Corrosivity patterns near a de-iced highway and a salt-water body were studied with wire-on-bolt coupons and simulations of the airflow. De-iced highways in the winter produce zones where the corrosivity is as high as that near a salt-water body and extend beyond 150 m from the road edge. In a study of the effects of wind sheltering, there was a 34-fold difference in corrosivity between the most wind-protected and the least wind-protected site even though each set was exposed to the same relative humidity. This is consistent with the concept that atmospheric corrosion rates in marineequivalent environments depend primarily on salt aerosol deposition rates, which in turn depend on local wind velocity and turbulence patterns. At the salt-water body site, there was a seasonal trend to the corrosivity with a three-fold difference between the maximum in December and the minimum in July. The seasonal trend in corrosivity correlated with the seasonal trend in the monthly average relative humidity. The corrosivity pattern around two buildings near the salt-water body was quite non-uniform due to differences in wind speeds.