Soil-air fluxes of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined using a novel application of passive samplers to measure air and soil air, which is air in close proximity and in equilibrium with soil. Existing methods to measure flux of semi-volatile compounds between soil and air require collecting samples from the top soil layer. Yet, the top soil layer is hard to define and oversampling may misrepresent the exchangeable fraction. Alternatively, modified active samplers can measure soil air in situ, but require electricity while deployed. We present a new method to measure time-weighted averages of soil air concentrations in situ using passive sampling and requiring no electricity: a box is placed over low-density polyethylene passive samplers deployed 1cm above the soil. Passive air samplers were also co-deployed 1.5m above the soil to measure ambient air concentrations in three U.S.
