Abstract
Discrepancies arise when sampling mineral oil mist using a glass fiber filter, a polyvinyl chloride filter, a polytetrafluoroethylene filter, an electrostatic precipitator, and two light-scattering devices. Most gravimetric methods show discrepancies because mist droplets, which have a high surface area, evaporate from the filters during sampling. Inconsistencies occur with light-scattering devices because these instruments are sensitive to particle size distributions, shapes, and refractive indices. Results from laboratory and field experiments show that concentrations measured using these methods vary by factors of two to five. Discrepancies were greatest when oil mist concentrations were relatively low.