A New Mathematical Model of Air Pollution Concentration

Abstract

Submicron particles play a major role in soiling processes and contribute to corrosion, current leakage and shorts in electronic equipment. For more than a year, optical particle counters have been used to continuously measure the concentrations of submicron particles at a telecommunications facility in Southern California. Separate instruments have simultaneously sampled at four locations: the outdoor air intake, immediately upstream of the HVAC filters, immediately downstream of the HVAC filters, and inside the office. The indoor concentrations can be explained in the context of a one-compartment mass balance model. Key parameters in the model (e.g., the air exchange rate) were monitored throughout the sampling period. In the latter part of this study, the particle counters were used as feedback elements in the HVAC system. An estimate of the concentration of indoor submicron particles, based on measurements of outdoor submicron particles, has been used as a control variable. When this variable exceeds a preset value, the outdoor air damper is partially closed, reducing the amount of outdoor air entering the building. That is, the position of the damper is based on the concentration of outdoor particles as well as the outdoor temperature. As a consequence, the average indoor concentration of submicron particles has been significantly reduced within this facility.     

A Finite Line Source Dispersion Model for Mobile Source Air Pollution

The body of information presented in this paper is directed to individuals interested in dispersion modeling, and in particular to those concerned with evaluation of air quality in the vicinities of airports and roadways. The paper describes briefly the formulation and application of a finite line source dispersion model constructed on the basis of a Gaussian-type transport kernel. The formulation is sufficiently general that any arbitrary orientation of the line can be handled. For cases where the line is at small angles with respect to the wind, approximate expressions as well as segmentation of the line, if necessary, are used. These are Integrated into the general algorithmic scheme by means of a series of geometric tests. The general capabilities of the model are tested first with some hypothetical cases and then with actual air quality data. The latter case studies correspond to three separate periods of air quality monitoring at O’Hare Airport during which the aircraft emissions and the ground vehicle emissions play alternately important roles. The generally good agreement between model predictions and air quality data provides support for the validity of the approach. The overall efficiency of the model in terms of computer time as well as its limitations are briefly discussed.     

A Load Shifting Model for Air Pollution Control in the Electric Power Industry

Load-shifting, a relatively inexpensive approach to air pollution control, involves transferring the generating load from one power plant to another according to meteorological conditions. In this paper, an atmospheric dispersion model is adapted to estimate the exposure of the urban population to sulfur dioxide from operating the power system in different ways. Then a mathematical model of the power system of a metropolitan area is constructed to determine the reduction in pollution exposure which could be achieved, and the costs involved. As a case study, the application of the model to St. Louis, Missouri, is simulated. Under favorable conditions, load shifting could reduce pollution exposure up to 95%, while increasing the costs of electric power generation by only 4%. The load-shifting model has use not only as an operational control strategy, but also as an analytical tool to evaluate alternative pollution control measures in the electric power industry.     

A Mesoclimatological Classification System for Air Pollution Engineers

A method of deriving 3 air pollution potential indexes based on selected climatic data and meso-climate topographic factors have been developed, though not yet adequately field tested, for use by engineers in choosing between alternate factory sites. Three indexes, one for general air pollution, one for photoreac-tive air pollutants, and one for fog-reactive air pollutants, the latter two based on the first one plus sunshine and humidity factors respectively, are presented. These indexes vary with locations, not with air pollutants or time. The first index, called the GSI (General Stagnation Index) is based on a series of national maps which present a variety of climatic parameters pertinent to air pollution potential for the mid-season months of July and October. These maps, useful by themselves, have been derived from climate records from 129 Weather Bureau airport stations and from radiosonde data. The parameters used include wind speed percentages in the 0-3 and 0-12 mile/hr categories, cloud cover percentages, a nighttime stagnation factor, and a vertical ventilation factor. The GSI provides a means of estimating the additional climatic stagnation that occurs in topographically sheltered areas due to width, height and area of the valley (if present), further modified by meso- and micro-climatological factors, such as angle and aspect of slope, solar intensity, sky cover and character of surface. Specialized wind speed summaries from a variety of topographical configurations in West Virginia resulted in a graph which may be helpful in such calculations for any sheltered location from a nearby measurement of relatively unrestricted air flow such as are typically measured at the Weather Bureau airport stations.Weaknesses and possible uses of the various stagnation indexes are discussed.     

