Correlating Agricultural Use with Ambient Concentration of Fumigant Chloropicrin During the Period of 2011-2014
Abstract
The Department of Pesticide Regulation’s (DPR) Air Monitoring Network (AMN) collected a 24-hour sample each week to measure airborne concentrations of the fumigant chloropicrin in three California communities during the period of 2011-2014. DPR also collected pesticide use information through the pesticide use report (PUR) database during this same time period. Availability of these two datasets allowed for the use of linear regression to relate ambient chloropicrin concentration to the location, timing, and amount of chloropicrin use in these three California communities.
Overall, we found evidence of a moderate, positive relationship between chloropicrin use and ambient concentration on an acute (24-hour) basis. Acute ambient concentrations were best predicted by use in a 4-mile radius surrounding the monitoring station in the 24-48 hours prior to the beginning of each air sample. A low count of positive and quantifiable detections during most years of monitoring restricted the analysis to data obtained from the Salinas monitoring station between the period of 2013-2014. The strength of the relationship varied by year and there appeared to be other important factors exhibiting influence on monitoring results. Large standard errors in the regression suggest that the results are not precise enough to accurately estimate acute air concentrations based on nearby applications alone.