LAKE ONTARIO REGULATION UNDER TRANSPOSED CLIMATES1

ABSTRACT: The implications of Lake Ontario regulation under transposed climates with changed means and variability are presented for seasonal and annual time scales. The current regulation plan is evaluated with climates other than the climate for which it was developed and tested. This provides insight into potential conflicts and management issues, development of regulation criteria for extreme conditions, and potential modification of the regulation plan. Transposed climates from the southeastern and south central continental United States are applied to thermodynamic models of the Great Lakes and hydrologic models of their watersheds; these climates provide four alternative scenarios of water supplies to Lake Ontario. The scenarios are analyzed with reference to the present Great Lakes climate. The responses of the Lake Ontario regulation plan to the transposed climate scenarios illustrate several key issues: (1) historical water supplies should no longer be the sole basis for testing and developing lake regulation plans; (2) during extreme supply conditions, none of the regulation criteria can be met simultaneously, priority of interests may change, and new interests may need to be considered, potentially requiring substantial revision to the Boundary Waters Treaty of 1909; (3) revised regulation criteria should be based on ecosystem health and socio-economic benefits for a wider spectrum of interests and not on frequencies and ranges of levels and flows of the historical climate; and (4) operational management of the lake should be improved under the present climate, and under any future climate with more variability, through the use of improved water supply forecasts and monitoring of current hydrologic conditions.     

Empowering environmentally-burdened communities in the US: A primer on the emerging role for information technology

This article is a primer on the emerging role for Information Technology (IT) in the Environmental Justice (EJ) movement. It explores current and potential uses of IT by EJ organisations fighting to protect vulnerable local environments and it addresses some of the barriers to more widespread movement efficacy via e-advocacy. We argue a chief but not insurmountable barrier is the disproportionate access to, and knowledge of, the benefits of using IT in the struggle for equitable decisions about environmental impacts.     

Evaluation of PFAS treatment technology: Alkaline ozonation

A bench‐scale treatability study was performed to evaluate the effectiveness of alkaline ozonation on removing per‐ and polyfluoroalkyl substances (PFAS) present in groundwater at a former industrial site in Michigan. The study involved testing the PFAS‐impacted groundwater under alkaline ozonating conditions under a range of experimental conditions, including modifying pH, hydrogen peroxide‐to‐ozone molar ratio doses, length of ozonation pretreatment times, and sampling techniques. PFAS‐spiked samples were used to determine if inorganic ions such as fluoride (F^?), sulfate (SO₄^2?), formate (HCOO^?), acetate (CH₃COO^?), and trifluoroacetate (CF₃COO^?) were generated or if there were decreases in total organic fluorine resulting from PFAS treatment. The results from all tests indicate that decreases in PFAS concentrations were due to a combination of removal and destructive mechanisms with enhanced removal under acidic pH ozonation pretreatment conditions. Short‐chain PFAS concentrations increased during the experiments followed by an overall decrease in concentration under continuous alkaline ozonation conditions. Reductions in concentrations in perfluorooctane sulfonic acid of 75–97% were observed. Reductions in concentrations were also observed in other PFAS such as 6:2 FTS, PFHxS, PFOA, and PFNA. To our best knowledge, this is the first time that alkaline ozonation has been performed on PFAS‐impacted water while monitoring a larger suite of PFAS analytes in addition to destruction byproducts. Treatment of PFAS under the conditions discussed in this paper suggests that alkaline ozonation may be a viable remediation option for PFAS‐impacted waters.     

Hybrid Neural Networks and Boosted Regression Tree Models for Predicting Roadside Particulate Matter

This paper examines the application of artificial neural network (ANN) and boosted regression tree (BRT) methods in air quality modelling. The methods were applied to developing air quality models for predicting roadside particle mass concentration (PM₁₀, PM_2.5) and particle number counts (PNC) based on air pollution, traffic and meteorological data from Marylebone Road in London. Elastic net, Lasso and principal components analysis were used as feature selection methods for the ANN models to reduce the number of predictor variables and improve their generalisation. The performance of the ANN with feature selection (ANN hybrid) and the BRT models was evaluated and compared using statistical performance metrics. The performance parameters include root mean square error (RMSE), fraction of prediction within a factor of two of the observation (FAC2), mean bias (MB), mean gross error (MGE), the coefficient of correlation (R) and coefficient of efficiency (CoE) values. The input variables selected by the elastic net produced the best performing ANN models. The ANN hybrid produced models performed only slightly better than the BRT models. The R values of the ANN elastic net and BRT models were 0.96 and 0.95 for PM₁₀, 0.96 and 0.96 for PM_2.5 and 0.89 and 0.87 for PNC, respectively. Their corresponding CoE values were 0.72 and 0.70 for PM₁₀, 0.74 and 0.76 for PM_2.5 and 0.81 and 0.71 for PNC respectively. About 80–99% of all the model predictions are within a factor of two of the observed particle concentrations. The BRT models offer more advantages regarding model interpretation and permit feature selection. Therefore, the study recommends the use of BRT over ANN where the model interpretation is a priority.     

Control of Fine Particulate (PM2.5) Emissions from Restaurant Operations

ABSTRACT

This paper describes efforts to reduce particulate matter (PM) emissions from restaurant operations, including application of an existing control method to a new equipment type. Commercial charbroiling in the South Coast Air Basin results in emissions of approximately 10 tons/day of fine particulate matter ₍PM_2.5) and 1.3 tons/day of volatile organic compounds (VOCs). Over a seven-year period, the South Coast Air Quality Management District worked with industry to develop test methods for measuring emissions from various cooking operations, evaluate control technologies, and develop a rule to reduce these emissions.

