Identification and characterization of potentially toxic organic compounds in carpet vacuum and air conditioner filter dusts

Indoor air quality and pollution is partly characterized by the presence of volatile or semi-volatile and potentially toxic organic compounds. Household dust, a common sediment in most indoor sites, and a manifestation of all used air conditioner filters and carpets, may serve as a sink and source of introduced or generated chemical components that are periodically emitted into, or redistributed about, the indoor site. Organic compounds that adhere to household dusts are of a more persistent and less fluctuating nature than previously investigated volatile organics such as formaldehyde or benzene. These compounds may be re-circulated in the indoor atmosphere, and retained in carpet dusts, thus providing opportunity for their inhalation or ingestion by residents. Urban and suburban air conditioner filter and carpet vacuum dusts were assayed for volatile and semi-volatile organic compounds by gas chromatography and mass spectroscopy (GCMS) headspace analysis and by GCMS analysis of microwave, soxhlet and supercritical fluid (SFE) dust extractions. GCFID (flame ionization detection), ECD (electron capture detection), NPD (nitrogen phosphorous detection) and FPD (flame photometric detection) were used for verification of chemical classes. Elemental analysis and dust particle topography and imaging were accomplished with scanning electron microscopy (SEM) and energy dispersive x-ray (EDX-ray) exploration. Headspace analysis revealed C6 through C10 aliphatic aldehydes, and the cyclic aldehydes, 2-furancarboxaldehyde and benzaldehyde as predominant compounds in air conditioner filter and carpet vacuum dusts. Carboxylic acids, phthalates, alkanes and alcohols were the most abundant compounds identified in supercritical fluid, soxhlet and microwave dust extractions. Halogenated, and cyclic compounds identified by GCMS included various chlorinated benzene compounds and limonene. Nicotine was identified in microwave extractions. The insecticides, diazinon and piperonyl butoxide were found in SFE extractions. From this study it is recognized that air conditioner filter and carpet vacuum dusts are definite sources and sinks of indoor air contaminants. Most compounds identified in this study are of semi-volatile nature and singularly maintain low orders of toxicity, however, it is the toxic effects of combined compounds over long exposure periods that is of greatest concern regarding adverse health effects of indoor pollutants. Future studies are projected regarding toxicity testing for identified dust compound mixtures.