Air basin

Lagrangian trajectory models can be viewed as foUowing a column of air as it is advected in the air basin at the local wind velocity. Simultaneously, the model describes the vertical diffusion of poUutants, deposition, and emissions into the air parcel as shown in Eigure 4. The underlying equation being solved is a simplification of equation 5 ... 

Fig. 8-3. Relationship between Los Angeles Basin s urban sources of photochemical smog and the San Bernardino Mountains, where ozone damage has occurred to the ponderosa pines. The solid lines are the average daily 1-hr maximum dose of ozone (ppm), )uly-September 1975-1977. Source Adapted from Davidson, A., Ozone trends in the south coast air basin of California, in "Ozone/Oxidants Interaction with the Total Environment.". A ir Pollution Control Association, Pittsburgh, 1979, pp. 433-450.

Fig. 15-1. CaUfomia South Coast Air Basin stationary monitoring locations operating during 1991. (L.A., Los Angeles). Source California Air Resources Board, "Summary of 1991 Air Quality Data, Gaseous and Particulate Pollutants," Vol. 23, 1991.

Taha, H. (1996). Modeling the Impacts of Increased Urban Vegetation on the Ozone Air Quality in the South Coast Air Basin. Atmospheric Environment 3(1 20) 3423—3430. 

Sabaliunas D, Webb SF, Hauk A, Jacob M, Eckhoff WS (2003) Environmental fate of Triclosan in the River Aire Basin, UK. Water Res 37(13) 3145-3154... 

Chemical Tracers for Organic Pollutants in the Southern California Air Basin (in preparation). 

Soil resuspension has the capability of entraining significant volumes of Pb into the air of urban areas. Harris Davidson (2005) calculated that resuspension of soil is responsible for generating 54,000 kg of airborne Pb each year in the South Coast Air Basin of California (SOCAB) and will remain a major source well into the future. Similarly, Lankey et al. (1998) concluded that 43% of Pb emissions in the South Coast Air Basin in California resulted from the resuspension of soil and road dust. 

Harris, A. Davidson, C. 2005. The role of resuspended soil in lead flows in the California south coast air basin. Environmental Science and Technology, 39, 7410-7415. 

Lankey, R.L., Davidson, C.I., Mcmichael, F.C. 1998. Mass balance for lead in the California south coast air basin an update. Environmental Research, 78, 86-93. 

Regional Human Exposure Modeling of Benzene in the California South Coast Air Basin... 

Shikiya J, Tsou G, Kowalski J, et al. 1984. Ambient monitoring of selected halogenated hydrocarbons and in the California South Coast Air Basin. Proceedings of the 77th Annual Meeting of the Air Pollution Control Association, 1-21. 

The most complete data on ozone and other oxidant concentrations have been obtained for the Los Angeles air basin, because of the severity of the problem there. Further measurements are needed in the central and eastern areas of the United States, to broaden the foundations of a national control strategy. Such studies should be designed with specific goals in mind, and not carried out as routine monitoring exercises. 

Rational air pollution control strategies require the establishment of reliable relationships between air quality and emission (Chapter 5). Diffusion models for inert (nonreacting) agents have long been used in air pollution control and in the study of air pollution effects. Major advances have been made in incorporating the complex chemical reaction schemes of photochemical smog in diffusion models for air basins. In addition to these deterministic models, statistical relationships that are based on aerometric data and that relate oxidant concentrations to emission measurements have been determined. 

FIGURE 4-18 Ozone isopleths (vertical cross section) from southern Caltfomta coast air basin survey, August 11, 1971. Reprinted with permission from Gloria et al. ... 

FIGURE 4-22 Number of days in 1973 on which the maximal hourly average oxidant concentration equaled or exceeded 0.20 ppm at six air monitoring stations in the southern California coast air basin. Data as reported Los Angeles, Pasadena, Pomona, and Azusa reported by Los Angeles County apcd Riverside reported by Riverside County apcd and San Bernardino reported by San Bernardino County APCD. Reprinted with permission from Ktts. ... 

FIGURE 4-34 Air pollution monitoring network for southern coastal air basin, California. Reprinted with permission from a National Academy of Sciences study. 

FIGURE 4-3S Southern Califimiia coastal air basin oxidant trends. Reprinted widi permission from Heitner and Krier. ... 

Kinosian, J. R., and S. Duckworth. Oxidant Trends in the South Coast Air Basin 1%3-1972. Sacramento California Air Resources Board, 1973. 29 pp. 

Holland et al. studied 14 subjects under conditions of short-term exposures to irradiated automobile exhaust. The environmental conditions simulated the moderate smog episodes in the Los Angeles air basin. Oxidant concentrations were reported as 0.22 0.27 ppm (on the basis of the alkaline potassum iodide method). No significant changes attributed to exposure were found in reaction time, vital capacity, work performance, or oxygen consumption. 

Descriptions of the vertical and horizontal distributions of photochemical smog in the Los Angeles basin (southern coastal air basin) during... 

FIGURE 12-3 Daytime changes in oxidant concentrations along a west-to-east transect in the southern coastal air basin, including the slopes of the San Bernardino Mountains (see Figure 12-1). Reprinted with permission from Edinger et al. 

Field surv have confirmed oxidant injury to ponderosa pine and associated species at numerous locations in the Sierra Nevada foothills east and southeast of Fresno. Oxidant measurements at ground stations and by instrumented aircraft show late-aftemoon peaks of transported oxidant on the western slopes of the Sierras. Limited measurements by instrumented aircraft suggest the development of a layer of oxidant approaching the forested mountain slopes between 610 and 1,829 m during the late afternoon. A very weak inversion or isothermal layer may serve as a reservoir of oxidant, which is advected to the mountain slope in the southern coastal air basin, as suggested by Edinger. Considerable concern has been registered about air quality in the Lake Tahoe basin, where local development may cause adverse oxidant concentrations. ... 

FIGURE 12-7 A hypothetical expression of the relationships of oxidant dose, natural ecosystems, agroecosystems, and the relative values of their vegetative components along a transect in the southern coastal air basin of California. The only real data are oxidant doses, which defme the pollutant concentration gradient from the coast to the interior. 

Some effort is needed to explore the feasibility of using plants to monitor the overall biologic activity (or biomass reductions) caused by photochemical oxidants in specific air basins or regions. The response of sensitive plants should be correlated with the response of plants of economic and aesthetic importance. Additional monitoring of multiple pollutants is needed in rural areas. 

There have been suggestions, however, that high relative humidity may cause rapid breakdown of PAN (18) but there is no experimental evidence to support such a statement. In the South Coast Air Basin of California, PAN injury to vegetation occurs most frequently when relative humidity is 50% or above and elevated concentrations of 10 to 30 ppb often persist all night, with relative humidity above 60%. 

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