Sulfuryl fluoride (SF) is a colorless, odorless gas primarily used to fumigate sealed structures and their contents to control existing infestations of pests such as drywood termites, powder post beetles, bedbugs, death-watch beetles, rodents, and so on. The California Department of Pesticide Regulation (CDPR) listed SF as a toxic air contaminant and initiated the development of regulatory measures for structural fumigations. The air dispersion model AERMOD is used to simulate and summarize different application scenarios and estimate potential pesticide exposures of fumigation bystanders. AERMOD modeling outputs hourly concentrations with nominal emission rates for 5-year meteorological conditions of surface weather station WBAN 93134. Data analysis on interior air monitoring studies summarizes the distribution of mass loss percentages (MLP) and hourly flux estimations of treatment and aeration periods. All the data are then input to R for post-processing with a Monte Carlo method. As the stochastic variable, total 1826 MLPs are randomly sampled from an estimated distribution for 1826 days of the 5-year period. For each day of the 5-year period, post-processing function extracts 24-hr modeling results starting from the specified emission starting time and pair them with the MLP sampled for that day to estimate corresponding hourly air concentrations. The averages of the 24-hr concentrations are calculated for all receptors on each day and processed to estimate the daily maximum concentrations and also their 95th percentiles over 5 years. This procedure is repeated to generate the distribution of the 95th percentiles of daily maximum concentrations. The mean of the 95th percentiles’ distribution are the final estimate for each application scenario and used for further data analysis.

Estimation of bystander exposure of sulfuryl fluoride during structural fumigations of California detached single family houses

2019 Fall National Meeting

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