Tag: causes of greenhouse effect

Oxides of nitrogen find their way to the environment when they are released from the fertilizers, farms, combustion of coal etc. These bear a similarity to the paraffinated halogens like the chlorofluorocarbons when they reach the stratosphere of the atmosphere. They get unstable when exposed to the UV rays and the reactive nitrogen atom recs with the ozone to form the nitrogen dioxide and the diatomic oxygen molecule, similar to the reaction catalysed by the CFCs which release reactive chlorine that break down the ozone.

Ozone is found in high concentration in the stratosphere of the earth's surface in the form of ozone blanket or commonly known as the ozone layer. The vital function of ozone is to absorb the sun's ultraviolet radiation before it reaches the ground hence protecting the earth from its harmful effect. But the ozone-depleting substance such as Chlorofluorocarbons, nitrous oxides, etc that reacting with the ozone layer cause depletion of it forming ozone hole.

Among the five layers of the earth's surface ozone is present in the stratosphere which absorbs UV radiation before it reaches the ground. The main cause of ozone depletion is manufactured chemicals especially CFCs, these compounds reach the stratosphere by winds, where they release halogen atoms through photodissociation and cause the breakdown of ozone into oxygen. The ozone hole formed due to this increase the exposure of direct UV rays on earth carrying the potential risk of skin cancer and other negative effects. Direct exposure of harmful UV rays that penetrates skin can damage the genetic material I.e., DNA in skin cells and if the body is unable to recover the damage the cells stars to divide and grow uncontrollably which eventually leads to a tumour.

Among the five layers of the earth's surface ozone is present in the stratosphere which absorbs UV radiation before it reaches the ground. The main cause of ozone depletion is manufactured paraffinated halogen chemicals especially CFCs, these compounds reach the stratosphere by winds, where they release halogen atoms through photodissociation and cause the breakdown of ozone into oxygen. The ozone hole formed due to this increase the exposure of direct UV rays on earth carrying the potential risk of skin cancer and other negative effects.

The intermediary lobe of the pituitary gland secreted the Melanocyte Stimulating Hormone (MSH) that acts on the types of cells in the skin called the melanocytes. These cells produce a coloured pigment called the melanin which diverts the UV-A radiations falling on the skin. This prevents the UV rays from reaching to the other sensitive cells of the body and prevents the possible damages to the DNA that can be caused by them. This is the reason that body develops tanning when exposed to the bright sunlight. It is a protective mechanism.

The ozone layer is part of the earth's atmosphere. Ozone is basically found in the stratosphere. Ozone layer contains the high concentration of ozone. It's is vital to human life on earth because it absorbs biologically harmful ultraviolet radiations from the sun. Direct exposure to such rays can cause serious illness and skin problems. The main cause of ozone depletion is manufactured chemicals especially CFCs, these compounds reach the stratosphere by winds, where they release halogen atoms through photodissociation and cause the breakdown of ozone into oxygen. The ozone hole formed due to this increase the exposure of direct UV rays on earth carrying the potential risk of skin cancer and other negative effects.

Methyl bromide, halon, nitrogen oxides and chlorofluorocarbons are the potent ozone-depleting substances. These accumulate in the stratosphere and undergo photodissociation when exposed to the UV rays. The reactive chlorine and bromine react with ozone to form diatomic oxygen and molecular oxygen.

The exposure to the UV radiations have an ionizing and distorting effect to the body of the humans. It causes damage to the eyes by destroying the essentials of the eye-lens. The sunburn occurs due to high intensity. Skin cancer is caused due to distortion of the DNA by the formation of the pyrimidine dimers, such that the DNA cannot be replicated properly.

•  The UV region covers the wavelength range 100-400 nm and is divided into three bands: UVA (315-400 nm) UVB (280-315 nm)
• The most common form of UV radiation is sunlight, which produces three main types of UV rays: UVA, UVB, UVC.
• At certain wavelengths, UV is mutagenic to bacteria, viruses and other microorganisms. Particularly at wavelengths around 260–270 nm, UV breaks molecular bonds within microorganismal DNA, producing thymine dimers that can kill or disable the organisms.
• UVB, the chief cause of skin reddening and sunburn, tends to damage the skin's more superficial epidermal layers. It plays a key role in the development of skin cancer and a contributory role in tanning and photoaging.

Cataracts and blindness are among the most common eye diseases associated with further ozone layer depletion and increased UV-B at the Earth's surface.  A 1% decrease in stratospheric ozone may result in 100,000 to 150,000 additional cases of blindness due to eye cataracts worldwide. The ozone layer is responsible for absorbing harmful ultraviolet rays, and preventing them from entering the Earth's atmosphere.