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Ozone
Levels and Their Effects
OZONE LEVELS AND THEIR EFFECTS
Data from IOA
Edited by Den (Zdenek) Rasplicka - Ozone Services
ppm = Parts per million volume air
concentration
0.001 ppm
Lowest value detectable by hypersensitive humans. Too low to measure
accurately with elaborate electronic equipment.
0.003 ppm
Threshold of odor perception in laboratory environment, 50 per cent
confidence level.
0.003 ppm to 0.010 ppm
The threshold of odor perception by the average person in clean air. Readily
detectable by most normal persons. These concentrations can be measured with
fair accuracy. Ozone levels measured in typical residences and offices
equipped with a properly operating electronic air cleaner when outdoor ozone
level is low. Infiltrating outdoor ozone could cause higher indoor
concentrations.
0.020 ppm
Threshold of odor perception in laboratory environment, 90 per cent
confidence level.
0.001 to 0.125 ppm
Typical ozone concentrations found in the natural atmosphere. These levels
of concentration vary with altitude, atmospheric conditions and locale.
0.020 to 0.040 ppm
Representative average total oxidant concentrations in some major cities in
1964. Approximately 95 per cent or greater of these oxidants are generally
accepted to be ozone.
0.040 ppm
CSA maximum limit for devices for household use. Measured as sustained
concentration in test room.
0.050 ppm
Maximum allowable ozone concentration recommended by ASHRAE in an air
conditioned and ventilated space.
0.050 ppm
Maximum ozone concentration produced by electronic air cleaners and similar
residential devices according to the proposed amendment of the Federal Food,
Drug and Cosmetic Act.
==============================================
EcoQuest Air Purification Systems are
designed to operate at less than .050 ppm
Higher levels of exposure are presented below
for educational purposes
0.064 ppm
Proposed national ambient air quality standards for photochemical oxidants
(maximum 1 hour concentration not to be exceeded more than once per year).
0.100 ppm
The maximum allowable ozone concentration in industrial working areas:
permissible human exposure - 8 hours per day, 6 days a week.
0.100 ppm
Continuous maximum ozone concentration allowable (per U.S. Navy_ in confined
quarters such as atomic submarines.
0.100 ppm
Maximum allowable limit for industrial, public, or occupied spaces in
England, Japan, France, the Netherlands and Germany.
0.15 to 0.51 ppm
Typical peak concentrations in American cities.
0.200 ppm
Prolonged exposure of humans under occupational and experimental conditions
produced no apparent ill effects. The threshold level at which nasal and
throat irritation will result appears to be about 0.300 ppm.
0.300 ppm
The ozone level at which some species of plant life began to show signs of
ozone effects. Foliage injury appears as dark stipples, light flecks, dead
patches and general discoloration. The stomata (pores) of adult leaves are
the first areas to show signs of damage.
0.500 ppm
The ozone level at which Los Angeles, California, declares its Smog Alert
No. 1. Can cause nausea and headaches in some individuals. Extended exposure
could cause lung edema (an abnormal accumulation of serous fluid in
connective tissue or serous cavity). Enhances the susceptibility to
respiratory infections.
1.00 to 2.00 ppm
Los Angeles, California, declares its Smog Alert No. 2 at 1.00 ppm ozone
concentration and Smog Alert No. 3 at 1.500 ppm. When this range of ozone
concentration was inhaled by human volunteers for 2 hours, it caused
symptoms which could be tolerated without incapacitation with the symptoms
subsiding after a few days. The symptoms were headache, pain in the chest,
and dryness of the respiratory tract.
1.40 to 5.60 ppm
The pinto bean exposed to 1.4 to 5.0 ppm ozone concentrations for 70 minutes
showed some signs of severe injury to mature leaves.
5.00 to 25.00 ppm
Experimentation showed that a 3 hour exposure at 12 ppm was lethal for
Guinea pigs. Welders who were exposed to 9 ppm concentration plus other air
pollutants developed pulmonary edema. Chest X-rays were normal in 2 to 3
weeks, but 9 months later they still complained of fatigue and exertional
dyspnea (labored respiration).
25.00 ppm and up
Ozone concentrations that are immediately hazardous to human life are
unknown but on the basis of animal experimentation, and exposure at 50 ppm
concentration for 60 minutes would probably be fatal. |
