Ozone Injury to Pinus Strobus

In a study of the ozone-induced needle blight of eastern white pine in central New York, acute injuries naturally induced on field trees during a year of relatively low ozone concentrations (1 966) were compared with injuries induced during a year of higher concentrations (1967). Injuries were more frequent and severe and were associated with higher mean ozone concentrations in 1967 than in 1966. Characteristic symptoms were induced on foliage of pine branches exposed to controlled doses of ozone as low as 7 ± 1 pphm for four hours or 3 ± 1 pphm for 48 hours. Such doses were equalled or exceeded two and four times, respectively, in the field during the 1 967 season. Ozone sensitivity of pine needle tissue was increased by fumigation in atmospheres containing water mist. High concentrations of ozone (40-60 pphm) caused general injury of foliage of both ozone-susceptible and resistant trees; the symptoms were unlike those found in the field or caused by fumigation with low concentrations of ozone.     

Variance Design and Air Pollution Control

Confronted with shortages of low sulfur content residual fuel oil and, consequently, faced with the threat of social and economic upheaval, several air pollution control authorities in the Northeastern states were forced to relax hard-won air quality standards during the winter of 1972. The authorities did so by granting variances to their sulfur content standards for residual fuel oil. This paper examines the institutional characteristics of these variance policies from an economic incentive standpoint. After setting up desirable structural criteria for institutional design of such crisis policies, the authors examine the experience of the winter of 1972 and arrive at policy guidelines which recommend themselves for consideration in future periods of fuel oil shortages.     

experience of the forest products industry in obtaining air quality permits for new and modified sources

A detailed study of the air quality permitting process for 65 different forest products industry projects requiring preconstruction permit approvals from EPA, state, and local air pollution control agencies was conducted. The projects included a wide array of sources including kraft recovery furnaces, lime kilns, fossil fuel and wood residue fired boilers, solid wood products manufacturing facilities, paper coaters, and printing presses. Information concerning the time involved in the permitting process, costs associated with obtaining the permits, use of air quality models and ambient monitoring data, emission control technology determinations, problem areas encountered during the permitting process, perceived benefits and drawbacks of the permitting process, and the effect of permitting requirements on project planning was obtained.

The results indicate that certain permitting requirements such as Best Available Control Technology (BACT) determinations, dispersion modeling results, and use of ambient air quality monitoring data seldom influence the emission limitations ultimately imposed in the final approved permit, with 87% of the final emission limits equivalent to the applicable New Source Performance Standard (NSPS). The 65 permitting case histories also show that obtaining permits for projects subject to Prevention of Significant Deterioration (PSD) requirements takes approximately twice as long and costs twice as much as obtaining permits for projects not subject to PSD requirements.     

The Regulation of Toxic Air Pollutants A Critical Review

ABSTRACT

Passage of the 1990 Clean Air Act Amendments launched the Acid Rain Program in the United States. This initiative, based on the market mechanism of a sulfur dioxide tradable “allowance” system, was a dramatic departure from traditional command and control strategies designed to reduce air pollution emissions. Power plant managers have flexibility under the program to select and implement a variety of options to reduce emissions below mandated levels. Federal agencies have collected annual performance data for affected facilities covered by the program for a number of years. Coal-burning plants are typically greater generators of sulfur dioxide (SO₂) than oil burners of equivalent size. This study examined the effect of fuel type as a significant factor influencing a plant's achievement in reducing pollution emissions. Achievement was measured by using a derived variable, delta (A), defined as the difference between pounds of SO₂ produced divided by the energy (in million Btu) generated, for the years 1990 and 1995. Rigorous nonparametric statistical analyses were used to compare the two populations of coal-fired and oil-fired plants. Results indicated that coal-burning facilities achieved greater program success, measured by the expected value of delta, than the oil combustors for the five-year period reviewed. Since utility managers must take steps to ensure all applicable requirements of the program are met, findings of the inquiry should prove to be useful in assessing achievable emissions reductions and aid in long-range facility planning.     

Physicochemical controls on initiation and evolution of desiccation cracks in sand-bentonite mixtures: X-ray CT imaging and stochastic modeling

The shrink-swell behavior of active clays in response to changes in physicochemical conditions creates great challenges for construction of geotechnical barriers for hazardous waste isolation, and is of significant importance for management of agricultural and natural resources. Initiation and evolution of desiccation cracks in active clays are strongly dependent on physicochemical initial and boundary conditions. To investigate effects of bentonite content (20, 40, 60%), pore fluid chemistry (0.05 and 0.5M NaCl) and drying rates (40 and 60°C) on cracking behavior, well-controlled dehydration experiments were conducted and X-ray Computed Tomography (CT) was applied to visualize and quantify geometrical features of evolving crack networks. A stochastic model based on the Fokker-Plank equation was adopted to describe the evolution of crack aperture distributions (CAD) and to assess the impact of physicochemical factors on cracking behavior. Analyses of crack porosity and crack specific surface area showed that both clay content and temperature had larger impact on cracking than pore fluid concentration. More cracks formed at high bentonite contents (40 and 60%) and at high drying rate (60°C). The drift, diffusion and source terms derived from stochastic analysis indicated that evaporative demand had greater influence on the dynamics of the CAD than solution chemistry.     

Preformed Amide-containing biopolymer for Improving the Environmental Performance of Synthesized Urea–formaldehyde in Agro-fiber Composites

Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches. This study examines the role of adding amide-containing biopolymers during synthesis of urea–formaldehyde (UF) on properties of adhesive produced, especially its adhesion potential. The environmental performance of UF-resin synthesized in the presence of modified amide-containing biopolymer was evaluated by evaluating the free-HCHO of both adhesive (during processing) and of the eventual engineered composite product. Also, the benefits of this synthesis-modified adhesive in enhancing the bondability of sugar-cane fibers used in engineered composite panels was evaluated and compared to using UF-resin. The results obtained show that, static bending of the produced composites varied from 27.7 to 33.13 N/mm² of modulus of rupture (MOR) and from 2860 to 3374 N/mm² of Modulus of Elasticity (MOE); while for internal bond (IB) it’s varied from 0.64 to 0.866 N/mm². Based on the ANSI and EN Standards modified UF-based agro composites produced meet the performance requirements for high grade particleboards with respect to static bending strength. These agro-based composite also tested out as having free-HCHO values of ~13 mg/100 g board.