Definition of ozone in US English:



  • 1A colorless unstable toxic gas with a pungent odor and powerful oxidizing properties, formed from oxygen by electrical discharges or ultraviolet light. It differs from normal oxygen (O₂) in having three atoms in its molecule (O₃).

    • ‘Already used to control bacteria in some pools and aquariums, ozone gas causes oxidizing reactions that damage tissue.’
    • ‘Carbon monoxide is not only a hazardous air pollutant itself, it is also a chemical compound that produces ozone, a greenhouse gas that is a human health hazard.’
    • ‘Photo chemical smog is caused by the chemical interacting with the sunlight creating ozone and other toxic substances.’
    • ‘Nitrogen Oxides, primarily from automobile exhaust, ramp up ozone production to toxic levels.’
    • ‘Biofuels, such as ethanol, can reduce carbon dioxide, ozone formation and carbon monoxide by as much as 90 percent.’
    • ‘Water vapour, carbon dioxide, ozone, methane, nitrous oxide, and the chlorofluorocarbons are known as Greenhouse Gases.’
    • ‘Although CO2 is by far the most well known green house gas, we humans also produce others in the form of methane, CFC's, ozone and nitrous oxide.’
    • ‘Adding that third oxygen atom makes ozone a very pushy and highly obnoxious little molecule.’
    • ‘Public water systems treat water with chlorine, ultraviolet light or ozone to kill E. coli.’
    • ‘The mean temperature of the earth's surface is about 33°C warmer than it would be in the absence of natural greenhouse gases such as water vapour, carbon dioxide, methane, nitrous oxide, and ozone.’
    • ‘A form of oxygen, ozone protects life on Earth from the harmful effects of ultraviolet radiation.’
    • ‘Recent experiments have begun identifying oxidizing gases, such as ozone and molecules containing the halogens bromine and chlorine, as triggers for that mercury fallout.’
    • ‘The four usual agents of deterioration in the air apart from oxygen and water are sulphur dioxide, hydrogen sulphide, ozone and nitrogen dioxide.’
    • ‘The sunlight splits the chlorine into highly reactive ions that break ozone down into normal oxygen molecules.’
    • ‘Your lungs may be exposed to pollutants such as ozone, carbon monoxide, sulfur dioxide, and sulfuric acid.’
    • ‘For example, plant tissues challenged with acutely toxic levels of ozone rapidly produce a burst of ethylene.’
    • ‘The city is constantly bathed in a visible haze of harmful pollutants: Sulphur dioxide, nitrogen oxides, ozone and smoke.’
    • ‘The District's urban forest improves air quality by removing nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, and particulate matter.’
    • ‘Even though it's made of only three little molecules of oxygen, ozone can be a pretty big topic.’
    • ‘Automotive emissions are a major source of ozone and carbon monoxide pollution.’
    1. 1.1
      short for ozone layer
      • ‘The Sun is a strong UV emitter but only near UV reaches the surface of the Earth because the ozone in the atmosphere absorbs all wavelengths below 290 nm.’
      • ‘Recent changes in surface UV solar radiation and stratospheric ozone have also been reported at a high Arctic site, although it is still too early to make trend estimates.’
      • ‘This story is too far fetched, because a hole in the ozone in Antartica would generate so much heat, that Antartica would be a tropical forest, or a fiery wasteland!’
      • ‘Between 1980 and 2000, the protective ozone in the stratosphere, about 10 to 30 miles high, decreased 3 percent.’
      • ‘Research published in 1994 suggests that increased ultraviolet radiation caused by stratospheric ozone depletion may be killing frog eggs.’
      • ‘Standard vertical profiles of pressure, temperature, relative humidity and ozone density are selected, according to the U.S. Standard Atmosphere.’
      • ‘The ozone hole still contains ozone, just at extremely low levels compared with the surrounding stratosphere.’
      • ‘The exhaust gases that these cars produce are very harmful to the environment, causing a variety of ecological problems such as ozone depletion and global warming.’
      • ‘In the upper atmosphere, or the stratosphere, ozone is very good, as it acts as a shield to protect life on Earth from harmful Ultraviolet sunlight.’
      • ‘The Institute Nacional de Meteorologia provided the radiometric, columnar ozone and meteorological information for the three stations used in this study.’
      • ‘Acid rain, stratospheric ozone depletion, and climate change are major regional or global problems arising from atmospheric pollution.’
      • ‘Part I of The Ozone Layer relates the history of our understanding of stratospheric ozone.’
      • ‘Also, the presence of stratospheric ozone sandwiched between the satellite and the troposphere makes seeing tropospheric ozone very difficult.’
      • ‘No one disputes that stratospheric ozone recovery is one of the environmental movement's great success stories.’
      • ‘The stratosphere is rich in ozone, a greenhouse gas that filters out dangerous solar particles such as ultraviolet light.’
      • ‘So, as we learn more about stratospheric ozone and climate change, what were once two separate problems have become more and more entwined.’
      • ‘High in the atmosphere this is not a problem as ozone blocks the harmful rays from the sun.’
      • ‘Researchers analyzed data from several sources, and found a strong correlation between cosmic ray intensity and ozone depletion.’
      • ‘Tropospheric ozone can permanently damage people's lungs and prohibit plants from producing and storing food.’
      • ‘‘No one predicted the dramatic loss of ozone in the upper stratosphere of the northern hemisphere in the spring of 2004,’ she said.’
    2. 1.2informal Fresh invigorating air, especially that blowing onto the shore from the sea.
      • ‘The rain had taken the city's baseline odor of fear and body fluids and replaced it with fresh, sweet-smelling ozone.’
      • ‘Because of wind patterns, most ozone blows east to Fountain Hills.’


Mid 19th century: from German Ozon, from Greek ozein ‘to smell’.