APM-3 Recommended Standard Methods for Continuing Air Monitoring for Gaseous Contaminants

The purpose of Manual APM-3 is to provide a guide which will help increase the uniformity between various surveys, and thereby increase the useability of the data by others.     

Forms and distribution of selenium at different depths and among particle size fractions of three Taiwan soils

The bioavailability of selenium in soils for plants depends more on its forms than on its total concentration. The purpose of the present study was to examine the solid-phase forms of selenium at different depths of three soil series representing major farming soil groups in Taiwan as well as the amounts of selenium in sand, silt and clay fractions of the soils. The study was conducted by means of sequential extraction to obtain the amounts of selenium and the distribution of various solid-phase forms of selenium at different depths of Pinchen (121 degrees 11(')E, 24 degrees 55(')N), Toulun-Sheto (120 degrees 55(')E, 24 degrees 50(')N), and Chunliao (120 degrees 25(')E, 23 degrees 57(')N) soil series. The amounts of metal oxide-bound form of selenium in the three soil series were the largest, with those of Pinchen and Toulun-Sheto soil series exceeding 50% of the total amounts of selenium and that of Chunliao soil series maintained at 30-40%. In the Pinchen and Toulun-Sheto soil series, the amounts of selenium in clay fractions were the largest, with a significant difference between the clays with and without metal oxides and organic matter removed. The amounts of selenium remained high in silt and/or sand fractions of the Chunliao soil series with metal oxides and organic matter removed. Metal oxide and organic matter contents of the three soil series mainly affect the amounts of various solid-phase forms of selenium and their distribution in different depths and particle size fractions of the soils. This observation of selenium associated with soil constituents was in good agreement with the results of the adsorption of selenite and selenate by the three soil series.     

Potential of <Emphasis Type="Italic">Ranunculus acris</Emphasis> L. for biomonitoring trace element contamination of riverbank soils: photosystem II activity and phenotypic responses for two soil series

Foliar ionome, photosystem II activity, and leaf growth parameters of Ranunculus acris L., a potential biomonitor of trace element (TE) contamination and phytoavailability, were assessed using two riverbank soil series. R. acris was cultivated on two potted soil series obtained by mixing a TE (Cd, Cu, Pb, and Zn)-contaminated technosol with either an uncontaminated sandy riverbank soil (A) or a silty clay one slightly contaminated by TE (B). Trace elements concentrations in the soil-pore water and the leaves, leaf dry weight (DW) yield, total leaf area (TLA), specific leaf area (SLA), and photosystem II activity were measured for both soil series after a 50-day growth period. As soil contamination increased, changes in soluble TE concentrations depended on soil texture. Increase in total soil TE did not affect the leaf DW yield, the TLA, the SLA, and the photosystem II activity of R. acris over the 50-day exposure. The foliar ionome did not reflect the total and soluble TE concentrations in both soil series. Foliar ionome of R. acris was only effective to biomonitor total and soluble soil Na concentrations in both soil series and total and soluble soil Mo concentrations in the soil series B.     

Estimates of global anthropogenic methane emissions 1860–1993

This paper provides the first time series estimates of global anthropogenic methane emissions from the mid-19th century to the present. Our purpose is to provide time series estimates of anthropogenic methane emissions for global climate models estimated or calibrated using historical time series data. Previous estimates of methane emissions include “top-down” (deconvolution) estimates of total emissions, estimates of global anthropogenic emissions for the 16th century, and various estimates of anthropogenic and natural emissions in the 1980s and 1990s. This study uses previously published point estimates for the 16th century and the 1980s and early 1990s and a variety of historical time series of proxy variables to estimate a time series of global anthropogenic methane emissions. We find that anthropogenic methane emissions have increased from about 80 million tonnes per annum in 1860 to about 380 million tonnes in 1990. The relative importance of various emission sources changes over time. The rate of increase now may be slowing. A comparison with the estimates generated by Khalil and Rasmussen suggests that natural sources of methane have declined over the period. There are, however, great uncertainties in these estimates which future research may be able to reduce.     

