Interactions of Environmental Factors on the Sensitivity of Plants to Air Pollution

Before potential damage to vegetation can be adequately forecast, even after an air pollution alert has been placed in effect, a clear understanding of the interactions of environment on plant sensitivity must be ascertained. This involves detailed study of single factors and then multiple factors using the phytotoxicants in question. Factors studied or suggested include light (quality, intensity, and duration), temperature, carbon dioxide concentration, humidity, wind, soil moisture, soil aeration, nutrient levels, and soil texture. This paper presents a review of the work relating plant injury to specific air pollutants as conditioned by several environmental conditions supported by research on the interactions of ozone with these environmental conditions.     

Environmental Appraisal-Particulate Matter,Oxides of Sulfur,and Sulfuric Acid

The role of particulate matter and oxides of sulfur in degradation of the atmospheric environment is discussed. The Federal Air Quality Criteria for these pollutants are analyzed for their conformance with the requirement of the Clean Air Act of 1967 that they reflect the latest scientific knowledge pertinent to the indication of their effects on health and welfare. Visibility reduction by suspended particulate matter is treated and the bases for the criteria issued in the documents “Air Quality Criteria for Particulate Matter” and “Air Quality Criteria for Sulfur Oxides” are examined. The reactions between particulate matter and gaseous pollutants are discussed, along with the Impact of particulate matter on modifications of weather processes. Local effects, such as precipitation, are considered. The relationship between pollution by particulate matter and cloud formation is discussed, as are persistence of fog and the observation that certain sources of particulate pollution are also sources of ice nuclei.     

enforcement of diesel smoke emissions for the state of new jersey

This paper reports on the research program undertaken by the State of New Jersey to determine those tests and instruments which can be used by authorized state agencies for the enforcement of diesel smoke emissions. The state agencies under consideration for the enforcement of diesel smoke emissions are the following: (1) The Division of Motor Vehicles, in its system of state owned inspection stations, will be able to inspect all diesel-powered trucks, and tractors which are registered in New Jersey. (2) The Public Utilities Commission will be able to inspect at their home garages all buses registered in the State. (3) The New Jersey State Police will be able to inspect diesel-powered vehicles on the road. It was decided that the maximum inspection time for each vehicle was not to exceed one minute. On the basis of the one minute per vehicle requirement, eight different tests were evaluated to determine which ones correlated well with normal vehicle operation. These tests included acceleration of a fixed external inertia, free acceleration of only the moving parts of the engine, three ramp tests, a test in which a heavy vehicle was towed, and a driving test in which the vehicle being tested was actually accelerated. The results of tests demonstrated that the modified free acceleration method correlates reasonably well with a loaded steady state cycle, distinguishes the high emitters and is simple to perform. Consequently, the free acceleration test method is recommended for use in inspection stations and on the road. Finally, nearly two hundred vehicles have been tested by this procedure to determine present and potential levels of diesel smoke emissions. Another phase of the program consisted of the determination of smoke measuring techniques and instrumentation. The use and design of smokemeters were extensively investigated, as well as the use of the visual and photographic techniques. Of the various smokemeters tested for this application, several measured smoke satisfactorily in the laboratory, but none were found adequate for field use; they either lacked portability or were unstable due to the deposition of soot on the optics. At the time of writing, specifications for the necessary smokemeter have been drafted and published for bid to interested manufacturers.     

Results of Field Measurements of Industrial Particulate Sources and Electrostatic Precipitator Performance

This paper presents results of source size distribution measurements over the size range from 0.1 μm to 5 μm for six classes of particulate sources and fractional efficiency measurements on five full scale electrostatic precipitators and one pilot scale precipitator. The precipitators all showed moderately high to high particulate collection efficiencies for particles having diameters larger than a few micrometers or smaller than a few hundredths of a micrometer and a minimum in collection efficiency for particles having diameters of a few tenths of a micrometer.     

Characterization of Particulates from Power Plants

The emphasis on participate control from industrial processes has been shifted recently towards fine particulates, having diameters less than 3 microns. There exists an urgent need for more scientific information of fine particle characterization.^1,2 Coal and oil fired power plants are among the largest anthropogenic point sources of particulate matter.³ Limited knowledge is available on particle size distribution and trace metal composition in power plant emissions.^4-7 The morphological properties of particle emissions have been largely neglected. In this report we present some information on particle characteristics for an oil-fired and coal-fired power plant.     

Workshop on Primary Sulfate Emissions

This article is a summary report on a workshop, Measurement Technology and Characterization of Primary Sulfur Oxides Emission from Combustion Sources, sponsored by the EPA Environmental Sciences Research Laboratory at Research Triangle Park, NC, held in Southern Pines, NC. The objectives of the workshop were: to review and discuss current measurement methods and problem areas for sulfur oxides emission with attention focused on sulfuric acid, sulfates, and sulfur-bearing particulate matter; to review and discuss emission data from various combustion sources operating under different conditions, which include various pollutant controls, fuel composition, excess boiler oxygen, etc.; to delineate and recommend areas in need of research and development effort. Scientists were invited to present the results of their studies on primary sulfate emissions. The 3-day workshop devoted one day to measurement technology, a second to characterization, and a third to critical assessment of the presented papers and development of summary working group reports on each half-day session of the initial 2 days. Thirty-one papers were presented by 29 participants on measurements and characterization. Four working group reports were developed and summarized in the last day. Highlights of the papers and reports are briefly reviewed. Workshop proceedings are available as an EPA publication.     

Environmental Impact of Residential Wood Combustion Emissions and its Implications

Currently available information suggests a substantial environmental impact from residential wood combustion emissions. Air pollution from this source is widespread and increasing. Current ambient measurements, surveys, and model predictions indicate winter respirable (<2 μm) emissions from residential wood combustion can easily exceed all other sources. Both the chemical potency and deliverability of the emissions from this source are of concern. The emissions are almost entirely in the inhalable size range and contain toxic and priority pollutants, carcinogens, co-carcinogens, cilia toxic, mucus coagulating agents, and other respiratory irritants such as phenols, aldehydes, etc. This source is contributing substantially to the nonattainment of current particulate, carbon monoxide, and hydrocarbon ambient air quality standards and will almost certainly have a significant impact on potential future standards such as inhalable particulates, visibility, and other chemically specific standards. Emission from this growing source is likely to require additional expenditures by industry for air pollution control equipment in nonattainment areas.     

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.     

Technique for Measuring the Total Concentration of Gaseous Fixed Nitrogen Species

This paper reports the development of a rapid, continuous technique for analyzing fixed nitrogen species (NH₃, HCN, CH₃NH₂, etc.). The technique uses a platinum catalyst at low pressure in combination with a conventional chemiluminescent NO _x analyzer. Previous workers observed that conventional stainless steel catalysts, and platinum catalysts operated at atmospheric pressure, do not reliably convert NH₃ to NO. The most serious problem was the variation in the efficiency of these catalysts with operating conditions. Changes in temperature, gas composition, or X_NH3 could change the conversion efficiency from 99.9% to <30%. The new conversion technique, however, is quantitative up to several thousand ppm NH₃ in either O₂/He or O₂/CO₂/N₂.