An Index of Air Pollution and its Relation to Health

Atmospheric pollution by sulfur oxides is discussed in terms of the sources of the pollutant and the possible methods of control. Possible approaches to control are classified in general categories, including fuel desulfurization, process modifications, and flue-gas desulfurization. Some of the more promising specific possibilities are discussed in relation to the organizations developing them.     

Detecting and Coping with Disruptive Shocks in Arctic Marine Systems: A Resilience Approach to Place and People

It seems inevitable that the ongoing and rapid changes in the physical environment of the marine Arctic will push components of the region’s existing social-ecological systems—small and large—beyond tipping points and into new regimes. Ongoing changes include warming, freshening, acidification, and alterations to food web structure. In anticipation we pose three distinct but interrelated challenges: (1) to explore existing connectivities within components of the marine system; (2) to seek indicators (if they exist) of approaching regime change through observation and modeling; and (3) to build functional resilience into existing systems through adaptation-oriented policy and to have in hand transformative options when tipping points are crossed and new development trajectories are required. Each of the above challenges is scale dependent, and each requires a much deeper understanding than we currently have of connectivity within existing systems and their response to external forcing. Here, we argue from a global perspective the need to understand the Arctic’s role in an increasingly nonlinear world; then describe emerging evidence from new observations on the connectivity of processes and system components from the Canada Basin and subarctic seas surrounding northern North America; and finally posit an approach founded in “resilience thinking” to allow northern residents living in small coastal communities to participate in the observation, adaption and—if necessary—transformation of the social-ecological system with which they live.     

DFT M06-2X investigation of alkaline hydrolysis of nitroaromatic compounds

The nitroaromatic compounds 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT) and 2,4-dinitroanisole (DNAN) are potential environmental contaminants and their transformations under a variety of environmental conditions are consequently of great interest. One possible method to safely degrade these nitrocompounds is alkaline hydrolysis. A mechanism of the initial stages of this reaction was investigated computationally. Simulations of UV-VIS and NMR spectra for this mechanism were also produced. The results obtained were compared to available experimental data on the alkaline hydrolysis of TNT and suggest that the formation of Meisenheimer complexes and an anion of TNT are potential first-step intermediates in the reaction path. As the reaction proceeds, computational results indicate that polynegative complexes dominate the degradation pathway, followed by cycles of carbon chain opening and breaking. A second possible pathway was identified that leads to polymeric products through Janovsky complex formation. Results from this study indicate that the order of increasing resistance to alkaline hydrolysis is TNT, DNT and DNAN.     

Spatial predictions of phylogenetic diversity in conservation decision making

Considering genetic relatedness among species has long been argued as an important step toward measuring biological diversity more accurately, rather than relying solely on species richness. Some researchers have correlated measures of phylogenetic diversity and species richness across a series of sites and suggest that values of phylogenetic diversity do not differ enough from those of species richness to justify their inclusion in conservation planning. We compared predictions of species richness and 10 measures of phylogenetic diversity by creating distribution models for 168 individual species of a species-rich plant family, the Cape Proteaceae. When we used average amounts of land set aside for conservation to compare areas selected on the basis of species richness with areas selected on the basis of phylogenetic diversity, correlations between species richness and different measures of phylogenetic diversity varied considerably. Correlations between species richness and measures that were based on the length of phylogenetic tree branches and tree shape were weaker than those that were based on tree shape alone. Elevation explained up to 31% of the segregation of species rich versus phylogenetically rich areas. Given these results, the increased availability of molecular data, and the known ecological effect of phylogenetically rich communities, consideration of phylogenetic diversity in conservation decision making may be feasible and informative.     

METHODOLOGY OF DELINEATING WELLHEAD PROTECTION ZONES IN CRYSTALLINE BEDROCK IN MAINE1

ABSTRACT: Delineation of contributing areas for wellhead protection around supply wells drilled into bedrock in Maine, USA, is currently achieved by assigning a fixed radius circle around the well. This project develops a methodology that incorporates hydrogeologic processes and ground water modeling (MODFLOW) and accounts for variable data availability to estimate the areas that contribute water to 26 bedrock supply wells. Outcrop fracture mapping and lineament analysis are used to characterize the fracture system. Multiple simulations are constructed of each site using ranges of values for recharge, hydraulic conductivity, and anisotropy. Uncertainty in the delineation process is accounted for by portraying the delineated areas as confidence zones that are constructed by overlapping the capture zones from the multiple simulations. The results are variable and depend on the ability to characterize a site in a way that can be easily modeled. Sites with complex hydrogeology tend to have larger contributing areas that reflect the greater uncertainty in the parameters. The majority of the sites, however, produce reasonable results that provide a much more accurate depiction of the area likely to contribute to a bedrock well than the fixed radius circle.     

