q_sharon
01/17/09, 08:06 PM
:itshere:
What are the effects of ozone depletion?
Ozone depletion allows the entry of harmful Ultraviolet-B (UV-B) radiation from the sun. The sun is the primary source of ultraviolet radiation.
There are three categories of UV:
• UV-A wavelengths – (320-400 nm) are only slightly affected by ozone levels. Most UV-A radiation is able to reach the earth’s surface and can contribute to tanning, skin aging, eye damage, and immune suppression.
• UV-B wavelengths – (280-320 nm) are strongly affected by ozone levels. Decreases in stratospheric ozone mean that more UV-B radiation can reach the earth’s surface, causing sunburns, snow blindness, immune suppression, and a variety of skin problems including skin cancer and premature aging. UV-B is harmful.
• UV-C wavelengths (100-280 nm) are very strongly affected by ozone levels, so that the levels of UV-C radiation reaching the earth’s surface is relatively small. UV-C is lethal.
In general, moderate exposure to UV radiation helps maintain an adequate level of vitamin D and is not detrimental. But too much exposure to UV-B harms not just humans but all life forms.
On land, UV-B radiation endangers all life forms. Humans exposed to high level of UV-B will find their immune systems deteriorating. They are more prone to diseases and other disabilities such as skin cancer, eye cataract, blindness, and age more rapidly. Further, humans will find their sources of food become more limited since UV-B inhibits the growth of crops and trees.
Ultraviolet light degrades polymers used in building, paints, packaging and countless other substances. Plastics used outdoors are also most likely to be affected. Countries in tropical regions will be severely affected by the degradation of these building materials and will cost billions of dollars in damage.
On water, UV-B radiation penetrates the ocean floor damaging the propagation of phytoplankton organisms, the primary food source of most marine life. This affects the marine food chain which also involves humans at the end of the food chain. A number of marine species are human’s main sources of food. Fish eggs and young plants with developing leaves are also particularly susceptible to damage from overexposure to UV.
What causes ozone layer depletion?
The depletion of the ozone layer is caused by certain man-made chemicals called Ozone Depleting Substances (ODS).
CFC-11, CFC-12, HCFC-22,
HCFC-123 Refrigerants: domestic, commercial and transport refrigerator; air-conditioning and heat pump systems; mobile air-conditioners
CFC11 Blowing agents: foam blowing agent for the manufacture of polyurethane, phenolic, polysterene, and polyefin foam plastic
CFC-113, Methyl Chloroform, Carbon Tetrachloride Cleanig solvents: for electronic assembly production processes, preciesion cleaning and general metal degreasing: also for dry cleaning and spot cleaning in textile industry
CFC-11, CFC-12,CFC-113, CFC-114 Propellants: for aerosols like deodorants, shaving foam, perfume, window cleaners, lubricants and oils
Mixture of CFC-12 and ethylene oxide Sterilants: for medical sterillization
Halon and HBFC, HCFC-123 Fire extingusihers
Methyl Bromide Fumigants: pesticide for soil fumigation, pre-shipment and quarantine applications, structural facilities, buildings, golf courses and stored commodities
HCFC and carbon tetrachloride Feedstock for chemical synthesis or laboratory testing
What are the ozone depleting substances (ODS) and what are their uses?
ODS are man-made compounds containing chlorine and bromine, particularly chlorofluorocarbons (CFCs), halons, and methyl bromide.
Discovered in 1928 by Thomas Midgely and considered as “miracle compounds” in the 1930s, CFCs had all the qualities of an ideal chemical: seemingly harmless to humans and the environment, inert and immensely stable, odorless, nonflammable, non-corrosive and nontoxic, inexpensive to produce and easy to store.
For the year 2003, CFC accounted for 89.86% of total ODS consumption in the country because of its widespread applications in homes, industries and the servicing sector. They are used as cooling agents in refrigerators, freezers, and air-conditioners, as propellants in spray cans, aerosols and metered-dose inhalers, solvents in computer and electronic circuits, and blowing agents for foams manufacturing and other industrial applications.
Halon, on the other hand, is a chemical used in fire extinguishers. Methyl Bromide is a broad spectrum pesticide used for the control various insect pest, nematodes, weeds, pathogens, and rodents.
