31 Green Road        Hillarys WA 6025        Tel. 61-8-9401 5699        Fax. 61-8-9401 5900      A/h:61-8-92951767      Mobile: 041 429 5176      Email: promicro@cygnus.liwa.edu.au  16 February 1999  Airpure  PO Box 1150  Osborne Park  Perth, WA 6017  Dear Bruce,  RE: MEASUREMENT OF OZONE  The experiment outfit of ozone from different machines was conducted in an enclosed room Measuring 2.5 x 8.5 metres. Estimation of the Ozone absorbed was carried out by Analytical Reference Laboratories – Analyst Adam His Cox. Four samples of each were measured using Flow rate of 1 litre perminute;  Results  Breeze -  average absorption of Ozone = .75 ug/45 minute;   ie 0.04 mgms/m or 0.02 ppm Cyclone- average absorption of Ozone = 3ug/45 minute;  ie 0.07 mgm/m or 0.035 ppm Hurricane- NB measurement carried out over 15 minutes Average absorption of Ozone = 10ug/45 minutes ie 0.02 mgms/m or 0.087 ppm TWA – Time weighed average ie The average airborne concentration of a substance when calculated over a normal eight-hour working day for a five-day working week is 0.2 mgm/m or 0.1 ppm. STEL – Short tern exposure limit Ic means a 15 minute TWA exposure which should not be exceeded at any time during a working day even if the right low TWA exposure standard 0.2 mgm/m or 0.1 ppm. Your Faithfully Ed Reed CONSULTANT MICROBIOLIGIST