A field comparison of ethylene vinyl acetate and low-density polyethylene thin films for equilibrium phase passive air sampling of polycyclic aromatic hydrocarbons

摘要

Ethylene vinyl acetate (EVA) and low-density polyethylene (LDPE) were compared as thin film polymer passive air samplers for polycyclic aromatic hydrocarbons (PAHs). These samplers were co-deployed for periods of up to 27 days at an urban field site in Brisbane. Despite demonstrated air side resistance to mass transfer, sampling rate ratios indicate rapid accumulation kinetics for EVA compared with LDPE. Confirming theoretically predicted values, sampler-air partition coefficients were greater for EVA as compared with LDPE. The relatively high capacity of EVA films may be an advantage in terms of sensitivity, when film thickness and hence amounts accumulated at equilibrium, are low.rnPredictions of times to effective equilibrium (t_(eq) (95%)) were made for a nominal film thickness of 1 μm. These predictions indicate that both types of films would be effective equilibrium phase samplers for predominantly vapour phase PAHs with log octanol-air partition coefficients (log K_(OA)) values of ≤ 8.7 (pyrene). Despite comparatively rapid linear stage kinetics for EVA, the predicted times to effective equilibrium for PAHs are less for LDPE. This arises due to the relative magnitude of their respective K_(SA) values. The predicted times to equilibrium (25 ℃) for pyrene for example are approximately 94 and 34 days for EVA and LDPE, respectively.