Effects of wind and air trajectory directions on atmospheric concentrations of persistent organic pollutants near the Great Lakes.

Three different regression models involving air temperature, time, and either wind direction or parametric or nonparametric air trajectory direction were used with concentrations of four representative persistent organic pollutants to quantitate the atmospheric transport of these compounds to the Great Lakes. The local wind and parametric trajectory models predicted an optimal source direction for each compound, whereas the nonparametric trajectory model was based on a hypothesized source region. All three regressions were used to calculate the factor by which the partial pressures of each compound measured at five sampling sites increased when the air came from a particular source direction. Dieldrin, chlordane, polychlorinated biphenyl, and polycyclic aromatic hydrocarbon partial pressures were used with each of these regressions, and the correlation coefficients (r2) were evaluated for each model, for each compound, and for each regression term. In general, with the exception of polycyclic aromatic hydrocarbons at some sites, the explanatory powers of the regressions were not improved by the inclusion of any of these directional terms.