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251.
Yunhee Kim Joshua S. Fu Terry L. Miller 《Atmospheric environment (Oxford, England : 1994)》2010,44(17):2116-2124
Part II presents a comprehensive evaluation of CMAQ for August of 2002 on twenty-one sensitivity simulations (detailed in Part I) in MM5 to investigate the model performance for O3 SIPs (State Implementation Plans) in the complex terrain. CMAQ performance was quite consistent with the results of MM5, meaning that accurate meteorological fields predicted in MM5 as an input resulted in good model performance of CMAQ. In this study, PBL scheme plays a more important role than its land surface models (LSMs) for the model performance of CMAQ. Our results have shown that the outputs of CMAQ on eighteen sensitivity simulations using two different nudging coefficients for winds (2.5 and 4.5 × 10?4 s?1, respectively) tend to under predict daily maximum 8-h ozone concentrations at valley areas except the TKE PBL sensitivity simulations (ETA M-Y PBL scheme with Noah LSMs and 5-layer soil model and Gayno-Seaman PBL) using 6.0 × 10?4 s?1 with positive MB (Mean Bias). At mountain areas, none of the sensitivity simulations has presented over predictions for 8-h O3, due to relatively poor meteorological model performance. When comparing 12-km and 4-km grid resolutions for the PX simulation in CMAQ statistics analysis, the CMAQ results at 12-km grid resolution consistently show under predictions of 8-h O3 at both of valley and mountain areas and particularly, it shows relatively poor model performance with a 15.1% of NMB (Normalized Mean Bias). Based on our sensitivity simulations, the TKE PBL sensitivity simulations using a maximum value (6 × 10?4) among other sensitivity simulations yielded better model performance of CMAQ at all areas in the complex terrain. As a result, the sensitivity of RRFs to the PBL scheme may be considerably significant with about 1–3 ppb in difference in determining whether the attainment test is passed or failed. Furthermore, we found that the result of CMAQ model performance depending on meteorological variations is affected on estimating RRFs for attainment demonstration, indicating that it is necessary to improve model performance. Overall, G_c (Gayo-Seaman PBL scheme) using the coefficient for winds, 6 × 10?4 s?1, sensitivity simulation predicts daily maximum 8-h ozone concentration closer to observations during a typical summer period from May to September and provides generally low future design values (DVFs) at valley and mountain areas compared to other simulations. 相似文献
252.
Wenjie Zhang Guoshun Zhuang Kan Huang Juan Li Rong Zhang Qiongzhen Wang Yele Sun Joshua S. Fu Ying Chen Dongqun Xu Wei Wang 《Atmospheric environment (Oxford, England : 1994)》2010,44(28):3394-3403
To study the mixing and transformation of Asian dust with pollution in the two dust storms over the northern China in 2006, both TSP and PM2.5 samples were collected at three sites of northern China in addition to the dry deposition samples collected in an episode in Beijing. 23 elements, 15 ions, and 16 PAHs in each sample were analyzed. The two dust storms in northern China were observed in April 8–10 (DS1) and April 16–18 (DS2). Compared to DS2, DS1 was weaker and more polluted with stronger mixing between crustal and pollutant aerosols during their long-range transport. The concentrations of pollution species, e.g. pollution elements, ions, and PAHs were higher in DS1 than that in DS2, while the crustal species showed adverse variation. The correlation between chemical species and Al and between PAH(4) and PAH(5,6) further confirmed the stronger chemical transformation and aerosol mixing in DS1 than that in DS2. Back trajectory and chemical analysis revealed that in DS1 the air masses at Beijing were mostly from southern or southwestern direction at lower altitude with much more pollution, while in DS2 the air masses were mostly from the northwestern and northern direction with dust mainly, which explained why there was a stronger mixing of dust with pollution aerosol in DS1 than that in DS2 over Beijing. 相似文献
253.
Joshua S. Fu Downey E. Brill Jr. Ranji S. Ranjithan 《Journal of the Air & Waste Management Association (1995)》2013,63(6):800-809
Abstract The management of tropospheric ozone (O3) is particularly difficult. The formulation of emission control strategies requires considerable information including: (1) emission inventories, (2) available control technologies, (3) meteorological data for critical design episodes, and (4) computer models that simulate atmospheric transport and chemistry. The simultaneous consideration of this information during control strategy design can be exceedingly difficult for a decision-maker. Traditional management approaches do not explicitly address cost minimization. This study presents a new approach for designing air quality management strategies; a simple air quality model is used conjunctively with a complex air quality model to obtain low-cost management strategies. A simple air quality model is used to identify potentially good solutions, and two heuristic methods are used to identify cost-effective control strategies using only a small number of simple air quality model simulations. Subsequently, the resulting strategies are verified and refined using a complex air quality model. The use of this approach may greatly reduce the number of complex air quality model runs that are required. An important component of this heuristic design framework is the use of the simple air quality model as a screening and exploratory tool. To achieve similar results with the simple and complex air quality models, it may be necessary to “tweak” or calibrate the simple model. A genetic algorithm-based optimization procedure is used to automate this tweaking process. These methods are demonstrated to be computationally practical using two realistic case studies, which are based on data from a metropolitan region in the United States. 相似文献
254.
