Atmospheric Dispersion of Vapors: Are Molecular Properties Unimportant?

Abstract

Vapor profiles of pesticide mixtures over fallow agricultural fields reveal consistent rapid shifts in the relative proportions of the components in air. These relative concentration changes are correlated with molecular weight and size and reveal a significant molecular contribution to dispersion in turbulent air. Atmospheric studies that rely upon tracer gases, or use calculations that assume the equality of eddy dispersion coefficients, may be in serious error.