Measuring performance of a half-mask respirator in a styrene environment

A workplace protection factor (WPF) study was conducted with a half-mask ai r-purifying respirator during fiber glass boat production. Styrene was the measured analyte, and the geometric mean WPF found was 39.7. Analytical det ection limits, sample contamination, and pulmonary elimination from previou s exposures or from skin absorption were identified as important considerat ions that can bias the WPFs measured. There were significant differences in the mean concentrations found inside the respirator when analyzed by time period. An increase in the concentration found inside the facepiece cavity and a decrease in the WPF over time was found for people with three or four measurements. This indicates either a change in performance of the respira tor over time or a bias from low-revel exposures during the day or skin abs orption.