Characterisation of CS Aerosol used in Mask Test Facilities

CS aerosol (o-chlorobenzylidene malonitrile) is a low to moderate toxicity irritant used by Australian Defence Force for respiratory protection training. It is classified as a hazardous substance with an occupational exposure limit of 0.39 mg/m3 (STEL-C). Currently the ADF has no means of measuring the concentration of CS aerosol used within the Mask Test Facilities (MTF) during CBRN training. Driven by the health concern associated with CS exposure to personnel in MTF, this study aimed to: (i) characterise the physico-chemical properties of CS aerosol; (ii) validate the use of a commercial off-the-shelf equipment to monitor CS aerosol concentrations, and (iii) quantify CS levels in MTF. The CS aerosol was identified as a poly-disperse, uni-modal aerosol with a dominant peak at 0.26 micrometers. The COTS optical photometer DustTrak, (TSI Inc Model 8520) was validated to accurately measure CS aerosol concentration. As anticipated, the CS levels in the MTF exceeded the concentrations that unprotected individuals could safely operate in by a factor of up to 40. However, protected individuals wearing a correctly fitted full face respirator are in compliance with the OH&S standards for respiratory protection.