Fuel Oil Additives for Controlling Air Contaminant Emissions

An addition of additives to fuel oils prior to combustion is one way of reducing combustible contaminant emissions to the outer air. Reported test results show that some additives improve, moderately, the combustive properties of fuel oils. Combustion is also improved but to a lesser degree, in boiler systems that are deficient in operation and design. Being combustible, polynuclear hydrocarbons emissions would be reduced by use of additives. Other types of additives to reduce slagging and inhibit corrosion from combustion of fuel oils are also available. The cost of using additives is low. Improved additives are required, especially ones to better combustion in the deficient boiler systems. These can be found by research and literature surveys. Their effectiveness and nontoxicity would be confirmed by laboratory and field testing.     

A Simulation Model for Air Pollution over Connecticut

A different approach to mathematically modeling large-scale atmospheric processes is presented. Whereas past approaches have been to develop a model based on an accumulation of information from a specific geographical area, resulting in a model applicable to that area only, we have developed a general mathematical model applicable to any geographical area. The model’s applicability is controlled by specifying the input information describing the meteorological situation and pollution source configuration. A rectangular array of grid points is used to specify both the wind field, by using stream functions, and the average source strength of some pollutant for the area represented by the grid. The diffusion problem is divided into two areas: transport by the mean wind field, and dispersion based on travel time and distance as described by empirical equations. Trajectories of pollutants are traced backwards from the points of interest in the course of the calculations and the contributions of all sources that affect the points of interest are accumulated. The model requires an array of source strength information. An inventory of pollution sources in the State of Connecticut was compiled and maps of source strengths were prepared for five pollutants on a 5000-ft grid-square array. Maps of sulfur dioxide and carbon monoxide source strengths are presented with the resulting concentration distribution for “typical” meteorological conditions. The model permits the changing of meteorological or source values at predetermined intervals so that diurnal changes are incorporated in the calculations. The model has not been verified, but the values of pollution concentration are the right order of magnitude and the resulting patterns are as expected.     

Determining the Costs of Air Pollution Control

A general procedure has been described that can be followed for estimating the cost of reducing air pollution emissions within a metropolitan region. The six step procedure examines emission inventories, regional trends, control trends, alternate control schemes, control costs, and optimum cost-effectiveness. The procedure is illustrated for one emission source in the Delaware Valley. By application of “feasible controls,” automobile emissions were shown to be reduced from 4.5 billion pounds per year in the Region during 1968 to 1.5 billion pounds in the year 2000. Annual control costs during the same period will increase from $30 million to over $300 million per year. This represents a cost increase from $15 per registered vehicle in 1968 to about $58 per vehicle per year in 2000. A method was illustrated for determining minimum cost to achieve any desired degree of emission reduction where alternate feasible control schemes are available. This method is especially useful where the allocation of scarce resources is involved. The general procedure is applicable to any number of pollutants and emission sources, and may be useful for calculations in any metropolitan area. The objectives of the present study are to apply this method to other sources within the Delaware Valley and to determine total regional costs for various levels of emission reduction. As one example of a practical application for this type of analysis, the economic impact of regulatory schemes can be evaluated on a cost-effectiveness basis     

The Survival of Airborne Serratia marcescens in Urban Concentrations of Sulfur Dioxide

Aerosols of Serratia marcescens ATCC 274 were suspended in a 709L rotating drum at 20 ± 1 °C and high to mid-range relative humidities. At specified times after bacterial aerosolization, sulfur dioxide was added to concentrations of 2.5, or 5 mg/m³. Viable cell decay rate constants, in control aerosols without added sulfur dioxide, increased rapidly from near 100% to 60% RH in the first hour (termed: young aerosol) of suspension, and from a minimum rate constant at 80% in the succeeding four hours (termed: old aerosol).Upon addition of sulfur dioxide to a cloud of S. marcescens, generally, viable cell decay rate constants increased further. One exception was at 80% relative humidity where maximum resistance to SO₂ accelerated death was observed for old aerosols. Cells in young aerosols were particularly sensitive to SO₂ addition at mid-range humidities, while in older aerosols the cells were insensitive to up to 5 mg SO₂/m³ introduced at high RH; but were up to 10 times more sensitive than cells in young aerosols to a given increase (from 2.5 to 5 mg/m³) in SO₂ concentration at mid-range humidities.     

