Published online by Cambridge University Press: 15 May 2009
Experiments were carried out in a test chamber of 16,500 cu.ft. capacity with air conditioned at 68° F. and 54% relative humidity. Ventilation was controlled at 3·0 changes/hr., air being recirculated with 0·5 air change/hr. of fresh air admitted. By spraying into the air ducting a concentrated suspension of Chr. prodigiosum a bacterial cloud was introduced into the chamber of over 5 × 106 organisms/cu.ft. of air as l μ particles. Viable organisms were still present in the atmosphere after 6 hr.
When a heat-generated vapour of hexylresorcinol was introduced in a concentration of between 6 and 7 μg/cu.ft. of air the bacterial count dropped from nearly one million organisms per cu.ft. to fewer than ten in 35 min.
When the bacterial suspension was sprayed into the chamber with hexylresorcinol vapour present, the peak concentration reached was about one-quarter and on stopping the spray, the bacterial count fell from one million per cu.ft. to fewer than ten in less than 25 min.
Hexylresorcinol is also effective when the bacterial aerosol is in particles of 6–7 μ in size (approx. 100 bacteria per particle).
Hexylresorcinol has no effect against a bacterial aerosol of B. subtilis spores in 1 μ particles.
No attempt has been made to analyse the mode of action of hexylresorcinol in diminishing the bacterial content of the air. The evidence collected clearly indicates the necessity for further study of this problem.