An integrated WRF/HYSPLIT modeling approach for the assessment of PM2.5 source regions over the Mississippi Gulf Coast region

Fine particulate matter (PM_2.5) is majorly formed by precursor gases, such as sulfur dioxide (SO₂) and nitrogen oxides (NO_x), which are emitted largely from intense industrial operations and transportation activities. PM_2.5 has been shown to affect respiratory health in humans. Evaluation of source regions and assessment of emission source contributions in the Gulf Coast region of the USA will be useful for the development of PM_2.5 regulatory and mitigation strategies. In the present study, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model driven by the Weather Research & Forecasting (WRF) model is used to identify the emission source locations and transportation trends. Meteorological observations as well as PM_2.5 sulfate and nitric acid concentrations were collected at two sites during the Mississippi Coastal Atmospheric Dispersion Study, a summer 2009 field experiment along the Mississippi Gulf Coast. Meteorological fields during the campaign were simulated using WRF with three nested domains of 36, 12, and 4?km horizontal resolutions and 43 vertical levels and validated with North American Mesoscale Analysis. The HYSPLIT model was integrated with meteorological fields derived from the WRF model to identify the source locations using backward trajectory analysis. The backward trajectories for a 24-h period were plotted at 1-h intervals starting from two observation locations to identify probable sources. The back trajectories distinctly indicated the sources to be in the direction between south and west, thus to have origin from local Mississippi, neighboring Louisiana state, and Gulf of Mexico. Out of the eight power plants located within the radius of 300?km of the two monitoring sites examined as sources, only Watson, Cajun, and Morrow power plants fall in the path of the derived back trajectories. Forward dispersions patterns computed using HYSPLIT were plotted from each of these source locations using the hourly mean emission concentrations as computed from past annual emission strength data to assess extent of their contribution. An assessment of the relative contributions from the eight sources reveal that only Cajun and Morrow power plants contribute to the observations at the Wiggins Airport to a certain extent while none of the eight power plants contribute to the observations at Harrison Central High School. As these observations represent a moderate event with daily average values of 5?C8???g?m^?3 for sulfate and 1?C3???g?m^?3 for HNO₃ with differences between the two spatially varied sites, the local sources may also be significant contributors for the observed values of PM_2.5.     

Air pollution modeling: a tool for management of regional air quality

Ambient air composition over the earth has undergone several changes. Anthropogenic pollutants generated locally often have regional air quality affected significantly. In addition to the short-term episodic effects, atmospheric pollutants are known to generate long-term adverse effects, which are difficult to forecast statistically. The air pollution dispersion modeling exercise forecasts fairly accurate air quality for a given emission scenario, incorporating geographical and meteorological conditions. Industrial Source Complex Dispersion Model is used to forecast ground level concentrations (GLC) of an industrial region as case study. The usefulness of mathematical modeling and computational simulation techniques used to predict the horizontal and vertical pollutant concentrations of pollutants are explained in this paper. Finally a case study of an industrial area in Gujarat region is presented to arrive at setting up of air quality monitoring station for monitoring/management of regional air quality.     

Air pollution emission inventory and air quality modeling for Can Tho City,Mekong Delta,Vietnam

Can Tho City has quickly become a modernized and industrialized city undergoing rapid population growth affecting the local environment, especially air quality and human health. In 2015, Can Tho had 1,251,809 inhabitants with a total of 566,593 motorcycles and 15,105 automobiles. There are about 1000 factories in the city. The top polluters are the industries of textile and dyeing, food processing, cement, and steel mill and rice processing. The aims of this research are to (i) conduct a detailed air pollution emission inventory (ii) study the formation of the air pollution plume over the city, and (iii) study different pollution abatement strategies for the city. We employ a combination of bottom-up and top-down approaches to conduct air pollution emission inventory, then, the finite volume model-transport and photochemistry mesoscale model is applied for studying the formation of the pollution plume. The results showed that transportation and industrial activities are the two main emission sources responsible for 80% of total NO _x , 90% of total SO_2, 75% of CO, 60% of total suspended particles, and 60% of non-methane volatile organic compounds. Modeling results showed that the highest average—1 h—of O₃ is 206 μg/m³ which is higher than the Vietnam ambient air quality standard. The pollution plume is developed in the northeastern part of the city. Finally, abatement measures were proposed. This is the first comprehensive study on air pollution emissions and air quality modeling in the Mekong Delta, yielding insight to support government authorities to promulgate plans and actions to reduce emissions, protecting human health and the environment while leading towards sustainable development.     