Modelling emission trends from non-constant time series of PM10 concentrations in Christchurch, New Zealand

This paper presents an attempt to model the trend of emissions through analysis of a time series of PPM₁₀ concentrations in Christchurch, New Zealand. Emissions are not constant over time, but show high seasonality. Fluctuations are removed by creating a time series in which concentrations do not show dependency on ambient air temperature. Remaining meteorological influences are removed through multiple linear regression. Finally, a moving average filter is applied to reveal the low-frequency trend in the residuals of the meteorologically adjusted time series. The modelled trend shows a peak in emissions in 2001-2002 with a steady decrease thereafter.     

Climate change impacts on the leaching of a heavy metal contamination in a small lowland catchment

The Keersop catchment (43km(2)) in the south of The Netherlands has been contaminated by the emissions of four zinc ore smelters. The objective of this study was to assess the effects of future projected climate change on the hydrology and the leaching of heavy metals (i.e. Cd and Zn) in the catchment. The numerical, quasi-2D, unsaturated zone Soil Water Atmosphere Plant model was used with 100-year simulated daily time series of precipitation and potential evapotranspiration. The time series are representative of stationary climates for the periods 1961-1990 ("baseline") and 2071-2100 ("future"). The time series of future climate were obtained by downscaling the results of eight regional climate model (RCM) experiments, driven by the SRES A2 emissions scenario, using change factors for a series of climate statistics and applying them to stochastic weather generator models. The time series are characterized by increased precipitation in winter, less precipitation in summer, and higher air temperatures (between 2°C and 5°C) throughout the year. Future climate scenarios project higher evapotranspiration rates, more irrigation, less drainage, lower discharge rates and lower groundwater levels, due to increased evapotranspiration and a slowing down of the groundwater system. As a result, lower concentrations of Cd and Zn in surface water are projected. The reduced leaching of heavy metals, due to drying of the catchment, showed a positive impact on a limited aspect of surface water quality.     

Atmospheric Nutrient Input to the Baltic Sea from 1850 to 2006: A Reconstruction from Modeling Results and Historical Data

In this study, a consistent basin-wise monthly time series of the atmospheric nutrient load to the Baltic Sea during 1850-2006 was compiled. Due to the lack of a long time series (1850-1960) of nutrient deposition to the Baltic Sea, the data set was compiled by combining a time series of deposition data at the Baltic Nest Institute from 1970 to 2006, published historical monitoring data and deposition estimates, as well as recent modeled Representative Concentration Pathways (RCP) emission estimates. The procedure for nitrogen compounds included estimation of the deposition in a few intermediate reference years, linear interpolation between them, and the decomposition of annual deposition into a seasonal deposition pattern. As no reliable monitoring results were found for the atmospheric deposition of phosphorus during the early period of our study, we used published estimates for the temporal and spatial pattern of the phosphorus load.     

厌氧折流板式微生物燃料电池堆影响因素研究

微生物燃料电池(MFC)中输出电压/电流的提升,以及反应器体积的扩展放大是其工程化应用的关键。本文构建了一个总体积为6.4 L的新型厌氧折流板式微生物燃料电池堆(ABSMFC)。以葡萄糖作为底物,探讨了阳极材料、液面高程差和水力停留时间(HRT)等因素对ABSMFC性能的影响。结果表明,碳纤维毡作为阳极时,电池单体外电路平均分压(R_(ex)=1 000Ω)为210 mV,填充石墨颗粒后增加到319.8 mV。格室间存在液面高程差时,电池单体、串联和并联的功率密度分别为207.1、181.1和215.7 mW/m~2,当无液面高程差(即水力相连)时为205.8、69.5和151.5 mW/m~2。4个电池单体串联和并联连接时,HRT对ABSMFC的产电稳定性无影响,溶解性COD的去除率和库仑效率均随HRT的增加而升高,且并联效果优于串联。     

Fabric Filter Technology for Utility Coal-Fired Power Plants

This is the fifth in a series of papers discussing the experience of electric utilities in applying baghouse technology for the collection of particulate matter at coal-fired electric power generating plants. The series presents new data obtained in research sponsored by the Electric Power Research Institute (EPRI) on reverse-gas and shake/deflate cleaned baghouses, and specifically addresses a number of unresolved issues in the design and operation of these units. This paper describes research to improve reverse-gas cleaning technology, and to characterize reverse-gas sonic assisted and shake/deflate cleaning.     