Sustaining the Gains Made in Ecological Restoration: Case Study Collingwood Harbour, Ontario

As part of the commitments made by the governments of Canada and the United States in the Great Lakes Water Quality Agreement, Remedial Action Plans (RAPs) are being developed and implemented at Great Lakes Areas of Concern. The Areas of Concern are specific places around the Great Lakes basin ecosystem where environmental quality is degraded to the point that certain beneficial uses (the ability of fish, wildlife and humans to thrive) are impaired. According to the United States and Canada Great Lakes Water Quality Agreement of 1987, the federal governments, in cooperation with state and provincial governments, are to ensure the public is consulted throughout the development and implementation of the RAPs. While not explicit in the Agreement, it is logical to posit that given the effort and investment in environmental improvements, community capacity to sustain the recovery of beneficial uses beyond the life of the RAP should be a product of the RAP. This report examines a case study to test the hypothesis that public ownership of the RAP process can result in the development of community capacity to sustain environmental recovery. The question is, were the principles of the RAP, 10 years after delisting, taken into account to ensure sustainability of growth along the waterfront and within the Town? To arrive at the answer it is important to explore the approach used in the Collingwood Harbour RAP process, and concepts and principles of sustainable cities and towns. This paper provides evidence that such principles are being applied in Collingwood and were nurtured during the development and implementation of the RAP.     

Air pollutant source characterization using the revised regional haze tracking metric and a photochemical grid model and implications for regional haze planning

The 2017 revisions to the Regional Haze Rule clarify that visibility progress at Class I national parks and wilderness areas should be tracked on days with the highest anthropogenic contributions to haze (impairment). We compare the natural and anthropogenic contributions to haze in the western United States in 2011 estimated using the Environmental Protection Agency (EPA) recommended method and using model projections from the Comprehensive Air Quality Model with Extensions (CAMx) and the Particulate Source Apportionment Tool (PSAT). We do so because these two methods will be used by states to demonstrate visibility progress by 2028. If the two methods assume different natural and anthropogenic contributions, the projected benefits of reducing U.S. anthropogenic emissions will differ. The EPA method assumes that episodic elevated carbonaceous aerosols greater than an annual 95th percentile threshold are natural events. For western U.S. IMPROVE monitoring sites reviewed in this paper, CAMx-PSAT confirms these episodes are impacted by carbon from wildfire or prescribed fire events. The EPA method assumes that most of the ammonium sulfate is anthropogenic in origin. At most western sites CAMx-PSAT apportions more of the ammonium sulfate on the most impaired days to global boundary conditions and anthropogenic Canadian, Mexican, and offshore shipping emissions than to U.S. anthropogenic sources. For ammonium nitrate and coarse mass, CAMx-PSAT apportions greater contributions to U.S. anthropogenic sources than the EPA method assigns to total anthropogenic contributions. We conclude that for western IMPROVE sites, the EPA method is effective in selecting days that are likely to be impacted by anthropogenic emissions and that CAMx-PSAT is an effective approach to estimate U.S. source contributions. Improved inventories, particularly international and natural emissions, and further evaluation of global and regional model performance and PSAT attribution methods are recommended to increase confidence in modeled source characterization.

Implications: The western states intend to use the CAMx model to project visibility progress by 2028. Modeled visibility response to changes in U.S. anthropogenic emissions may be less than estimated using the EPA assumptions based on total U.S. and international anthropogenic contributions to visibility impairment. Additional model improvements are needed to better account for contributions to haze from natural and international emissions in current and future modeling years. These improvements will allow more direct comparison of model and EPA estimates of natural and anthropogenic contributions to haze and future visibility progress.     

To vote or not to vote: abstaining from voting in union representation elections

We conducted two studies addressing abstaining from voting in union representation elections. In Study 1 of a faculty representation election, we showed that compared to voters abstainers possessed less extreme work and union attitudes, believed less in the ability of their vote to affect the election outcomes, and were less involved in the election (e.g., less interested, felt less responsibility to vote). To assess the practical utility of these findings, Study 2 used vignettes in a 2 (traditional bread‐and‐butter issues) × 2 (emerging issues related to fairness) × 2 (voting instrumentality) × 2 (responsibility to vote) experimental manipulation. Results showed that the likelihood of abstaining is reduced when efforts to emphasize the responsibility to vote are presented together with information on both traditional and emerging issues. The two studies show why people abstain from voting in union representation elections, and suggest how abstaining might be reduced. Conceptual implications, practical interventions and research directions raised by the two studies are discussed. Copyright © 2001 John Wiley & Sons, Ltd.