The total fluxes of ∑16PAH due to dermal contact (0.2–50 ng day–1 of BaPeq, out of which ∼99% was attributed to the uptake of gaseous PAHs) were comparable to or larger than those via inhalation (2.8–26 ng day–1 of BaPeq) (Table 2), similar to what was reported previously.(24) Furthermore, light and thin cloths are expected to provide negligible resistance to the transport of gaseous organic compounds from air to skin,(22) further emphasizing the possibility of dermal exposure in warmer months. Uncertainty analyses indicated that the transdermal permeability coefficient (kp_g) had the greatest contribution (>83%) to the total variance of transdermal fluxes. Apparently, additional research is warranted because there are limited measured values of kp_g available in the literature.(34)
Table 2
Daily Exposure (BaP equivalent (BaPeq) dosage, ng day–1) via Dermal Contact, Inhalation, and Stall Food Consumption by Adult Consumersa
In fact, dermal exposure from air is common in occupational exposure scenarios(35-38) yet is largely overlooked as a pathway for human exposure to semivolatile organic compounds, with only a few assessments done in indoor microenvironments.(24, 39) Previous studies found that levels of aromatics and some PAHs and their metabolites were significantly elevated in urinary samples of firefighters post-firefighting.(40, 41) Because firefighters’ protective gear was effective in blocking external inhalation exposures during firefighting, higher levels of PAH metabolites post-firefighting suggested that dermal contact was the main input route of airborne pollutants in the firefighters. Consequently, human exposure to outdoor air pollutants, e.g., charcoal-grilled-barbeque fumes, for extended time durations may substantially increase the possibility of dermal contact as a major route of air-pollutant intake.