What does the ozone layer do for us

what does the ozone layer do for us

Ozone Layer Protection

May 09, The ozone layer acts as a shield for life on Earth. Ozone is good at trapping a type of radiation called ultraviolet radiation, or UV light, which can penetrate organisms protective layers, like skin, damaging DNA molecules in plants and animals. There are . The Earth's ozone layer ozone layerThe region of the stratosphere containing the bulk of atmospheric ozone. The ozone layer lies approximately kilometers ( miles) above the Earth's surface, in the stratosphere. Depletion of this layer by ozone depleting substances (ODS) will lead to higher UVB levels, which in turn will cause increased skin cancers and cataracts and potential damage to some marine organisms, plants, and plastics.

In the stratosphere the temperature of the atmosphere rises with increasing height, a phenomenon created by the absorption of solar radiation by the ozone layer. In the midlatitudes the peak concentrations of ozone occur at altitudes from 20 to 25 km about 12 to 16 miles. Peak concentrations are found at altitudes from 26 to 28 km about 16 to 17 miles in the tropics and from about 12 to 20 km about 7 to 12 miles toward the poles.

The lower height of the peak-concentration region in the high latitudes largely results from poleward and downward atmospheric transport processes that occur in the middle and high latitudes and the reduced height of the tropopause the transition region between the troposphere and stratosphere. Near-surface ozone often results from interactions between certain pollutants such as nitrogen oxides and volatile organic compoundsstrong sunlightand hot weather. It is one of the primary ingredients in photochemical smoga phenomenon that plagues many urban and suburban areas around the world, especially during the summer months.

The production of ozone in the stratosphere results primarily from the breaking of the chemical bonds within oxygen molecules O 2 by high-energy solar photons. This process, called photodissociationresults in the release of single oxygen atoms, which later join with intact oxygen molecules to form ozone.

Scientists believe that the formation of the ozone layer played an important role in the development of life on Earth by screening out lethal levels of UVB radiation ultraviolet radiation with wavelengths between and nanometres and thus facilitating the migration of life-forms from the oceans to land. The amount of ozone in the stratosphere varies naturally throughout the year as a result of chemical processes that create and destroy ozone molecules and as a result of winds and other transport processes that move ozone molecules around the planet.

Over the course of several decades, however, human activities substantially altered the ozone layer. Ozone depletionthe global decrease in stratospheric ozone observed since the s, is most pronounced in polar regionsand it is well correlated with the increase of chlorine and bromine in the stratosphere.

Those chemicals, once freed by UV radiation from the chlorofluorocarbons CFCs and other halocarbons carbon-halogen compounds that contain them, destroy ozone by stripping away single oxygen atoms from ozone molecules. Depletion is so extensive that so-called ozone holes regions of severely reduced ozone coverage form over the poles during the onset of their respective spring seasons. The largest such holewhich has spanned more than The Montreal Protocol has been a success, with some 99 percent of the ozone-depleting chemicals regulated by the treaty having been phased out since its adoption in Compliance with international treaties that phased out the production and delivery of many ozone-depleting chemicals, combined with upper stratospheric cooling how to make candy buffet tags to increased carbon dioxide what does the ozone layer do for us, is thought to have contributed to the shrinking of the ozone holes over the poles and to slightly higher stratospheric ozone levels overall.

Continued reductions in chlorine loading are expected to result in smaller ozone holes above Antarctica after However, some scientists noted that gains in stratospheric ozone levels have only occurred in the upper stratospherewith declines in ozone concentrations in the lower stratosphere outpacing increases in the upper stratosphere.

Ozone layer. Additional Info. Print print Print. Table Of Contents. While every effort has been made to follow what is nitrogen made up of style rules, there may be some discrepancies.

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External Websites. Donald Wuebbles Harry E. See Article History. The layers of Earth's atmosphere, with a yellow line showing the air temperature at various heights. Ozone damage on the leaf of an English walnut Juglans regia. Changes in the size of the ozone hole from October to October Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now. Antarctic ozone hole, September 17, Two bar graphs depicting the maximum ozone hole size and the minimum ozone coverage in Dobson units of the Southern Hemisphere ozone hole, Researchers launching a balloon carrying an ozonesonde, an instrument that measures ozone in the atmosphere, at Amundsen-Scott South Pole Station in Antarctica.

