Tuesday, November 14, 2006 - 9:30 AM
146-1

Pesticide VOC Emissions as an Agricultural Air Quality Concern: Predicting Emissions to the Atmosphere.

Scott Yates, USDA-ARS, U.S. Salinity Lab, 450 W. Big Springs Rd., Riverside, CA 92507-4617

Pesticides are widely used for crop production, which significantly benefits public health.  However, recent studies have shown that the use of pesticides can contribute to both atmospheric and water contamination.  Pesticide movement in the soil zone and volatilization to the atmosphere is affected by many interrelated factors such as pesticide application methods, soil and environmental conditions, chemical properties and water management practices.  Volatilization leads to increases in exposure to potentially toxic chemicals and increases the VOC content of the atmosphere.  The USEPA has recently established a new 8-hour ozone standard that requires state regulators to develop and submit plans to reduce near surface ozone in non-attainment areas.  The new standard may lead to restrictions being placed on pesticide use, or require expensive reformulation of pesticide products. The purpose of this presentation is to provide an overview of some of the regulatory issues facing the use of agricultural VOC (i.e., pesticides) in non-attainment areas and to describe current research efforts to improve the prediction of emissions to the atmosphere.  Emissions of an herbicide, triallate, from a 0.2 ha field were measured using micrometeorological and flux chamber methods.  Several simulations were conducted to determine the accuracy of methods for characterizing the volatilization boundary condition. The goal of the study was to develop new and improved methodology that will help to protect the environment and allow the continued use of these important chemicals in agriculture.