Joint modeling quality of life and survival using a terminal decline model in palliative care studies

Palliative medicine is a relatively new specialty that focuses on preventing and relieving the suffering of patients facing life‐threatening illness. For cancer patients, clinical trials have been carried out to compare concurrent palliative care with usual cancer care in terms of longitudinal measurements of quality of life (QOL) until death, and overall survival is usually treated as a secondary endpoint. It is known that QOL of patients with advanced cancer decreases as death approaches; however, in previous clinical trials, this association has generally not been taken into account when inferences about the effect of an intervention on QOL or survival have been made. We developed a new joint modeling approach, a terminal decline model, to study the trajectory of repeated measurements and survival in a recently completed palliative care study. This approach takes the association of survival and QOL into account by modeling QOL retrospectively from death. For those patients whose death times are censored, marginal likelihood is used to incorporate them into the analysis. Our approach has two submodels: a piecewise linear random intercept model with serial correlation and measurement error for the retrospective trajectory of QOL and a piecewise exponential model for the survival distribution. Maximum likelihood estimators of the parameters are obtained by maximizing the closed‐form expression of log‐likelihood function. An explicit expression of quality‐adjusted life years can also be derived from our approach. We present a detailed data analysis of our previously reported palliative care randomized clinical trial. Copyright © 2012 John Wiley & Sons, Ltd.     

Assessment of lead toxicity to the marine bacterium, Vibrio fischeri, and to a heterogeneous population of microorganisms derived from the Pearl River in Jackson, Mississippi, USA.

Microorganisms are known to be excellent test organisms because of the relative ease for handling and suitability for analysis related to their small size, large number and convenient growing conditions. In this research, we tested the toxic effects of lead against a marine bacterium (Vibrio fischeri), and a heterogeneous population of bacteria derived from the Pearl River in Jackson, Mississippi. Using the level of bioluminescence in the Microtox Assay (V. fischeri), and the kinetics of dissolved oxygen uptake and growth (mixed bacterial population) as measures of toxicity, lead concentrations effecting a 50% reduction in these parameters (EC50) were determined as the toxic end-points. The activity quotients were also computed to determine the degrees of toxicity. Optical density (measure of growth) and oxygen uptake were measured over an extended period of time (20 h). EC50 values of 0.34 +/- 0.03, 3.10 +/- 0.01, and 3.80 +/- 0.02 mg/L were recorded for bioluminescence, growth, and oxygen uptake, respectively. As expected, the results indicated that the sensitivity to lead toxicity of V. fischeri was about one order of magnitude (10 times) greater than that of the mixed population of Pearl River microorganisms. Reductions in bioluminescence, growth, and oxygen uptake were directly correlated to lead concentrations, with toxic levels ranging from slightly toxic in lower concentrations to extremely toxic in higher concentrations. Upon 20 h of exposure, the times required to produce 50% reduction in dissolved oxygen uptake were (TD50S) 8.01 +/- 0.44, 9.60 +/- 0.46, 11.29 +/- 0.46, 13.03 +/- 0.57, 17.32 +/- 0.95, and 20.00 +/- 0.00 h in 0, 1, 2, 3, 4, 5, and 6 mg/L of lead, respectively, indicating a time-response relationship with respect to lead toxicity.     

