Tag: global environmental change

• Due to the ozone depletion, the UV rays are filtered in the Earth's atmosphere. 
• This ray results in the development of various diseases. One of the common disorder is erythema. 
• This is a disease in which there are reddening and swelling of the skin. There is swelling of the mucous membranes. 
• There is an increase in the blood flow from the peripheral capillaries which results in inflammation.
• Thus, the correct answer is option D. 

Free radicals have unpaired electrons. These are extremely reactive. As one chlorine free radical can remove 11000 ozone molecules from stratosphere.

• Nitrous oxide is stable at ground level and breaks down when it reaches the stratosphere to form nitrogen oxides, that trigger ozone-destruction. 
  
• The main cause of ozone depletion are halocarbon refrigerants, such as chlorofluorocarbons (CFCs), HCFCs, halons).
  
• So, the correct option is 'Both B and C'.
  

Ozone layer is formed in the stratosphere of the atmosphere by the action of UV rays on the oxygen molecules. This ozone layer acts as absorbant for the harmful UV radiations and so, these radiation do not cross the troposphere to reach the earth's surface. However, the ozone depleting pollutants like chlorofluorocarbons reach the stratosphere and break when exposed to the UV rays. This process releases the reactive chlorine which further reacts with ozone to form simple oxygen. That is how the ozone layer is depleted. Hence, the correct answer is 'Chlorofluorocarbons'.

Ultraviolet radiations cause photochemical splitting of oxygen molecules in the stratosphere. The nascent oxygen combines with molecular oxygen to form ozone. In troposphere nascent oxygen comes from nitrogen dioxide.

ODS refers to the ozone-depleting substances like chlorofluorocarbons, methyl bromide, methyl chloroform, carbon tetrachloride, hexaflurocarbons that release the chlorine and oxides of chlorine. These react with the UV rays and ozone to release the nascent oxygen. 

The ozone depleting substances include the chlorofluorocarbons, oxides of nitrogen, methyl bromide, carbon tetrachloride etc because these split up when exposed to UV radiations and release the reactive chlorine and bromine. These reactive species of chlorine and bromine then react with ozone to release the nascent oxygen. Sulphur dioxide and carbon dioxide are greenhouse gases. Carbon monoxide is an air pollutant.