An Operational Hygiene Study for Ozone in the Cabin of the Canadian Forces (CC137) Boeing 707 Aircraft

摘要

A study was carried out to determine the concentration of ozone in the cabin of the Boeing 707 (CC137) at altitude on a cross-Canada flight during a seasonal period of high atmospheric ozone. An ozone monitor manufactured by Columbia Scientific Industries (CSI), Austin, Texas was used to measure O3 levels during the study. Prior to actual flight monitoring the analytical measuring equipment was calibrated at ground level and under simulated altitude conditions. Since ideal gas law corrections were not applicable at altitude it was necessary to prepare a correction factor for the CSI ozone meter under hypobaric conditions. In the flight trials, the maximum O3 value obtained during the westerly segment of the flight at an altitude of 39,000 feet, was 135 parts per billion (ppb) and 106 ppb on the return easterly portion of the flight. These values slightly exceed the Threshold Limit Value (TLV) for ozone of 100 ppb. However, they are below the Short Term Exposure Limit (STEL) of 300 ppb. During a similar time period, Atmospheric Environment Services (AES), Environment Canada, measured an ozone concentration of 1670 ppb in the atmosphere at an altitude of 39,370 feet in the Edmonton, Alberta area. A comparison of the maximum cabin concentration obtained during this study with that found externally by AES indicates that the engines of the Boeing 707 were removing greater than 90% of the atmospher ozone prior to its entry into the aircraft cabin. The findings of this study indicate that ancillary ozone removing equipment need not be added to the aircraft. (Author)