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5C.i Health Hazards – Detection Levels
Gaseous ozone can be detected in the air by its distinctive odor at
concentrations of about 0.02 ppm. Although each nose varies, olfacto-
ry fatigue occurs quickly.
Initial small exposure may reduce cell sensitivity and/or increase mu-
cous thickness producing resistance to low gaseous ozone levels.
DO NOT RELY ON ODOR AS A WARNING OF HIGH OZONECON-
CENTRATIONS.
The Permissible Exposure Level (PEL) or time-weighted concentration
for gaseous ozone to which workers may be exposed is 0.1 ppm av-
eraged over 8 hours, 5 days a week (OSHA). The short-term exposure
limit is 0.3 ppm averaged over 15 minutes. The concentration of 5.0
ppm ozone in air is generally accepted as Immediately Dangerous to
Life or Health (IDLH).
SECTION 5 OVERVIEW AND SAFETY PROCEDURES
5C.ii Health Hazards – Effect in Humans
Gaseous ozone acts as a primary irritant, affecting mainly the eyes, up-
per respiratory tract, and lungs. Inhalation produces various degrees
of respiratory effects from irritation to pulmonary edema (fluid in the
lungs). Short exposure to 1-2 ppm concentrations causes headache
as well as irritation to the respiratory system but symptoms subside
when exposure ends. High concentrations of ozone produce severe
irritation to the eyes and respiratory system. Exposure above the AC-
GIH/OSHA limits may produce nausea, chest pain, coughing, fatigue,
reduced visual acuity, and pulmonary edema. Symptoms of edema
from excessive exposure can be delayed one or more hours. There is
no threshold limit and so no exposure (regardless of how small) is the-
oretically without effect from ozone’s strong oxidative ability.
