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101.
Using improved neural network model to analyze RSP,NOx and NO2 levels in urban air in Mong Kok,Hong Kong 总被引:4,自引:0,他引:4
As the health impact of air pollutants existing in ambient addresses much attention in recent years, forecasting of airpollutant parameters becomes an important and popular topic inenvironmental science. Airborne pollution is a serious, and willbe a major problem in Hong Kong within the next few years. InHong Kong, Respirable Suspended Particulate (RSP) and NitrogenOxides NOx and NO2 are major air pollutants due to thedominant diesel fuel usage by public transportation and heavyvehicles. Hence, the investigation and prediction of the influence and the tendency of these pollutants are ofsignificance to public and the city image. The multi-layerperceptron (MLP) neural network is regarded as a reliable andcost-effective method to achieve such tasks. The works presentedhere involve developing an improved neural network model, whichcombines the principal component analysis (PCA) technique and theradial basis function (RBF) network, and forecasting thepollutant levels and tendencies based in the recorded data. Inthe study, the PCA is firstly used to reduce and orthogonalizethe original input variables (data), these treated variables arethen used as new input vectors in RBF neural network modelestablished for forecasting the pollutant tendencies. Comparingwith the general neural network models, the proposed modelpossesses simpler network architecture, faster training speed,and more satisfactory predicting performance. This improvedmodel is evaluated by using hourly time series of RSP, NOx and NO2 concentrations collected at Mong Kok Roadside Gaseous Monitory Station in Hong Kong during the year 2000. By comparing the predicted RSP, NOx and NO2 concentrationswith the actual data of these pollutants recorded at the monitorystation, the effectiveness of the proposed model has been proven.Therefore, in authors' opinion, the model presented in the paper is a potential tool in forecasting air quality parameters and hasadvantages over the traditional neural network methods. 相似文献
102.
Llansó RJ Dauer DM Vølstad JH Scott LC 《Environmental monitoring and assessment》2003,81(1-3):163-174
The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI provides Chesapeake Bay monitoring programs with a uniform tool with which to characterize bay-wide benthic community condition and assess the health of the Bay. A probability-based design permits unbiased annual estimates of areal degradation within the Chesapeake Bay and its tributaries with quantifiable precision. However, of greatest interest to managers is the identification of problem areas most in need of restoration. Here we apply the B-IBI to benthic data collected in the Bay since 1994 to assess benthic community degradation by Chesapeake Bay Program segment and water depth. We used a new B-IBI classification system that improves the reliability of the estimates of degradation. Estimates were produced for 67 Chesapeake Bay Program segments. Greatest degradation was found in areas that are known to experience hypoxia or show toxic contamination, such as the mesohaline portion of the Potomac River, the Patapsco River, and the Maryland mainstem. Logistic regression models revealed increased probability of degraded benthos with depth for the lower Potomac River, Patapsco River, Nanticoke River, lower York River, and the Maryland mainstem. Our assessment of degradation by segment and water depth provided greater resolution of relative condition than previously available, and helped define the extent of degradation in Chesapeake Bay. 相似文献
103.
Mehaffey MH Nash MS Wade TG Ebert DW Jones KB Rager A 《Environmental monitoring and assessment》2005,107(1-3):29-44
The Catskill/Delaware reservoirs supply 90% of New York City’s drinking water. The City has implemented a series of watershed protection measures, including land acquisition, aimed at preserving water quality in the Catskill/Delaware watersheds. The objective of this study was to examine how relationships between landscape and surface water measurements change between years. Thirty-two drainage areas delineated from surface water sample points (total nitrogen, total phosphorus, and fecal coliform bacteria concentrations) were used in step-wise regression analyses to test landscape and surface-water quality relationships. Two measurements of land use, percent agriculture and percent urban development, were positively related to water quality and consistently present in all regression models. Together these two land uses explained 25 to 75% of the regression model variation. However, the contribution of agriculture to water quality condition showed a decreasing trend with time as overall agricultural land cover decreased. Results from this study demonstrate that relationships between land cover and surface water concentrations of total nitrogen, total phosphorus, and fecal coliform bacteria counts over a large area can be evaluated using a relatively simple geographic information system method. Land managers may find this method useful for targeting resources in relation to a particular water quality concern, focusing best management efforts, and maximizing benefits to water quality with minimal costs.The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency’s administrative review and approved for publication as an EPA document. 相似文献
104.