Optimization of integrated water quality management for agricultural efficiency and environmental conservation

The scarcity of water resources in Egypt has necessitated the use of various types of lower quality water. Agricultural drainage water is considered a strategic reserve for meeting increasing freshwater demands. In this study, a novel model series was applied to a drainage basin in the Nile Delta to optimize integrated water quality management for agriculture and the aquatic environment. The proposed model series includes a waste load allocation model, an export coefficient model, a stream water quality model, and a genetic algorithm. This model series offers an optimized solution for determining the required removal levels of total suspended solids (TSS), the chemical oxygen demand (COD) at point and non-point pollution sources, and the source flows that require treatment to meet a given water quality target. The model series was applied during the summer and winter to the El-Qalaa basin in the western delta of the Nile River. Increased pollutant removal and treated fractions at point and non-point sources reduced violations of the TSS standards from 732.6 to 238.9 mg/L in summer and from 543.1 to 380.9 mg/L in winter. Likewise, violations of the COD standards decreased from 112.4 mg/L to 0 (no violations) in summer and from 91.7 mg/L to no violations in winter. Thus, this model is recommended as a decision support tool for determining a desirable waste load allocation solution from a trade-off curve considering costs and the degree of compliance with water quality standards.     

Spatial and temporal variations in the trace elemental data over the northeastern United States

Time series of trace elemental concentrations (14 species) of atmospheric fine particles measured in the northeastern United States between 1988 and 1998 are analyzed for spatial and temporal variations. The influence of synoptic-scale systems to the transport and accumulation of pollutants can be investigated successfully if the short-term fluctuations (i.e. weather-induced variations) embedded in the time series of pollutant concentrations are separated from the original time series. The spatial short-term correlation coefficients for Al, Br, Fe, Se, and Zn permit good predictions of pollutant concentrations up to distances of about 350 km from a given monitor. The species correlation matrices for individual sites reveal that As, Br, Se, and Zn are highly correlated in New York State, while Fe, Mn, and V show also strong correlations, suggesting the commonality of source regions for these industrial and urban pollutants impacting New York.     

Assessing the impact of the acid deposition control program

A goal of the acidic deposition control program in the United States has been to link emissions control policies, such as those mandated under Title IV of the US Clean Air Act Amendments (CAAA) of 1990, to improvements in air and water quality. Recently, several researchers have reported trends in the time series of pollutant data in an effort to evaluate the effectiveness of the CAAA in reducing the acidic deposition problem. It is well known that pollutant concentrations are highly influenced by meteorological and climatic variations. Also, spatial and temporal inhomogeneities in time series of pollutant concentrations, induced by differences in the data collection, reduction, and reporting practices, can significantly affect the trend estimates. We present a method to discern breaks or discontinuities in the time series of pollutants stemming from emission reductions in the presence of meteorological and climatological variability. Using data from a few sites, this paper illustrates that linear trend estimates of concentrations of SO₂, aerosol SO₄²⁻, and precipitation-weighted SO₄²⁻ and NO₃⁻ can be biased because of such complex features embedded in pollutant time series.     