Source: Ozone Trivia
:Fish Smiley 6068:
What are the effects of ozone depletion?
Ozone depletion allows the entry of harmful Ultraviolet-B (UV-B) radiation from the sun. The sun is the primary source of ultraviolet radiation.
There are three categories of UV:
• UV-A wavelengths – (320-400 nm) are only slightly affected by ozone levels. Most UV-A radiation is able to reach the earth’s surface and can contribute to tanning, skin aging, eye damage, and immune suppression.
• UV-B wavelengths – (280-320 nm) are strongly affected by ozone levels. Decreases in stratospheric ozone mean that more UV-B radiation can reach the earth’s surface, causing sunburns, snow blindness, immune suppression, and a variety of skin problems including skin cancer and premature aging. UV-B is harmful.
• UV-C wavelengths (100-280 nm) are very strongly affected by ozone levels, so that the levels of UV-C radiation reaching the earth’s surface is relatively small. UV-C is lethal.
In general, moderate exposure to UV radiation helps maintain an adequate level of vitamin D and is not detrimental. But too much exposure to UV-B harms not just humans but all life forms.
On land, UV-B radiation endangers all life forms. Humans exposed to high level of UV-B will find their immune systems deteriorating. They are more prone to diseases and other disabilities such as skin cancer, eye cataract, blindness, and age more rapidly. Further, humans will find their sources of food become more limited since UV-B inhibits the growth of crops and trees.
Ultraviolet light degrades polymers used in building, paints, packaging and countless other substances. Plastics used outdoors are also most likely to be affected. Countries in tropical regions will be severely affected by the degradation of these building materials and will cost billions of dollars in damage.
On water, UV-B radiation penetrates the ocean floor damaging the propagation of phytoplankton organisms, the primary food source of most marine life. This affects the marine food chain which also involves humans at the end of the food chain. A number of marine species are human’s main sources of food. Fish eggs and young plants with developing leaves are also particularly susceptible to damage from overexposure to UV.
What causes ozone layer depletion?
The depletion of the ozone layer is caused by certain man-made chemicals called Ozone Depleting Substances (ODS).
CFC-11, CFC-12, HCFC-22,
HCFC-123 Refrigerants: domestic, commercial and transport refrigerator; air-conditioning and heat pump systems; mobile air-conditioners
CFC11 Blowing agents: foam blowing agent for the manufacture of polyurethane, phenolic, polysterene, and polyefin foam plastic
CFC-113, Methyl Chloroform, Carbon Tetrachloride Cleanig solvents: for electronic assembly production processes, preciesion cleaning and general metal degreasing: also for dry cleaning and spot cleaning in textile industry
CFC-11, CFC-12,CFC-113, CFC-114 Propellants: for aerosols like deodorants, shaving foam, perfume, window cleaners, lubricants and oils
Mixture of CFC-12 and ethylene oxide Sterilants: for medical sterillization
Halon and HBFC, HCFC-123 Fire extingusihers
Methyl Bromide Fumigants: pesticide for soil fumigation, pre-shipment and quarantine applications, structural facilities, buildings, golf courses and stored commodities
HCFC and carbon tetrachloride Feedstock for chemical synthesis or laboratory testing
What are the ozone depleting substances (ODS) and what are their uses?
ODS are man-made compounds containing chlorine and bromine, particularly chlorofluorocarbons (CFCs), halons, and methyl bromide.
Discovered in 1928 by Thomas Midgely and considered as “miracle compounds” in the 1930s, CFCs had all the qualities of an ideal chemical: seemingly harmless to humans and the environment, inert and immensely stable, odorless, nonflammable, non-corrosive and nontoxic, inexpensive to produce and easy to store.
For the year 2003, CFC accounted for 89.86% of total ODS consumption in the country because of its widespread applications in homes, industries and the servicing sector. They are used as cooling agents in refrigerators, freezers, and air-conditioners, as propellants in spray cans, aerosols and metered-dose inhalers, solvents in computer and electronic circuits, and blowing agents for foams manufacturing and other industrial applications.
Halon, on the other hand, is a chemical used in fire extinguishers. Methyl Bromide is a broad spectrum pesticide used for the control various insect pest, nematodes, weeds, pathogens, and rodents.
Source: Ozone Trivia
:Fish Smiley 6068: