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A New Method for Assessing the Efficacy of Emission Control Strategies.

ABSTRACT: Regional-scale air quality models and observations at routine air quality monitoring sites are used to determine attainment/non-attainment of the ozone air quality standard in the United States. In current regulatory applications, a regional-scale air quality model is applied for a base year and a future year with reduced emissions using the same meteorological conditions as those in the base year. Because of the stochastic nature of the atmosphere, the same meteorological conditions would not prevail in the future year. Therefore, we use multi-decadal observations to develop a new method for estimating the confidence bounds for the future ozone design value (based on the 4th highest value in the daily maximum 8-hr ozone concentration time series, DM8HR) for each emission loading scenario along with the probability of the design value exceeding a given ozone threshold concentration at all monitoring sites in the contiguous United States. To this end, we spectrally decompose the observed DM8HR ozone time series covering the period from 1981 to 2014 using the Kolmogorov-Zurbenko (KZ) filter and examine the variability in the relative strengths of the short-term variations (induced by synoptic-scale weather fluctuations; referred to as synoptic component, SY) and the long-term component (dictated by changes in emissions, seasonality and other slow-changing processes such as climate change; referred to as baseline component, BL). Results indicate that combining the projected change in the ozone baseline level with the adjusted synoptic forcing in historical ozone observations enables us to provide a probabilistic assessment of the efficacy of a selected emissions control strategy in complying with the ozone standard in future years. In addition, attainment demonstration is illustrated with a real-world application of the proposed methodology by using air quality model simulations, thereby helping build confidence in the use of regional-scale air quality models for supporting regulatory policies.

SUBMITTER: Luo H

PROVIDER: S-EPMC6605770 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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A New Method for Assessing the Efficacy of Emission Control Strategies.

Luo Huiying H Astitha Marina M Hogrefe Christian C Mathur Rohit R Rao S Trivikrama ST

Atmospheric environment (Oxford, England : 1994) 20190101

Regional-scale air quality models and observations at routine air quality monitoring sites are used to determine attainment/non-attainment of the ozone air quality standard in the United States. In current regulatory applications, a regional-scale air quality model is applied for a base year and a future year with reduced emissions using the same meteorological conditions as those in the base year. Because of the stochastic nature of the atmosphere, the same meteorological conditions would not p ...[more]

PMID: 31275052

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Project description:BackgroundDue to improved treatments and ageing population, many countries now report increasing prevalence in rates of ischemic heart disease and heart failure. Cardiac rehabilitation has potential to reduce morbidity and mortality, but not all patients complete. In light of favourable effects of cardiac rehabilitation it is important to develop patient education methods which can enhance adherence to this effective program. The LC-REHAB study aims to compare the effect of a new patient education strategy in cardiac rehabilitation called 'learning and coping' to that of standard care. Further, this paper aims to describe the theoretical basis and details of this intervention.Methods/designOpen parallel randomised controlled trial conducted in three hospital units in Denmark among patients recently discharged with ischemic heart disease or heart failure. Patients are allocated to either the intervention group with learning and coping strategies incorporated into standard care in cardiac rehabilitation or the control group who receive the usual cardiac rehabilitation program. Learning and coping consists of two individual clarifying interviews, participation of experienced patients as educators together with health professionals and theory based, situated and inductive teaching. Usual care in cardiac rehabilitation is characterised by a structured deductive teaching style with use of identical pre-written slides in all hospital units. In both groups, cardiac rehabilitation consists of training three times a week and education once a week over eight weeks. The primary outcomes are adherence to cardiac rehabilitation, morbidity and mortality, while secondary outcomes are quality of life (SF-12, Health education impact questionnaire and Major Depression Inventory) and lifestyle and risk factors (Body Mass Index, waist circumference, blood pressure, exercise work capacity, lipid profile and DXA-scan). Data collection occurs four times; at baseline, at immediate completion of cardiac rehabilitation, and at three months and three years after the finished program.DiscussionIt is expected that learning and coping incorporated in cardiac rehabilitation will improve adherence in cardiac rehabilitation and may decrease morbidity and mortality. By describing learning and coping strategies the study aims to provide knowledge that can contribute to an increased transparency in patient education in cardiac rehabilitation.Trial registrationIdentifier NCT01668394.

Project description:Mosquitoes function as important vectors for many diseases globally and can have substantial negative economic, environmental, and health impacts. Specifically, West Nile virus (WNv) is a significant and increasing threat to wildlife populations and human health throughout North America. Mosquito control is an important means of controlling the spread of WNv, as the virus is primarily spread between avian and mosquito vectors. This is of particular concern for avian host species such as the Greater sage-grouse (Centrocercus urophasianus), in which WNv negatively impacts fitness parameters. Most mosquito control methods focus on the larval stages. In North America, control efforts are largely limited to larvicides, which require repeated application and have potentially negative ecological impacts. There are multiple potential advantages to using indigenous fish species as an alternative for larval control including lowered environmental impact, decreased costs in terms of time and financial inputs, and the potential for the establishment of self-sustaining fish populations. We tested the efficacy of using fathead minnows (Pimephales promelas) as biological control for mosquito populations in livestock reservoirs of semiarid rangelands. We introduced minnows into 10 treatment reservoirs and monitored an additional 6 non-treated reservoirs as controls over 3 years. Adult mosquitoes of species known to transmit WNv (e.g., Culex tarsalis) were captured at each site and mosquito larvae were also present at all sites. Stable isotope analysis confirmed that introduced fathead minnows were feeding at the mosquito larvae trophic level in all but one treatment pond. Treatment ponds demonstrated suppressed levels of mosquito larva over each season compared to controls with a model-predicted 114% decrease in larva density within treatment ponds. Minnows established self-sustaining populations throughout the study in all reservoirs that maintained sufficient water levels. Minnow survival was not influenced by water quality. Though minnows did not completely eradicate mosquito larvae, minnows are a promising alternative to controlling mosquito larvae density within reservoirs. We caution that careful site selection is critical to avoid potential negative impacts, but suggest the introduction of fathead minnows in reservoirs can dramatically reduce mosquito larva abundance and potentially help mitigate vector-borne disease transmission.

Project description:BackgroundDecompressive craniectomy (DC) is a surgical intervention used following traumatic brain injury to prevent or alleviate raised intracranial pressure. However the clinical effectiveness of the intervention remains in doubt. The location of the craniectomy (unilateral or bifrontal) might be expected to change the brain deformation associated with the operation and hence the clinical outcome. As existing methods for assessing brain deformation have several limitations, we sought to develop and validate a new improved method.MethodsComputed tomography (CT) scans were taken from 27 patients who underwent DC (17 bifrontal patients and 10 unilateral patients). Pre-operative and post-operative images were processed and registered to determine the change in brain position associated with the operation. The maximum deformation in the herniated brain, the change in volume and estimates of the craniectomy area were determined from the images. Statistical comparison was made using the Pearson's correlation coefficient r and a Welch's two-tailed T-test, with statistical significance reported at the 5% level.ResultsThere was a reasonable correlation between the volume increase and the maximum brain displacement (r = 0.64), a low correlation between the volume increase and the craniectomy area (r = 0.30) and no correlation between the maximum displacement and the craniectomy area (r = -0.01). The maximum deformation was significantly lower (P = 0.023) in the bifrontal patients (mean = 22.5 mm) compared with the unilateral patients (mean = 29.8 mm). Herniation volume was significantly lower (P = 0.023) in bifrontal (mean = 50.0 ml) than unilateral patients (mean = 107.3 ml). Craniectomy area was not significantly different for the two craniectomy locations (P = 0.29).ConclusionsA method has been developed to quantify changes in brain deformation due to decompressive craniectomy from CT images and allow comparison between different craniectomy locations. Measured displacement is a reasonable way to characterise volume changes.

