Comparative toxicity of various ozonized olefins to bacteria suspended in air.

Air containing olefin vapour was treated with known amounts of ozone simulating natural concentrations. The bactericidal effect of the mixture was tested using microthreads sprayed with washed cultures of Escherichia coli var. communis or Micrococcus albus, aerosol strain. With 20 different olefins a wide range of activity was found, those in which the double bond formed part of a ring being the most bactericidal; petrol vapour was about as active as the average open-chain olefin. The two organisms behaved similarly at the experimental relative humidity of 80%. The estimated amount of bactericidal substance present was only about one hundredth of that required to give the same kill with a ;conventional' air disinfectant; a simple physical explanation is proposed for this enhanced effect.