U.S. DEPARTMENT OF LABOR

Occupational Safety and Health Administration

EXCERPTS FROM REGULATIONS
Occupational Health
Guidelines for Ozone


INTRODUCTION This guideline is intended as a source of information for employees, employers, physicians, industrial hygienists, and other occupational health professionals who may have a need for such information. It does not attempt to present all data; rather, it presents pertinent information and data in summary form.
SUBSTANCE IDENTIFICATION
·Formula: O3
·Synonyms: None
·Appearance and odor: Colorless gas with a sharp, characteristic odor; it can be smelled at concentrations below the permissible exposure level.
·The characteristic odor is readily detectable at low concentrations (0.01 ppm to 0.05 ppm).
PERMISSIBLE EXPOSURE LIMIT (PEL)
The current OSHA standard for ozone is 0.1 part of ozone per million parts of air (ppm) averaged over an eight-hour work shift. This may also be expressed as 0.2 milligram of ozone per cubic meter of air (mg/m3).

EXPOSURE LIMITS

Several governmental agencies and organizations have established limits for ozone measured in parts per million (ppm). The following ppm values apply:
.12 Environmental Protection Agency for city, out-of-doors, air quality.
.10 American Conference of Governmental Industrial Hygienists. Limit for exposure for 8 hours a day with no side effects.
.05 Food and Drug Administration restrict selling an ozone generator labeled as a medical device.
.03 to .06 Value frequently measured in cities.
.010 to .015 Odor threshold for most people.
.005 to .01 Value measured in fresh country air.
The Maximum Allowable Concentration (MAC) of ozone for human beings, as established by the American Council of Governmental Industrial Hygienists, is 0.1 parts per million by volume (ppm/v) for continuous exposure under occupational conditions. This is a safe level, exposure to ozone concentrations at or below this level can be tolerated. Concentrations above this level are intolerable only when exposure continues for certain durations. The chart below illustrates this by plotting various concentrations against exposure time.

HEALTH HAZARD INFORMATION
·Routes of exposure
Ozone affects the body by being inhaled or
by irritating the eyes, nose, and throat.
·Effects of exposure
When a person is exposed to very low concentrations of ozone for even a brief
period of time, the person may notice a sharp, irritating odor. As the concentration of ozone increases, the ability to smell it may decrease. Irritation of the eyes, dryness of the nose and throat, and cough may be experienced.

COMMENTS BY THE CLEAN AIR STORE
One objection that has been raised to the use
of ozone for deodorizing indoor environments is its toxicity level. While ozone is toxic, there are factors which reduce the danger to individuals using an ozone generator. Toxicity is dependent on concentration and exposure time.

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