Application of Gas-Aerosol Adsorption Data to the Selection of Air Quality Standards

A quantitative approach is presented for selecting air quality standards which take into account pollutant gas-aerosol synergistic effects. These synergistic health effects have been postulated to be due to the adsorption or absorption of the pollutant gas by the aerosol particles. The approach presented in this paper assumes that the synergistic toxic agent is the adsorbed pollutant gas. Therefore, limiting the concentration of the adsorbed pollutant gas limits the magnitude of the synergistic effects. The concentration of the adsorbed pollutant gas is related to the concentrations of the gaseous phase pollutant gas and the atmospheric aerosol using the Langmuir adsorption isotherm. An example is presented of the selection of air quality standards for sulfur dioxide and the atmospheric aerosol using concentration data for these two pollutants along with health effect data.     

An Approach to Air Quality Management Standards

The Clean Air Amendments of 1970 impose a stringent set of uniform air quality standards and a rigid timetable for achieving them. Such an approach is open to serious question, since it fails to take account of variations in relevant local conditions. This paper sketches a proposal for a more realistic approach to air quality. It suggests a program of management standards that would reflect the needs and circumstances of particular regions. An institutional framework is outlined that would consider the technical, economic, and social constraints that determine how quickly and how much any area can improve its air quality. The framework would provide the needed flexibility, and would employ a feedback approach that avoids the need to resolve all uncertainties before any progress can be made. At the same time, it would impose a timetable and planning process to assure that all feasible progress in air quality improvement is realized nationwide.     

The Limitations of Air Quality Standards

This paper describes a diffusion model designed to permit calculation of seasonal average concentrations of an air pollutant, in particular, sulfur dioxide. The calculations can encompass multiple sources and multiple receptors. For each receptor location the model sums the effect of all sources over a wide range of meteorological conditions. Input data include source pollutant emissions, source configuration and location, receptor location, and meteorological data expressed as a joint frequency distribution of wind direction, wind speed, stability. To determine the model’s accuracy, concentration estimates for St. Louis, Mo., are compared with measured SO₂ concentrations. The overall correlation with observed data is satisfactory. A computer program to handle the numerous calculations was written in Fortran IV language for use on an IBM 1130 computer.     

California Experience with Air Quality Standards

Air quality standards have existed in California for almost six years. They have become an important part of the State’s air pollution control program.

The two principal uses of the standards have been to establish the goals for controlling motor vehicle emissions and to provide a basis for evaluating air quality throughout the State. The standards have also proved to be valuable as a means of communicating on air pollution problems with legislators, administrators, the press, the public, and dischargers of pollutants.

Lack of adequate data on the effects of varying concentrations of contaminants of concern in air pollution is a serious limitation in any effort to establish air quality standards.It is important that this data be obtained.

The concept of employing air quality standards as administrative goals is not unique to the air pollution field but is part of a broad trend to utilize standards for insuring a satisfactory environment. Those engaged in the air pollution field can expect to see increasing emphasis on such standards.

Air quality standards do not provide a magic formula for eliminating air pollution; they are but one element in a comprehensive program. They have limitations and are no better than the data upon which they are based. The standards, however, can play an important role in preserving satisfactory air quality and protecting man’s health.

In using air quality standards, one should keep in mind the comments of H. W. Streeter⁵ on water quality standards—“Let us devise them, try them, revise them, and apply them, but also remember that they are but ’feeble instruments of the human will’ and like all other such tools are made to be discarded for better ones when they become worn out.“     

Air Quality Standards National And International

The advantages and disadvantages of establishingworldwide air quality standards are reviewed. Inter-national standards would represent the best and mostadvanced procedures and might lead to improvementin standards in some countries where air quality isfar from adequate. International standards alsowould permit accurate comparisons of air pollutionamong countries and would provide a sound basis forcombatting pollution.     

