EXPOSURE ASSESSMENT AND HAZARD EVALUATION OF A POLYOXYALKYLENE GLYCOLAEROSOL RELEASED FROM A NON-CFC MOBILE AIR-CONDITIONING SYSTEM

This study was designed to evaluate the potential health hazards resul ting from an unintentional exposure to a polyoxyalkylene glycol (PAG, a lubricant) aerosol from a non-CFC air-conditioning (A/C) refrigerant system. Four scenarios simulating the worst-case exposures to drivers , mechanics, or test engineers were used as test conditions. The time- averaged total airborne particulate concentration over a 20-min period ranged from 0.1 to 42 mg/m(3). In each case the lubricant aerosol had a mass median aerodynamic diameter (MMAD) of 1 mu m (sigma g of 2.3-2 .8). The peak PAG aerosol concentration of 155 mg/m(3) inside an unven ted simulated vehicle cabin was reached 30 sec after a simulated total rupture of the entire A/C refrigerant system into the vehicle compart ment, an extremely unlikely event. However, with ventilation at the '' normal'' A/C setting, peak concentration inside the vehicle cabin was 14 mg/m(3), and background levels were reached in less than 3 min. Alt hough pulmonary toxicity associated with subacute exposure to PAG aero sols has been reported in the literature, a no observable effect level of 5 mg/m(3) was suggested for repeated exposures to the lubricant us ed with non-CFC mobile A/C refrigerants. During simulated normal diagn ostic procedures performed on or near the A/C system, the airborne con centration of PAG aerosols to mechanics was found to be at or below 0. 1 mg/m(3) for only 1-2 min while the vehicle was serviced over an open hood. This exposure scenario is unlikely to cause adverse health effe cts. Thus using low molecular weight PAG and practicing good industria l hygiene will minimize health risks.