This document provides guidance for using the volatilization algorithm in the Pesticide in Water Calculator (PWC). The release of the PWC (Version 1.5) includes additional inputs needed to execute the volatilization algorithm. These include the Diffusion in Air Coefficient, Heat of Henry, and Henry’s Law Constant. Additional volatilization-related outputs are also now available, including pesticide mass distribution within the soil profile and the amount of pesticide lost due to volatilization.

• Guidance for Using the Volatilization Algorithm in the Pesticide in Water Calculator and Water Exposure Models (PDF)(17 pp, 818 K, December 8, 2015)
  This document describes these new additions and provides guidance for assessing pre-emergent and bare soil applications in the PWC with the volatilization algorithm.