Research

Nam Le

METR112

Section 1

ASSIGNMENT 2 : Ozone Depletion in the Stratosphere

1 . What is ozone

Ans : Ozone is a gas of three oxygen atoms (O3 .Ozone can be formed when a mixture of oxides of Nitrogen and volatile organic compounds is exposed to the sunlight at ground level and action of ultraviolet light on oxygen in the stratosphere

2 . How is ozone produced in the stratosphere

Ans : Ozone is formed in the stratosphere by the action of sunlight on oxygen . The high

energy ultra violet light causes

a molecule of oxygen to split into two atoms , one of these

two atoms then join an oxygen molecule to form ozone . In this process ozone absorbs

most of the ultra violet light preventing it from reaching the atmosphere of the earth

3 . Distinguish between good ozone ' and bad ozone

Ans : Good ozone is the ozone that is present high up in the stratosphere where it absorbs most of the ultra violet light and prevents it from reaching the earth . Hence the harmful effects of ultra violet on humans are prevented due to the presence of ozone high up This is the good ozone . It is present about 10 to 20 miles above the earth

Bad ozone is the ozone that is present at the ground level due to pollution . It is formed by the combination of oxides of Nitrogen (which are emitted in combustion processes and in vehicle exhaust ) and volatile organic compounds in the presence of sunlight . It makes the eyes water and causes various problems for people with certain diseases This is the bad ozone which is present at the ground level

4 . What are the potential health effects due to depletion of stratospheric ozone

Ans : The depletion of stratospheric ozone increases the amount of UV radiation to which we are exposed . This has damaging effects on both humans and animals . It causes skin cancer (non melanoma skin cancer and malignant melanoma , cataracts and immunosuppression . Severe photo allergies (allergy to light , faster aging of the skin , sunburn , tanning and eye damage can occur

5 . What are CFCs ? When were they invented and what have they been used for

Ans : CFC 's , chloroflourocarbons are several of many organic compounds which are

made up of carbon , chlorine , fluorine and hydrogen as a name of Freon They were

developed for the first time in the 1930s after the Second World War more than 70 years

ago . Trichlorofluoromethane (CFC11 ) and dichlorodifluoromethane (CFC12 are

important CFC 's which have applications as refrigerants , aerosol spray propellants

solvents and foam blowing agents

6 . How long do CFCs last in the atmosphere

Ans : CFC 's are very inert compounds and last in the atmosphere for a very long time , for

decades and even up to a hundred years and then they move into the upper part of the

atmosphere where the high energy ultra violet radiation breaks it down .CFC11 lasts for

40 to 80 years and CFC 12 for 75 to 150 years

7 . What component...