Learn More in these related Britannica articles:. Sunlight causes nitric oxide to react chemically with ozone O 3thereby converting the ozone to molecular oxygen O 2. Equally important as an absorber in the longer wavelengths is water vapour.

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Stratospheric Ozone Layer

Ozone Layer Protection. The stratospheric ozone layer is Earths sunscreen protecting living things from too much ultraviolet radiation from the sun. The emission of ozone depleting substances has been damaging the ozone layer. But through domestic and international action, the ozone layer is healing and should fully recover by about This website addresses stratospheric ozone issues, including . Most ozone resides in the stratosphere (a layer of the atmosphere between 10 and 40 km above us), where it acts as a shield to protect Earth's surface from the sun's harmful ultraviolet radiation. With a weakening of this shield, we would be more susceptible to . Sep 11, Beneficial ozone is present naturally in the Earths upper atmosphere, 1030 miles above the Earths surface. This natural ozone shields us from the suns ultraviolet rays. Harmful ozone forms near ground level when air pollutants (from sources such as cars, power plants, and chemical plants) react chemically in the presence of sunlight.

Explore This Park. Ozone Effects on Human Health. South entrance to Zion National Park, Utah. Ozone, the main ingredient of smog, presents a serious air quality problem in several National Park Service areas. Even at low levels, ozone can cause health effects. How can ground-level ozone affect your health? What are National Park Service ozone health advisories? How does ground-level ozone affect natural resources? Last updated: September 11, Tools Site Index. What is ozone? Who is at risk?

Ozone is a colorless gas found in the air we breathe. Ozone can be beneficial or harmful to people, depending where it occurs.

Harmful ozone forms near ground level when air pollutants from sources such as cars, power plants, and chemical plants react chemically in the presence of sunlight. Ozone pollution is more likely to form during warmer months. Ozone is mainly formed by chemical reactions between volatile organic compounds VOCs and oxides of nitrogen in the presence of sunlight and higher temperatures. The human-caused sources of VOCs and nitrogen oxides are industrial and automobile emissions. Ozone concentrations can be transported hundreds of miles and affect remote areas of the country.

Ozone can irritate your respiratory system. When this happens, you may cough, feel irritation or soreness in your throat, or experience chest tightness or pain when taking a deep breath. Reduced lung function can make it more difficult for you to breathe as deeply and easily as you normally would. This is especially true when exercising at higher elevations. Exposure to ozone can also increase the susceptibility of the lungs to infections, allergens, and other air pollutants.

Medical studies have shown that health problems caused by ozone may continue long after exposure has ended. When ozone levels are very high, everyone should be concerned about ozone exposure. In general, as concentrations of ground-level ozone increase, both the number of people affected and the seriousness of the health effects increase.

Several groups of people are particularly sensitive to ozone, especially when they are active outdoors. Ozone levels are higher outdoors, and physical activity causes faster and deeper breathing, drawing more ozone into the body. People particularly sensitive to ozone include: People with lung diseases , such as asthma, chronic bronchitis, and emphysema will generally experience more serious health effects at lower ozone levels.

Children are at higher risk from ozone exposure because they often play outdoors in summer when ozone levels are higher and their lungs are still developing. Older adults may be more affected by ozone exposure, possibly because they are more likely to have pre-existing lung disease. Active people of all ages who exercise or work outdoors have higher exposure to ozone than people who are less active.

Some healthy people may experience health effects at lower ozone levels than the average person even though they have none of the risk factors listed above. There may be a genetic basis for this increased sensitivity. The ozone health standard is an 8-hour average concentration of 70 parts per billion ppb. View ozone health advisories issued for National Park Service areas. Moderate 5570 ppb Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors.

Unhealthy for Sensitive Groups 7185 ppb Children, older adults, active people, and people with lung disease such as asthma should reduce prolonged or heavy exertion outdoors. Unhealthy 86 ppb Children, older adults, active people, and people with lung disease such as asthma should avoid prolonged or heavy exertion outdoors. Everyone else should reduce prolonged or heavy exertion outdoors.

Everyone else should avoid prolonged or heavy exertion outdoors. Some plants are actually sensitive to ozone at levels well under the national health standards. Lichens, mosses, and liverworts often are most sensitive within an ecosystem and can serve as early indicators of air pollution effects. Learn more .



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