One-year monitoring survey of organic compounds (PAHs, PCBs, TBT), heavy metals and biomarkers in blue mussels from the Arcachon Bay, France 总被引:2,自引:0,他引:2
Devier MH Augagneur S Budzinski H Le Menach K Mora P Narbonne JF Garrigues P 《Journal of environmental monitoring : JEM》2005,7(3):224-240
Marine mussels Mytilus sp. were transplanted on a monthly basis in cages over one year to oyster farms and harbours in the Arcachon Bay (France) in order to assess the water quality of the bay. Contaminant levels (organotin compounds, trace metals, PCBs and PAHs) were measured in tissues of transplanted mussels and mussels from a reference station, along with physiological parameters of the mussels (condition indexes, lipid content and dry weight). Four biomarkers (AChE: acetylcholinesterase activity, GST: gluthathione S-transferase activity, CAT: catalase activity and TBARS: thiobarbituric acid-reactive substance content) were also monitored. The remote stations monitored (oyster parks) exhibited no accumulation pattern of pollutants. Their respective concentrations therefore constitute a background level of the contamination in the bay ([TBT]= 30 ng Sn g(-1) dw, [SigmaHAPs]= 100 ng g(-1) dw, [SigmaPCBs]= 35 ng g(-1) dw). The elevated chemical contamination of the largest harbour of the bay, the Arcachon harbour, can be interpreted in terms of persistence of organotin compounds ([SigmaOTs]= 1500-2000 ng Sn g(-1) dw) and PAHs ([SigmaHAPs]= 4500-5000 ng g(-1) dw) in sediments and, to a lesser extent, of direct inputs of copper ([Cu]= 20 microg g(-1) dw in harbours versus 7 in oyster parks) and petrogenic PAHs ([methylphenanthrenes]= 1600 ng g(-1) dw in the dockyard versus 170 at the gas stations), related to the use of copper-based antifouling paints and to dockyard activity, respectively. However, the Arcachon Bay presents a low contamination level by PCBs and metals, including harbour stations. Furthermore, higher levels of other PAHs (particularly alkyl PAHs such as methylphenanthrenes/1600 ng g(-1) dw) not included in the 16 PAHs from the EPA priority list (usually studied in biomonitoring programmes/1500 ng g(-1) dw) in the Arcachon harbour underline the need to integrate these compounds in biomonitoring of highly PAH-polluted areas such as harbours in order to avoid misinterpretation of the biological responses observed. Biomarker responses were not able to discriminate the different chemical contamination levels recorded in the Arcachon Bay and rather reflected changes in environmental factors. Furthermore, the strong intraspecies variability of biological responses could be due to genetic differences of mussels from the Arcachon Bay. It is the first time that such an integrated monitoring is performed in the Arcachon Bay, also taking into account seasonal variations of chemical contents and biomarkers levels in mussel tissues. 相似文献
105.
Bhat R Sridhar KR Rajashekara KM Narayana Y 《Journal of environmental monitoring : JEM》2005,7(9):856-860
In view of considerable natural background radioactivity reported from southwest coast of India, the current study documents bioaccumulation of 210Po in two dominant coastal sand dune perennial mat-forming wild legumes, Canavalia cathartica and C. maritima. Root, stem, leaf, mature beans, dry seeds and rhizosphere sand were analyzed for 210Po concentration. 210Po activity decreased in the order of leaves > roots > seeds > stems > beans. The highest 210Po activity was recorded in rhizosphere sand samples (5.78-5.88 Bq kg(-1)) followed by the leaf samples (3.27-3.07 Bq kg(-1)), while it was lowest in mature beans (0.13-0.20 Bq kg(-1)). 210Po activities or tissue moisture between plant species were not significantly different (p > 0.05; t-test). But 210Po activity vs. moisture differed significantly in all tissues (p = 0.0001), vegetative tissues (root, stem and leaf) (p = 0.0016), seeds (p = 0.0393) and proteins in seeds (p = 2.355 x 10(-6)) indicating the importance of moisture and protein in 210Po accumulation. Although 210Po has affinity for proteins, it did not concentrate too much in seed proteins of Canavalia. Concentration of 210Po in mature beans is at safe levels as fisher folk only consume tender pods occasionally. 210Po activity in Canavalia is compared with other plant materials. As the landraces of C. cathartica and C. maritima are distributed throughout pantropical coastal areas, the current study emphasizes on considering them as bioindicators to monitor 210Po in coastal sand dune biomes and in turn the health of coastal population. 相似文献
106.