Jet Aircraft Operations: Impact on the Air Environment

This paper is directed to those concerned with the air environment and its degradation by the burden of pollution from jet aircraft operations. A summary is presented of the results of a comprehensive air pollution study of jet aircraft operations at the Los Angeles International Airport (LAX). Included in the data obtained from this study are jet engine exhaust measurements for currently used turboprop, turbojet and turbofan engines; measurements of specific contaminants in the atmosphere inside and outside of passenger terminals and ticketing areas, and in aircraft cabins during ground operations including passenger loading and taxiing prior to takeoff; also presented are ambient air measurements in a two-mile radius of the airport. An evaluation is made of the emissions of contaminants from air transport operations and all related ground activities including motor vehicles, that contribute to the total atmospheric contaminant burden at the airport.     

Roof Monitor Emissions: Test Methodology

Studies of roof monitor emissions are conducted for two reasons: (1) to obtain design data necessary to engineer control systems to meet existing regulations, and (2) to determine projected control costs which can influence present day proposals for process change. Heated wire anemometers and rotating vane anemometers have been selected for velocity measurements, and high-volume air samplers have been selected to collect the particulate sample. Evaluation of other types of velocity sensing devices are described in the paper.

Roof monitor studies must be preceded by a preliminary survey to allow the project engineer to determine the test sampling locations and specific methodology necessary for the given study, and to allow the engineer to determine the type of safety equipment, scaffolds, and power requirements necessary to complete the study.

Field tests are conducted by operating a number of high-volume air samplers simultaneously while at the same time measuring the velocity of the gas through the monitor opening. Curves of particulate concentration and velocity as a function of monitor length are constructed. The concentration and velocity curves are then integrated together and the resultant curve is multiplied by the monitor width to determine a curve of mass emission rate as a function of monitor length. The total mass emission rate is represented by the area under the mass emission rate curve.

Procedures for calibrating the anemometers and correcting for the effect of power fluctuation on the high-volume sampler operation are described. Data evaluation procedures and discussion of test error are also described.

A study can cost between 10 and 20 thousand dollars, including the cost of manpower and the cost of scaffolds, power, cables, etc. It can take four months or more to conduct a study, from the preliminary survey phase through the report phase.     

Mesoscale Air Pollution Transport in the Chicago Lake Breeze

A two-day field program in Chicago studied mesoscale pollution transport during typical lake breezes. Streamlines calculated from serial pibal data suggest that a nearly closed circulation cell traps pollutants emitted near a shore line. Optically tracked tetroons confirm the helical trajectory of air within the lake breeze regime. Pollutants released within the inflow layer move inland, rise in a narrow zone of updrafts (100 cm/sec) at the lake breeze front, advect lakeward in the return flow layer aloft, and then subside back down into the inflow layer. Pollution then fumigates back to the surface as the air returns inland a second time causing concentrations higher than would otherwise be expected. Spectral aerosol measurements (0.5-3.0 and 7.0-9.0 micrometer size ranges) made by an instrumented aircraft reveal a marked particle size sorting.     

Ethylene: An Urban Air Pollutant

Ethylene is an unusual air pollutant in that it is a plant hormone. Motor vehicle exhaust is a primary source. In the Washington, D. C, area, ethylene concentrations ranged from 700 ppb in the city center to 39 ppb in areas outside the circumferential beltway. Plants grown in these concentrations of ethylene, using controlled environment chambers, exhibited typical symptoms of ethylene toxicity: reduced growth, premature senescence, and reduced flowering and fruit production. When plants were grown in carbon-filtered ambient air, which was also filtered through KMnO₄ to remove ethylene by oxidation, growth, flowering, and fruit production increased. These observations demonstrate that ethylene air pollution is a continual source of stress for plant growth and development in an urban environment.     

Surface Transportation Noise and Its Control

Surface transportation creates most of the noise pollution imposed on our communities today. Reduction of this noise impact requires effective preparation and enforcement of regulations to control noise sources, and methods and locations of operation. At the Federal level, such action has begun, within the limited authority available. Concurrently, research and development programs are demonstrating that means to satisfy noise control regulations are technically practical and economically reasonable. This paper provides a brief review of Federal regulatory areas and corresponding R&D activities pertinent to surface transportation noise abatement.