Studies on Aerosol (Part 2)

Abstract

In our previous paper on dust aerosol it was pointed out that reconsideration should be given to the present allowable level of atmospheric contamination based on a quantitative evaluation of dust.Following the investigations on dust aerosol in ordinary living environments, bacterial aerosol, especially hemolytic bacteria, was analysed as to its environmental medical significance.The results are summarized as follows:1. There were no correlations among the numbers of dust aerosol (measured with Millipore Filter), bacterial aerosol (with Millipore Filter) and fallen bacteria (by Koch's method).2. The number of hemolytic bacteria in the air was closely related to the number of persons gathered as well as to the cold-epidemic.It is known that hemolytic bacteria is related to humans as a carrier of bacteria in contrast to fallen bacteria by Koch's method. This fact suggests that hemolytic bacteria in the air may be a new useful indicator of atmospheric bacterial contamination in living environment.3. Among the strains of hemolytic bacteria, staphylococcus was observed most frequently, biological characteristics of which were tested with the coagulase reaction and deoxyribonuclease reaction which are understood as being closely related to the pathogenecity of microorganisms.4. In a cold-epidemic, coagulase-positive staphylococci were observed, but rarely in a non-cold epidemic. In contrast, deoxyribonuclease-positive staphylococci were found even in a non-cold epidemic.These results indicate that the deoxyribonuclease reaction may be valuable for determination of the pathogenecity of staphylococci in the air.