Office of Aerospace Medicine Technical Reports
FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-80/16
Title and Subtitle: Effects of long-term exposure to low levels of ozone: A review
Report Date: September 1980
Authors: Melton CE
Abstract: Available literature regarding long-term effects of ozone on animals and humans is reviewed. Emphasis is placed on reports that have appeared since 1976, but some earlier reports are cited for completeness and perspective. This review shows that ozone concentration is more important than is duration of exposure in determining the effectiveness of an ozone exposure (dose).
This conclusion calls into question the validity of the Time-Weighted Average (TWA) as an index of severity of ozone exposure. The literature review further reveals that there is wide variation in susceptibility of different animal species to ozone, making it difficult to apply results of animal experiments to humans. It further appears that a dose of ozone that is acutely innocuous is also innocuous over the long term.
The effects of a symptom-producing dose of ozone are initially cumulative for the first two or three exposures, then an adaptive response may ensue that involves a plateau of response or even a reversal. These effects are shown by both animals and humans. The mechanisms are unknown. Ozone probably causes damage by free radical formation. Free radical scavengers such as vitamins E and C may provide protection against ozone damage.
Key Words: Ozone toxicity, Chronic effects of ozone, Ozone in aviation
No. of Pages: 14
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-80/16
Title and Subtitle: Effects of long-term exposure to low levels of ozone: A review
Report Date: September 1980
Authors: Melton CE
Abstract: Available literature regarding long-term effects of ozone on animals and humans is reviewed. Emphasis is placed on reports that have appeared since 1976, but some earlier reports are cited for completeness and perspective. This review shows that ozone concentration is more important than is duration of exposure in determining the effectiveness of an ozone exposure (dose).
This conclusion calls into question the validity of the Time-Weighted Average (TWA) as an index of severity of ozone exposure. The literature review further reveals that there is wide variation in susceptibility of different animal species to ozone, making it difficult to apply results of animal experiments to humans. It further appears that a dose of ozone that is acutely innocuous is also innocuous over the long term.
The effects of a symptom-producing dose of ozone are initially cumulative for the first two or three exposures, then an adaptive response may ensue that involves a plateau of response or even a reversal. These effects are shown by both animals and humans. The mechanisms are unknown. Ozone probably causes damage by free radical formation. Free radical scavengers such as vitamins E and C may provide protection against ozone damage.
Key Words: Ozone toxicity, Chronic effects of ozone, Ozone in aviation
No. of Pages: 14
Last updated: Friday, June 1, 2012