Human tolerance for ozone

Ozone and humans

Ozone is a toxic gas, after inhalation it can cause sickness if inhaled in sufficient quantity.
Humans can stand a limited exposure of ozone, symptoms like dryness in the mouth and throat, coughing, headache and chest restriction can occur and nearby the lethal limits, more acute problems will follow in a higher concentration.

Limits

* 0,06 PPM for 8 hours a day, 5 days a week (PPM = Parts Per Million)
* 0,3 PPM for maximum 15 minutes
These limits are a Maximum Acceptable Concentration (MAC), these concentration are much higher than the odour threshold at which ozone can be smelled.

The following diagram gives information about exposure times at different concentration and their influences on humans.

Safety

All ozone generators should be equiped with ozone monitors and a safety system which shuts down the generator at 0,3 PPM. Best is also to set up an alarm at 0,1 PPM so people can take action in time.