Predicting pesticide emissions and downwind concentrations using correlations with estimated vapor pressures

Pesticide emissions to air have been shown to correlate with compound vapor pressure values taken from the published literature. In the present study, emissions correlations based on vapor pressures derived from chemical prop erty estimation methods are formulated and compared with correlations based on the literature data. Comparison was made by using the two types of corr elations to estimate emission rates for five herbicides, a fungicide, and a n insecticide, for which field-measured emission rates from treated soil, f oliage, and water were available. In addition, downwind concentrations were estimated for two herbicides, three fungicides, four insecticides, and two fumigants, for which concentration measurements had been made near treated sources. The comparison results demonstrated that correlations based on va por pressures derived from chemical property estimation methods were essent ially equivalent to correlations based on literature data. The estimation a pproach for vapor pressures is a viable alternative to the inherently more subjective process of selecting literature values.