Reproducibility of image quality for moving objects using respiratory-gated computed tomography: a study using a phantom model

To investigate the reproducibility of computed tomography (CT) imaging quality in respiratory-gated radiation treatment planning is essential in radiotherapy of movable tumors. Seven series of regular and six series of irregular respiratory motions were performed using a thorax dynamic phantom. For the regular respiratory motions, the respiratory cycle was changed from 2.5 to 4 s and the amplitude was changed from 4 to 10 mm. For the irregular respiratory motions, a cycle of 2.5 to 4 or an amplitude of 4 to 10 mm was added to the base data (i.e. 3.5-s cycle, 6-mm amplitude) every three cycles. Images of the object were acquired six times using respiratory-gated data acquisition. The volume of the object was calculated and the reproducibility of the volume was decided based on the variety. The registered image of the object was added and the reproducibility of the shape was decided based on the degree of overlap of objects. The variety in the volumes and shapes differed significantly as the respiratory cycle changed according to regular respiratory motions. In irregular respiratory motion, shape reproducibility was further inferior, and the percentage of overlap among the six images was 35.26% in the 2.5- and 3.5-s cycle mixed group. Amplitude changes did not produce significant differences in the variety of the volumes and shapes. Respiratory cycle changes reduced the reproducibility of the image quality in respiratory-gated CT.     

Air pollutant exposure field modeling using air quality model-data fusion methods and comparison with satellite AOD-derived fields: application over North Carolina,USA

In order to generate air-pollutant exposure fields for health studies, a data fusion (DF) approach is developed that combines observations from ambient monitors and simulated data from the Community Multiscale Air Quality (CMAQ) model. These resulting fields capture the spatiotemporal information provided by the air quality model, as well as the finer temporal scale variations from the pollutant observations and decrease model biases. Here, the approach is applied to develop daily concentration fields for PM_2.5 total mass, five major particulate species (OC, EC, SO₄ ^2?, NO₃ ^?, and NH₄ ⁺), and three gaseous pollutants (CO, NO _x , and NO₂) from 2006 to 2008 over North Carolina (USA). Several data withholding methods are then conducted to evaluate the data fusion method, and the results suggest that typical approaches may overestimate the ability of spatiotemporal estimation methods to capture pollutant concentrations in areas with limited or no monitors. The results show improvements in capturing spatial and temporal variability compared with CMAQ results. Evaluation tests for PM_2.5 led to an R ² of 0.95 (no withholding) and 0.82 when using 10% random data withholding. If spatially based data withholding is used, the R ² is 0.73. Comparisons of DF-developed PM_2.5 total mass concentration with the spatiotemporal fields derived from two other methods (both use satellite aerosol optical depth (AOD) data) find that, in this case, the data fusion fields have slightly less overall error, with an RMSE of 1.28 compared with 3.06 μg/m³ (two-stage statistical model) and 2.74 (neural network-based hybrid model). Applying the Integrated Mobile Source Indicator (IMSI) method shows that the data fusion fields can be used to estimate mobile source impacts. Overall, the growing availability of chemically detailed air quality model fields and the accuracy of the DF field, suggest that this approach is better able to provide spatiotemporal pollutant fields for gaseous and speciated particulate pollutants for health and planning studies.     

Analyzing the efficiency of short-term air quality plans in European cities,using the CHIMERE air quality model

Regional and local authorities have the obligation to design air quality plans and assess their impacts when concentration levels exceed the limit values. Because these limit values cover both short- (day) and long-term (year) effects, air quality plans also follow these two formats. In this work, we propose a methodology to analyze modeled air quality forecast results, looking at emission reduction for different sectors (residential, transport, agriculture, etc.) with the aim of supporting policy makers in assessing the impact of short-term action plans. Regarding PM₁₀, results highlight the diversity of responses across European cities, in terms of magnitude and type that raises the necessity of designing area-specific air quality plans. Action plans extended from 1 to 3 days (i.e., emissions reductions applied for 24 and 72 h, respectively) point to the added value of trans-city coordinated actions. The largest benefits are seen in central Europe (Vienna, Prague) while major cities (e.g., Paris) already solve a large part of the problem on their own. Eastern Europe would particularly benefit from plans based on emission reduction in the residential sectors; while in northern cities, agriculture seems to be the key sector on which to focus attention. Transport is playing a key role in most cities whereas the impact of industry is limited to a few cities in south-eastern Europe. For NO₂, short-term action plans focusing on traffic emission reductions are efficient in all cities. This is due to the local character of this type of pollution. It is important, however, to stress that these results remain dependent on the selected months available for this study.     

