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91.
Daniel Q. Tong Nicholas Z. Muller Haidong Kan Robert O. Mendelsohn 《Environment international》2009,35(8):1109-1117
Human exposure to ambient ozone (O3) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source–receptor relationships between nitrogen oxides (NOx) emissions and population exposure to ambient O3 in 48 states over the continental United States. By removing NOx emissions from each state one at a time, we calculate the change in O3 exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source–receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NOx emissions from upwind states contribute more to O3 exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O3 exposures in 90% of U.S. states. A state's NOx emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O3 exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O3 exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NOx is equal. In this study, the average O3 exposures caused by one ton of NOx emissions ranges from ? 2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NOx emissions varies considerably over space. 相似文献
92.
Chester W. Spicer Michael W. Holdren Kenneth A. Cowen Darrell W. Joseph Jan Satola Bradley Goodwin Howard Mayfield Alexander Laskin M. Lizabeth Alexander John V. Ortega Matthew Newburn Robert Kagann Ram Hashmonay 《Atmospheric environment (Oxford, England : 1994)》2009,43(16):2612-2622
Aircraft emissions affect air quality on scales from local to global. More than 20% of the jet fuel used in the U.S. is consumed by military aircraft, and emissions from this source are facing increasingly stringent environmental regulations, so improved methods for quickly and accurately determining emissions from existing and new engines are needed. This paper reports results of a study to advance the methods used for detailed characterization of military aircraft emissions, and provides emission factors for two aircraft: the F-15 fighter and the C-130 cargo plane. The measurements involved outdoor ground-level sampling downstream behind operational military aircraft. This permits rapid change-out of the aircraft so that engines can be tested quickly on operational aircraft. Measurements were made at throttle settings from idle to afterburner using a simple extractive probe in the dilute exhaust. Emission factors determined using this approach agree very well with those from the traditional method of extractive sampling at the exhaust exit. Emission factors are reported for CO2, CO, NO, NOx, and more than 60 hazardous and/or reactive organic gases. Particle size, mass and composition also were measured and are being reported separately. Comparison of the emissions of nine hazardous air pollutants from these two engines with emissions from nine other aircraft engines is discussed. 相似文献
93.
Loos R Gawlik BM Locoro G Rimaviciute E Contini S Bidoglio G 《Environmental pollution (Barking, Essex : 1987)》2009,157(2):561-568
This study provides the first EU-wide reconnaissance of the occurrence of polar organic persistent pollutants in European river waters. More than 100 individual water samples from over 100 European rivers from 27 European Countries were analysed for 35 selected compounds, comprising pharmaceuticals, pesticides, PFOS, PFOA, benzotriazoles, hormones, and endocrine disrupters. Around 40 laboratories participated in this sampling exercise. The most frequently and at the highest concentration levels detected compounds were benzotriazole, caffeine, carbamazepine, tolyltriazole, and nonylphenoxy acetic acid (NPE1C). Only about 10% of the river water samples analysed could be classified as “very clean” in terms of chemical pollution. The rivers responsible for the major aqueous emissions of PFOS and PFOA from the European Continent could be identified. For the target compounds chosen, we are proposing “indicative warning levels” in surface waters, which are (for most compounds) close to the 90th percentile of all water samples analysed. 相似文献
94.
Robert Kase Peter D. Hansen Birgit Fischer Werner Manz Peter Heininger Georg Reifferscheid 《Environmental science and pollution research international》2009,16(1):54-64
Background, aim, and scope The enzyme-linked receptor assay (ELRA) detects estrogenic and anti-estrogenic effects at the molecular level of receptor
binding and is a useful tool for the integrative assessment of ecotoxicological potentials caused by hormonally active agents
(HAA) and endocrine disrupting compounds (EDC). The main advantage of the ELRA is its high sample throughput and its robustness
against cytotoxicity and microbial contamination. After a methodological adaptation to salinity of the ELRA, according to
the first part of this study, which increased its salinity tolerance and sensitivity for 17-β-estradiol, the optimised ELRA
was used to investigate 13 native sediments characterised by different levels of salinity and chemical contamination. The
applicability of the ELRA for routine analysis in environmental assessment was evaluated. Salinity is often a critical factor
for bioassays in ecotoxicological sediment assessment. Therefore, salinity of the samples was additionally adjusted to different
levels to characterise its influence on elution and binding processes of receptor-binding substances.
Materials and methods The ELRA was carried out with the human estrogen receptor α (ER) in a 96-well microplate format using the experimental setup
known from the competitive immunoassay based on ligand–protein interaction. It is an important improvement that a physiologically
relevant receptor was used as a linking protein instead of an antibody. The microplates were coated with a 17-β-estradiol-BSA
conjugate, and dilution series of estradiol and of native sediment samples were added and incubated with the ER. After a washing
step, a biotinylated mouse anti-ER antibody was added to each well. Receptor binding to estradiol, agonistic and antagonistic
receptor binding, were determined by a streptavidin-POD-biotin complex with subsequent measurement of the peroxidase activity
at the wavelength of 450 nm using a commercial ELISA multiplate reader. The sediment elutriates and pore water samples of
sediments were tested in a dilution series to evaluate at which dilution step the receptor-binding potential ends. In the
elution process (see Section 2.1 to 2.2), a method was developed to adjust the salinity to the levels of the reference testings, which offers an appropriate option
to adjust the salinity in both directions. Statistical evaluation was made with a combination of the Mann–Whitney U test and the pT-method.
