MUTAGENS IN INDOOR AIR PARTICULATE

Twenty-seven extracts of airborne particulate from domestic environmen ts, both in the absence of sources of pollution and during activities such as smoking tobacco, using a fireplace, and cooking using grills a nd barbecues, and eight control samples of outdoor particulate were te sted using the Salmonella/microsome assay on strains TA98 and TA98NR. Dust levels and mutagenic activity in the indoor environments turned o ut to be very low in the absence of polluting sources, with highest me an values in winter of less than 0.1 mg/m(3) and 6 and 12 revertants/m (3), respectively without and with S9. The specific mutagenic activity of indoor dust ranged from 22 and 137 revertants/mg, with a contribut ion of nitroarene compounds of about 50%, indicating that, in city ind oor air, the main cause of background particulate pollution is very pr obably penetration of traffic fumes from the outside. In contrast, in a country house far from traffic, very low dust and mutagenicity level s were found, without the influence of nitroarene compounds. The prese nce of autochthonous polluting sources, such as tobacco smoke and fume s from cooking and wood or charcoal burning, greatly increased indoor dust levels, especially during cooking operations, which reached 25.5 and 31.6 mg/m(3). The particulate produced by the various indoor pollu tion sources showed varying specific mutagenic activities. The highest values were found for fumes produced by burning charcoal and wood, sm oking tobacco, and cooking foods with high animal protein contents. Mu tagens responsible were mainly direct-acting in the case of fumes from burning wood or charcoal, and required mammalian metabolic activation in the case of fumes from tobacco and meat, with a lower contribution (maximum 33%) of nitroarenes than in urban particulate.