Ozone in Indoor Air

Ozone is a colorless gas with a noticeable smell.

Although ozone is a natural part of the atmosphere, it is also the main part of air pollution called smog. In the upper layer of the sky, ozone is helpful in protecting us from some of the effects of the sun. However, when it is in the lower layer close to Earth (outdoors and in our homes), it can be harmful if we breathe it in.

What are the health effects of ozone?

Breathing in ozone damage the lungs and irritates the throat. Low amounts of ozone can cause coughing, congestion, wheezing, shortness of breath and chest pain in some healthy people. People with asthma, bronchitis, heart disease and emphysema may find their conditions worsen when breathing in ozone.

Children are at higher risk from the health effects of ozone since they are more likely to have asthma, their lungs are still developing, they breathe in more air per body weight, and they are more active outside than adults.

How could I come in contact with ozone?

Ozone can be released into the air from some office equipment, such as laser printers and copiers, and from certain types of air cleaning devices. Although most electronic and ion generating air cleaners produce a small amount of ozone, some air cleaners such as “ozone generators” are specifically designed to produce larger amounts.

Some manufacturers of air cleaning equipment claim that ozone generators can decrease volatile organic compounds (VOCs) in the air. However, research has shown that such devices may, in fact, increase some types of VOCs. If an air cleaning device produces ozone at a level that is effective in killing molds and viruses, then it is also at a level that can be harmful to humans and pets.

What contributes to the amount of ozone in my home, school or workplace?

Ozone can build up inside your home, school or workplace if:

  • The building is tightly insulated, weatherproofed or sealed.
  • The building lacks ventilation or enough fresh air coming in.
  • The ozone-producing equipment is not properly installed, maintained, vented and operated.
How can I reduce the amount of ozone inside my home, school or workplace?

We do not recommend testing for ozone in indoor air.

There are several steps you can take to lower the amount of ozone in the air:

  • Choose alternatives to equipment and devices that produce ozone – for example, use vacuums that have HEPA (high efficiency particulate air) filters and air cleaners that do not produce ozone.
  • Increase ventilation – in some cases, opening the windows and doors to allow in fresh air from the outside can help.
  • Install exhaust fans for certain types of office equipment (e.g. copiers and laser printers) that can produce ozone. Do not place such equipment in small closed settings like closets or supply rooms.
  • Maintain and service office and industrial type equipment and air handling systems.
  • Use cleaning products and building materials that contain no or low volatile organic chemicals (VOCs).
Are there standards for ozone?

There are national standards relating to the amount of ozone that certain types of equipment or devices may produce. Also, the Food and Drug Administration has established an ozone level of 0.05 ppm (parts per million) as the maximum level allowed in an enclosed space where people are for extended periods of time. This includes homes, apartments and offices.

There are standards for workplace levels. They are set and enforced by other agencies such as the Vermont Occupational Safety and Health Administration (VOSHA).

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