- No.3.State the major sources of CO and CO2 emission
Answer. The major sources of CO and CO2 emission are volcanic eruption and decomposition of organic matter naturally. However, the major source for the emission of these gases is combustion of fossil fuels. Forest fires and burning of wood also emit CO2 and CO. Especially, when supply of oxygen is limited, emission of CO dominates
- No.4. CO2 is responsible for heating up atmosphere, how?
Answer. The CO2 forms a layer around the Earth like an envelope. It allows the heat rays of the Sun to pass through it, and reaches up to the Earth. These rays are reflected from the Earth surface and go back to upper atmosphere as shown in figure. Normal concentration of CO2 layer retains enough heat to keep the atmosphere warm. So, normal 1 concentration of CO2 is necessary and beneficial for keeping the temperature warm. Otherwise, the Earth would have been uninhabitable. The Earth’s average temperature would be about -20°C, rather than presently average temperature 15°C.
The natural process of heat going out.
- No.5. CO is a hidden enemy, explain its action.
Answer. CO is a health hazard being highly poisonous gas. Being colorless and odourless, its presence cannot be noticed easily and readily. When inhaled, it binds with the hemoglobin most strongly than that of oxygen. Thus hindering the supply of oxygen in body. Exposure to higher concentration of CO causes headache and fatigue. If inhaled for a longer time it results in breathing difficulties and ultimately death.
- No. 6.What threats are to human health due to SO gas as air pollutant?
Answer. SO2 is a colorless gas having irritating smell. It causes suffocation, irritation and severe respiratory problems to asthmatic people.
- No. 7. Which air pollutant is produced on anaerobic decomposition of organic matter?
Answer. Anaerobic decomposition of organic matter produces CO2 and CO gases.
- No. 8.How acid rain increases the acidity of soil?
Answer. Normal rain water is weakly acidic because it consists of dissolved CO2 of air. Its pH is about 5.6 to 6. But rain-water on dissolving air pollutants (acidic gases SO2 and NOx) becomes more acidic and its pH decreases. As a result, normal rain water changes into acidic rain. When this acid rain falls on soil it increases the acidity of soil.
- No. 9.Point out two serious effects of ozone depletion.
(i) Depletion of ozone enables ultraviolet radiations of Sun to reach to the Earth that can cause skin cancer to human beings and other animals.
(ii) Decreased ozone layer will increase infectious diseases like malaria.