Antagonistic Action of Oil Mists on Air Pollutants

While simultaneous exposure to oxidant (O/sub 3/ or NO/sub 2/) and oil mist resulted in moderate intensification of toxicity to mice, a latent period following oil exposure and prior to oxidant exposure reduced acute lethal effects. Maximum protecton was observed after 18 hr, persisting for several days but gone after 8 to 9 days. Effective particle size range was between 0.5 and 1.2 ..mu..m. Minimal effective concentration was approx. 3 ppM for 6 hr or 1 ppM for 17 hr (concentration-times-time relation). Mineral oil was more effective than motor oil. Oil mists did not affect development of O/sub 3/ tolerance. O/sub 3/ concentrations studied were in the 5 to 7 ppM range; NO/sub 2/ concentrations approximated 70 to 90 ppM. It is postulated that oil mists form a surface barrier to O/sub 3/ and NO/sub 2/ while allowing O/sub 2/ and CO/sub 2/ to pass because of their higher partial pressures.