Prediction of ambient PM10 and toxic metals using artificial neural networks

In this study, an artificial neural network is employed to predict the concentration of ambient respirable particulate matter (PM10) and toxic metals observed in the city of Jaipur, India. A feed-forward network with a back-propagation learning algorithm is used to train the neural network the behavior of the data patterns. The meteorological variables of wind speed, wind direction, relative humidity, temperature, and time are taken as input to the network. The results indicate that the network is able to predict concentrations of PM10 and toxic metals quite accurately.     

Characterization of aerosols from biomass burning--a case study from Mizoram (Northeast), India

Physical and optical properties of biomass burning aerosols in Northeastern region, India analyzed based on measurements made during February 2002. Large spatial extent of Northeastern Region moist tropical to moist sub-tropical forests in India have high frequency of burning in annual dry seasons. Characterization of resultant trace gases and aerosols from biomass burning is important for the atmospheric radiative process. Aerosol optical depth (AOD) observed to be high during burning period compared to pre- and post-burning days. Peak period of biomass burning is highly correlated with measured AOD and total columnar water vapor. Size distribution of aerosols showed bimodal size distribution during burning day and unimodal size distribution during pre- and post-burning days. Size distribution retrievals from biomass burning aerosols show dominance of accumulation mode particles. Weighted mean radius is high (0.22 microm) during burning period. Columnar content of aerosols observed to be high during burning period in addition to the drastic reduction of visibility. During the burning day Anderson sampler measurements showed dominance of accumulation mode particles. The diurnal averaged values of surface shortwave aerosol radiative forcing af biomass burning aerosols varies from -59 to -87 Wm(-2) on different days. Measured and modeled solar irradiances are also discussed in the paper.     

Detecting Changes in Natural Resources Using Land Condition Trend Analysis Data

The Land Condition Trend Analysis (LCTA) program is the US Army's standard for land inventory and monitoring, employing standardized methods of natural resources data collection, analyses, and reporting designed to meet multiple goals and objectives. Critical to using LCTA data in natural resources management decisions is the ability of the LCTA protocols to detect changes in natural resources. To quantify the ability of LCTA protocols to detect resource changes, power analysis techniques were used to estimate minimum detectable effect sizes (MDES) for selected primary and secondary management variables for three Army installations. MDES for a subset of primary variables were estimated using data from 27 installation LCTA programs. MDES for primary and secondary variables varied widely. However, LCTA programs implemented at larger installations with lower sampling intensities detected changes in installation resources as well as programs implemented at smaller more intensively sampled installations. As a national monitoring program that is implemented at individual installations, LCTA protocols provide relatively consistent monitoring data to detect changes in resources despite diverse resource characteristics and implementation constraints.     

Isomer specific syntheses of chlorinated catechols and guaiacols relevant to pulp bleaching

A variety of chlorinated catechols and guaiacols relevant to pulp bleaching were synthesized by employing fundamental differences in the acidities of phenolic hydroxyl groups in chlorinated catechols, and directive effects in guaiacols.     

Using Decision Analysis to Choose Phosphorus Targets for Lake Erie

Lake Erie water quality has improved dramatically since the degraded conditions of the 1960s. Additional gains could be made, but at the expense of further investment and reductions in fishery productivity. In facing such cross-jurisdictional issues, natural resource managers in Canada and the United States must grapple with conflicting objectives and important uncertainties, while considering the priorities of the public that live in the basin. The techniques and tools of decision analysis have been used successfully to deal with such decision problems in a range of environmental settings, but infrequently in the Great Lakes. The objective of this paper is to illustrate how such techniques might be brought to bear on an important, real decision currently facing Lake Erie resource managers and stakeholders: the choice of new phosphorus loading targets for the lake. The heart of our approach is a systematic elicitation of stakeholder preferences and an investigation of the degree to which different phosphorus-loading policies might satisfy ecosystem objectives. Results show that there are potential benefits to changing the historical policy of reducing phosphorus loads in Lake Erie.     

