Relationships Between Inhalable, Thoracic, and Respirable Aerosols of Metalworking Fluids

Abstract

The aim of the study described in this companion paper was to assesses relationships among inhalable, thoracic, and respirable aerosol fractions of metalworking fluids. A RespiCon sampler, which simultaneously collects all three fractions, was used at four Ontario plants to collect 37 samples of 120 to 400 min duration. The ratios of the slopes of the lines of a regression model forced through the origin between inhalable and thoracic, inhalable and respirable, and thoracic and respirable were 1.38, 1.51, and 1.13, respectively. These ratios would be useful in assessing metalworking fluid airborne exposure data based on different aerosol fractions and for interpreting occupational exposure standards based on different fractions.

Keywords:

• aerosol
• exposure limits
• inhalable
• metalworking fluids
• respirable
• thoracic
• total aerosol

ACKNOWLEDGMENTS

This project was funded by a research grant provided by the Workplace Safety and Insurance Board of Ontario. I am grateful to the managements, unions, joint occupational health and safety committees, and workers at the companies who participated in the study. I also thank Don Shaw, Jim Julian, and Karen des Tombe for their help.

Notes

^A Two-sided t-test where the Slope = 1.

^A Based on slope of regression.

^B Based on average of ratios.

^C There were 37 samples from which each of three fractions were obtained.

^A Standards have been converted based on conversion factor of 1.4 = inhalable/thoracic.