The germicidal effect of the open air in different parts of The Netherlands

Abstract

In the absence of ozone the OAF concentration was always low. In the presence of ozone the OAF concentration was dependent on wind direction. At the selected microthread exposure sites air from areas with high traffic intensity contributed more to OAF production than air from industrial areas. OAF production is probably related to the nature of hydrocarbons in the air.

Some factors affecting the airborne survival of bacteria outdoors

“…This was marginally less than 20°C. Escherichia coli strain MRE 162 was grown in tryptone soy broth (TSB) (Lab M) for 18 h at 37°C and subsequently stored at 4°C for up to 4 weeks (de Mik and de Groot 1977). Pseudomonads were grown initially for 24 h to what appeared to be the onset of stationary phase, by examination of growth curves.…”

“…Druett and May (1969) identified a toxic factor which they named 'Open Air Factor' (OAF). OAF was shown to disappear rapidly on enclosure ( Hood 1971( Hood ,1973 and was thought to result from the reaction between ozone and olephins, aerial pollutants arising from car exhausts Harper 1973;de Mik and de Groot 1977). Druett (1973) suggested that it would be likely that the OAF would differ in nature in various geographic locations.…”

“…Studies of survival of Escherichia coli strain MRE 162 were conducted concurrently with those of the test pseudomonad. This strain has been used in many airborne survival studies as it is fairly aerosol-stable indoors but sensitive to OAF de Mik and de Groot 1973, 1977, 1978Cox 1987).…”

An alternative microthread for the study of airborne survival of bacteria outdoors

“…This has been described as the Open Air Factor, or OAF. Further studies by these workers and by Harper (1973) and de Mik and de Groot (1973, 1977, 1978 showed that OAF was formed by the reaction of ozone with olephins produced from unburnt petroleum fumes. This product rapidly decays and is absorbed on to surfaces, so it is effectively destroyed on enclosure unless rapidly ventilated with outdoor air (Hood 1973).…”

“…Preparation of spray suspensions. Pseudomonas maltophifa strain K', a soil isolate, was provided by D r R. Camp- de Mik and de Groot 1973, 1977, 1978Cox 1987). Bacteria were maintained and grown as described by Handley and Webster (1993).…”