Spatial and seasonal variations of polycyclic aromatic hydrocarbons in Haihe Plain, China

A dynamic fugacity model was developed to simulate the spatial and seasonal variations of PAHs in Haihe Plain, China. The calculated and measured concentrations exhibited good consistency in magnitude with deviations within a factor of 4 in air and 2 in soil. The spatial distributions of PAHs in air were mainly controlled by emission while the seasonal variations were dominated by emission and gas–particle partition. In soil, the spatial distributions of PAHs were controlled by the soil organic carbon content while the seasonal variations were insignificant. The severest soil contamination was observed in Shanxi and followed by the southwest of Hebei province. Transfer fluxes of total PAHs between air and soil were calculated. The spatial distribution of air-to-soil flux was closely related to the landcover while the soil-to-air flux changed with soil organic matter content. Monte Carlo simulation was done to evaluate the uncertainty of the estimated results in air.

► A Level IV dynamic model with spatial resolution was developed.
► The model was applied to address the fate of PAHs in Haihe Plain, China.
► The severest soil contamination was observed in Shanxi and followed by the southwest of Hebei province.
► The air-to-soil flux was closely related to the landcover while the soil-to-air flux changed with soil organic matter content.
► The model results proved to have less uncertainty than regular level IV model without spatial resolution.