Godderis L Vanderheyden W Van Geel J Moens G Masschelein R Veulemans H 《Journal of environmental monitoring : JEM》2005,7(12):1359-1363
To date the exposure, absorption and respiratory health effects of cast-house workers have not been described since most studies performed in the aluminium industry are focused on exposure and health effects of potroom personnel. In the present study, we assessed the external exposure and the absorbed dose of metals in personnel from the aluminium cast house. This was combined with an evaluation of respiratory complaints and the lung function of the personnel. 30 workers from an aluminium casting plant participated and 17 individuals of the packaging and distribution departments were selected as controls. The exposure was assessed by the quantification of total inhalable fume with metal fraction and by the determination of urinary aluminium, chromium, beryllium, manganese and lead concentration. Carbon monoxide (CO), carbon dioxide (CO2), aldehydes and polyaromatic hydrocarbons and man-made mineral fibres concentration were assessed as well. In order to evaluate their respiratory status each participant filled out a questionnaire and their lung function was tested by forced spirometry. Total inhalable fume exposure was maximum 4.37 mg m(-3). Exposure to the combustion gases, man-made mineral fibres and metal fume was well below the exposure limits. Beryllium could not be detected in the urine. The values of aluminium, manganese and lead in the urine were all under the respective reference value. One individual had a urinary chromium excretion above the ACGIH defined biological exposure index (BEI) of 30 microg g(-1) creatinine. There was no significant difference in any of the categories of the respiratory questionnaire and in the results of the spirometry between cast house personnel and referents (Chi-square, all p > 0.05). Exposure in cast houses seem to be acceptable under these conditions. However, peak exposure to fumes cannot be excluded and the potential risk of chromium and beryllium exposure due to the recycling of aluminium requires further attention. 相似文献
107.
108.
Magnuson ML Kelty CA Urbansky ET Owens JH Kelty KC Speth TF 《Journal of environmental monitoring : JEM》2002,4(1):102-108
Analytical chemistry is an important tier of environmental protection and has been traditionally linked to compliance and/or exposure monitoring activities for environmental contaminants. The adoption of the risk management paradigm has led to special challenges for analytical chemistry applied to environmental risk analysis. Namely, methods developed for regulated contaminants may not be appropriate and/or applicable to risk management scenarios. This paper contains examples of analytical chemistry applied to risk management challenges broken down by the analytical approach and analyte for some selected work in our laboratory. Specific techniques discussed include stable association complex electrospray mass spectrometry (cESI-MS), gas chromatography-mass spectrometry (GC-MS), split-flow thin cell (SPLITT) fractionation and matrix-assisted laser desorption time of flight mass spectrometry (MALDI-ToF-MS). Specific analytes include haloacetic acids (HAA9), perchlorate, bromate, triazine degradation products, metal-contaminated colloids and Cryptosporidium parvum oocysts. 相似文献
109.
B. Beck-Friis M. Pell U. Sonesson H. Jönsson H. Kirchmann 《Environmental monitoring and assessment》2000,62(3):317-331
Composting can be a source of N2O andCH4 production. In this investigation, differentcompost heaps of organic household waste weremonitored with the focus on potential formation ofCH4 and N2O in the heaps and emission ofthese gases from the heaps. The studied compost heapshad different compost ages, turning intervals andcompost sizes. The analysed compost gases containedbetween 1–3421 L of N2O-N L-1 and 0–470 mL of CH4 L-1. The emission rates ofN2O and CH4 from the compost heaps werebetween 1–1464 mg N2O m-2 day-1 and0–119 000 mg CH4 m-2 day-1. These verylarge differences in compost gas composition andemission indicate the importance of compostmanagement. The results also give an understanding ofwhere in the composting process an increasing emissionof N2O and CH4 can occur. 相似文献
110.
This paper discusses the REAP1 model and its application for the analysis of CO2 reduction and waste management policies for Japanese petrochemicals. The pros and cons of this modelling approach in comparison to other tools is elaborated. This is followed by a discussion of the model code and the modelling results. The results show that CO2 policies can have significant impacts on waste flows and waste policies can have significant CO2 benefits. As a consequence both effects must be considered in policy assessment. Pricing instruments are recommended instead of regulations because of the complex physical relations in the materials life cycle that extend beyond sector boundaries. A taxation approach is superior to a subsidy approach because rebound effects can be avoided. 相似文献