INDOOR OUTDOOR CONCENTRATIONS AND CORRELATIONS OF PM10-ASSOCIATED MUTAGENIC ACTIVITY IN NONSMOKERS AND ASTHMATICS HOMES

The indoor-outdoor relations of mutagenic compounds associated with ai rborne particles less than 10-mum aerodynamic diameter (PMIO) were stu died in the homes of 10 nonsmokers located in southern California. Ast hmatics lived in nine of the 10 homes studied. Low-volume samplers (4 and 2 L/min) fitted with PM10 and cyclone (5-mum nominal particle size cut) particle preselectros were used to collect 24-h air samples indo ors and outdoors. In addition, three individuals carried personal samp lers for 24-h periods. Filter extracts were tested for mutagenicity us ing a sensitive Salmonella microsuspension assay. The concentrations o f particle-associated mutagens were significantly higher outdoors comp ared to indoors. For the PM10- and cyclone-collected samples, indoor-o utdoor ratios averaged 0.46 and 0.49, respectively. There were signifi cant correlations between indoor and outdoor mutagenicity (revertants/ m3) for all samples (Spearman rank, R(s) = 0.74; n = 25 pairs; p < 0.0 01). Further, the indoor and outdoor correlation of specific-mass muta genic activity [revertants per unit particle mass (revertants/mug)] wa s highly significant [p < 0.001; R(s) = 0.90 (n = 25 pairs)]. The muta genic activity of personal samples was very similar to the fixed-site samples collected indoors. The results support the hypothesis that mut agen composition of the indoor and outdoor particles are similar and t hat outdoor particles which infiltrate into homes may be a significant source of respirable mutagenic particles in the homes of nonsmokers.