Tetrakis-(4-sulfonatophenyl)porphyrin cobalt was identified as a highly-active reductive dechlorination catalyst for chlorinated ethylenes. Through batch reactor kinetic studies, degradation of chlorinated ethylenes proceeded in a step-wise fashion with the sequential replacement of Cl by H. For perchloroethylene (PCE) and trichloroethylene (TCE), the dechlorination products were quantified and the C2 mass was accounted for. Degradation of the chlorinated ethylenes was found to be first-order in substrate. Dechlorination trials with increasing catalyst concentration showed a linearly increasing pseudo first-order rate constant which yielded rate laws for PCE and TCE degradation that are first-order in catalyst. The dechlorination activity of this catalyst was compared to that of another water-soluble cobalt porphyrin under the same reaction conditions and found to be comparable for PCE and TCE. 相似文献
255.
Joshua Parreco Sarah A. Eidelson Scott Revell Tanya L. Zakrison Carl I. Schulman 《Traffic injury prevention》2018,19(8):S127-S132
AbstractObjective: Some drivers involved in motor vehicle crashes across the United States may be identified as at risk of subsequent injury by a similar mechanism. The purpose of this study was to perform a national review of the risk factors for hospitalization for a new injury due to a subsequent motor vehicle crash. It was hypothesized that presenting to a different hospital after subsequent injury would result in worse patient outcomes when compared to presentation at the same hospital.Methods: The Nationwide Readmissions Database for 2010–2014 was queried for all inpatient hospitalizations with injury related to motor vehicle traffic. The primary patient outcome of interest was subsequent motor vehicle crash–related injury within 1 year. The secondary patient outcomes were different hospital subsequent injury presentation, higher Injury Severity Score (ISS), longer length of stay (LOS), and in-hospital death after subsequent injury. The analysis of secondary patient outcomes was performed only on patients who were reinjured. Univariable analysis was performed for each outcome using all variables during the index admission. Multivariable logistic regression was performed using all significant (P < .05) variables on univariate analysis. Results were weighted for national estimates.Results: During the study period, 1,008,991 patients were admitted for motor vehicle–related injury; 12,474 patients (1.2%) suffered a subsequent injury within 1 year. From the reinjured patients, 32.9% presented to a different hospital, 48.9% had a higher ISS, and 22.1% had a longer LOS. The in-hospital mortality rate after subsequent injury was 1.1%. Presentation to a different hospital for subsequent injury was associated with a longer LOS (odds ratio [OR]?=?1.32; 95% confidence interval [CI], 1.20–1.45; P < .01) and a higher ISS (OR?=?1.38; 95% CI, 1.27–1.49; P < .01). Motorcyclists were more likely to suffer subsequent injury (OR?=?1.39; 95% CI, 1.32–1.46; P < .01) and motorcycle passengers were more likely to present to a different hospital with a subsequent injury (OR?=?2.49; 95% CI, 1.73–3.59; P < .01). Alcohol abuse was associated with subsequent injury (OR?=?1.12; 95% CI, 1.07–1.18; P < .01).Conclusions: Nearly a third of patients suffering subsequent motor vehicle crash–related injury after an initial motor vehicle crash in the United States present to a different hospital. These patients are more likely to suffer more severe injuries and longer hospitalizations due to their subsequent injury. Future efforts to prevent these injuries must consider the impact of this fragmentation of care and the implications for quality and cost improvements. 相似文献
256.
M. Joshua Collins Phillip L. Williams David L. McIntosh 《Environmental monitoring and assessment》2001,68(2):137-152
Prior to the 1950's, manufactured gas was commerciallyproduced from the pyrolysis of coal, coke, and oil atfacilities that are termed manufactured gas plants (MGPs). The constituents of residual coal tar present on many MGPsites are an environmental health concern because of theirtoxicity and the possibility for their off-site migration viawater and air. Atmospheric concentrations of five volatileorganic compounds (VOCs, e.g., benzene), sixteen polycyclicaromatic hydrocarbons (PAHs, e.g., naphthalene), and particulate matter less than 10 microns in aerodynamicdiameter (PM10) were measured at the site of a former MGP. Air samples were obtained before, during, and after excavationof subterranean coal tar at the site. The results of thisinvestigation indicate that subterranean coal tar was not aprimary source of VOCs and PAHs in the local atmosphere beforeor after remediation of the site. However, excavation,treatment, blending, and transfer of the coal tar duringremediation generated concentrations of selected aromatic andsemi-volatile organic compounds that were substantiallygreater than typical ambient levels. In addition, these datasuggest that blending and mixing of coal tars could lead toexceedance of the U.S. National Ambient Air Quality Standardfor PM10, although additional research is required to fullyevaluate this possibility. Nuisance odors associated with thesite remediation were likely the result of naphthalene andpossibly isomers of xylene. Air pollutant concentrationsmeasured adjacent to the excavation area and at the siteperimeter during remediation activities were less than therelevant occupational and environmental exposure limits. 相似文献
257.
