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571.
为了脱除CO2温室气体,提出了利用氨水土壤混合物去除CO2的新方法。分别考察了土壤颗粒粒径、CO2初始流量、氨水浓度(质量比)和温度对CO2脱除量和脱除率的影响。实验结果表明,该方法去除CO2的量较土壤物理吸附量和氨水化学吸收量的总和提高了大约15%;随着氨水浓度的增大,CO2的脱除率和脱除量都增大;随着土壤颗粒粒径和CO2初始流量的增大,CO2的脱除率和脱除量都减小;当温度由22℃升高到31℃,CO2的脱除率随着温度的升高而增大,但是继续升高温度到40℃,CO2的脱除率反而下降。 相似文献
572.
提出了一种利用移动监测技术研究区域大气环境中PM2.5/PM10空间分布的方法,并在2004年12月进行了宁波市全市域PM2.5/PM10空间分布的研究。数据显示:相同路径所代表的地区PM2.5和PM10具有很好的相关性,多数路径上PM2.5与PM10数据的相关系数平方在0.95以上,而不同路径上PM2.5与PM10的比值不同。文中给出了宁波市PM2.5/PM10污染的空间分布图,直观地显示出PM2.5/PM10污染的空间分布情况,突出了污染的重点点位和地区。 相似文献
573.
Tim S. Nawrot Nino Kuenzli Jordi Sunyer Tingming Shi Teresa Moreno Mar Viana Joachim Heinrich Bertil Forsberg Frank J. Kelly Muhammad Sughis Benoit Nemery Paul Borm 《Atmospheric environment (Oxford, England : 1994)》2009,43(30):4595-4602
We assessed the extent to which constituents of PM2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium. 相似文献
574.
While convenient and often used, on-site surveys are biased by the fact that users who visit the site more often are proportionately more likely to be sampled. This so-called avidity or size biased sampling results in over-estimating the visitation patterns of the average user. This analysis develops a rule of thumb method that may easily be applied by recreation site managers to visitation data collected on-site in order to infer behavior of the average user of the site. The key assumption that drives the derivation is that the visitation data of users is logarithmically distributed. To evaluate the methodology, we analyze several data sets of recreational users assuming that they reflect the populations of users and from these construct hypothetical on-site samples. 相似文献
575.
Allen CD 《Environmental management》2009,43(2):346-356
Characterized by expensive housing, high socioeconomic status, and topographic relief, Upper Sonoran Lifestyle communities
are found primarily along the Wildland-Urban Interface (WUI) in the Phoenix, Arizona metro area. Communities like these sprawl
into the wildlands in the United States Southwest, creating a distinct urban fringe. This article, through locational comparison,
introduces and evaluates a new field assessment tool for monitoring anthropogenic impact on soil–vegetation interactions along
the well-maintained multi-use recreational trails in Upper Sonoran Lifestyle region. Comparing data from randomly selected
transects along other multi-use trails with data from a control site revealed three key indicators of anthropogenic disturbances
on soil–vegetation interactions: soil disturbance, vegetation disturbance, and vegetation density. Soil and vegetation disturbance
displayed an average distance decay exponent factor of −0.60, while vegetation density displayed a reverse decay average of
0.60. Other important indicators of disturbance included vegetation type, biological soil crusts, and soil bulk density. The
predictive ability of this new field tool enhances its applicability, offering a powerful rapid ecological assessment method
for monitoring long-term anthropogenic impact in the Upper Sonoran Lifestyle, and other sprawling cities along the WUI. 相似文献
576.
Fertilization with 2.5 t/ha limestone: (83% CaCO3, 8% MgO, 6% K2O, 3% P2O5) reduces the 137Cs transfer from spruce forest soil into plants like fern (Dryopteris carthusiana) and blackberry (Rubus fruticosus) by a factor of 2–5 during at least 11 years as measured by the aggregated transfer factor Tag. In 1997 and 2006 these results were confirmed by additional measurements of the 137Cs transfer factor TF, related to the root zone (Oh horizon), which were explained by the selective sorption of 137Cs in the root zone by measurements of the Radiocaesium Interception Potential (RIP) in fertilized (RIP > 179 meq/kg) and non-fertilized soils (RIP < 74 meq/kg). 相似文献
577.
