Ozone forms harmful smog, but in the upper atmosphere, it protects the earth from the sun.
What is ozone?
Ozone is a gas that occurs both at the earth's ground level and in the earth's upper atmosphere. Its chemical formula is O3. The ozone in the atmosphere occurs naturally and protects life on earth from the sun's harmful ultraviolet rays.
The ozone that occurs on the ground level is formed when sunlight reacts with pollution from motor vehicles, power plants, industrial boilers, refineries, chemical plants, and other industrial sources. Nitrogen oxides combine with volatile organic compounds to form ozone. Ground-level ozone is the main ingredient of smog, a kind of air pollution found in many U.S. cities, which contributes to climate change.
Ozone can also be industrially manufactured. Manufactured ozone is a colorless to blue gas with a pungent odor. It is used for purifying air and drinking water; treating industrial waste; drying varnishes and printing inks; deodorizing feathers; bleaching waxes; and making oils and other chemicals. It is used to control mold and bacteria in cold storage and to age liquor and wood.
You are most likely to be exposed to ozone in the summer, when the sun and hot temperatures react with pollution to form ozone. You can be exposed to ozone if you exercise or work outdoors during the summer.
As levels of ozone increase, more people are exposed, especially if "ozone alerts" are issued by local governments to warn of dangerous ozone levels. You will be exposed to more ozone in the middle of the day, when ozone levels are highest.
Active children are likely to be exposed to ozone if they spend a lot of time playing outdoors in the summer. You will be more sensitive to ozone if you exercise or work vigorously outdoors, if you are elderly, or if you have asthma or other respiratory diseases.
You can be exposed to ozone at work if you work in a facility that exposes you to gasoline vapors, chemical solvents, or processes that produce ozone.
Repeated exposure to ozone may cause permanent damage to the lungs, especially in children whose lungs are still developing. It can cause reproductive and genetic damage. Exposure to ozone may increase the risk of damage to a developing fetus.
Exposure to ozone can aggravate chronic lung diseases, such as emphysema and bronchitis, and reduce the immune system's ability to fight off infections in the respiratory system. Exposure to ozone can aggravate asthma and heart disease, reduce lung capacity, and cause a build-up of fluid in the lungs, causing difficulty breathing.
Exposure to ozone can irritate your respiratory system, causing you to cough, feel irritation in your throat, or feel uncomfortable in your chest. Breathing ozone can cause headache, upset stomach, congestion, fatigue, and vomiting.
Having skin or eye contact with liquefied ozone in the workplace can produce severe burns. Moderate exposure to ozone can cause eye irritation, burning of the throat and eyes, and a bitter taste and smell.
For poisoning emergencies or questions about possible poisons, please contact your local poison control center at 1-800-222-1222.
This description is based on the information found in the Web links listed with this topic.
Web Links from MedlinePlus (National Library of Medicine)
Air Quality Guide for Ozone (Environmental Protection Agency)
Air Trends: Ozone (Environmental Protection Agency)
Map of Releases of Ozone in the United States. TOXMAP (National Library of Medicine)
Ozone (National Institute of Environmental Health Sciences)
Ozone Layer Protection (Environmental Protection Agency)
Ozone. Haz-Map (National Library of Medicine)
Ozone. Hazardous Substances Data Bank (National Library of Medicine)
Ozone: Good Up High, Bad Nearby (Environmental Protection Agency) (PDF — 1.22 MB)
The Ozone Hole and Science (United Nations Organization)
Why Is the Ozone Layer Threatened? (United Nations Environment Programme)
Last Updated: November 2, 2016