Anthropogenically derived substances

For the purposes of this discussion, it is reasonable to assume that the outdoor environment is the source of most of the anthropogenically derived substances (4) that are present in the indoor environment. The accumulation rates of species on indoor surfaces are related to the outdoor concentrations of these substances through the relationships among the indoor and outdoor concentrations and the indoor deposition velocities of these species. A substantial amount of data is available on outdoor concentrations (4-13). Simultaneous measurements of outdoor and indoor concentrations are less numerous. Very few measurements of indoor deposition velocities have been made. Estimated ratios of outdoor to indoor concentrations will be used that are based on field data, where available, or best judgments. From the limited experimental measurements, taking into account the relative variations in outdoor deposition velocities as a function of particle size, indoor deposition velocities will be estimated. Using these approximate indoor/outdoor ratios and deposition velocities, the indoor surface accumulation rates for substances contained in airborne particles can then be estimated from prevailing outdoor concentrations. 

As anthropogenically derived substances accumulate on indoor surfaces, reactions with the surfaces and among the substances on the surfaces can occur. The acidity of these surfaces will be a result of a complex interplay among many factors, including the amounts of both natural and anthropogenic acidic and non-acidic substances, and the natural acidity and buffering capacity of the surfaces. The concentrations of natural coarse particles will also affect the acidity and, for this reason, a distinction should be made between horizontal and vertical surfaces. 

The intent of this paper is to present a methodology for estimating, from available information on concentrations and deposition velocities, the potential effects of anthropogenically derived acidic substances on indoor surfaces. Surface accumulation rates are derived that are applicable to all types of indoor surfaces. The discussion of the possible effects of the accumulated substances will concentrate on zinc and aluminum surfaces because data exists on the behavior of these metals in indoor environments (0. Aluminum forms a passivating oxide which protects against corrosion in most environments, while zinc is expected to corrode at a roughly linear rate over its lifetime. 

As has been documented in a number of continuing and completed studies, the concentrations of the precursors of acid rain and the concentrations of the acidic substances in wet and dry deposition are quite variable from region to region. The anthropogenically derived particles associated with acid rain are expected to have aerodynamic diameters < 2.5 /nm. Such... 

Particulate pollutants are emitted from many sources. Additionally, particles are formed in the atmosphere by both chemical and physical conversions from natural and anthropogenic gaseous substances. Particulate pollutants cover a size range from <10 nm to >100 pm. The major proportion of the aerosol below 1 pm is generally man-made, including sulfates from SO2 oxidation and carbon from vehicle exhausts, for example. Particles of a greater size are frequently natural (e.g., soil-derived, marine aerosol) but this division cannot be regarded as absolute. 

The ocean is the penultimate repository for most chemical substances, natural and anthropogenic, prior to their incorporation and burial in marine sediments. In spite of an enormous annual input of terrestrially derived chemicals, with respect to many reactive chemical species, the pelagic ocean is a relatively clean environment. This is due, in large part, to the intensity of near-shore sedimentation. This chapter highlights chemical speciation in the vast, and relatively clean, interior region of the ocean. 

Aside from accidents in nuclear facilities (e.g., Chernobyl), the main source of anthropogenic radioactive pollution is probably derived from medical applications. Documented reports of radioactive residue mismanagement indicate that sometimes these substances end up in garbage dumps, with the consequent danger of public exposure. The main radioactive isotopes in medical applications are listed in Table 8.7. 

These substances are appropriate to reflect anthropogenic emissions to natural systems especially in terms of source specifity. On the contrary all contaminants discussed so far are only general indicators of human activities, because they derived from multiple sources. 

Anthropogenic marker compounds are both natural substances derived from human feces or urine and xenobiotics. Apart from information on the emission sources they also provide information on transport pathways and fate of anthropogenic contaminants. In case of undisturbed sedimentation... 

Apart from these obviously biogenic compounds only very few definite anthropogenic substances were identified. Within the group of xenobiotics 2,4 - and 4,4 -dichlorophenylmethane, DDT-derived metabolites, were most abundant. A pyrolytic conversion of related DDT metabolites to DDM cannot be excluded. Thus the occurrence of DDM in the pyrogram is only suggestive for DDT group metabolites in general. 

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