Ozone is made up of three oxygen atoms, but it is very different then the oxygen that we breathe, which only has two oxygen atoms. One more atom does not sound all that bad, but it causes a 'two's company, three's a crowd' situation, and entire compound becomes unstable. That one atom is the difference between a healthy gas (air) that our bodies require and a toxic gas (ozone) that is highly reactive, unstable and a major component of smog1.
There is also an ozone layer high up in the atmosphere. The ozone up there is referred to as stratospheric ozone. It protects us from the dangerous ultraviolet (UV) light that comes from the sun. The two should not be confused. The US Environmental Protection Agency (EPA) distinguishes between the two layers of ozone with the phrase "good up high, bad nearby"2.
Ground level outdoor ozone forms during a reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. NOx and VOCs are mainly released by industrial processes and motor vehicles2, and outdoor ozone finds its way indoors through building openings and ventilation systems5,6. Several "air purifiers" or "air cleaners" also produce ozone intentionally or as a byproduct. These include ozone generators, ionic air cleaners and electrostatic precipitators1. Multiple state and federal agencies strongly advise against using ozone generators in occupied spaces1,3,4.
Indoor ozone concentrations can vary widely because they depend on many different factors, including outdoor ozone concentrations, the presence of indoor ozone sources, building ventilation, and the size of the building. Ozone concentrations tend to be highest on sunny summer afternoons in urban areas, because that is when and where the ingredients to make ozone are most prevalent. Indoor concentrations of ozone tend to be lower than outdoor concentrations because ozone reacts with many surfaces and chemicals found indoors5. Even though concentrations are lower, indoor exposure can account for as much as 60% of total exposure to ozone, depending on how much time is spent indoors6.
Young children, persons with respiratory problems such as asthma, the elderly, and persons with heightened sensitivity to chemicals may be more susceptible to illness from ozone exposure1,2,3,4,5,6.
"Breathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. "Bad" [ground level] ozone also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue. Healthy people also experience difficulty breathing when exposed to ozone pollution. Because ozone forms in hot weather, anyone who spends time outdoors in the summer may be affected, particularly children, outdoor workers and people exercising. Millions of Americans live in areas where the national ozone health standards are exceeded."2
If you think you may be having health problems caused by ozone exposure, consult an occupational/environmental health physician who specializes in this area.
There are several ways to reduce the amount of ozone present in the home: