Pollutant profiles

An exposure and risk assessment will usually integrate a number of different inputs, including health and environmental effects evaluations as well as pollutant profiles for environmental releases, ambient monitoring data, and environmental fate... 

The test technique shown in Fig. 7 is used to determine the variation of D with depth (i.e., length of the soil-solid sample) and with number of pore volumes (i. e.,PV) of passage of COM solution. By analyzing the various sections of a soil-solid sample, one can obtain the pollutant profile shown in Fig. 7. Casting Eq. (82) in the finite difference form yields the following ... 

FIGURE 16.7 Typical primary and secondary pollutant profiles in a propene-NO, irradiation in a smog chamber (adapted from Pitts et al., 1975). 

Reynolds analogy allows estimates to be made of SO2 deposition velocity (V ) based on heat transfer or skin friction tests (or theory), of which the literature abounds. In so doing, one must realize that such a calculation deals only with the delivery of pollutant to the surface, through diffusion. If we assume that the concentration is zero at the surface (perfect absorption), we have tacitly assumed that the physical chemistry is not limiting, which will only be the case with reactive materials such as zinc or calcareous stones. For less reactive materials, the surface concentration in the pollutant profile may not be zero, leading to an interaction between physical and chemical processes. Such a situation may occur if the pH in the liquid film drops too low to permit additional SO2 dissolution, as given by Henry s law. Buffering of the film with corrosion products can prevent this from... 

Fig. 9.5 a Ozone profiles over KCO as measured from balloon sondes and calculated with a chemistry GCM (dashed lines). The soundings show instances where the pronounced layering of the lower troposphere has remained intact as far south as 5 °N. b Pollutant profiles downwind of India (7.5 °N, 72 °E), including atansol absorption and scattering, obstaved from the C-130 aircraft on 13 March 1999... 

Once a flow profile has been established, samphng strategy can be considered. Since samphng collection can be simphfied and greatly reduced depending on flow characteristics, it is best to complete the flow-profile measurement before sampling or measuring pollutant concentrations. 

Fig. 12-2. NO-NO2-O3 ambient concentration profiles from average of four Regional Air Monitoring Stations (RAPS) in downtown St. Louis, Missouri (USA) on October 1, 1976. Source RAPS, Data obtained from the 1976 data file for the Regional Air Pollution Study Program. U.S. Environmental Protection Agency, Research Triangle Park, NC, 1976.

Wind speed generally increases with height. A number of expressions describe the variation of wind speed in the surface boundary layer. A power law profile has frequently been used in air pollution work ... 

In its most common form, a trajectory model moves a vertical column, with a square cross section intersecting the ground, at the mean wind speed, with pollutants added to the bottom of the column as they are generated by each location over which the column passes. Treatment of vertical dispersion varies among models, from those which assume immediate vertical mixing throughout the column to those which assume vertical dispersion using a vertical coefficient with a suitable profile (15). 

Detailed measurements of temperature, humidity, airflow, or other parameters are more appropriate to a later stage of profile development. However, chemical smoke can be used to observe airflow patterns and pressure relationships between special use areas or other identified pollutant sources and surrounding rooms. Odors in inappropriate locations may indicate that ventilation system components require adjustment or repair. 

The earliest and still widely used dispersion model to compute pollutant concentration profiles is the Gaussian plume model for single or multiple source pollution problems. Box-type model techniques, which can take into account nonlinear interactions among different species arising from chemical reactions, have been used in longer-range dispersion computations. 

Temperature change with altitude has great influence on the motion of air pollutants. For example, inversion conditions result in only limited vertical mixing. The amount of turbulence available to diffuse pollutants is also a function of the temperature profile. The decrease of temperature with altitude is known as the lapse rate. The normal or standard lapse rate in the United States is -3.5" F/1,000 ft. An adiabatic lapse rate has a value of -5.4" F/1,000 ft. Temperature as a function of altitude is expressed by the following equation ... 

Figures 32 and 33 shows profiles obtained with a SIMS device to detect pollution by sodium, and to a less extent by potassium. Such analyzes greatly improve the efficiency of fhe search for fhe origin of unexpected problems in the deposition process.

Figure 5. Diurnal HO profiles as predicted by 20 polluted air chemical models. From Hough (165) see that reference for model identities.

Sediment pollution. The concentrations of pollutants in the dated sediment cores have been determined in our laboratory by atomic absorption spectrophotometry (AAS). Donazzolo et al. (15) and Pavoni et al. (16) reported mainly heavy metal concentrations. Marcomini et al. (17) and Pavoni et al. (18) discussed the concentration profiles of organic pollutants such as chlorinated hydrocarbons and polycyclic aromatic hydrocarbons. 

Heavy metals. The profiles of sediment and pollutant depositions and the relationships of concentrations with time have been reconstructed. For most metals the highest accumulations took place between the fifties and the sixties, when the fastest industrial development of Porto Marghera took place. In Figure 2 the concentration profiles of three of the most interesting metals (Hg, Pb, Cd) are plotted vs. depth. Data were "normalized" (i.e. divided) by the background levels, as metals have different natural presence in the environment. This leads to accumulation factors, referred to pre-industrial background values. Any derived data tell... 

In the profiles of the core from the industrial area, mercury displays the highest accumulation. Mercury in this area, close to the industrial district, has probably derived from a large chloralkali plant which has employed mercury cathodes since the fifties. Whereas, at present, very severe measures are taken to prevent mercury spills into the Lagoon, in the past, polluted waters and solid materials were discharged almost untreated. In the most superficial strata a marked decrease in the accumulations is, in fact, recorded. Lead and Cd accumulations are lower here by a factor of 5-10. The presence of cadmium in the sediments of the Lagoon has been referred to sphalerite (ZnS) processing on the basis of a strict concomitant... 

For any section of the core, being known the in situ density and the sedimentation rate calculated from the radioisotope profiles, the pollutant... 

Biotic indices that are relatively simple and inexpensive to apply can be very useful for identifying environmental problems caused by pollutants. Serious effects of pollutants can cause departures from normal profiles. The problem is, however, identifying which pollutants—or which other enviromnental factors—are responsible for significant departures from normality. This dilemma illustrates well the importance of having both a top-down and a bottom-up approach to pollution problems in the field. Chemical analysis and biomarker assays can be used to identify chemicals responsible for adverse changes in communities detected by the use of biotic indices. 

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