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.     

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.     

Ultrastructural Effects Of Air Pollution on Lung Cells

The lungs of exposed mice taken during 2- to 3-hour heavy smog periods (over 0.4 ppm total oxidants) showed various degrees of cytoplasmic damage in the alveolar epithelial cells. The extent of damage was markedly age-dependent. Alveolar wall cells taken during heavy smog from 5-month-old animals contained slightly more lamellar inclusion bodies than corresponding animals kept in clean air. The cytoplasm of alveolar cells of 9-month-old animals sacrificed during heavy smog was severely disorganized; however, animals of this age showed a marked recovery 14 hours following the smog peak. In a group of older mice (21 months), similar cytoplasmic damage was obvious, and those sacrificed 24 hours after the heavy smog peak showed even more cellular disruption, suggesting irreversible damage in the older animals. The effect of synthetic photochemical smog showed a pattern of ultrastructural alterations similar to that of the heavy natural smog. Some permanent changes occurred in alveolar cells of 15-month-old mice. Partial recovery of lining cells took place, but few wall cells and phagocytes remained. If older lung tissue has relatively fewer wall cells as is indicated, recovery is decreased to the point of permanent damage. Coupled with extensive disruption of lining membranes, exposures of this nature may well cause the death of older animals.     

底泥营养盐的释磷对富营养化湖泊的影响

富营养化是中国湖泊的重大环境问题。当湖泊的污染外源受到控制以后，由于沉积物（底泥）中营养盐内负荷的存在和释放，湖泊仍然可以发生富营养化。底泥营养盐就成为湖泊富营养化的主导因子，特别是溶解态的磷会逐步释放，成为水体富营养化的主导因子。沉积物中磷的循环在一定程度上决定着富营养化的进程，对水体磷含量有深刻的影响。结合国内外研究动态，对底泥磷形态、磷释放与水体水质的关系作了概述，并对底泥磷释放的研究方向以及控制湖泊富营养化发表了一些见解。     

The Effects of Air Pollution on Exposed Cotton Fabrics

This report covers the results of one-year exposure studies of cotton fabrics exposed at different environmental sites in the metropolitan St. Louis, Mo., and Chicago, III. areas. The 12 sites range from heavy industrial to essentially rural. The data presented definitely establish a relationship between air pollution and accelerated degradation of cotton fabrics. The data include strength retention of several cotton fabrics and air pollution data, as determined by periodic measurement of dustfall, suspended particulate matter, sulfation, and sulfur dioxide.     

Air Pollution Effects of Incinerator Firing Practices and Combustion Air Distribution

A survey of academic programs in air pollution control was made. Results from the 127 schools reporting are tabulated by state. Faculty involved in air pollution instruction are identified. Some conclusions and recommendations are presented.     

The Interstate Air Pollution Surveillance Program Effects Network

A program has been designed to meet a nationwide intelligence-gathering responsibility to obtain general and relative information on current and potential air pollution in areas where interstate transport of pollution may reasonably be expected to exist. This paper describes the field devices utilized in the program. By means of these static “effects packages,” data will be accumulated on: dustfall, particulate impingement, sulfation, corrosion, and tarnishing of metals, and deterioration of textiles, dyes, and rubber. Data accumulated during the “pilot phase” of the program will be discussed.     

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.     

Problems of Relating Atmospheric Analyses to Effects of Air Pollution on Agriculture

Relating of air pollution concentrations to effects on agriculture is hampered by deficiencies in present methods of atmospheric analysis and by inadequate knowledge about how various factors modify the effects. Analytical methods frequently lack sufficient sensitivity or specificity to determine accurately the substances involved. Typical examples include the difficulty of distinguishing among fluoride compounds with loidely differing phytotoxic activity, the serious interference from concomitant air pollutants with the usual methods of determining ozone, and the common failure or inability to detect short interval concentration extremes which may cause acute injury. The interrelationship of pollutant concentration and length of exposure in determining plant injury is poorly understood, as are the modifying effects of environmental conditions and age of tissue. The identity of some of the phytotoxic components of the urban photochemical pollution complex is still uncertain, making it difficult to select appropriate analytical methods. Caution should be exercised in using atmospheric analysis data to predict effects of air pollution on agriculture until these deficiencies in analytical methods and understanding of the problem are overcome.     

Air Monitoring Reflects Air Pollution Control Activity

Air monitoring by the A.I.S.I. filter sampling device which both preceded and was concurrent with source control of particulates demonstrated air quality improvement over a ten-year period. A difference in improvement from that estimated by the pollution control agency resulted from difference in the measurement parameters.     

Air Pollution Research Problems

The TR-l Research Committee of the Air Pollution Control Association conducted a survey during 1969–70 to determine what air pollution research problems require attention. All APCA committees were requested to contribute topics to this survey, especially within their area of activity. Other professional societies were contacted through liaison representatives of APCA. The responses to the survey have been reviewed, categorized, selected, and edited for inclusion in this report. Additional material and concepts have been contributed by members of the TR-l Committee.     

Air Pollution and Health

The use of multistage, dry, fluidized beds of continuously recycled, coal-based activated carbon appears technically and economically attractive for both adsorption of stack gas So₂ and sequential conversion to elemental sulfur. Conceptual design details and economic factors are discussed for the treatment of power plant or oil refinery SO₂ effluents with by-product sulfur recovery.