Tag: global environmental change

Chlorofluorocarbons are the halogenated paraffin hydrocarbons containing chlorine, fluorine and carbon. These have been extensively used as the refrigerants and the spray propellants due to their non-toxic nature. But, the CFCs have found their way to the stratosphere of the atmosphere where the incidence of the UV rays is very high. The CFC splits up when exposed to the UV rays and release the reactive chlorine species. This is harmful to the ozone in the stratosphere because the chlorine reacts with ozone to release the simple oxygen, that is further converted to the reactive nascent oxygen.

The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). These compounds are transported into the stratosphere by the winds after being emitted from the surface.[2] Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone (O3) into oxygen (O2).[3] Both types of ozone depletion were observed to increase as emissions of halocarbons increased.

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.