Relationship between polycyclic aromatic hydrocarbons measured in dust collected inside cars and from ambient air.

Polycyclic aromatic hydrocarbons (PAH) are organic compounds with a high capacity for bioaccumulation and carcinogenic and mutagenic effects on human health. They can exist in both outdoor and indoor air. Indoors, except in the air, they can be bound to dust particles, and human intake occurs not only by inhalation but also by ingestion and dermal absorption of dust. Therefore, dust is an important source of human exposure to indoor carcinogenic contaminants. The aim of this research was to determine the contribution of individual PAHs in the total amounts of PAHs (ΣPAH) in dust collected inside cars and compare those concentrations with PAH concentrations and profiles in ambient air. Data on PAH concentrations in dust from the interior of 22 cars with diesel or gasoline engines was compared with the ambient concentration of PAHs bound to the PM10 particle fraction. The total concentration of 11 PAHs (Σ11PAH) in dust ranged from 0.39 µg g-1 to 12.1 µg g-1. Spearman correlation analysis revealed significant positive correlations (p < 0.05) between benzo(a)anthracene (BaA), chrysene (Chry), benzo(k)fluoranthene (BkF), and dibenzo(ah)anthracene (DahA) concentration in dust and ambient air. These PAHs are specific to diesel and gasoline combustion and originate from vehicle exhaust. The highest contribution in dust samples came from pyrene (Pyr) (26%), fluoranthene (Flu) (18%), and benzo(ghi)perylene (BghiP) (14%), while in ambient air samples, the highest contribution was from benzo(b)fluoranthene (BbF) (16%), BghiP (13%) and indeno(1,2,3-cd)pyrene (IP) (15%). The contribution of benzo(a)pyrene (BaP) in total PAHs was 6% and 10% in dust and ambient air, respectively, while for other PAHs below 5% in dust samples and below 10% in particles. This study has shown that passengers in cars may be exposed to elevated levels of PAHs, but that the contribution of the most toxic PAHs (BaP and DahA) in car dust is lower than that of other PAHs.