Monitoring stations

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.

Code of Federal Regulations, Title 40, Part 58, Ambient Air Quality Surveillance, Appendix D— Network Design for State and Local Air Monitoring Stations (SLAMS). U.S. Government Printing Office, Washington, DC, July 1992, pp. 158-172. 

Determine how many monitoring stations per million people are located in the four cou nties in southern California shown in Fig. 15-1. 

The maximum 1-h concentration at an urban monitoring station is 800 /rg m. If the concentration varies with averaging time with a power law relation when the power is - 0 3, what is the expected maximum concentration for a 1-week averaging time ... 

Note N is the number of monitoring stations, M is measured, E is esbmated from the model, d is residual (measured - estimated), and S values are standard deviations. 

What is the advantage in using trajectory models for estimating air pollutant concentratiui i at specific air monitoring stations ... 

Aides (administrative, data reduction, engineering, environmental health, laboratory, sanitarian, and unspecified), assistants (administrative, fiscal, laboratory, and legal), draftspersons, laboratory workers, mechanics, project illustrators, samplers, and technicians (air pollution control, air quality monitoring station, electronic, engineering, instrument, and unspecified). 

Atmospheric emissions of sulphur dioxide are either measured or estimated at their source and are thus calculated on a provincial or state basis for both Canada and the United States (Figure 2). While much research and debate continues, computer-based simulation models can use this emission information to provide reasonable estimates of how sulphur dioxide and sulphate (the final oxidized form of sulphur dioxide) are transported, transformed, and deposited via atmospheric air masses to selected regions. Such "source-receptor" models are of varying complexity but all are evaluated on their ability to reproduce the measured pattern of sulphate deposition over a network of acid rain monitoring stations across United States and Canada. In a joint effort of the U.S. Environmental Protection Agency and the Canadian Atmospheric Environment Service, eleven linear-chemistry atmospheric models of sulphur deposition were evaluated using data from 1980. It was found that on an annual basis, all but three models were able to simulate the observed deposition patterns within the uncertainty limits of the observations (22). 

Figure 1. Map of the Mexico City Metropolitan Area showing the location of the following monitoring stations 10-C Azcapotzalco 11-F Tlanepantla 12-L Xalostoc 13-X Merced 14-T Pedregal 15-Q Cerro de la Estrella 16-U Plateros 17-Y Hangeras ...

In a report comparing community responses to low-level exposure to a mixture of air pollutants from pulp mills, Jaakkola et al. (1990) reported significant differences in respiratory symptoms between polluted and unpolluted communities. The pollutant mixture associated with the pulp mills included particulates, sulfur dioxide, and a series of malodorous sulfur compounds. Major contributors in the latter mixture include hydrogen sulfide, methyl mercaptan, and methyl sulfides. In this study the responses of populations from three communities were compared, a nonpolluted community, a moderately polluted community, and a severely polluted community. Initial exposure estimates were derived from dispersion modeling these estimates were subsequently confirmed with measurements taken from monitoring stations located in the two polluted communities. These measurements indicated that both the mean and the maximum 4-hour concentrations of hydrogen sulfide were higher in the more severely polluted community (4 and 56 g/m3 2.9 and 40 ppb) than in the moderately polluted one (2 and 22 g/m3 1.4 and 16 ppb). Particulate measurements made concurrently, and sulfur dioxide measurements made subsequently, showed a similar difference in the concentrations of these two pollutants between the two polluted communities. 

Film samples were exposed to natural weathering conditions on an exposure rack constructed of wooden 2 X 4 s. The samples were mounted directly on a 2 X 4 facing south at an angle of 45° to the horizontal. A measure of the UV light received by the samples was originally obtained from New York State Department of Environmental Conservation (ENCON) reports, kindly supplied by Mr. William Delaware of ENCON. These reports included both total sun and sky radiation and UV radiation measured by Eppley radiometers (photometers). The ENCON monitoring station in Schenectady is within four miles of the exposure rack so no appreciable differences in light intensity should be expected. More recently, a UV radiometer has been mounted directly on the exposure rack to obtain more accurate measurements. 

It should be noted that an overall material balance requires that all the tracer pass the monitoring station. 

If the measuring points are chosen far enough away from the ends of the test vessel so that end effects are negligible, this expression may be used with confidence. Bischoff and Levenspiel (12) have presented design charts that permit one to locate monitoring stations so as to avoid end effects. For example, in a packed bed reactor with a tube to pellet diameter ratio of 15, where the packed bed is followed by an open tube, at least 8 pellet diameters are required between the measurement point and the open tube if errors below 1% are to be obtained. 

L is the distance between monitoring stations L/u is again defined as 7 ... 

For cases where two monitoring stations are used, equation 11.1.49 is applicable, and... 

China Environmental Monitor Station. Background concentrations of elements in soils of China. Beijing, China Chinese Environ Science Press, 1990. 

Optical fibre based optical detection systems offer a number of advantages over bulk optical sensing systems. The principal one is that a robust passive sensing head may be remoted from the monitoring station a factor giving particular advantages in severe environments. This also allows... 

Fig. I Location map of the Ebro basin in Spain and scheme of the Ebro River basin with the monitoring stations (name and code) selected for this study...

Most of the data from the complete set at each station do not show a substantial charge imbalance, considering that the cationic composition should be balanced by the anionic composition. The magnitude of the imbalance is best seen by using the Normalised Inorganic Charge Balance (NICB = X — X+/X + X+ 100). Most points plot within the 5% field with a mean NICB close to 0% and a standard deviation of 2% for all the Ebro monitoring stations and the tributaries. 

Table 1 Relations between TDS and EC, and EC and W at each monitoring station...

The EC (pS cm-1) and the TDS (mg L ) both reflect the water ionic content, i.e. the dissolved load also called water salinity. The EC, easily obtained compared to chemical data, is thus widely documented in the CHEBRO database (n = 2,860 versus 999 complete major element analyses). These two parameters (EC and TDS) are linked by a linear relation TDS (mg L ) = b EC (pS cm-1), with a mean b factor 0.54 < b < 0.96 according to water types and range of salinity [21, 22], The linear relations between TDS and EC were calculated for each monitoring station, b factor ranging from 0.713 (Arga) and 0.86 (Aragon), whereas the Ebro River stations present less variability (0.774—0.798) with R2 always better than 0.72, all the relations are summarised in Table 1. These relations are very similar to that defined for the whole Ebro basin with b = 0.81 [23]. 

Fig. 5 Mean annual TDS (a) expressed in mg L 1 and TDS Flux (b) expressed in t year 1, together with mean value and standard deviation at each monitoring station. All the data are reported versus the distance from the source of the Ebro River...

Fig. 9 TDS derived from carbonate weathering (TDScarb) and from evaporite (gypsum) dissolution ("l DSevaplGY,.,) versus total TDS for all the monitoring stations. All expressed in mg L 1...

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