Time-series analysis of air pollution data

Time-series analysis of air pollution environmental levels involves the identification of long-term variation in the mean (trend) and of cyclical or periodic components. A model based on a stepwise approach to time-series analysis was applied to the daily average concentrations of strong acidity (SA) and black smoke (BS) in the Oporto area, using an available computer program. Each step is completed by a correlation analysis of the residuals, allowing the identification of an optimal structure with a residual white noise. A periodic component with harmonics defined through “peaks” of concentration on week middle days and “troughs” on weekends was observed. SA concentration behaviour can be related with industrial activities, mainly through fossil-fuel burning in discontinuous working cycles. The observed evolution for BS is most probably related with weekly patterns of motor traffic, with observed minimum values during weekends. The periodic components represent, on the average, about 5% of the total variance for the SA series and 15% for the BS series. However, the weekly cycles are predominant in the SA series, representing on the average 75% of the periodic variance, against 46% for the BS series. Statistically significant higher frequency (≈2–4 day) periodic components were observed for both pollutant indicators and for all collection sites analysed. This may be due to synoptic weather variations of minimum and maximum daily temperature and precipitation, which show similar periods in the study area.     

Ozone recovery as seen in perspective of the Dobson spectrophotometer measurements at Belsk (52°N, 21°E) in the period 1963–2008

The total ozone monthly means derived from measurements by the Dobson spectrophotometer at Belsk (52°N, 21°E) and satellite observations over central and midlatitudinal Europe are analyzed for the long-term changes between 1995 and 2008. Standard explanatory variables representing physical and chemical processes known to influence the ozone distribution are considered. The potential proxies are: atmospheric loading by the ozone depleting substances characterized by the equivalent effective stratospheric chlorine (EESC) time series, various drivers of ozone dynamical variability including solar cycle, teleconnection patterns, temperature at 50 hPa, and pressure at the tropopause level. The multivariate adaptive regression splines (MARS) methodology is used to find optimal set of the explanatory variables and shape of the anthropogenic trend curve. Following options for the trend curve are examined: proportional to EESC, piecewise linear (with the turning points in 1980 and 1995), and selected from a smooth curve fit to the total ozone time series having “natural variations” removed. Statistical estimates and their uncertainties are calculated using block bootstrapping. The analyses indicate that ozone over Belsk, in central Europe, and in midlatitudinal Europe reaches at least first stage of recovery as defined by the World Meteorological Organization: a statistically significant reduction in the rate of decline. Model using the EESC time series as a proxy for the anthropogenic trend pattern yields even the second stage, i.e., a positive trend in time series that remains after removal dynamical signal from the analyzed data. Substantial seasonal dependent long-term ozone oscillations by the dynamical drivers are revealed causing estimation of the ozone recovery time even more uncertain.     

连云港市大气污染物时间序列的长程相关性分析

运用R/S分析(Rescaled Range Analysis)方法对连云港市3个大气环境定位监测点近10年来的SO2、NOx和TSP序列数据进行了时间序列的长程相关性分析.结果表明,连云港市SO2、NOx和TSP月均值序列的Hurst指数在0.500～1.000,表现出明显的长程相关性,并且这种相关性程度的强弱随着城市功能区的不同而表现出一定的差异.研究结果对于认识连云港市城市大气环境质量变化过程和科学制定环保决策具有重要意义.     

Environmental specimen bank samples of Pleurozium schreberi and Hylocomium splendens as indicators of the radiation environment at the surface

Pleurozium schreberi (Brid.) Mitt. and Hylocomium splendens (Hedw.) Schimp. samples from the Finnish Environmental Specimen Bank were used to study the UV-B-absorbing compounds as potential screens of the past radiation environment. The first series from southern and central Finland consisted of samples collected from 18 P. schreberi or H. splendens dominated sites in 1985 and 1995. The second series from four H. splendens dominated sites (two in southern and two in northern Finland) and two P. schreberi dominated sites (one southern and one northern) were from the years 1985, 1990, 1995 and 2000. In the first series, the moss surface area of the analyzed specimens (5 +/- 0.2 mg DW) was smaller in 1995 (40% of both species collected in June) than in 1985 (40% of P. schreberi and 55% of H. splendens collected in September). The methanol-extractable UV-B-absorbing compounds of P. schreberi in 1985 and 1995 measured as absorbance at 10 nm intervals at 280-360 nm per mg DW revealed a negative correlation with reconstructed UV-radiation data. In the second series, the UV-B-absorbing compounds per specific surface area (surface area mm2 per DW) showed significant differences between the years. The highest values in both species were obtained in 1990. In H. splendens, a difference between the southern and northern samples was observed. The preliminary study encouraged the use of environmental specimen bank samples to indicate changes in surface radiation conditions.     

