Ozone Layer Conservation Day on September 16, is a warning of an impending disaster
The Ozone layer is a deep blanket in the stratosphere made up of comparatively high concentration of the ozone. The ozone layer encircles the earth and occurs naturally. It is mainly found in the lower part of the stratosphere, approximately 15 to 30 kilometers above the earth. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth’s atmosphere as a whole is about 0.3 parts per million. The ozone is an extremely reactive layer and it acts as a shield from the harmful ultraviolet B rays discharged from the sun. The thickness of the ozone layer differs as per season and geography. The highest concentrations of ozone occur at altitudes from 26 to 28 km (16 to 17 miles) in the tropics and from 12 to 20 km (7 to 12 miles) towards the poles.
An essential property of ozone molecule is its ability to block solar radiations of wavelengths less than 290 nanometers from reaching Earth’s surface. In this process, it also absorbs ultraviolet radiations that are dangerous for most living beings. UV radiation could injure or kill life on Earth. Though the absorption of UV radiations warms the stratosphere but it is important for life to flourish on planet Earth. Research scientists have anticipated disruption of susceptible terrestrial and aquatic ecosystems due to depletion of ozone layer.
Ultraviolet radiation could destroy the organic matter. Plants and plankton cannot thrive, both acts as food for land and sea animals, respectively. For humans, excessive exposure to ultraviolet radiation leads to higher risks of cancer (especially skin cancer) and cataracts. It is calculated that every 1 percent decrease in ozone layer results in a 2-5 percent increase in the occurrence of skin cancer. Other ill-effects of the reduction of protective ozone layer include – increase in the incidence of cataracts, sunburns and suppression of the immune system.
Chlorofluorocarbons (CFCs), chemicals found mainly in spray aerosols heavily used by industrialized nations for much of the past 50 years, are the primary culprits in ozone layer breakdown. When CFCs reach the upper atmosphere, they are exposed to ultraviolet rays, which causes them to break down into substances that include chlorine. The chlorine reacts with the oxygen atoms in ozone and rips apart the ozone molecule. One atom of chlorine can destroy more than a hundred thousand ozone molecules, according to the the U.S. Environmental Protection Agency.
In the mid-latitude, for example, over Australia, ozone layer is thinned. This has led to an increase in the UV radiation reaching the earth. It is estimated that about 5-9% thickness of the ozone layer has decreased, increasing the risk of humans to over-exposure to UV radiation owing to outdoor lifestyle.
In atmospheric regions over Antarctica, ozone layer is significantly thinned, especially in spring season. This has led to the formation of what is called ‘ozone hole’. Ozone holes refer to the regions of severely reduced ozone layers. Usually ozone holes form over the Poles during the onset of spring seasons. One of the largest such hole appears annually over Antarctica between September and November. In other regions, the ozone layer has deteriorated by about 20 percent.
About 90 percent of CFCs currently in the atmosphere were emitted by industrialized countries in the Northern Hemisphere, including the United States and Europe. These countries banned CFCs by 1996, and the amount of chlorine in the atmosphere is falling now. But scientists estimate it will take another 50 years for chlorine levels to return to their natural levels.
Effect on health of humans
With depletion in ozone’s layer, we humans are more prone to UV rays that reaches the Earth’s surface. Studies suggests that high levels of UV Rays cause non-melanoma skin cancer and plays a major role in malignant melanoma development. Direct exposure to UV rays can lead to development of cataracts which clouds the eye’s lens.
Permanent exposure to UV rays can also lead to weakening of the response of immune system and even permanent damage to immune system in some cases. Aging of skin is yet another problem that will make you look older than what you really are. Extensive exposure to UV rays can lead to acceleration of the aging process of your skin.
Effect on plants
Plants become another casualty by radiation effects of UV rays. The physiological and developmental processes of plants are also severely affected apart from the growth. Some other changes that are caused by UV inlcude the way plants form, timing of development and growth, how nutrients are distributied within the plant and metabolism, etc.
Depletion to ozone layer depletion does not affect a region or a country. In fact whole world is vulnerable to its after affects. The increase in the levels of UV rays lead to high rate of skin cancer and eye related problems. Lets have a look at some of the solutions to ozone layer depletion.
If you are out for shopping, don’t buy aerosol products with chlorofluorocarbons. Do check your fire extinguishers if “halon” or “halogenated hydrocarbon” is the main ingredient. Dispose of old air co2nditioning units, refrigerators that use chlorofluorocarbons to function. This could release the toxic chemicals into the atmosphere.
Fertilisers and pesticides are extensively used in agriculture and are also a source of nitrous oxide production which is the main culprit in depletion of ozone layer. Encourage local political representatives to raise a campaign to put forth laws governing fertilizer use. Ozone layer depletion is something that could prove hazardous for the entire human community. Speak to your friends, family members, colleagues and encourage them to drive less, eat local, to dispose of fire extinguishers and air conditioning units containing ozone depleting substances.
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