Ozone is a strong oxidizer and very effective when used to disinfect water. Because this compound is so good at breaking down organic cells, many people are understandably concerned about the potential ozone health effects and possible ozone generator dangers. It's important to note that the amount of ozone in water is small and concentrations are low, so it poses no risk at all to humans or animals. Both people and animals should avoid prolonged exposure to ozone gas, however, which can be a safety risk at high concentrations.
Depending on the type of system you're using, the ozone generator dangers are very low, as long as the system is installed correctly and maintained appropriately. If you're using a corona discharge system, for example, you may need an air dryer to prevent the buildup of nitric acid, which will corrode the ozone generation components. Ozone generator systems should be regularly monitored for ozone leaks.
All systems also require an off-gassing system to remove any ozone not changed during the oxidation process. In smaller systems, this is often simply a vent from the contact tank to the outside, where the low levels of ozone discharge are quickly converted into atmospheric oxygen. Larger systems may require an ozone destruction unit to prevent safety issues.
On its own, ozone gas is dangerous, particularly in high concentrations. It's such an effective disinfectant because it can break down the cell walls of bacteria and other microorganisms – and it can do the same thing to the cells your lungs. Healthy people often experience difficulty breathing when exposed to high levels of ozone, and it can worsen chronic respiratory diseases. The negative ozone health effects can usually be reversed after short-term exposure, but people who have a longer exposure may suffer more lasting damage.
You'll often see local news reports on "ozone alerts" during the summer. When common pollutants – including the emissions from cars, industrial plants, and other sources – are combined with heat and sunlight, ozone is one of the byproducts. As the gas builds up at ground level, it makes breathing more difficult and can be dangerous for people with chronic lung issues.
So if ozone's health effects are bad in the air, why is it OK to use this gas as a water treatment? First and foremost, when ozone is dissolved in water, you aren't breathing it in.
When ozone is added to water, it reacts with other compounds, changing both the ozone and the contaminants. The three oxygen atoms in a molecule of ozone are relatively easy to break apart, and the isolated oxygen atom will quickly bond with another compound in the water. As a result, the ozone is mostly destroyed during the oxidation process. Any remaining ozone is in small enough amounts and concentrations that it's typically not dangerous.
While ozone systems for water treatment are very safe, there is much more concern about potential air purifier ozone generator dangers. There are many ozone air purifiers that claim to kill mold and bacteria in the air, as well as removing bad odors. According to the U.S. Environmental Protection Agency, no ozone air cleaners have been approved for use in any occupied space by any U.S. government agency.
The concern about ozone air purifiers is twofold. First, in high concentrations, ozone can damage the lung tissue. Second, in low enough concentrations to be safe in an occupied space, research shows that ozone won't be able to kill bacteria or other microorganisms, or remove odors. So if the air purifier produces enough ozone to actually clean the air, it's not safe to breathe the air it produces.
While most ozone air purifiers don't produce high levels of ozone, the actual location where they are used can increase the ozone generator dangers. When placed in a smaller room than recommended, for example, the ozone concentration in the air can quickly exceed public health standards.
If you have questions about ozone air purifiers, you can read the EPA's report on Ozone Generators that are Sold as Air Cleaners.