Question

Briefly describe what you know about Ozone depletion and Global warming.and Name the major risks caused by a SOx on humans? -What air pollution control device is better in removing SO4? Draw the device and label all the important components.

Answer 1

OZONE LAYER DEPLETION

Ozone occurs in the troposphere and plays an important role for the atmosphere protection. About 90% of the total ozone content of our atmosphere occurs in stratosphere at altitude between 15 to 50 km.

Primary reason for ozone layer depletion is CFC i.e. chlorofluoro carbon or freons.

The freons are a group of CFCs used as areosol propellants, refrigerants, solvents and as gases for the production of foamed plastics.

Ozone is destroyed due to the photolytic reaction of CFC as : CFCl3 --------> Cl + other substances (due to UV radiations)

Cl + O3 -------> ClO2 + O2

GLOBAL WARMIMG

The effect of increasing concentration of Co2 is known as global warming. This is also called green house effect.

A green house is a construction of transparent walls and roofs in cold countries to provide adequate heat to soil and plants. The solar energy penetrates the green house but prevented from escaping and thus heat remains within the green house keeping it warm. A similar process keeping atmosphere warm is therefore called the green house effect where mainly carbon dioxide entraps the incoming solar heat.

The green house gases act like a thermal blanket surrounding earth as due to the presence of green house gases the hear remains within atmosphere and doesn't escape out of it. If the concentration of CO2 keeps increasing more and more, heat will be built up in the atmosphere and on the earths surface. Major green house gases are:

Carbon dioxide, methane, nitrous oxide and CFC.

Major risks caused by SOx to humans are:

Sulphur dioxide causes irritation on skin and mucous membrane of eyes, throat , nose and lungs. High concentration of SO2 can lead to inflammation and irritation of the respiratory system. It may also cause pain during breathing, coughing, throat infection and breathing difficulties. It can affect lung function, worsen asthma attacks and heart diseases in sensitive groups.

Scrubbers are used widely to collect and remove SOx from the environment. The details of scrubber are drawn as follows:

Generally scrubbers are of two types : wet scrubber and dry scrubber. Image given is of wet scrubber.