Results This part of the study characterised the environmental factor ‘salinity’ for prospective applications of the ELRA. Using reference
substances such as 17-β-estradiol, the ELRA showed sigmoid concentration-effect relations over a broad range from 0.05 μg/l
to 100 μg/l under physiological conditions. After methodological optimisation, both sensitivity and tolerance of the assay
against salinity could be significantly raised, and the ELRA became applicable under salinity conditions up to concentrations
of 20.5‰. The mean relative inter-test error (n = 3) was around 11% with reference substances and below 5% for single sediments elutriates in three replicates each. For
sediment testings, the pore water and different salinity-adjusted elutriates of 13 sediments were used. A clear differentiation
of the receptor-binding potential could be reached by application of the pT-method. Thereby, pT-values from one to six could
be assigned to the sediments, and the deviation caused by the different salinity conditions was one pT-value. The mean standard
deviation in the salinity adaptation procedure of the elutriates was below 5%.
Discussion Although the ELRA has already been used for assessments of wastewater, sludge and soil, its applicability for samples to different
salinity levels has not been investigated so far. Even if the ELRA is not as sensitive as the E-screen or the YES-assay, with
regard to reference substances like 17-β-estradiol, it is a very useful tool for pre-screening, because it is able to integrate
both estrogenic as well as anti-estrogenic receptor-binding effects. According to the results of sediment testing, and given
the integrative power to detect different directions of effects, the ELRA shows sufficient sensitivity and salinity tolerance
to discriminate receptor-binding potentials in environmental samples.
Conclusions The optimised ELRA assay is a fast, cost-effective, reliable and highly reproducible tool that can be used for high-throughput
screening in a microplate format in detecting both estrogenic and anti-estrogenic effects. Additionally, the ELRA is robust
against microbial contaminations, and is not susceptible towards cytotoxic interferences like the common cell-culture methods.
The general applicability and sufficient sensitivity of the ELRA was shown in freshwater environments. Marine and brackish
samples can be measured up to salinity levels of 20.5‰.
Recommendations and perspectives In view of the proven sensitivity, functionality and the fastness of the ELRA, it is recommendable to standardise the test
method. At the moment, no adequate in vitro test procedure exists which is standardised to DIN or ISO levels. The E-screen
and the yeast estrogen/androgen screens (YES/YAS) sometimes underlie strong cytotoxic effects, as reported in the first part
of this study. Further development of an ELRA assay using human androgen receptors appears to be very promising to gain information
about androgenic and anti-androgenic effects, too. This would offer a possibility to use the ELRA as a fast and reliable pre-screening
tool for the detection of endocrine potentials, thus minimising time and cost-expensive animal experiments. 相似文献
95.
Dev E. Millstein Robert A. Harley 《Atmospheric environment (Oxford, England : 1994)》2009,43(40):6328-6335
Emissions from diesel-powered construction equipment are an important source of nitrogen oxides (NOx) and particulate matter (PM). A new emission inventory for construction equipment emissions is developed based on surveys of diesel fuel use; the revised inventory is compared to current emission inventories. California's OFFROAD model estimates are 4.5 and 3.1 times greater, for NOx and PM respectively, than the fuel-based estimates developed here. The most relevant uncertainties are the overall amount of construction activity/diesel fuel use, exhaust emission factors for PM and NOx, and the spatial allocation of emissions to county level and finer spatial scales. Construction permit data were used in this study to estimate spatial distributions of emissions; the resulting distribution is well correlated with population growth. An air quality model was used to assess the impacts of revised emission estimates. Increases of up to 15 ppb in predicted peak ozone concentrations were found in southern California. Elemental carbon and fine particle mass concentrations were in better agreement with observations using revised emission estimates, whereas negative bias in predictions of ambient NOx concentrations increased. 相似文献
96.
97.
Waste materials from the clam processing industry (offal, shells) have several special characteristics such as a high salinity level, a high nitrogen content, and a low C/N ratio. The traditional disposal of clam waste through landfilling is facing the challenges of limited land available, increasing tipping fees, and strict environmental and regulatory scrutiny. The aim of this work is to investigate the performance of in-vessel composting as an alternative for landfill application of these materials. Experiments were performed in both laboratory-scale (5L) and pilot-scale (120L) reactors, with woodchips as the bulking agent. In the laboratory-scale composting test, the clam waste and woodchips were mixed in ratios from 1:0.5 to 1:3 (w/w, wet weight). The high ratios resulted in a better temperature performance, a higher electrical conductivity, and a higher ash content than the low-ratio composting. The C/N ratio of the composts was in the range of 9:1-18:1. In the pilot-scale composting test, a 1:1 ratio of clam waste to woodchips was used. The temperature profile during the composting process met the US Environmental Protection Agency sanitary requirement. The final cured compost had a C/N ratio of 14.6, with an ash content of 167.0+/-14.1g/kg dry matter. In addition to the major nutrients (carbon, nitrogen, calcium, magnesium, phosphorus, potassium, sulfur, and sodium), the compost also contained trace amounts of zinc, manganese, copper, and boron, indicating that the material can be used as a good resource for plant nutrients. 相似文献
98.