Of the two basic types of charbroilers—chain-driven and underfired—underfired produce four times the emissions when equivalent amounts of product are cooked. Cost-effective control technology is currently available only for chain-driven charbroilers. The application of flameless catalytic oxidizers to chain-driven charbroilers was found to effectively reduce emissions by at least 83% and is cost-effective. The catalysts have been used worldwide at restaurants for several years. Research efforts are underway to identify control options for underfired charbroilers.

Implementation of Rule 1138, Control of Emissions from Restaurant Operations, adopted November 14, 1997, will result in reductions of 0.5 tons/day of PM_2.5 and 0.2 tons/day of VOCs. Future rules will result in reductions from underfired charbroilers and possibly other restaurant equipment when cost-effective solutions are available.     

Toxic effects of oral 2-amino-4,6-dinitrotoluene in the Western fence lizard (Sceloporus occidentalis)

The compound 2-amino-4,6-dinitrotoluene (2A-DNT) was evaluated under laboratory conditions in the Western fence lizard (Sceloporus occidentalis) to assess the potential for reptile toxicity. Oral LD₅₀ values were 1406 and 1867 mg/kg for male and female lizards, respectively. Based on responses from a 14-day subacute study, a 60-day subchronic experiment followed where lizards were orally dosed at 0, 5, 15, 20, 25, 30 mg/kg-d. At day 60, number of days and survivors, food consumption, and change in body weight were inversely related to dose. Signs of toxicity were characterized by anorexia and generalized cachexia. Significant adverse histopathology was observed in hepatic tissue at ≥15 mg/kg-d, consistent with hepatocellular transdifferentiation. Based on survival, loss of body weight, diminished food intake, changes in liver, kidney, and testes, and increased blood urea nitrogen, these data suggest a LOAEL of 15 mg/kg-d and a NOAEL of 5 mg/kg-d in S. occidentalis.     

Sources,distribution, and acidity of sulfate–ammonium aerosol in the Arctic in winter–spring

We use GEOS-Chem chemical transport model simulations of sulfate–ammonium aerosol data from the NASA ARCTAS and NOAA ARCPAC aircraft campaigns in the North American Arctic in April 2008, together with longer-term data from surface sites, to better understand aerosol sources in the Arctic in winter–spring and the implications for aerosol acidity. Arctic pollution is dominated by transport from mid-latitudes, and we test the relevant ammonia and sulfur dioxide emission inventories in the model by comparison with wet deposition flux data over the source continents. We find that a complicated mix of natural and anthropogenic sources with different vertical signatures is responsible for sulfate concentrations in the Arctic. East Asian pollution influence is weak in winter but becomes important in spring through transport in the free troposphere. European influence is important at all altitudes but never dominant. West Asia (non-Arctic Russia and Kazakhstan) is the largest contributor to Arctic sulfate in surface air in winter, reflecting a southward extension of the Arctic front over that region. Ammonium in Arctic spring mostly originates from anthropogenic sources in East Asia and Europe, with added contribution from boreal fires, resulting in a more neutralized aerosol in the free troposphere than at the surface. The ARCTAS and ARCPAC data indicate a median aerosol neutralization fraction [NH₄⁺]/(2[SO₄^2?] + [NO₃^?]) of 0.5 mol mol^?1 below 2 km and 0.7 mol mol^?1 above. We find that East Asian and European aerosol transported to the Arctic is mostly neutralized, whereas West Asian and North American aerosol is highly acidic. Growth of sulfur emissions in West Asia may be responsible for the observed increase in aerosol acidity at Barrow over the past decade. As global sulfur emissions decline over the next decades, increasing aerosol neutralization in the Arctic is expected, potentially accelerating Arctic warming through indirect radiative forcing and feedbacks.     

The safety observer effect: the effects of conducting safety observations

INTRODUCTION: Some research suggests that conducting safety observations of another's safety performance may serve as an effective tool in increasing the safety performance of the observer. The primary purpose of the present study was to assess the effects of conducting safety observations on the postural safety performance of observers engaging in an assembly task for short time periods. The secondary objectives of the study were: (a) to measure productivity, and (b) to measure the accuracy of participant safety observations. METHOD: An ABC (A: baseline, B: information, C: observation) multiple-baseline design counterbalanced across postural behaviors (back, shoulder, and feet position) was implemented with six participants. RESULTS AND DISCUSSION: Substantial improvements in postural safety occurred after participants conducted safety observations, and these improvements did not appear to negatively affect productivity. Results also suggest that there is no relation between the accuracy of an observer's safety observation and their subsequent safety performance. IMPACT ON INDUSTRY: This research provides evidence that a safety observation process can function to increase safe postural behavior of observers. Thus, the implementation of such a process may contribute to the prevention of musculoskeletal disorders and related costs in the workplace.     

Ammonia assessment from agriculture: U.S. status and needs

Recent studies suggest that human activities accelerate the production of reactive nitrogen on a global scale. Increased nitrogen emissions may lead to environmental impacts including photochemical air pollution, reduced visibility, changes in biodiversity, and stratospheric ozone depletion. In the last 50 yr, emissions of ammonia (NH3), which is the most abundant form of reduced reactive nitrogen in the atmosphere, have significantly increased as a result of intensive agricultural management and greater livestock production in many developed countries. These agricultural production practices are increasingly subject to governmental regulations intended to protect air resources. It is therefore important that an accurate and robust agricultural emission factors database exist to provide valid scientific support of these regulations. This paper highlights some of the recent work that was presented at the 2006 Workshop on Agricultural Air Quality in Washington, D.C. regarding NH3 emissions estimates and emission factors from agricultural sources in the U.S. and Europe. In addition, several best management practices are explored as the scientific community attempts to maximize the beneficial use of reactive nitrogen while simultaneously minimizing negative environmental impacts.