A Critical Review

Abstract

There are many requirements for dispersion models in the Clean Air Act Amendments of 1977 including prevention of significant deterioration, air quality maintenance plans, and new source permits. The historical perspective of dispersion modeling includes both theoretical and practical developments, rural and urban field studies including tracer studies, plume rise, and urban modeling. Photochemical modeling includes both grid point and trajectory models. Off-the-shelf models include level terrain models for elevated point sources, urban point and area sources, and transportation sources; and complex terrain models for point sources. Models are needed for photochemical pollutants, sulfates, and nitrates; they should treat long range transport, topographic effects, build-up of urban concentrations, and aerodynamic downwash. Emphasis is placed herein upon proper interpretation of vertical temperature structure measurements, and the difficulties in determining the magnitude and locations of the highest and second highest concentrations in a year. Modeling improvements can be expected with representative on-site measurements of input parameters, and improved dispersion parameter schemes which must be verified with appropriate field investigations. Terms related to model evaluation are defined. A primary source of error, in comparing model estimates with monitored air quality, is not including the actual change of wind direction with height which determines elevated plume position. Measures for model evaluation will differ depending upon model use. The paper concludes asking for 1) encouragement of model development, 2) improvement of model inputs through on-site measurements, and 3) detailed field investigations.Mr. Turner is presently on assignment from the National

Minimizing the cost of air pollution control

“…Within the broad air quality modeling categories shown, specific calculation procedures with differing assumptions abound. For further description of air quality modeling methods, the reader is referred to reviews by; Roth et al (1976) , National Academy of Sciences (1977) , Dimitriades (1977), Myrabo et al (1977, and Turner (1979). Mathematical programming algorithms are presented by Franklin (1980), Shapiro (1979, and Wismer and Chattergy (1978).…”

Simulating Changes in Source Profiles from Coal-Fired Power Stations: Use in Chemical Mass Balance of PM2.5 in the Mount Zirkel Wilderness

“…This approach does not rely on exact descriptions of plume movement, dispersion, plume mixing with background air, chemical reactants from other sources, deposition rates, absolute chemical concentrations, and a variety of other variables because it does not intend to determine precise concentrations of SO 2 or SO 4 2- at a receptor, as in a point source dispersion model (e.g., Turner). The approach examines a wide enough range of values for most of these variables to group the relative abundances of precursors, end products, and nonreactive emissions from coal-fired power stations into a few categories of aged source profiles that correspond to other atmospheric observations.…”

Temporal Trends in Ambient Fine Particulate Air Pollution in Grenada, West Indies, 2020

“…Mobile monitoring, whether done while driving, riding a bicycle, or walking may allow for improved spatial coverage of air pollution measurements. Predictive modeling spans an array of methods (e.g., land use regression (LUR), atmospheric dispersion modeling) [127][128][129] to estimate air pollution levels across an area based off of existing data.…”

“…Generally, dispersion models are used to estimate pollutant concentrations under different scenarios in the future. 128,129 Satellite sensors are capable of monitoring air pollution over large geographical areas. Satellite instruments such as Moderate Resolution Imaging Spectrometer and Multiangle Imaging Spectro-Radiometer are able to collect Aerosol Optical Depth (AOD) data that, when combined with the use of global chemical transport models, can estimate ground-level PM2.5 concentrations.…”