ABSTRACT
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References .................................................................................................................................... 175
Metals have long been recognized as toxic components of particles found in occupational settings.
There are a number of well-characterized pathological entities caused by the inhalation of particles
of specific metallic compounds (Table 8.1). While no single physicochemical property has emerged
as the common etiological factor, a substantial body of work carried out over the last decade
supports a role for metals in the toxicity of ambient air pollution. Epidemiological studies have
correlated health outcomes with the content of specific metallic components in a particle. Studies
on Utah Valley particulate matter (PM) suggest that soluble ions of Cu, V, and Zn participate in its
biological effects (Kennedy et al. 1998). Metal depletion and reconstitution experiments strengthen
these findings and provide some insight on the speciation of the metals involved, pointing to soluble
metal salts rather than insoluble oxides. A series of studies using the fugitive emission PM residual
oil fly ash (ROFA) as a model particle has also yielded a significant amount of information
demonstrating the biological effects of PM metal compounds. ROFA can be distinguished from
other combustion PM by its high content of V, which has been demonstrated to be the major, but not
sole, contributor to its toxicity.