Association mapping,using a mixture model for complex traits

Association mapping for complex diseases using unrelated individuals can be more powerful than family-based analysis in many settings. In addition, this approach has major practical advantages, including greater efficiency in sample recruitment. Association mapping may lead to false-positive findings, however, if population stratification is not properly considered. In this paper, we propose a method that makes it possible to infer the number of subpopulations by a mixture model, using a set of independent genetic markers and then testing the association between a genetic marker and a trait. The proposed method can be effectively applied in the analysis of both qualitative and quantitative traits. Extensive simulations demonstrate that the method is valid in the presence of a population structure.     

Applications of WRF/CALPUFF modeling system and multi-monitoring methods to investigate the effect of seasonal variations on odor dispersion: a case study of Changwon City,South Korea

Changwon is an industrial city located in the southeastern region of South Korea. Surrounded by coastal and mountainous areas with contiguous industrial and residential areas, the city of Changwon has experienced a high number of malodor complaints in recent years. This study was carried out to investigate the effect of seasonal variations on odor dispersion from industrial to community areas, which were considerably higher from the late spring through fall according to complaint statistics. Investigation methods comprise the applications of electronic odor detector, questionnaire, olfactory system, weather observation data, and weather research and forecasting/CALPUFF modeling system. Results from all methods were consistent in showing that the change of seasons affected the direction of odor diffusion. From summer to early fall, the pollutions emitted from the industrial zone had the highest impact on the residential zone, covering the three most common areas of complaints for unpleasant odors. The reasons are that during the summer period, the reduction of a planetary boundary layer and the prevalence of a consistent sea breeze resulted in the presence of south–southwesterly ocean winds which swept through the factories to a residential area. In contrast, synoptic winds which prevailed during other seasons restrained sea breeze circulation, leading to diverse wind directions. During the fall season, the higher number of complaints could be attributed to a lower wind speed, which caused the poor spread of pollutants from the area with the topography of the basin.     

Applying a framework for assessing the quality of maternal health services in urban India

This paper presents findings from the application of a framework for assessing the quality of care of institutional maternity services in an urban slum in India. The framework divides quality into two parts: the quality of users' experience of care and the quality of the provision of care. Data from public and private hospitals were collected via observation, exit interviews, provider interviews, review of hospital records, the mystery client approach and a household survey of 650 women in the immediate vicinity of the case study hospitals. Findings provide evidence that quality is far from optimal in both public and private facilities. Problems identified included a lack of essential drugs, women being left unsupported, evidence of physical and verbal abuse, and births occurring in hospitals without a health professional in attendance. The paper concludes that while many governments have explicit targets to increase institutional deliveries, many do not have explicit targets or even a commitment to assess and improve the quality of institutional services for childbirth.     

Measles immunization strategies for countries with high transmission rates: interim guidelines predicted using a mathematical model

This study addresses the problem of measles immunization in communities experiencing unacceptably high numbers of cases in young infants, under circumstances where high dose Edmonston-Zagreb vaccine is not yet available. Where the continued use of standard potency vaccines (eg Schwarz) is unavoidable we have investigated the merits of new policies which aim to offer better protection to children below the currently recommended vaccination age of nine months. These policies are intended for implementation in communities with intense measles transmission. Predictions, spanning five years, using a previously developed mathematical model are presented for two types of potential new policies: a 'switch' to a younger target age, or a 'two-dose' strategy incorporating vaccination at a younger age in addition to the current schedule at nine months. We conclude that a switch in immunization policy to a younger age is of doubtful worth, but that supplementary vaccination at around six months in addition to existing coverage at nine months (ie two-dose policy) is a desirable option.     

Transforming the urban food desert from the grassroots up: a model for community change

Confronted by continuing health disparities in vulnerable communities, Community Health Councils (CHC), a nonprofit community-based organization in South Los Angeles, worked with the African Americans Building a Legacy of Health Coalition and research partners to develop a community change model to address the root causes of health disparities within the community's African American population. This article discusses how the CHC Model's development and application led to public policy interventions in a "food desert." The CHC Model provided a systematic approach to engaging impacted communities in support of societal level reforms, with the goal to influence health outcomes.     

