce the FeVCr particles. The large sizeattained by some of these particles (greater than 50 μm inaggregates) suggest that long range transport was probably notinvolved. 相似文献
13.
密闭式猪舍多环境因子调控系统设计及调控策略 总被引：8，自引：6，他引：2
大多数猪舍环境调控是建立在传统控制方法基础上的单一环境变量控制系统,难以对具有多个变量的系统建立精确的数值模型。该文基于模糊控制理论,以温度偏差和温度偏差变化率作为输入量,以通风模式和加热模式为输出控制量建立温度控制器;以相对湿度偏差和氨气浓度偏差为输入量,以通风模式为输出控制量建立通风控制器;并对不同季节多环境因子进行模糊化及逻辑推理,生成不同季节的调控策略及规则,建立2个具有双输入变量的非线性控制系统,加入动态补偿控制,优化猪舍环境调控系统。该文以在美国普渡大学环境研究猪舍监测所得的数据对建立的方法进行了模拟验证。结果表明,舍内温度与设定值最大相对误差为5%,实现了舍内温度稳定控制;舍内相对湿度与设定值最大相对误差为6.3%,充分满足湿度控制要求;猪舍氨气浓度变化范围为2.0~3.7 mg/m~3,远远小于设定值9.1 mg/m~3。因此,该文提出的猪舍多环境因子模糊控制系统及策略,能够很好地满足猪舍环境控制要求,为解决寒冷冬季猪舍温度与通风调控提供可行的思路。 相似文献
14.
Marc J. Assael Dimitris Melas Konstantinos E. Kakosimos 《Water, air, and soil pollution》2010,211(1-4):395-408
Modern European cities are characterized by high particulate matter (PM) concentrations. Unfortunately, the number of stations monitoring air pollution, especially PM, is never sufficient for the overall representation of the problem. In the present work, an inexpensive outdoor passive sampler (based on an indoor passive sampler) was developed and assembled in an effort to provide the means to extend current PM monitoring networks. The uncertainty of the sampler was tested in vitro and in vivo. Twenty such outdoor passive samplers were assembled and installed at specific locations in the Greater Thessaloniki Area and measurements of PM were carried out. The results were in good agreement with the official monitoring stations. In addition, they revealed the aggravated air quality in the center of the city and in the west suburbs. 相似文献
15.
阐述了酸沉降产生的原因及其对生态环境和人类健康的影响,指出由于矿质燃料的燃烧、人为排放SO_2和NO_x导致气溶胶和云雨逐渐酸化。当森林暴露在高浓度SO_2和NO_x下时森林会衰退,表现为叶片发黄和落叶甚至死亡,土壤持续酸化导致盐基离子淋失和土壤溶液中铝离子富集是森林衰退的主要机制,土壤养分亏缺也是森林衰退的主要原因。在酸沉降敏感地区水体酸化和铝离子富集造成湖泊和河流严重酸化及鱼类大量损失。酸沉降与气态污染对水生与陆地生态系统造成大面积损害,并影响到人类的健康。 相似文献
16.
J. D. Whyatt J. R. Stedman S. E. Metcalfe G. W. Campbell 《Water, air, and soil pollution》1995,85(4):1961-1966
Precipitation composition has been measured daily at five UK EMEP sites since 1987. Sulphur dioxide and sulphate aerosol concentrations are also measured daily at the sites. Back trajectories and wind sectors calculated by the Norwegian Meteorological Institute have been used to characterise the variation in wet deposition in terms of air mass source. Contributions to wet deposition from various source regions have been estimated for Eskdalemuir. Observations from the EMEP sites have been compared with output from the Hull Acid Rain Model (HARM). HARM is a Lagrangian model using simplified meteorology but straight-line trajectories. Results are compared on a site-by-site and sector-by-sector basis and the model reproduces the general features of pollutant concentration and wet deposition indicated by the measurements. The possible effects of future reductions in emissions of SO2 and NOx on precipitation concentrations by wind sector are described. 相似文献
17.
为了探究调合生物柴油掺烧甲醇对柴油机燃烧特性及微粒粒径分布的影响,该文利用燃烧分析仪及EEPS 3090型微粒粒径测试系统研究了柴油机燃用甲醇-调合生物柴油微乳化燃料的燃烧过程及微粒数量浓度分布特性。试验结果表明,与燃用调合生物柴油相比,柴油机掺烧甲醇后缸内燃烧压力、压力升高率以及放热率曲线均后移,压力升高率峰值及放热率峰值均增加;当柴油机处于低负荷时,排气中的微粒粒径均处于6~22 nm之间,呈现核态;在高负荷时,微粒粒径处于6~275 nm之间,主要呈现积聚态,且数量浓度呈单峰正态分布。随着甲醇添加比例的增加,核态微粒比例上升,积聚态微粒比例下降,且排气中微粒的总数下降。研究结果为甲醇-生物柴油混合燃料的燃烧及微粒排放控制提供了参考。 相似文献
18.
Kovačević Goran Gregorović Gordana Kalafatić Mirjana Jaklinović Ivica 《Water, air, and soil pollution》2009,204(1-4):333-350
Water, Air, & Soil Pollution - The relative contribution of the main mechanisms that control indoor air quality in residential flats was examined. Indoor and outdoor concentration measurements... 相似文献
19.
C. M. Sheih 《Water, air, and soil pollution》1987,32(3-4):417-425
The impact of a potential increase in vehicular diesel emissions on atmospheric particle concentrations and size distributions in a large urban area (Chigago) is investigated numerically, for idealized meteorological conditions. Results indicate that the projected increase in diesel emissions would affect mainly the concentrations of particles with diameters smaller than 1 μm; larger particles would not be affected significantly. The particle concentrations in the accumulation mode (diameter near 0.2 μm) would be increased by about a factor of ten, while the concentration of particles of the Aitken nuclei mode (diameter near 0.02 μm) would be reduced significantly. The area in which the annual average air quality particulate standard is exceeded is quite small for the reference case based on emissions in 1983, but would increase to cover almost the entire urban area for the projected increase in diesel emissions in 2000. 相似文献
20.
The internal concentrations and emission rates of ammonia (NH3), total bacteria, respirable endotoxins, and inhalable and respirable particles were monitored in 160 piggery buildings in four states of Australia (Queensland, Victoria, Western Australia, and South Australia) between autumn 1997 and autumn 1999. Emissions were calculated for individual buildings as a product of internal concentration and ventilation rate, which were estimated by a carbon dioxide balance method. Relative humidity and temperature were also measured. The overall mean emission rates of NH3, total bacteria, respirable endotoxins, inhalable particles, and respirable particles per 500 kg live weight from Australian piggery buildings were 1442.5 mg h(-1), 82.2 x 10(6) cfu h(-1), 20.1 x 10(3) EU h(-1), 1306.7 mg h(-1), and 254.7 mg h(-1), respectively. Internal concentrations of key airborne pollutants have been reported in companion articles. Building characteristics and management systems used in the piggeries were documented at the time of sampling and used in the subsequent statistical modeling of variations in pollutant emission rates. The emissions model used all statistically significant factors identified during prior modeling conducted for individual pollutant concentrations and ventilation airflow. The identification of highly significant factors affecting emission rates and internal concentrations should aid the development of strategies for the industry to reduce emission rates from individual buildings, thus improving the environmental performance of piggery operations. In the second part of the article, specific recommendations are made based on the overall study results. 相似文献