GSS (Gas Sensitive Semi-Conductor) Technology Introduction

A Nalgene box (30•30•17.5 cm, ~1 cm wall thickness, volume ~12 litres) was used to investigate the Aeroqual S500 (A500) at ozone mixing ratios above ambient levels. The A500 was enclosed in the box with its inlet sampling the same volume as the Thermo Electron TEI49C photometer, via 1 metre of 0.25" Teflon lined Tygon tube. Ozone was generated by the DEC5008 ozone generator and added to the box in a 5slm flow of 4:1 N2:O2. This flow was mixed with a humidified (~85% RH.) 2 slm flow of N2, leading to a relative humidity of ~20% and an oxygen mixing ratio of 0.14 within the box. A relative humidity of > 5% is necessary for the A500 to function. Reducing the relative humidity in the box to 10% did not affect the A500 readings.