A comparison study between passive and active workplace personal air monitoring techniques for airborne isopropyl alcohol concentrations

This research project involved a comparison between the performance of active and passive sampling methods used to collect isopropyl alcohol vapor in an industrial setting. This field experiment was conducted in a real-world industry setting with workers exposed to isopropyl alcohol. In order to create sample sets, passive diffusive samplers (3M 3520 Organic Vapor Monitor) were paired, side-by-side, with active samplers (charcoal solid sorbent tubes). A total of 17 paired sample sets were collected, which yielded data with a non-parametric distribution. Post hoc analysis showed that 4 of the 17 paired sample sets were potential outliers. A Wilcoxon signed-rank test showed that the passive samplers were significantly different from the active air samples (alpha = 0.05), regardless whether or not the potential outliers were included or excluded from the data. A linear regression analysis found a linear relationship between active and passive sampling results. An R2 value of 0.97 (when including potential outliers) and 0.79 (when excluding potential outliers) suggests that the model fits well with the data. Satisfactory correlation between the samplers was found when including potential outliers (r = 0.9859) and excluding potential outliers (r = 0.8863). The passive samplers reported higher concentrations than the active samplers in 15 of the 17 sample sets. On average, the passive samplers reported 25% higher results when including potential outliers and 16% higher results when excluding potential outliers when compared to the paired active sampling results. Based on the strong correlation values and the trend of passive samplers reporting higher results than the active samplers, occupational health specialists could reliably use the passive samplers in this study to demonstrate compliance to isopropyl alcohol exposure limits.