Layers of the atmosphere: troposphere, stratosphere, mesosphere and thermosphere. Earth's atmosphere has a series of layers, each with its own specific traits.
Moving upward from ground level, these layers are named the troposphere, stratosphere, mesosphere, thermosphere and exosphere. The exosphere gradually fades away into the realm of interplanetary space. The troposphere is the lowest layer of our atmosphere. Starting at ground level, it extends upward to about 10 km 6. We humans live in the troposphere, and nearly all weather occurs in this lowest layer. Air pressure drops, and temperatures get colder, as you climb higher in the troposphere.
The next layer up is called the stratosphere. The stratosphere extends from the top of the troposphere to about 50 km 31 miles above the ground. The ozone layer is thinnest near the pole s. In the s, people all over the world started realizing that the ozone layer was getting thinner and that this was a bad thing. Many government s and businesses agreed that some chemicals, like aerosol can s, should be outlaw ed.
There are fewer aerosol cans produced today. The ozone layer has slowly recovered as people, businesses, and governments work to control such pollution. Million to One Compared to other gases in the atmosphere, ozone is pretty rare. According to NOAA, there are only about three molecules of ozone for every ten million molecules of air. When released through a small opening, the liquid becomes a spray or foam. Some CFCs have destructive effects on the ozone layer.
Gas molecules are in constant, random motion. Ultraviolet is often shortened to UV. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
The Rights Holder for media is the person or group credited. Caryl-Sue, National Geographic Society. Dunn, Margery G. For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. 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. It has also been linked to damage to some materials, crops, and marine organisms.
The ozone layer protects the Earth against most UVB coming from the sun. It is always important to protect oneself against UVB, even in the absence of ozone depletion, by wearing hats, sunglasses, and sunscreen.
However, these precautions will become more important as ozone depletion worsens. UVB has been linked to many harmful effects , including skin cancers, cataracts, and harm to some crops and marine life. Scientists have established records spanning several decades that detail normal ozone levels during natural cycles. Ozone concentrations in the atmosphere vary naturally with sunspots, seasons, and latitude.
These processes are well understood and predictable. Each natural reduction in ozone levels has been followed by a recovery. Beginning in the s, however, scientific evidence showed that the ozone shield was being depleted well beyond natural processes. When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules.
One chlorine atom can destroy over , ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created. As suggested by many experiments on plants and animals and clinical research on humans, an increased exposure to UV-B radiation has its damaging effects. 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.
Tropospheric ozone is a poisonous substance that harms humans, animals and plants. It results from complex chemical reactions , with a substantial role for the following players:.
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