Polycyclic aromatic hydrocarbons in residential air of ten Chicago area homes: Concentrations and influencing factors

Indoor and outdoor air samples at 10 non-smoker homes in the Chicago area were concurrently collected once per month for a 14-month period starting June 2000. During each sampling event, temperature, humidity, CO2, and CO were recorded. Questionnaires were used to register household activities. For each sample, 16 polycyclic aromatic hydrocarbons (PAHs) were measured using gas chromatograph and mass spectrometer (GC/MS). The total concentration of the 16 PAHs (Sigma PAHs) ranged from 13 to 2454 ng m(-3) in the indoor air and from 13 to 1865 ng m-3 in the outdoor air. In most cases, the concentrations were found to be log-normally distributed. The sum of PAHs with molecular mass <= 202 (Sigma Light-PAHs, excluding naphthalene and anthracene) were found to behave differently than the sum of those with molecular mass >= 228 (Sigma Heavy-PAHs). Variations among seasons were significant for indoor Sigma Light-PAHs, and temperature was found to positively correlate with indoor Sigma Light-PAHs for nine of the 10 homes. For Sigma Heavy-PAHs, the outdoor concentrations were found to be significantly higher in the fall and winter seasons than in the summer. The correlations of indoor and outdoor concentrations appear to be weak for light PAHs, but reasonably strong for heavy PAHs. The medians of indoor-to-outdoor ratio (I/O) are less than or very close to I for all PAHs except anthracene. The indoor concentrations of Sigma PAHs tend to be higher as the age of the houses increases, and the surrounding industrial pollution was found to have impact on outdoor Sigma Heavy-PAHs. For light PAHs indoors, comparison among homes indicates that the impact of house characteristics and indoor activities tends to be greater than the influence of the penetrating outdoor air. (c) 2005 Elsevier Ltd. All rights reserved.