Potential assessment of a neural network model with PCA/RBF approach for forecasting pollutant trends in Mong Kok urban air, Hong Kong

The forecasting of air pollutant trends has received much attention in recent years. It is an important and popular topic in environmental science, as concerns have been raised about the health impacts caused by unacceptable ambient air pollutant levels. Of greatest concern are metropolitan cities like Hong Kong. In Hong Kong, respirable suspended particulates (RSP), nitrogen oxides (NOx), and nitrogen dioxide (NO2) are major air pollutants due to the dominant usage of diesel fuel by commercial vehicles and buses. Hence, the study of the influence and the trends relating to these pollutants is extremely significant to the public health and the image of the city. The use of neural network techniques to predict trends relating to air pollutants is regarded as a reliable and cost-effective method for the task of prediction. The works reported here involve developing an improved neural network model that combines both the principal component analysis technique and the radial basis function network and forecasts pollutant tendencies based on a recorded database. Compared with general neural network models, the proposed model features a more simple network architecture, a faster training speed, and a more satisfactory prediction performance. The improved model was evaluated with hourly time series of RSP, NOx and NO2 concentrations monitored at the Mong Kok Roadside Gaseous Monitory Station in Hong Kong during the year 2000 and proved to be effective. The model developed is a potential tool for forecasting air quality parameters and is superior to traditional neural network methods.     

以质量为核心维修为基础全面建设一支高素质的医学工程队伍提高医学工程保障管理水平

抓医学工程科质量,建设促进专科业务技术水平,全面发展自力更生,走出一条符合我院医学工程发展之路。     

南昌市社区老年人轻度认知功能障碍向阿尔茨海默病转归研究

  目的  了解安徽省马鞍山市社区空巢老年人生活质量的2年动态变化情况及影响因素,为制定老年人卫生保健对策、开展老年卫生保健服务和健康教育提供科学依据。  方法  于2016年12月 — 2017年3月采用分层整群随机抽样方法在马鞍山市抽取3476名 ≥ 60岁社区老年人进行生活质量基线调查,并于2018年12月 — 2019年3月进行随访,以2次调查均为空巢状态的2344名老年人组成纵向队列,分析社区空巢老年人生活质量的2年动态变化情况及影响因素。  结果  马鞍山市社区空巢老年人随访调查时心理领域和社会关系领域生活质量得分分别为（55.40 ± 10.76）和（65.70 ± 12.56）分,均低于基线调查时的（65.71 ± 13.52）和（67.43 ± 12.42）分（均P < 0.05）;生理领域和环境领域生活质量得分分别为（64.62 ± 13.92）和（63.53 ± 11.90）分,与基线调查时的（65.22 ± 14.55）和（63.97 ± 12.67）分比较,差异均无统计学意义（均P > 0.05）。广义估计方程分析结果显示,年龄 ≥ 70岁、日常生活能力障碍、抑郁是马鞍山市社区空巢老年人心理领域生活质量的危险因素,自评经济水平中等和好、吸烟、饮酒、参加体育锻炼、心理弹性中等和高是马鞍山市社区空巢老年人心理领域生活质量的保护因素;年龄 ≥ 70岁、文化程度小学及以上、独居、患慢性病、日常生活能力下降和障碍、抑郁是马鞍山市社区空巢老年人生理领域生活质量的危险因素,自评经济水平中等和好、吸烟、饮酒、参加体育锻炼、心理弹性中等和高是马鞍山市社区空巢老年人生理领域生活质量的保护因素;年龄70～79岁、独居、日常生活能力障碍、抑郁是马鞍山市社区空巢老年人社会关系领域生活质量的危险因素,女性、自评经济水平中等和好、饮酒、心理弹性中等和高是马鞍山市社区空巢老年人社会关系领域生活质量的保护因素;日常生活能力障碍和抑郁是马鞍山市社区空巢老年人环境领域生活质量的危险因素,自评经济水平中等和好、吸烟、饮酒、参加体育锻炼、心理弹性中等和高是马鞍山市社区空巢老年人环境领域生活质量的保护因素。  结论  马鞍山市社区空巢老年人生活质量主要问题在于心理领域和社会关系领域质量的下降,年龄、自评经济水平、是否饮酒、日常生活能力、是否抑郁和心理弹性状况为该地区社区空巢老年人心理领域和社会关系领域生活质量的共同影响因素。