The inhalable aerosol sampling criterion has been developed to characterize the efficiency of particles entering the nose and/or mouth. However, pesticides can exist in the air in both vapor and particulate phases, which complicates exposure assessments. The American Conference of Governmental Industrial Hygienists (ACGIH) has established an IFV (inhalable fraction and vapor) endnote for chemicals such as many pesticides that need to be evaluated for both their inhalable fraction and vapor concentrations to fully characterize worker exposures. The purpose of this study was to evaluate the particle-phase collection efficiency of a commonly-used pesticide sampler, the OSHA Versatile Sampler (OVS) as well as a recently developed sampler, the IFV Pro. The OVS was not designed as an inhalable aerosol sampler, whereas the IFV Pro contains a sampling head scaled to that of the Institute of Medicine (IOM) sampler, which is known to closely follow the inhalable sampling criterion. Laboratory experiments involving a vertical-flow, low-velocity scheme, and finely graded test dusts with known median aerodynamic diameter were used to determine sampler collection efficiencies. The collection efficiency of the OVS was evaluated as recommended by the manufacturer and after two modifications made to potentially improve its collection efficiency. The OVS was found to substantially under-sample relative to the inhalable criterion, and the two modifications did not provide substantial improvements to the original configuration. Conversely, the collection efficiency of the IFV Pro was found to compare closely to that of the IOM, although collecting 9% more mass. When applied side-by-side with the OVS sampler in a chamber into which ethylene glycol was sprayed as a proxy for a pesticide, the IFV Pro collected an average of 1.9-fold more mass than the OVS for the same flow rate and sample time.
Keywords: Efficiency; inhalable; pesticides; samplers.