Preferred modes of travel among older adults: What factors affect the choice to walk instead of drive? 总被引:1,自引:0,他引:1
Rebecca B. Naumann Author Vitae Ann M. Dellinger Author Vitae Author Vitae Amy E. Bonomi Author Vitae Author Vitae Robert S. Thompson Author Vitae 《Journal of Safety Research》2009,40(5):395-36
Introduction
There are many factors that influence older adults' travel choices. This paper explores the associations between mode of travel choice for a short trip and older adults' personal characteristics.Methods
This study included 406 drivers over the age of 64 who were enrolled in a large integrated health plan in the United States between 1991 and 2001. Bivariate analyses and generalized linear modeling were used to examine associations between choosing to walk or drive and respondents' self-reported general health, physical and functional abilities, and confidence in walking and driving.Results
Having more confidence in their ability to walk versus drive increased an older adult's likelihood of walking to make a short trip by about 20% (PR = 1.22; 95% CI: 1.06-1.40), and walking for exercise increased the likelihood by about 50% (PR = 1.53; 95% CI = 1.22-1.91). Reporting fair or poor health decreased the likelihood of walking, as did cutting down on the amount of driving due to a physical problem.Discussion
Factors affecting a person's decision to walk for exercise may not be the same as those that influence their decision to walk as a mode of travel. It is important to understand the barriers to walking for exercise and walking for travel to develop strategies to help older adults meet both their exercise and mobility needs. Impact on Industry: Increasing walking over driving among older adults may require programs that increase confidence in walking and encourage walking for exercise. 相似文献99.
Richard Roth Paul R. Marques Robert B. VoasAuthor vitae 《Journal of Safety Research》2009,40(6):437-441
Introduction
The effectiveness of ignition interlocks at reducing drunk driving has been limited by the ability of driving-while-intoxicated (DWI) offenders to avoid court orders to install the devices.Methods
In a pilot program in New Mexico, four Santa Fe County judges imposed home confinement (via electronic monitoring bracelets) on offenders who claimed to have no car or no intention to drive. Interlock installation rates for Santa Fe County were compared with all other counties in New Mexico over a 2-year program and 2-year post-program period.Results
During the two program years, 70% of the drivers convicted of DWI in Santa Fe County installed interlocks, compared to only 17% in the other counties, but when the program was terminated, the Santa Fe installation rate fell by 18.8 percentage points.Summary
Mandating the alternative sanction of house arrest led to the highest reported interlock installation rate for DWI offenders.Impact on Industry
Impaired driving is a substantial expense to employers, particularly when it bars driving that interferes with employment. Interlocks provide a method of protecting the public while permitting the offender to drive sober. This study was directed at increasing interlock use by DWI offenders. 相似文献100.
Monitoring Australian Rangeland Sites Using Landscape Function Indicators and Ground- and Remote-Based Techniques 总被引:5,自引:0,他引:5
John A. Ludwig Gary N. Bastin Robert W. Eager Robert Karfs Pieter Ketner Graham Pearce 《Environmental monitoring and assessment》2000,64(1):167-178
If the goal for managing rangelands is to achieve a balance between production and conservation, then monitoring is essential to detect change and apply corrective action. In some range-land areas of northern Australia, monitoring has detected a tilt in the production-conservation balance towards excessive production. How big is this imbalance? Can it shift back? Robust monitoring is needed to answer these questions. The aim is to know what to monitor, and where. For example, to detect changes caused by livestock on rangeland forage production and soil erosion, indicators linking grazing disturbances to landscape function are needed, that is, indicators that signal how well landscapes are capturing, concentrating, and utilizing scarce water, nutrient, and organic resources. Studies in Australia and the USA document that simple vegetation and soil patch attributes can be measured as indicators of the 'state of health' of landscape function. For example, field and remote sensing-based grazing studies in Australia document that landscapes with a high cover of perennial plant patches function effectively to capture runoff water and nutrients in sediments, whereas landscapes with a low cover of these patches do not — they are dysfunctional — as indicated by large patches of bare soil. Aerial videography is proving to be a robust technique for measuring indicators of landscape function such as small patches of vegetation and the extent of bare soil. These indicators typically have a sigmoidal response to grazing impacts. We illustrate that if these indicators are measured on monitoring sites established near the sigmoidal 'point of inflection’ then small changes in these indicators can be detected. 相似文献