Project description:BackgroundImplementation strategies have flourished in an effort to increase integration of research evidence into clinical practice. Most strategies are complex, socially mediated processes. Many are complicated, expensive, and ultimately impractical to deliver in real-world settings. The field lacks methods to assess the extent to which strategies are usable and aligned with the needs and constraints of the individuals and contexts who will deliver or receive them. Drawn from the field of human-centered design, cognitive walkthroughs are an efficient assessment method with potential to identify aspects of strategies that may inhibit their usability and, ultimately, effectiveness. This article presents a novel walkthrough methodology for evaluating strategy usability as well as an example application to a post-training consultation strategy to support school mental health clinicians to adopt measurement-based care.MethodThe Cognitive Walkthrough for Implementation Strategies (CWIS) is a pragmatic, mixed-methods approach for evaluating complex, socially mediated implementation strategies. CWIS includes six steps: (1) determine preconditions; (2) hierarchical task analysis; (3) task prioritization; (4) convert tasks to scenarios; (5) pragmatic group testing; and (6) usability issue identification, classification, and prioritization. A facilitator conducted two group testing sessions with clinician users (N = 10), guiding participants through 6 scenarios and 11 associated subtasks. Clinicians reported their anticipated likelihood of completing each subtask and provided qualitative justifications during group discussion. Following the walkthrough sessions, users completed an adapted quantitative assessment of strategy usability.ResultsAverage anticipated success ratings indicated substantial variability across participants and subtasks. Usability ratings (scale 0-100) of the consultation protocol averaged 71.3 (SD = 10.6). Twenty-one usability problems were identified via qualitative content analysis with consensus coding, and classified by severity and problem type. High-severity problems included potential misalignment between consultation and clinical service timelines as well as digressions during consultation processes.ConclusionsCWIS quantitative usability ratings indicated that the consultation protocol was at the low end of the "acceptable" range (based on norms from the unadapted scale). Collectively, the 21 resulting usability issues explained the quantitative usability data and provided specific direction for usability enhancements. The current study provides preliminary evidence for the utility of CWIS to assess strategy usability and generate a blueprint for redesign.

Project description:The interaction between transport and chemistry is pivotal for local ozone (O3) concentration, especially for a coastal region where the upstream sources might change diurnally. In the current emission control policy, most pollutants, such as particulate matter, SO2, NOx, and CO, decrease while the annual O3 trend might increase due to the complex feedbacks of precursors. In this study, we investigate the influence of transport upon the wintertime O3 diurnal trend over ZuoYing Kaohsiung, an urban coastal site in southern Taiwan, by constructing a two-dimensional numerical model coupling both physical mechanisms and core chemical processes and provide a feasible emission control strategy. The transport process (i.e., import vs. export) for the daytime is determined using the Leighton Ratio (Φ), the ratio of O3-production over O3-loss rate, under the pseudo-steady-state condition. Φ shows a deviation of -9 to +13% from the photo-stationary state, and experiences a transition from import effect before 10:15 to weakening import or net export effect afterward associated with a net O3 production as sea breeze starts developing. The significantly higher Φ derived from observation than from simulation by a factor of 1.35 might be resulted from the over-reported NO2 due to NOy contribution on the NO2 measurement, and the influence of aerosol and cloud possibly reducing ∼30% on applied NO2 photolysis rate constant, associated with aerosol optical depth of 0.75 ± 0.15 and single scattering albedo of 0.85 ± 0.15. In this studied NOx-saturated regime, the addition of sea breeze convergence over the land enhances the maximal O3 by ∼10%, mainly due to the O3 accumulation (∼88%). Furthermore, the ozone isopleth analysis as a function of non-methane hydrocarbons and NOx emissions provides an achievable strategy to decrease both maximum daily ozone and the increment of ozone from morning to maximum by reducing hydrocarbons and NOx emissions, which can also eliminate the additional nitrate contribution on the aerosols. Highlights • Leighton Ratio variation illustrates the transition of the ozone transport process.• Transport causes the noontime O3 time lag under pseudo-steady state conditions.• AOD and SSA are derived under the apparent photo-stationary condition.• Sea breeze convergence increases O3 primarily via physical accumulation.• A feasible emission control strategy is proposed by superposed isopleth diagrams. Ozone, Photochemistry, Leighton Ratio, Sea Breeze, Ozone Isopleth

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A New Method for Assessing the Efficacy of Emission Control Strategies.

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A New Method for Assessing the Efficacy of Emission Control Strategies.

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