Share sensitive information only on official, secure websites. JavaScript appears to be disabled on this computer. Please click here to see any active alerts. Ozone O3 is a highly reactive gas composed of three oxygen atoms. It is both a natural and a man-made product that occurs in the Earth's upper atmosphere the stratosphere and lower atmosphere the troposphere. Depending on where it is in the atmosphere, ozone affects life on Earth in either good or bad ways.
Stratospheric ozone is formed naturally through the interaction of solar ultraviolet UV radiation with molecular oxygen O2. The "ozone layer," approximately 6 through 30 miles above the Earth's surface, reduces the amount of harmful UV radiation reaching the Earth's surface. Tropospheric or ground-level ozone — what we breathe — is formed primarily from photochemical reactions between two major classes of air pollutants, volatile organic compounds VOC and nitrogen oxides NOx.
These reactions have traditionally been viewed as depending upon the presence of heat and sunlight, resulting in higher ambient ozone concentrations in summer months. Within the last decade, however, high ozone concentrations have also been observed under specific circumstances in cold months, where a few high elevation areas in the Western U. Ozone contributes to what we typically experience as "smog" or haze, which still occurs most frequently in the summertime, but can occur throughout the year in some southern and mountain regions.
Although some stratospheric ozone is transported into the troposphere, and some VOC and NOx occur naturally, the majority of ground-level ozone is the result of reactions of man-made VOC and NOx.
Ozone molecules, mainly found in two layers of our atmosphere. Ozone in the stratosphere absorbs dangerous UV radiation Stratospheric ozone plays a critical role for the biosphere because it largely absorbs the damaging ultraviolet radiation , allowing only a small part of the radiation to reach the Earth.
Ozone in the troposphere is poisonous substance Tropospheric ozone, on the contrary, is a so-called secondary pollutant , a photo oxidant which is formed by the interaction of solar radiation with primary polluting precursors. It results from complex chemical reactions , with a substantial role for the following players: nitrogen oxides volatile organic compounds carbon monoxide temperature sunlight.
Ozone O3 is mainly found in two layers of our atmosphere: the troposphere and the stratosphere. Troposphere, why is it an important atmospheric layer? 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.
Less ozone-layer protection from ultraviolet UV light ultraviolet UV light Ultraviolet radiation is a portion of the electromagnetic spectrum with wavelengths shorter than visible light.
UVA is not absorbed by ozone. UVB is mostly absorbed by ozone, although some reaches the Earth. UVC is completely absorbed by ozone and normal oxygen. Scientific Assessment of Ozone Depletion: The Earth's atmosphere is composed of several layers.
The lowest layer, the troposphere troposphere The region of the atmosphere closest to the Earth. The troposphere extends from the surface up to about 10 km in altitude, although this height varies with latitude. Almost all weather takes place in the troposphere. Everest, the highest mountain on Earth, is only 8. Temperatures decrease with altitude in the troposphere.
As warm air rises, it cools, falling back to Earth. This process, known as convection, means there are huge air movements that mix the troposphere very efficiently. Virtually all human activities occur in the troposphere. Everest, the tallest mountain on the planet, is only about 5. The next layer, the stratosphere stratosphere The region of the atmosphere above the troposphere. The stratosphere extends from about 10km to about 50km in altitude.
Commercial airlines fly in the lower stratosphere. The stratosphere gets warmer at higher altitudes. In fact, this warming is caused by ozone absorbing ultraviolet radiation. Warm air remains in the upper stratosphere, and cool air remains lower, so there is much less vertical mixing in this region than in the troposphere.
Most commercial airplanes fly in the lower part of the stratosphere. Health and Environmental Effects of Ozone Depletion. Ozone Layer Research and Technical Resources. Information for students about the Ozone Layer. Addressing Ozone Layer Depletion.
Adapting to a Changed Ozone Layer. Phasing Out Ozone-Depleting Substances. Managing Refrigerant Emissions. Most atmospheric ozone is concentrated in a layer in the stratosphere, about 9 to 18 miles 15 to 30 km above the Earth's surface see the figure below. Ozone is a molecule that contains three oxygen atoms. At any given time, ozone molecules are constantly formed and destroyed in the stratosphere. The total amount has remained relatively stable during the decades that it has been measured.
The ozone layer in the stratosphere absorbs a portion of the radiation from the sun, preventing it from reaching the planet's surface. UVB is a kind of ultraviolet light from the sun and sun lamps that has several harmful effects.
It is a cause of melanoma and other types of skin cancer.
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