Particulate population monitoring

A challenge for online monitoring hence involves the early detection and characterization of particulate populations amidst the polymers being produced. An immediate solution is the use of LS and other optical techniques. Because LS is exquisitely sensitive to even tiny populations of aggregates, it should be possible to achieve very early stage particulate detection. For more advanced and dense populations of particulates, simple turbidity measurements can be useful. Another approach outlined in the following takes an inexpensive, nonoptical approach using an analytical filtration method. 

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. 

The metallic element whose concentration in air is most clearly ascribable to man s activities is lead. The level of lead found varies from about 0.1 iig/vn in sparsely populated areas to about 10 /xg/m in areas where automobile traflBc is at a maximum. In a study conducted at Los Angeles, two sites were monitored on either side of a freeway which had approximately 200,000 cars per day as a traflBc level 21), One site was downind a preponderance of the time. If the concentrations at the downwind site are divided by the concentrations of the site that was usually upwind, one can see, in Table XII, ratios that vary from 1.03 (where the percentage of favorable wind was 28) to 4.3 (where the favorable wind percentage was 68). In Table XIII are shown the results obtained when a massive respirable particulate sampler was field tested. The collector was built for EPA by Battelle Columbus. Particles greater than 20 /xm are eliminated with a cyclone. The first stage collects particles by impaction... 

Exposure Levels in Environmental Media. Information about concentrations of strontium and 90Sr in air, water, soil, and food are available. However, updated information on the concentration levels in air, soil, and food may be useful. Specific monitoring of 90Sr in airborne particulates may also be beneficial. Reliable monitoring data for the levels of 90Sr in contaminated media at hazardous waste sites may be useful so that the information obtained on levels of 90Sr in the environment can be used in combination of the known body burden with strontium to assess the potential risk of adverse health effects in populations living in the vicinity of hazardous waste sites. 

Up to 6 to 8 air-monitoring stations were spelled out for areas with populations exceeding 500,000 and where prior testings showed particulate air levels within the high range, that is, when the TSP level exceeded 20% of the TSP standard. At the other extreme, areas with populations of only 50,000—100,000 and where the TSP level is less than the ambient air standard require no monitoring sites (Appendix D, CFR, 1982, 40 58). 

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