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.
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Any interactives on this page can only be played while you are visiting our website. You cannot download interactives. An element is a substance that cannot be broken down into a simpler format. They are distinguished by a unique atomic number. The current scientific understanding, supported by numerical model projections, suggests the ozone layer should return to pre-ODS levels of in the late 21 st century with continued compliance with the Protocol, barring unforeseen events.
This result stands as a shining example for the societal impacts of basic scientific discoveries and research, and for the application of research results to policy development.
Stratospheric ozone influences weather, and this influence is detectable due to the ozone hole. Through the influence of stratospheric ozone on radiative heating and cooling, there are couplings between ozone and atmospheric circulation. Increasing levels of greenhouse gases in the atmosphere have cooled the stratosphere. This cooling in turn affects the rates of chemical reactions governing stratospheric ozone abundances.
Such effects of ozone concentrations on radiation, and therefore temperature and moisture budgets, and the associated feedbacks with climate, are becoming routinely included in climate models as well as operational weather prediction systems for improved simulations of short- and long-term variations in atmospheric circulation. Observational and computer modeling studies demonstrate that the Antarctic ozone hole has led to a delay in the seasonal breakdown of the stratospheric polar vortex, which influences both the recovery of the ozone hole and the lower atmospheric circulation in the Southern Hemisphere summer.
In contrast to the stratosphere, ozone concentrations in the lower atmosphere have increased since preindustrial times, often most profoundly in and downwind of large urban areas, degrading human and ecosystem health as well as agricultural crop yields. Human activities associated with industrialization and modernization, such as power generation and transportation, have dramatically increased emissions of ozone precursors such as nitrogen oxides NO x and volatile organic compounds VOC.
Research in the s showed that together with sunlight, these pollutants catalyze the rapid formation of ozone in the air — a process known as photochemical smog formation of which ozone and secondary aerosol particulate matter are the main byproducts. Prevalent in major cities and surrounding areas around the world, high ozone concentrations in photochemical smog can adversely affect human health, the built environment, ecosystems, and agricultural yields. For example, epidemiological studies show an increase in asthma-related hospital visits following enhanced ozone exposure.
Forests downwind of regions with high surface ozone show decreased productivity and visible leaf and needle damage. High- ozone episodes lead to deterioration of common polymers. For these and other reasons, many localities now aim to regulate ozone concentrations at the surface to remain below specific threshold values.
The recognition that chemical processes, especially those influenced by human actions, contribute greatly to ozone concentrations in the lower atmosphere was the foundation for policy action.
Effective policies to reduce surface and lower atmospheric ozone concentrations must incorporate an understanding of meteorological processes which might lead to elevated concentrations of ozone, natural and anthropogenic activities which lead to emissions of ozone precursors, and the atmospheric chemical reactions that form ozone. Ozone concentrations respond nonlinearly to changes in emitted precursor gases, with some precursors being more influenced by human activities than others.
Moreover, each locale has a different background ozone concentration set by circulation patterns and pollution sources upwind, which can vary significantly from day to day. Furthermore, ozone in a given location can increase as the result of influences beyond the control of that region, for example, due to ozone transport from the stratosphere, production from wildfires, and from international precursor emission.
Therefore, exemptions are included in U. 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.
Second, when inhaled, it reacts chemically with many biological molecules in the respiratory tract, leading to a number of adverse health effects. This course addresses this second property. Review Key Points. Skip to main content. Ozone Pollution and Your Patients' Health. Contact Us. What is Ozone? What is ozone and where is it in the atmosphere? Are high ambient ozone concentrations found only in heavily urbanized areas?
How does atmospheric ozone affect human health?
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