Gas/particle partitioning of atmospheric PCDD/Fs in a satellite town in Eastern China 总被引:3,自引:0,他引:3
Meng-xia Xu Jian-hua Yan Sheng-yong Lu Xiao-dong Li Tong Chen Ming-jiang Ni Hui-fen Dai Fei Wang Ke-fa Cen 《Chemosphere》2009,76(11):1540-1549
Gas/particle partitioning of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in ambient air was investigated in a satellite town in Eastern China from April 2007 to January 2008 comprehending large temperature variations (from 3 to 34 °C, daily average). Molecular weight, molecular structure and ambient temperatures are the three major factors that govern the gas/particle partitioning of atmospheric PCDD/Fs throughout the year. Generally, good agreements were obtained (except for winter) between measured particulate fractions and theoretical estimates of both the Junge–Pankow adsorption model and Harner Bidleman absorption model using different sets of subcooled liquid vapor pressure and octanol–air partition coefficient (Koa), respectively. Models utilizing estimates, derived from gas chromatographic retention indices (GC-RIs), are more accurate than that of entropy-based. Moreover, during winter, the Koa-based model using the GC-RIs approach performs better on lower chlorinated PCDD/Fs than that of -based. Furthermore, possible sources of mismatch between measured and predicted values in winter (3–7 °C) were discussed. Gas adsorption artifact was demonstrated to be of minor importance for the phenomena observed. On the other hand, large deviations of slopes (mr) and intercepts (br) in logKp vs. plots from theoretical values are observed in the literature data and these are found to be linearly correlated with ambient temperatures (P<0.001) in this study. This indicates that the non-equilibrium partitioning of PCDD/Fs in winter may be significantly influenced by the colder temperatures that may have slowed down the exchange between gaseous and particulate fractions. 相似文献
578.
Soil and atmospheric concentrations, dry deposition and soil-air gas exchange of organochlorine pesticides (OCPs) were investigated at an industrial site in Aliaga, Izmir, Turkey. Current-use pesticides, endosulfan and chlorpyrifos, had the highest atmospheric levels in summer and winter. Summertime total (gas + particle) OCP concentrations in air were higher, probably due to increased volatilization at higher temperatures and seasonal local/regional applications of current-use pesticides. Particle deposition fluxes were generally higher in summer than in winter. Overall average dry particle deposition velocity for all the OCPs was 4.9 ± 4.1 cm s−1 (average ± SD). ΣDDXs (sum of p,p′-DDT, p,p′-DDD, and p,p′-DDE) were the most abundant OCPs in Aliaga soils (n = 48), probably due to their heavy historical use and persistence. Calculated fugacity ratios and average net gas fluxes across the soil-air interface indicated volatilization for α-CHL, γ-CHL, heptachlorepoxide, cis-nonachlor, trans-nonachlor, and p,p′-DDT in summer, and for α-CHL, γ-CHL, trans-nonachlor, endosulfan sulfate, and p,p′-DDT in winter. For the remaining OCPs, soil acted as a sink during both seasons. Comparison of the determined fluxes showed that dry particle, gas-phase, and wet deposition are significant OCP input mechanisms to the soil in the study area. 相似文献
579.
Viivi Hassinen Veli-Matti Vallinkoski Sirpa Kärenlampi 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):922-930
Metal uptake and its effect on foliar metallothionein 2b (MT2b) mRNA levels were studied in hybrid aspen (Populus tremula × tremuloides) in field conditions. The trees were planted on a site contaminated with several metals, including cadmium (mean 5.1 mg kg−1), chromium (80 mg kg−1), copper (180 mg kg−1), nickel (81 mg kg−1), vanadium (240 mg kg−1) and zinc (520 mg kg−1). Of the ten trace elements analyzed, only Cd and Zn accumulated in the leaves with maximal foliar concentrations of 35 and 2400 mg kg−1 (dry weight), respectively. There was a strong correlation between Cd and Zn concentrations and bioaccumulation factors (concentration in plant/soil) in the leaves, branches and roots, suggesting similar transport mechanisms for these two metals. The levels of MT2b correlated with Cd and Zn concentrations in the leaves, demonstrating that increased MT2b expression is one of the responses of hybrid aspen to chronic metal exposure. 相似文献
580.
Protection of the environment from ionising radiation in a regulatory context (protect): proposed numerical benchmark values 总被引:1,自引:1,他引:0