大气污染事故预测系统的研究

将地理信息系统应用于城市突发性的大气污染事故，对大气扩散模型的图形技术进行开发研究。介绍了设计的总体结构；详细叙述了数学模型的建立、编程语言及其关键技术。该技术能模拟显示化学品泄漏后的大气污染扩散范围，为应急反应科学决策服务。     

Designing for Air Pollution Control

This paper was one of several presented at the Workshop on Air Pollution Control in Portland, Oregon, on May 6, 1968. The Workshop was sponsored by the Manufacturing Chemists Association and the Chemical Industry Council of the Pacific Northwest in cooperation with the Association of Oregon Industries, Association of Washington Industries, and the Environmental Committee of the Portland Chamber of Commerce. While many of the papers were of localized interest, this paper speaks to anyone designing air pollution control systems.     

A Bibliography of Air Pollution Films

The purpose of this bibliography is to list and describe the motion pictures and film strips that are recent enough to be of use not only to those interested in air pollution control but also to those deeply involved in air pollution control effort.     

A Special Purpose Plant Environmental Chamber for Air Pollution Studies

The controlled atmosphere aspects of the environmental chambers at the University of Utah are described. Control of wind velocity, CO₂, concentration, temperature, relative humidity, and pollutant concentration are discussed. Requirements of our research program dictating the chamber design include: (1) ability to expose plants to air pollutants under the same environmental conditions at different times; (2) ability to simulate field environmental conditions within acceptable limits; (3) ability to study the effects of temperature, light, relative humidity, and wind velocity on response of plants to air pollutants; (4) ability to measure growth suppression, respiration, and transpiration; and (5) ability to measure the pollutant uptake rate of the plants.     

Interregional Exchanges of Air Pollution: Model Types and Applications

Regional scale air quality simulation models covering spatial scales of thousands of kilometers are finding increasing applications in studies of acid deposition and other air pollution problems. The purpose of this paper is to familiarize the nonexpert with the characteristics of the major types of interregional air quality models currently in use: Eulerian grid, statistical trajectory, and Lagrangian trajectory. The basic features, advantages, and disadvantages of each of these modeling approaches are summarized, as are the important limitations and problems associated with interregional modeling in general. Typical applications are illustrated using examples from the use of a representative Lagrangian trajectory model, ENAMAP, over the eastern North American area.     

Air Pollution Equipment for Foundry Cupolas

The choice of air pollution equipment best suited for a specific foundry cupola involves the consideration of a number of factors.—They are: (1) The design of the cupola, including openings, door enclosures, height of stack, etc. These features greatly affect the size, cost, and efficiency of control systems. (2) The constituents of the effluent gas and the other properties, such as temperature and volume, are extremely important because corrosion, warpage, and low efficiency can result from these variables. (3) Four distinctly different types of air pollution control equipment are available for cupolas. They vary widely in initial cost, operating cost, and maintenance, but also vary widely in efficiency. (4) Local air pollution regulations and community considerations dictate the choice of air pollution equipment. Those regulations now in force are quite stringent in some localities, but quite lenient in others. An incremental approach to installation of systems would make one economically feasible for the small foundry.     

Industrial Planning for Air Pollution Control

Seven general planning concepts for air pollution control are presented for industry’s consideration in this text of a speech delivered at the Air Pollution Control Workshop, New England Conference on Urban Planning for Environmental Health, Tufts University, Medford, Massachusetts, September 9, 1965.     

