Effects of Filter Type on the Organic Composition and Mutagenicity of Inhalable Particulate Matter

Paired daily samples of inhalable (D ₅₀ = 15 μm) particulate matter collected on fiberglass filters and on Teflon-coated fiberglass filters were sequentially extracted with cyclohexane, dichloromethane, and finally acetone. The two filter types were compared with respect to the apparent concentrations of the three organic-soluble fractions, organic and inorganic species in the fractions, and the mutagenic activity of the fractions in the Aines assay. Only minor compositional differences were observed between the nonpolar (cyclohexane-soluble) fractions collected on the two filter types. However, significant differences between the two filter types were observed for the more polar organic fractions. The apparent concentrations of the dichloromethane- (DCM) and acetone-soluble (ACE) fractions were higher for samples collected on the Teflon-coated filters; alkylating and acylating agents in the ACE fraction were also higher for this filter medium. Mutagenic activity was generally higher for DCM extracts of samples collected on the Teflon-coated fiberglass filter. With the polar ACE fractions, mutagenic activity (± S-9) was 40%-375% greater for the fiberglass filter with bacterial strains TA-98 and TA-1537 while the reverse pattern was observed with strain TA-100. Compositional differences in the ACE extracts from the two filter types were observed but their relationship to the differences in the mutagenic activity is not clear.