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Monitoring Stations (monitoring + stations)
Selected AbstractsVariations of chemical compositions in coarse aerosols and fine aerosols in two successive episodesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2006Chung-Yih Kuo Abstract Particulate matter with diameters less than 2.5 ,m (PM2.5) and ranging between 10 to 2.5 ,m (PM10-2.5) were simultaneously collected at four air-quality monitoring stations in the Taichung area of central Taiwan during the period of February 12 to 22, 2004. Two different types of PM10 episodes, a nonlocal dust-storm episode and a local episode, were observed in the present study. High concentrations of coarse aerosols occurred during the dust-storm episode, whereas high concentrations of fine aerosols were present during the local episode. Relatively high levels of Na+, Mg2+, Ca2+, and Cl, in coarse aerosols were observed during the dust-storm episode. Very high concentrations of secondary aerosols (NH+4, SO2,4, and NO,3) in fine aerosols were observed during the local episode. The nitrate ion demonstrated the greatest increase in the ratios of ionic species to PM2.5 and ionic species to PM10-2.5 during the local episode. Significantly high ratios (0.444) of NO,3 to NO2 in fine aerosols were present during the local episode, indicating that the relatively high formation rate of NO,3 was one of the important factors leading to the increase of the NO,3 to PM2.5 ratio during the local episode. Results also showed that an abundant quantity of fine ammonium nitrate was formed during the local episode, and chloride depletion probably was the major pathway to form coarse NaNO3 during this episode. [source] Estimation of trends in high urban ozone levels using the quantiles of (GEV)ENVIRONMETRICS, Issue 5 2010Hortensia J. Reyes Abstract In this paper we propose a statistical methodology to analyze the trends of very high values of tropospheric ozone. The methodology is based on the estimation of percentiles of the distribution of extreme values. The asymptotic distribution of the estimated percentiles is obtained with a normal result. This allows us to use a linear regression to investigate linear and non-linear trends. To illustrate the proposed methodology we use the information on ozone levels from some monitoring stations in Mexico City during the period from 1986 to 2005. The analysis of the information indicates a decrease in the very high ozone levels in the later years. Copyright © 2009 John Wiley & Sons, Ltd. [source] Analysis of air quality monitoring networks by functional clusteringENVIRONMETRICS, Issue 7 2008R. Ignaccolo Abstract Air quality monitoring networks are important tools in management and evaluation of air quality. Classifying monitoring stations via homogeneous clusters allows e dentification of similarities in pollution, of representative sites, and of spatial patterns. Instead of summaries by statistical indicators, we propose to consider the air pollutant concentrations as functional data. We then classify using functional cluster analysis, where Partitioning Around Medoids (PAM) algorithm is embedded. The proposed data analysis approach is applied to the air quality monitoring network in Piemonte (Northern Italy); we consider the three more critical pollutants: NO2, PM10, and O3. Copyright © 2008 John Wiley & Sons, Ltd. [source] Statistical analysis of temperature impact on daily hospital admissions: analysis of data from Udine, ItalyENVIRONMETRICS, Issue 1 2006Francesco Pauli Abstract This article is devoted to the analysis of the relationship between the health status of an urban population and meteorological variables. The analysis considers daily number of hospital admissions, not due to surgery, regarding the population resident in the Municipality of Udine, aged 75 and over. Hourly records on temperature, humidity, rain, atmospheric pressure, solar radiation, wind velocity and direction recorded at an observation site located near the center of Udine are considered. The study also considers hourly measures of pollutant concentrations collected by six monitoring stations. All data are relative to the summer periods of years 1995,2003. Generalized additive models (GAM) are used in which the response variable is the number of hospital admissions and is assumed to be distributed as a Poisson whose rate varies as a possibly non-linear function of the meteorological variables and variables allowing for calendar effects and pollutant concentrations. The subsequent part of the analysis explores the distribution of temperature conditional on the number of daily admissions through quantile regression. A non-linear (N-shaped) relationship between hospital admissions and temperature is estimated; temperature at 07:00 is selected as a covariate, revealing that nighttime temperature is more relevant than daytime. The quantile regression analysis points out, as expected, that the distribution of temperature on days with more admissions has higher q -quantiles with q near unity, while a clear-cut conclusion is not reached for q quantiles with q near 0. Copyright © 2005 John Wiley & Sons, Ltd. [source] Rainfall-discharge relationships for a monsoonal climate in the Ethiopian highlandsHYDROLOGICAL PROCESSES, Issue 7 2008Ben M. Liu Abstract This study presents a simple rainfall-discharge analysis for the Andit Tid, Anjeni, and Maybar watersheds of northern Ethiopia. The Soil Conservation Research Programme (SCRP) established monitoring stations in each of these sites during the 1980s, with climate and stream flow measurements being recorded up to the present. To show how these data could be used to provide insight into catchment-level runoff mechanisms, simple linear relationships between effective precipitation and runoff are developed for each watershed, with the conclusion that all three watersheds exhibit consistent hydrologic behaviour after approximately 500 mm of cumulative effective seasonal rainfall