Mist concentration measurements. II: Laboratory and field evaluations.

Area of Science:

• Occupational Health
• Industrial Hygiene
• Aerosol Science

Background:

• Occupational exposure to metalworking fluid (MWF) mists requires accurate monitoring.
• Current sampling methods, including light-scattering devices and gravimetric filters, are known to be susceptible to various biases.
• Understanding these biases is crucial for reliable exposure assessment in industrial settings.

Purpose of the Study:

• To evaluate the performance of different sampling methods for metalworking fluid (MWF) mists.
• To compare light-scattering devices, electrostatic precipitators, and filters with gravimetric analysis under laboratory and field conditions.
• To identify and quantify biases associated with each method in measuring MWF mist exposure.

Main Methods:

• Laboratory and field testing of MWF mist sampling techniques.
• Inclusion of two light-scattering devices, an electrostatic precipitator, and filters for gravimetric analysis.
• Utilized soluble oil, straight oil, and semi-synthetic MWF formulations in tests.

Main Results:

• Significant evaporative losses were observed from filters, particularly with semi-volatile components.
• Light-scattering devices showed size-dependent bias, overestimating concentrations for particles <2 microns and underestimating for larger particles.
• Filters were found to underestimate occupational exposures when semi-volatile components were present in MWF mists.

Conclusions:

• Standard sampling methods for metalworking fluid (MWF) mist can introduce significant bias.
• Evaporative losses from filters and particle size sensitivity of light-scattering devices impact exposure assessment accuracy.
• Improved or alternative sampling strategies are needed for reliable occupational exposure monitoring of MWF mists.