Effects of instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, Georgia

Data from the U.S. Environmental Protection Agency Air Quality System, the Southeastern Aerosol Research and Characterization database, and the Assessment of Spatial Aerosol Composition in Atlanta database for 1999 through 2002 have been used to characterize error associated with instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, GA. These data are being used in time series epidemiologic studies in which associations of acute respiratory and cardiovascular health outcomes and daily ambient air pollutant levels are assessed. Modified semivariograms are used to quantify the effects of instrument precision and spatial variability on the assessment of daily metrics of ambient gaseous pollutants (SO2, CO, NOx, and O3) and fine particulate matter ([PM2.5] PM2.5 mass, sulfate, nitrate, ammonium, elemental carbon [EC], and organic carbon [OC]). Variation because of instrument imprecision represented 7-40% of the temporal variation in the daily pollutant measures and was largest for the PM2.5 EC and OC. Spatial variability was greatest for primary pollutants (SO2, CO, NOx, and EC). Population-weighted variation in daily ambient air pollutant levels because of both instrument imprecision and spatial variability ranged from 20% of the temporal variation for O3 to 70% of the temporal variation for SO2 and EC. Wind     

A land management history for central Queensland,Australia as determined from land-holder questionnaire and aerial photography

Features of the land management history over a 125,755 km(2) area of central Queensland, Australia were determined from a variety of sources. A random sample of 205 site locations provided the basis for determining trends in land use. Trends in vegetation clearing were determined using sequential aerial photography for the sample sites, revealing a steady rate averaging nearly 1% of the region per annum over 41 years. This measure of sustained clearing over a large region is higher than recently published clearing rates from South America. Land types have been selectively cleared with over 90% of the Acacia on clay land type having been cleared. A land-holder questionnaire pertaining to the random sites yielded a response rate of 71% and provided information on vegetation clearing, ploughing, tree killing (ring-barking or tree poisoning), and fire frequency, season and intensity. The land-holder responses were compared with independent data sources where possible and revealed no mis-information. However, land-holders may have been marginally less likely to respond if the sample area had been cleared, although this effect was not statistically significant. Ploughing and tree killing are variable depending on land type, but the former has affected about 40% of the Acacia on clay land type, effectively eliminating options for natural regrowth. The proportion of decade-site combinations that were reported as having no fires increased from 22% in the 1950s to an average of 42% for subsequent decades, although the reporting of more than one fire per decade has been relatively constant through the study period. The reporting of at least one fire per decade varies from 46% for the Acacia on sand land type to 77% for the Eucalypt on sand land type for decade-site combinations. Fires are more intense when associated with clearing than in uncleared vegetation, but the proportion of cool and hot fires is relatively constant between land types in uncleared vegetation. Nearly all fires reported were either in spring or summer and this seasonally restricted regime is probably at variance with Aboriginal fire regimes. This study describes the rapid transformation of central Queensland. This has yielded substantially increased agricultural production but may also result in a range of negative impacts and these are discussed.     

Modelling trends in woody vegetation structure in semi-arid Australia as determined from aerial photography

Accounting of carbon stocks in woody vegetation for greenhouse purposes requires definition of medium term trends with accurate error assessment. Tree and shrub cover was sampled through time at randomly located sites over a large area of central Queensland, Australia using aerial photography from 1945 to 1999. Calibration models developed from field data for the same land types as those represented within the study area allowed for the extrapolation of overstorey and understorey cover, basal area and biomass values and these were modelled as trends over the latter half of the 20th century. These structural attributes have declined over the region because of land clearing with values for biomass changing from a mean of 58.0(+/-1.2)t/ha in 1953 to 41.1(+/-1.0)t/ha in 1991. The biomass of Acacia on clay and Eucalypt on texture contrast soils land types has declined most dramatically. Within uncleared vegetation there was an overall trend of increase from 56.1(+/-1.2)t/ha in 1951 to 67.6(+/-1.3)t/ha in 1995. The increase in structural attributes within uncleared vegetation was most pronounced for the Eucalypt on texture contrast soils and Eucalypt on clay land types. It was demonstrated that the sites sampled were representative of their land types and that spatial bias of the photography, undetected tree-killing, sampling error, inherent variability of structural attributes and measurement error should not have impacted greatly on bias or precision of trend estimates for well-sampled land types. Certainly the errors are not likely to be substantial for trends averaged over all land types and they provide an accurate assessment of the magnitude and direction of change. The technique presented here would appear to be a robust means of accounting for the above-ground woody component of woodlands and open forests and will also contribute to a broader understanding of savanna dynamics.     