Sampling and Mapping a Soil Erosion Cover Factor by Integrating Stratification,Model Updating and Cokriging with Images

Cost-efficient sample designs for collection of ground data and accurate mapping of variables are required to monitor natural resources and environmental and ecological systems. In this study, a sample design and mapping method was developed by integrating stratification, model updating, and cokriging with Landsat Thematic Mapper (TM) imagery. This method is based on the spatial autocorrelation of variables and the spatial cross-correlation among them. It can lead to sample designs with variable grid spacing, where sampling distances between plots vary depending on spatial variability of the variables from location to location. This has potential cost-efficiencies in terms of sample design and mapping. This method is also applicable for mapping in the case in which no ground data can be collected in some parts of a study area because of the high cost. The method was validated in a case study in which a ground and vegetation cover factor was sampled and mapped for monitoring soil erosion. The results showed that when the sample obtained with three strata using the developed method was used for sampling and mapping the cover factor, the sampling cost was greatly decreased, although the error of the map was slightly increased compared to that without stratification; that is, the sample cost-efficiency quantified by the product of cost and error was greatly increased. The increase of cost-efficiency was more obvious when the cover factor values of the plots within the no-significant-change stratum were updated by a model developed using the previous observations instead of remeasuring them in the field.     

马尔代夫和不丹的旅游业持续发展

可持续的旅游业要求精心规划和有控制的发展。本文提出的案例研究,叙述了两个成鲜明对照但同样脆弱的环境和社会中的旅游业持续发展途径。马尔代夫由一个小岛与海洋环境以及一个伊斯兰教社会组成,已经实现了旅游业持续发展,这正在给该国带来巨大经济效益。不丹国座落在一个高山与峡谷环境中,具有佛教文化,已采取了发展非常有限但高价值的旅游业的方法,这也产生了预期的效益。这两个国家都正在有计划、分阶段地发展旅游业,实施严格的环境和游客人数控制。他们在制定规划方面是灵活的,用不同类型的方法进行试验,以确定适合于它们各自特定环境与文化情况的最有效方法。这些国家中所采用的旅游业发展途径,经过适当调整,可用作为其它地方有强烈文化传统的岛屿/海洋和山地环境中旅游业的规划与管理模式。     

Human teeth as historical biomonitors of environmental and dietary lead: some lessons from isotopic studies of 19th and 20th century archival material

The lead isotopic composition of various sections (crown, crown base, root) of teeth was determined in specimens collected from 19th century skulls preserved in museum collections and, upon extraction or exfoliation, from humans of known ages residing in Scotland in the 1990s. For most 20th century samples, calculation of accurate crown-complete or root-complete dates of tooth formation ranging from the 1920s to the 1990s enabled comparison of ²⁰⁶Pb/²⁰⁷Pb ratios for teeth sections (crown base root) with corresponding decadally averaged data for archival herbarium Sphagnum moss samples. This showed that the teeth sections had been significantly influenced by incorporation of non-contemporaneous (more recent) lead subsequent to the time of tooth formation, most probably via continuous uptake by dentine. This finding confirmed that separation of enamel from dentine is necessary for the potential of teeth sections as historical biomonitors of environmental (and dietary) lead exposure at the time of tooth formation to be realised. Nevertheless, the mean 19th century value of 1.172±0.007 for the ²⁰⁶Pb/²⁰⁷Pb ratio in teeth was very similar to the corresponding mean value of 1.173±0.004 for 19th century archival moss, although relative contributions from environmental sources – whether direct, by inhalation/ingestion of dust contaminated by local lead smelting (²⁰⁶Pb/²⁰⁷Pb~1.17) and coal combustion (²⁰⁶Pb/²⁰⁷Pb~1.18) emissions, or indirect, through ingestion of similarly contaminated food – and drinking/cooking water contaminated by lead pipes of local origin, cannot readily be determined. In the 20th century, however, the much lower values of the ²⁰⁶Pb/²⁰⁷Pb ratio (range 1.100–1.166, mean 1.126±0.013, median 1.124) for the teeth collected from various age groups in the 1990s reflect the significant influence of imported Australian lead of lower ²⁰⁶Pb/²⁰⁷Pb ratio (~1.04) and released to the environment most notably through car-exhaust emissions arising from the use of alkyl lead additives (²⁰⁶Pb/²⁰⁷Pb~1.06–1.09) in petrol in the U.K. from ca. 1930 until the end of the 20th century.     

荷兰的污染预防和环境软件

荷兰已认识到需要用于污染预防的新计算机程序。虽然各荷兰公司尚不能得到所需类型的软件,但现有的一些程序可充当综合性更强的程序的基础。目前可得到的软件多数是专为帮助地方政府执行环境法律和帮助各公司遵守这些法律而设计的。这两个领域都正在开发新的程序。