Static Methods Of Air Monitoring

Static sensors used to monitor air quality require the minimum capital cost. While averaging times are in terms of weeks and sensitivity is low, in many cases, static monitors provide the most information for the amount of investment. Although inexpensive, they should not be rejected but should be considered as useful adjuncts to more sophisticated systems.

FIG. 5.10.7 Dustfall jar.

rated with an aqueous mixture of lead peroxide and a gel, commonly gum tragacanth, and is allowed to dry. These dishes or plates are exposed in an inverted position for periods of 1 to 4 wk.

The lead peroxide estimation of sulfur dioxide has inherent weaknesses. All sulfur gases, including reduced sulfur, react with lead peroxide to form lead sulfate. More importantly, the reactivity of lead peroxide depends on its particle size distribution. For this reason, the results from different investigators are not directly comparable. Nevertheless, a network of lead peroxide plates over an area provides a good indication of the exposure to sulfur gases during the exposure period. This technique is useful for determining the geographical extent of sulfur pollution.

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