Standards for Air Quality in California

Abstract

During the 1950s and 1960s, hundreds of thousands of underground storage tanks (and above-ground storage tanks) containing petroleum products and hazardous chemicals were installed. Many of these tanks either have been abandoned or have exceeded their useful lives and are leaking, thereby posing a serious threat to the nation’s surface and groundwater supplies, as well as to public health. Cleaning up releases of petroleum hydrocarbons or other organic chemicals in the subsurface environment is a real-world problem,

Biological treatment of hydrocarbon-contaminated soil is considered to be a relatively low-cost and safe technology; however, its potential for effectively treating recalcitrant wastes has not been fully explored. For millions of years, microorganisms such as bacteria, fungi, actinomycete, protozoa, and others have performed the function of recycling organic matter from which new plant life can grow.

This paper examines the biological treatment technology for cleaning up petroleum product-contaminated soils, with special emphasis on microbial enzyme systems for enhancing the rate of biodegradation of petroleum hydrocarbons. Classifications and functions of enzymes, as well as the microbes, in degrading the organic contaminants are discussed. In addition, the weathering effect on biodegradation, types of hydrocarbon degraders, advantages associated with enzyme use, methods of enzyme extraction, and future research needs for development and evaluation of enzyme-assisted bioremediation are examined.     

Selected International Receptor-Based Air Quality Standards

Abstract

The ambient air quality standards (AAQS) of twenty-one nations for eight commonly regulated substances are presented. Many countries are adding a receptor-based component to their air quality management, which traditionally have been emission oriented. Automation of air quality monitoring stations has meant that local air quality evaluation can now be more easily achieved. However, a majority of countries have no active air quality standards (emission or receptor-based) or ambient air quality monitoring. One possible monitoring procedure is outlined and the variation in international standards is discussed.     

Consideration of Air Quality Standards for Vegetation With Respect to Ozone

Present evidence suggests that ozone is the most damaging of all air pollutants affecting vegetation. It is the principal oxidant in the photochemical smog complex. Concentrations of ozone have exceeded 0.5 part per million (ppm) in the Los Angeles area. One-tenth of this level for 8 hours is known to injure very sensitive tobacco varieties. Many plant species are visibly affected after a few hours exposure at concentrations much lower than 0.5 ppm. There is also some evidence that ozone reduces plant growth. Many factors must be taken into account when considering standards to protect vegetation from ozone damage. These include ozone concentration and methods of measurement, time of exposure, possible additive effects of other pollutants, sensitivity of plant species, their economic value, and the extent of injury which can be tolerated. The response of a species to the pollutant is conditioned by genetic factors and environmental conditions. Lack of specific routine methods for measuring ozone in ambient air is a handicap. California and Colorado established standards for oxidants at 0.15 and 0.10 ppm, respectively, for 1 hour. How these standards relate to the ozone dosage causing acute and chronic injury to various plant species is discussed.     

A Quantitative Approach to the Traffic Air Quality Problem: The Traffic Air Quality Index

Abstract

The Traffic Air Quality (TAQ) model is a simple tool to estimate traffic fine particulate emissions on roadways (g/km) and can be used for both real-time analysis and for localized conformity analysis (“hot-spot” analysis for nonattainment areas) as defined by 40 CFR 93.123. This paper is a follow-up to a study published earlier regarding the development of the TAQ model. This paper shows how local air quality levels can be a factor in traffic management in nonattainment areas. Similar to the industrial source quotas measured in tons per year, it is proposed that road segments are to be assigned emission quotas (or TAQ indices) measured in pollutant mass emitted per road length (g/km) above which traffic-measures have to be taken to reduce the fine-particulates emissions on such road links. The TAQ model as well as traffic-rerouting measures along with the Intelligent Transportation System (ITS) protocols can be used to have a real-time control of the traffic conditions along expressways to maintain the fine-particulates emissions below the quota assigned per road link and consequently improving the over all local air quality in nonattainment areas.     

Air Quality Standards for Fluoride Vegetation Effects

Facts that must be taken into consideration in developing fluoride standards for vegetation effects include: (1) Fluoride is an accumulative toxicant and injury is usually associated with long-term exposure; (2) gaseous and particulate fluorides differ in their phytotoxicity; (3) plant species and varieties differ greatly in susceptibility to fluoride; (4) extremely low concentrations can cause damage to sensitive species. Three possible approaches to standards are discussed: Atmospheric fluoride concentration, vegetation fluoride concentration, and the presence of leaf necrosis or chlorosis. Atmospheric fluoride concentration has the advantage that it fits the conventional concept of standards and that it is objective. Accurately measuring low fluoride concentrations, separating gaseous from particulate fluorides in the air sample, and establishing a safe concentration present technical problems, however. Vegetation analysis may more closely represent fluorides available to affect the plant. The presence of significant amounts of fluoride-induced leaf necrosis (e.g., 3% of the leaf area) may be the most practical approach to standards for fluoride vegetation effects. Advantages are that the combined effects of the forms of fluoride, species and varieties, and concentration-time relationships are all manifest in the factor that is measured. Relatively little time is required to examine the vegetation in a large area and only 2 or 3 surveys a year are required.     

Are We Ready for Ambient Air Quality Standards

The legal basis for the control of air pollution has progressed from nuisance law to the statutory regulation of specific substances as the sophistication of the sciences involved has progressed. But, the control of air pollution by pursuing air pollutants one by one as evidence accumulates against them seems clearly inadequate to a technology producing new pollutants at an almost geometric rate and inappropriate to the gathering body of evidence relating air pollution to health effects. To understand the need for changed control concepts it is necessary to understand the biological problem and the evidence that has been accumulated.     

A Method for Determining Source Reduction Required to Meet Air Quality Standards

Governmental boundaries which divide our states frequently do not coincide with the natural geographic and atmospheric conditions affecting regional air pollution problems. Moreover, the control regulations of one state may vary from those of its neighbors. Such areal synthesis of air pollution control measures might only minimally curb the difficulties.

Continuity of control will require cooperation among contiguous states. In this study the attitudes of incumbent elected officials and air pollution experts (both from within the Philadelphia metropolitan area) toward governmental responsiveness have been investigated. It was hypothesized that politicians would want to demonstrate a status quo approach while experts would advocate the creation of an environmental agency for the Philadelphia region’s pollution problems. However, both sample groups responded to the questionnaire survey affirming that they want government to establish an environmental regional control agency, based upon an interstate compact, that has authority strong enough to be a strict enforcing agent. This regional agency should meet all federal conditions and thus receive maximum federal financial assistance. The policy level officials of this agency should be appointed experts—so as to avoid partisan politics, and to acquire the most qualified personnel.     

A Method for Using Air Pollution Measurements and Public Opinion to Establish Ambient Air Quality Standards

Air quality was comprehensively evaluated by means of sampling at 21 locations over metropolitan Birmingham during a period of one year. Thousands of integrated samples of three common atmospheric gaseous pollutants and two common particulate pollutants were collected and analyzed. Following the year of sampling in 1964, a random household survey was completed by conducting personal interviews at more than 7200 households over metropolitan Birmingham. Statistical reduction of household survey results by census tract and by neighborhood area provided domestic fuel and waste burning emission data as well as public (resident) opinion on specific air pollution effects. The relationship between ambient air quality and neighborhood opinion of air pollution effects on health and property are evaluated statistically. Ambient standards are suggested which are based upon those air pollution levels shown to have adverse effects on approximately one-third of the people.     

Air Quality Standards for the Protection of Farm Animals from Fluorides

The ingestion of forages contaminated with inorganic fluorides from industrial sources constitutes an air pollution problem for domestic livestock. In cattle, which have been studied most extensively, the syndrome is characterized by dental and skeletal lesions, lameness, chemical evidence of increased fluoride ingestion, and in severe cases by effects on appetite and milk production. The only practical basis for a standard appears to be one based on forage fluoride concentrations. It is concluded that a standard should protect cattle from loss of milk production and from severe dental fluorosis, but need not be set so low that the animals will be protected against any discernible deviations from normal which do not influence their general health, productive ability, or the soundness and wearing quality of their dentition. As there may be wide seasonal variations in forage fluoride concentrations, the basic standard should be expressed as a yearly average of the forage fluoride concentration. However, as the developing teeth may be adversely influenced by short periods of high exposure, the standard should contain a provision which limits both the extent and duration of time that high concentrations may be tolerated even though they are balanced by lower values at other months. Based on these criteria, a tentative standard which limits forage fluoride to an average of 40 ppm, and limits the time that forage concentrations may exceed 60 or 80 ppm F is proposed.