Availability and access of financial support for renewables: issues and an illustrative innovation

This paper examines issues related to increasing the market penetration of renewable forms of energy in developing countries. It particularly focuses on availability and access of financial support for investments relating to renewable energy and a case study is presented illustrating innovative financing. While the main focus of the discussion is on renewable energy (RE) attention is also devoted to energy efficiency (EE) projects and investment. An underlying premise is that, if RE projects are to reach their market potential, they must be fiscally sustainable and the appropriate promotion of such fiscally sustainable RE projects yields multiple environmental and developmental synergies. Commercial viability is not primarily a question of technology. There is a broad range of RE products with proven performance and commercial operation in selected market situations. The challenge of extending this market penetration is to establish the institutional, organizational and financial conditions under which a commercial market for these products can develop, particularly in developing countries. This article reflects current emphasis on increased private participation in the energy sector, as well as policy reform at the national level.     

Changing corporate environmental philosophy: Project renewal gets companies started

Project RENEWAL is an innovative new environmental business project taking place in New Jersey. Project RENEWAL stands for Resource Efficiency Network to Eliminate Waste and Liability. The purpose of this project is to investigate and promote the linkages between ecology, technology, and business economics for the benefit of the economy and the environment. This is a collaborative effort, initially focused on equipment and inventory assets, between the business and environmental communities in order to explore new ways to increase business efficiency and profitability and also benefit the environment. Participants in the project include representatives from industry, consulting, local and state government, environmental agencies, trade groups and academia. This article will outline the background and initial framework of Project RENEWAL's initiatives. (The authors are open to comments, suggestions, criticism, and most importantly input from others who share their vision and are willing to cooperatively accelerate the change process).     

UV peroxidation with air stripping for optimized removal of VOCs from groundwater

No one remedial technology is best suited to treat every groundwater contaminant plume. This article describes how pilot testing and analytical evaluation targeted selection of two treatment technologies, UV peroxidation and air stripping, to be used in series to create a synergistic, cost-effective pump-and-treat system for the removal of VOCs from groundwater. Pilot plant size equipment was employed to treat the VOC-contaminated groundwater in order to obtain site-specific reaction rates and to develop full-scale design parameters. It was found that by using the two treatment technologies in combination, the influent concentration of 2,000 ppb total VOCs could be reduced to less than 1 ppb, thus meeting drinking water standards.     

Expanding the Range of Choice in Water Management: An Evaluation of Policy Approaches

This paper examines the ‘range of choice’ concept in water management. Although many efforts have been made to design policies that broaden the consideration of water resources alternatives, the experiences gained from these policy experiments have not been adequately assessed. What insights might American policy approaches offer for developing countries? To address this question, four general policy types were identified and compared: (1) comprehensive single-objective policies; (2) comprehensive multiple-objective policies; (3) specific non-structural policies; and (4) specific technological policies. Case studies of each approach revealed that effective institutional development occurs when policies are: (1) stated in clear and specific language; (2) modified as experience is gained; (3) adequate in terms of statutory and administrative authority; and (4) subject to an orderly process of public and judicial review. The most successful policy efforts to date have involved specific alternatives, while multiple-objective policies have encountered the most difficulties. Common institutional problems are identified, and their potential relevance for developing countries is discussed.     

A SIMPLE TECHNIQUE FOR ESTIMATING ABSORPTION AND SCATTERING COEFFICIENTS1

ABSTRACT: Results from five different test systems, which include a wide range of optical conditions, indicate credible estimates of the values of the absorption and scattering coefficients can be calculated from paired measurements of Secchi disc transparency and the diffuse attenuation coefficient. The diagnostic utility of the estimates in identifying components and processes that regulate light penetration is demonstrated for three different cases. The simple estimation technique is valuable in the analysis of existing data bases that lack comprehensive optical information to develop and evaluate alternate models for light penetration and to establish the experimental needs of future field programs to support lake management efforts.     

Organizational politics and organizational support as predictors of work attitudes,job performance,and organizational citizenship behavior

This study investigated the relationship of organizational politics and organizational support to various work attitudes and behaviors among a field sample of 128 participants. Consistent with our hypothesis, politics and support were related to job satisfaction, commitment, turnover intentions, and supervisor ratings of organizational citizenship behaviors. However, only support was related to job performance. We also examined whether or not organizational politics and organizational support comprise two distinct constructs or one global factor. The evidence here was ambiguous. Fit indices obtained from confirmatory factor analysis suggested that it is more parsimonious to treat politics and support as opposite ends of the same construct, though the two‐factor model did show a slightly better fit. On the other hand, subsequent multiple regression analyses showed that support tended to account for additional criterion variance beyond the effect of politics, implying that there may be some practical utility to retaining politics and support as distinct constructs. Copyright © 1999 John Wiley & Sons, Ltd.