Planning A State-Wide Air Pollution Advisory Service

An investigation of high volume particle sampling and sample handling procedures was undertaken to evaluate variations of protocols being used by the U.S. Environmental Protection Agency. These protocols are used in urban ambient air studies which collect ambient and source samples for subsequent mutagenicity analysis of the organic extracts of the aerosol fraction. Specific protocol issues investigated include: (a) duration of sampling period, (b) type of filter media used to collect air particles, (c) necessity for cryogenic field site storage and dry ice shipping of filter samples, and (d) sample handling at the receiving laboratory. Six PM₁₀ Hi-Vol samplers were collocated at an urban site in downtown Durham, North Carolina and operated simultaneously to evaluate 12 h versus 24 h collection periods and filter media choices of glass fiber, Teflon® impregnated glass fiber (TIGF), and quartz fiber. Filters from the samplers plus field blanks were collected during each of 25 sampling periods. TIGF filters from two samplers were immediately placed on dry ice in the field and transported directly to cryogenic storage. TIGF, quartz, and glass fiber filters from three samplers were transported at ambient and maintained at room temperature for three to six days prior to cryogenic storage. One TIGF sample, which was collected on a previously tared filter, was subjected to controlled environment equilibration (40 percent relative humidity, 22°C) for 8 to 24 h and weighed prior to cryogenic storage. All filters were subsequently stored at ?70°C to ?80°C prior to a one-time extraction and Salmonella (Ames) mutagenicity bioassay of the entire sample set. Results indicate that the sample handling variations and collection period variables had no significant effect on recovery of organics or mutagens. However, a filter type difference was observed. The sonication extraction of organics and mutagens was significantly greater for TIGF filters than for glass fiber or quartz. Results from a second phase of study indicated differences in extracted organics and mutagens for these filter types.     

A Cost-Benefit Approach to Air Pollution Control

Air pollution has plagued the urban areas of our Nation for many years, both as a serious health hazard and as a costly economic burden. Users of the air as a waste disposal medium have treated it as a free resource with no regard for the damages incurred by receptors of the dirty air. Unfortunately, no self-regulating market forces exist that will bring this diseconomy into an acceptable equilibrium. An outside regulating force, which can affect abatement of air pollution, is needed to achieve control of air pollution to a level acceptable to a community. A prerequisite of any proposed regulatory action to be applied by an outside force, however, is the need to define an acceptable level of pollution. One means of accomplishing the task is to apply an economic evaluation, in the form of a cost-benefit analysis, to the problem. Previous analyses of the economic aspects of air pollution have stressed only one side of the problem. That is, they have dealt only with the cost of control or the damages caused by air pollution. No analysis has combined both aspects into a meaningful analysis of the overall economic impact. The objective of this paper is to present a technique that can be used to find the level of pollution abatement in an area that balances the cost of controlling pollution with the benefits received from its control. To present a clearer picture of this technique and its results, it has been applied to the Washington, D. C. area to find the optimum level of particulate abatement. This method is generally applicable to any area, in which an air pollution problem exists.     

Annotated Bibliography for Air Pollution Meteorology

This annotated bibliography was prepared for the purpose of directing interested persons to some of the more helpful references in the field of air pollution meteorology. It obviously is not a complete listing. The reader who requires more information is directed to the references in the articles listed.     

Air Pollution Acronyms

Abstract

Computational fluid dynamic (CFD) analysis of the thermal flow in the combustion chamber of a solid waste incinerator provides crucial insight into the incinerator’s performance. However, the interrelation of the gas flow with the burning waste has not been adequately treated in many CFD models. A strategy for a combined simulation of the waste combustion and the gas flow in the furnace is introduced here. When coupled with CFD, a model of the waste combustion in the bed provides the inlet conditions for the gas flow field and receives the radiative heat flux onto the bed from the furnace wall and gaseous species. An unsteady one-dimensional bed model was used for the test simulation, in which the moving bed was treated as a packed bed of homogeneous fuel particles. The simulation results show the physical processes of the waste combustion and its interaction with the gas flow for various operational parameters.     

A Movable Laboratory for Controlled Clinical Studies of Air Pollution Exposure

The cause of the Yokkaichi asthma episode (1960-1969) has been analyzed. It Is concluded that the respiratory diseases were due not to sulfur dioxide but to concentrated sulfuric acid mists emitted from stacks of calciners of a titanium oxide manufacturing plant located windward of the residential area.