The Role of Industry

A series of partitioning agents were studied to determine their ability to separate organic sulfur compounds by gas chromatography. Several columns showed promise, but did not separate organic sulfur compounds from normally occurring atmospheric hydrocarbons. Higher concentrations of organic sulfur compounds in stack gases are separated as metallic salts in a series of impingers. The nature of the precipitated sulfur compound can be determined by gas chromatography after regeneration of the compound by addition of acid to the metallic precipitate.     

A critical assessment of shrinkage-based regression approaches for estimating the adverse health effects of multiple air pollutants

Most investigations of the adverse health effects of multiple air pollutants analyse the time series involved by simultaneously entering the multiple pollutants into a Poisson log-linear model. Concerns have been raised about this type of analysis, and it has been stated that new methodology or models should be developed for investigating the adverse health effects of multiple air pollutants. In this paper, we introduce the use of the lasso for this purpose and compare its statistical properties to those of ridge regression and the Poisson log-linear model. Ridge regression has been used in time series analyses on the adverse health effects of multiple air pollutants but its properties for this purpose have not been investigated. A series of simulation studies was used to compare the performance of the lasso, ridge regression, and the Poisson log-linear model. In these simulations, realistic mortality time series were generated with known air pollution mortality effects permitting the performance of the three models to be compared. Both the lasso and ridge regression produced more accurate estimates of the adverse health effects of the multiple air pollutants than those produced using the Poisson log-linear model. This increase in accuracy came at the expense of increased bias. Ridge regression produced more accurate estimates than the lasso, but the lasso produced more interpretable models. The lasso and ridge regression offer a flexible way of obtaining more accurate estimation of pollutant effects than that provided by the standard Poisson log-linear model.     

Time series analysis in acid rain modeling: Evaluation of filling missing values by linear interpolation

This paper describes the results of a study to evaluate how well the linear interpolation of the two nearest bracketing values (LIBV) scheme for filling missing values might be expected to perform. Computer simulation techniques were used to generate simulated time series which were probabilistically equivalent to the types that are likely to be found in practice. Actual data on the frequency and duration of missing value episodes were analyzed to determine the probability models which described the behavior of these missing value episodes. The models were then used to inject missing value episodes into the simulated time series. The LIBV scheme was then used to fill these missing values. The values of the parameters of the time series model were then estimated. The estimated parameter values were then compared to the true values of the parameters which were used to generate the lime series. The results of these comparisons suggest that the LIBV scheme could yield good results if only one dominant seasonal component is present in the data and that it should be used with caution when more than one dominant seasonal component is likely to be present.     

Relating meteorological variables and trends in motor vehicle emissions to monthly urban carbon monoxide concentrations

A model which quantifies the relationship between the monthly time series for CO emissions, the monthly time series in ambient CO concentration, and meteorologically driven dispersion was developed. Fifteen cities representing a wide range of geographical and climatic conditions were selected. An eight-year time series (1984–1991 inclusive) of monthly averaged data were examined in each city. A new method of handling missing ambient concentration values which is designed to calculate city-wide average concentrations that follow the trend seen at individual monitor sites is presented. This method is general and can be used in other applications involving missing data. The model uses emissions estimates along with two meteorological variables (wind speed and mixing height) to estimate monthly averages of ambient air pollution concentrations. The model is shown to have a wide range of applicability; it works equally well for a wide range of cities that have very different temporal CO distributions. The model is suited for assessing long-term trends in ambient air pollutants and can also be used for estimating seasonal variations in concentration, estimation of trends in emissions, and for filling in gaps in the ambient concentration record.