Metalworking fluid-related aerosols in machining plants.

TLDR: Most workstations respected the suggested minimum values for fluid mist and showed low concentrations of airborne endotoxin, culturable microorganisms and inhalable dust despite fluid contamination, even when air exchange rates were below the recommendations.

Abstract: Respiratory problems are observed in machinists using soluble metalworking fluid (MWF). Evidences suggest that these problems could be related to the aerosolized microorganisms and their byproducts from MWF. To establish MWF aerosol exposure thresholds and to better understand their effect on human health, these aerosols must be fully characterized. This article evaluates airborne microorganisms and aerosols from soluble MWF in the working environment. Air quality parameters (endotoxin levels, culturable airborne microorganisms, fluid mist, inhalable dust and air exchange rates) were evaluated at 44 sites, in 25 shops in Quebec, Canada. Microorganism concentrations were also measured in MWF. Culturable airborne bacteria concentrations were low, ranging from 1.2 × 101 to 1.5 × 103 CFU (colony forming units) m− 3, even for metalworking fluid highly contaminated by bacteria (up to 2.4 × 109 CFU mL− 1). Inhalable dust varied between < 0.1 to 2.6 mg m− 3, while air exchange rates were mostly below the standard...