Rural industries and water pollution in China 总被引:10,自引:0,他引:10
Water pollution from small rural industries is a serious problem throughout China. Over half of all river sections monitored for water quality are rated as being unsafe for human contact, and this pollution is estimated to cost several per cent of GDP. While China has some of the toughest environmental protection laws in the world, the implementation of these laws in rural areas is not effective. This paper explains the reasons for this implementation gap. It argues that the factors that have underpinned the economic success of rural industry are precisely the same factors that cause water pollution from rural industry to remain such a serious problem in China. This means that the control of rural water pollution is not simply a technical problem of designing a more appropriate governance system, or finding better policy instruments or more funding. Instead, solutions lie in changes in the model that underpins rural development in China. 相似文献
258.
Brad Griffith J. Michael Scott Robert Adamcik Daniel Ashe Brian Czech Robert Fischman Patrick Gonzalez Joshua Lawler A. David McGuire Anna Pidgorna 《Environmental management》2009,44(6):1043-1052
Since its establishment in 1903, the National Wildlife Refuge System (NWRS) has grown to 635 units and 37 Wetland Management
Districts in the United States and its territories. These units provide the seasonal habitats necessary for migratory waterfowl
and other species to complete their annual life cycles. Habitat conversion and fragmentation, invasive species, pollution,
and competition for water have stressed refuges for decades, but the interaction of climate change with these stressors presents
the most recent, pervasive, and complex conservation challenge to the NWRS. Geographic isolation and small unit size compound
the challenges of climate change, but a combined emphasis on species that refuges were established to conserve and on maintaining
biological integrity, diversity, and environmental health provides the NWRS with substantial latitude to respond. Individual
symptoms of climate change can be addressed at the refuge level, but the strategic response requires system-wide planning.
A dynamic vision of the NWRS in a changing climate, an explicit national strategic plan to implement that vision, and an assessment
of representation, redundancy, size, and total number of units in relation to conservation targets are the first steps toward
adaptation. This adaptation must begin immediately and be built on more closely integrated research and management. Rigorous
projections of possible futures are required to facilitate adaptation to change. Furthermore, the effective conservation footprint
of the NWRS must be increased through land acquisition, creative partnerships, and educational programs in order for the NWRS
to meet its legal mandate to maintain the biological integrity, diversity, and environmental health of the system and the
species and ecosystems that it supports. 相似文献
259.
Jordan M. West Susan H. Julius Peter Kareiva Carolyn Enquist Joshua J. Lawler Brian Petersen Ayana E. Johnson M. Rebecca Shaw 《Environmental management》2009,44(6):1001-1021
Public lands and waters in the United States traditionally have been managed using frameworks and objectives that were established
under an implicit assumption of stable climatic conditions. However, projected climatic changes render this assumption invalid.
Here, we summarize general principles for management adaptations that have emerged from a major literature review. These general
principles cover many topics including: (1) how to assess climate impacts to ecosystem processes that are key to management
goals; (2) using management practices to support ecosystem resilience; (3) converting barriers that may inhibit management
responses into opportunities for successful implementation; and (4) promoting flexible decision making that takes into account
challenges of scale and thresholds. To date, the literature on management adaptations to climate change has mostly focused
on strategies for bolstering the resilience of ecosystems to persist in their current states. Yet in the longer term, it is
anticipated that climate change will push certain ecosystems and species beyond their capacity to recover. When managing to
support resilience becomes infeasible, adaptation may require more than simply changing management practices—it may require
changing management goals and managing transitions to new ecosystem states. After transitions have occurred, management will
again support resilience—this time for a new ecosystem state. Thus, successful management of natural resources in the context
of climate change will require recognition on the part of managers and decisions makers of the need to cycle between “managing
for resilience” and “managing for change.” 相似文献
260.
Peter A. Valberg Barbara D. Beck Pamela D. Boardman Joshua T. Cohen 《Environmental geochemistry and health》1998,20(2):61-66
Several published studies have examined skin-cancer prevalence in regions of the USA that have concentrations of arsenic above the USA drinking-water standard. Those studies with adequate exposure and health outcome data did not report any skin cancer cases. Because the USA's arsenic concentrations are relatively low compared to some other countries and the study populations are small, the absence of reported skin-cancer cases could be due to an absence of risk in USA populations or random variability from a predicted risk. We used the current EPA arsenic cancer slope factor (CSF) model, which is derived from Taiwanese populations exposed to high levels of arsenic, to predict the expected number of skin cancers. We then conducted a likelihood ratio analysis, which showed that a null hypothesis (no additional skin cancer risk from arsenic) was approximately 2.2 times more likely than the hypothesis that ingested arsenic causes the predicted rate of skin cancers. Although based on small numbers, our analysis of USA populations indicates that the CSF derived from arsenic exposure in Taiwanese populations may be an overestimate when applied to USA populations. 相似文献