THE DEPOSITION OF SELECTED POLLUTANTS ADJACENT TO A MAJOR RURAL HIGHWAY

Deposition fluxes of Pb, Cd and Cu, the organic compounds of lead and eight polycyclic aromatic hydrocarbon (PAH) compounds have been measured over a period of 1 year at distances up to 50 m from a major rural highway in northwest England. A rapid decline in deposition fluxes with distance from the road edge was observed, with background fluxes seen at 50 m. Dry deposition velocities in the range 0.1-1.0 cm s-1 and washout ratios in the range 24-129 were seen for the three metals. It is estimated that 13.7% of the Pb, 11.8% of the organic lead and 4.6% of the total PAH emitted by vehicles on the highway are deposited on the central reservation or within 50 m of the carriageway.