has fallen since the beginning of season. After the 500 mm rainfall threshold is reached, approximately 50% of any further precipitation on these watersheds will directly contribute to catchment runoff. Copyright © 2008 John Wiley & Sons, Ltd. [source] UNEP-GEMS/Water Programme,water quality data, GEMStat and open web services,and Japanese cooperationHYDROLOGICAL PROCESSES, Issue 9 2007Sabrina Barker Abstract The purpose of this paper is threefold. First, it demonstrates how monitoring stations that collect water quality data can be situated globally via satellite data from Google Earth. Important technical issues such as interoperability and Open Web Services are discussed in this context. Second, it illustrates how researchers at local levels can benefit from this global technology. The discussion draws from the online water quality database, GEMStat, which contains water quality data and sediment load calculations from around the world. These types of data, collected locally, can be shown to bear global implications through Internet technology. GEMStat has been expanded to include Open Web Services to enable interoperability with other online databases. Third, it illustrate an international framework of cooperation through GEMS/Water Japan, introducing on-site monitoring activities as well as management of international river basin (Mekong/La Plata). Considerations for future application framework are presented in conclusion. Copyright © 2007 John Wiley & Sons, Ltd. [source] A vertically moving grid finite-element modelling of tidal flow in the Changjiang Estuary, ChinaINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2003Z. Shi Abstract An estuarine two-dimensional vertical finite-element model of tidal flow has been established by laterally integrating Navier,Stokes equation. To this end, a moving grid finite-element method has been used. An arbitrarily shaped quadrilateral element has been selected. This model has been validated by using field data from two monitoring stations at the North Passage of the Changjiang Estuary. Using this numerical model, two types of modelled results were obtained: (1) vertical distributions of tidal current velocities at the North Passage of the Changjiang Estuary; (2) longitudinal distributions of tidal current velocities at maximum flood tide, at high slack water, at maximum ebb tide and at low slack water tide at the North Passage of the Changjiang Estuary. The conclusion is that the model provides a reasonable agreement with observed data. Copyright © 2003 John Wiley & Sons, Ltd. [source] The role of zoos in biosurveillanceINTERNATIONAL ZOO YEARBOOK, Issue 1 2007T. McNAMARA Zoos are ideally placed to act as epidemiological monitoring stations because for decades, many have been building up detailed collections of serum banks, tissue banks and medical record-keeping systems that could be mined for information that would be beneficial to public health. For example, in 1999 wild Crows Corvus brachyrhynchos in the United States of America started to die of unknown causes but it was not until some died in the grounds of a zoological institution that West Nile virus, which is a threat to both human and animal health, was identified. There is a serious disparity in the type and amount of biosurveillance provided for humans, agricultural livestock and wildlife agencies, often driven by economic factors. There is an argument for public-health entities to contribute funds to the cost of managing serum-banks and testing stations within zoos to enhance biosurveillance in urban settings, in a cost-effective and mutually beneficial manner. The key to sustainable and integrated biosurveillance lies in public-health professionals working with zoo professionals, who care for wild animals on a day-to-day basis, to create electronic surveillance networks. This could be of utmost benefit to everyone. [source] Breeding latitude and timing of spring migration in songbirds crossing the Gulf of MexicoJOURNAL OF AVIAN BIOLOGY, Issue 3 2009Kathryn M. Langin Each spring, millions of songbirds migrate across the Gulf of Mexico on their way to breeding sites in North America. Data from radar and migration monitoring stations have revealed broad patterns in the spatial and temporal course of trans-Gulf migration. Unfortunately, we have limited information on where these birds have previously spent the winter and where they are migrating to breed. Here we measure stable-hydrogen isotopes in feathers (,Df) to infer the breeding latitude of five species of songbirds , hooded warblers Wilsonia citrina, American redstarts Setophaga ruticilla, black-and-white warblers Mniotilta varia, ovenbirds Seiurus aurocapilla, and northern waterthrushes S. noveboracensis, that were captured at a stopover site along the coast of southwestern Louisiana in spring 2004. Values of ,Df across all species ranged from ,163 to ,35, (n=212), and within most species the range was consistent with the latitudinal extent of known breeding sites in central and eastern North America. Individuals that arrived first along the northern Gulf coast had ,Df values indicative of southerly breeding sites in hooded warblers, American redstarts, black-and-white warblers, and ovenbirds, but no relationship was found between passage timing and ,Df for northern waterthrushes. Our findings suggest that spring passage is often timed to coincide with the emergence of suitable conditions on breeding areas, with southern breeding birds migrating first. [source] A ground-level ozone forecasting model for Santiago, ChileJOURNAL OF FORECASTING, Issue 6 2002Héctor Jorquera Abstract A physically based model for ground-level ozone forecasting is evaluated for Santiago, Chile. The model predicts the daily peak ozone concentration, with the daily rise of air temperature as input variable; weekends and rainy days appear as interventions. This model was used to analyse historical data, using the Linear Transfer Function/Finite Impulse Response (LTF/FIR) formalism; the Simultaneous Transfer Function (STF) method was used to analyse several monitoring stations together. Model evaluation showed a good forecasting performance across stations,for low and high ozone impacts,with power of detection (POD) values between 70 and 100%, Heidke's Skill Scores between 40% and 70% and low false alarm rates (FAR). The model consistently outperforms a pure persistence forecast. Model performance was not sensitive to different implementation options. The model performance degrades for two- and three-days ahead forecast, but is still acceptable for the purpose of developing an environmental warning system at Santiago. Copyright © 2002 John Wiley & Sons, Ltd. [source] Changing prevalence of asthma in Taiwanese adolescents: two surveys 6 years apartPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 2 2005Yung-Ling Lee This study compared the prevalence of asthma among Taiwanese adolescents with individual-level risk factors and municipal-level air pollution and meteorology data to determine whether changes in these factors could explain the observed change in prevalence. We conducted two national surveys of respiratory illness and symptoms in Taiwanese middle-school students in 1995,96 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with asthma prevalence difference. A total of 44,104 children from the 1995,96 survey and 11,048 children from the 2001 survey attended schools located within 1 km of 22 monitoring stations. Lifetime prevalences of physician-diagnosed and questionnaire-determined asthma increased during this period. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed most, changes in investigated personal and environmental factors might not explain the observed changes in asthma prevalence. Municipalities with higher temperature increase were significantly associated with prevalence difference in questionnaire-determined asthma. We concluded that correlates of the investigated individual-level factors, which have changed over time, still underlie changes in asthma prevalence. Increasing temperature might be the main reason for the rising trends of asthma in Taiwanese adolescents. [source] Process Analysis of In-situ Strain during the Ms8.0 Wenchuan Earthquake,Data from the Stress Monitoring Station at ShandanACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2009Hua PENG Abstract: There were huge life and property losses during the Ms8.0 Wenchuan earthquake on May 12, 2008. Strain fluctuation curves were completely recorded at stress observatory stations in the Qinghai-Tibet plateau and its surroundings in the process of the earthquake. This paper introduces the geological background of the Wenchuan earthquake and the profile of in-situ stress monitoring stations. In particular, data of 174 earthquakes (Ms4.0,Ms8.5) were processed and analyzed with various methods, which were recorded at the Shandan station from August 2007 to December 2008. The results were compared with other seismic data, and further analyses were done for the recoded strain seismic waves, co-seismic strain stepovers, pre-earthquake strain valleys, Earth's free oscillations before and after the earthquake and their physical implications. During the Wenchuan earthquake, the strainmeter recorded a huge extensional strain of 70 seconds, which shows that the Wenchuan earthquake is a rupture process predominated by thrusting. Significant precursory strain anomalies were detected 48 hours, 30 hours, 8 hours and 37 minutes before the earthquake. The anomalies are very high and their forms are very similar to that of the main shock. Similar anomalies can also be found in strain curves of other shocks greater than Ms7.0, indicating that such anomalies are prevalent before a great earthquake. In this paper, it is shown that medium aftershocks (Ms5.5,6.0) can also cause Earth's free oscillations. Study of free oscillations is of great significance to understand the internal structure of the Earth and focal mechanisms of earthquakes and to recognize slow shocks, thus providing a scientific basis for the prevention and treatment of geological disasters and the prediction of future earthquakes. [source] Increasing prevalence of atopic eczema in Taiwanese adolescents from 1995 to 2001CLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2007Y.-L. Lee Summary Background The prevalence of atopic eczema in adolescents has recently been reported as increasing in many countries, a phenomenon yet to be fully explained. This study compared the prevalence of atopic eczema among Taiwanese adolescents with individual-level risk factors and community-level data of temperature, relative humidity, and air pollutants to determine whether changes in these factors could explain the observed change in prevalence. Methods We conducted two nationwide, cross-sectional surveys of atopic illness and symptoms among Taiwanese 12,15-year-old schoolchildren in 1995,1996 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with the prevalence difference of atopic eczema. Results A total of 42 919 adolescents from the 1995 to 1996 survey and 10 215 adolescents from the 2001 survey attended schools located within 1 km of 22 monitoring stations. The 12-month prevalence of atopic eczema increased significantly during this period [adjusted prevalence ratio (PR)=1.43, 95% confidence interval (CI) 1.21,1.70 in boys; PR=1.77, 95% CI 1.49,2.10 in girls]. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed the most, changes in personal and environmental factors might not explain the observed prevalence increases of atopic eczema. Temporal change in the relative humidity was significantly associated with prevalence increase among boys but its contribution was also small. Conclusion Correlates of the investigated risk factors that have changed over time still underlie the prevalence increases of atopic eczema in Taiwanese adolescents. The exact reasons for the rising trends remain to be elucidated. [source] | ||||||||||||||||