Air

Question 1 Name the gases present in air?
Question 2 What is the role of atmosphere in climate control?
Question 3 What are the major sinks of carbon dioxide?
Question 4 How water vapours are formed?
Question 5 What is air pollution?
Question 6 What are the causes of air pollution?
Question 7 What happens in coastal regions during day and night?
Question 8 How rain is formed?
Question 9 What are the harmful effects of air pollution?
 
Air
Air is a mixture of many gases like nitrogen,oxygen,carbon dioxide,water vapour,suspended particles.
On venus and mars the major component of atmosphere is found to be carbon dioxide. Eukaryotic and prokaryotic cells need oxygen to breakdown glucose molecules and get energy for their activities.This result in production of Carbon dioxide.
Carbon dioxide is produced during combustion:
Carbon dioxide is fixed in 2 ways:
1)Green plants convert Carbon dioxide into glucose in the presence of sunlight.
2)Many marine animals use carbonates dissolved in sea-water to make their shells.
 
Role of atmosphere in climate control
1)It keeps the average temperature of earth fairly steady during the day and even during he course of whole year.
2)It prevents sudden increase in temperature during the daylight hours.
3)During the night,it slow down the escape of heat into outer space.
 
Movement of air-wind
All the phenomena(movement of air,whether this movement of air will be in the form of a gentle breeze or strong wind or terrible storm)are result of changes that takes place in our atmosphere due to heating of air and the formation of water vapours.
Water Vapours is formed due to heating of water bodies and activities of living organism.When the solar radiation falls on the earth,some are absorbed and majority of these are reflected back or re radiated by the land and water bodies.These reflected or re radiated solar radiations heat the atmosphere from below.A a result,convection currents are set up in the air.Since the land gets heated faster than the water,the air over land also gets heated faster than the air over water bodies.
 
What happens in coastal regions during day and night.
During the day,the air above the land gets heated faster and start rising,creating a region of low pressure.The movement of air from one region to other creates winds.Thus during day the direction of wind is from sea to the land.During night,both land and sea starts to cool.Since,water cools down slower than the land,the air above water would be warmer than the air above land.Thus during night direction of wind is from land to the sea.
All the movement of air resulting in diverse atmospheric phenomena are caused by uneven heating of atmosphere in different regions of the earth.
 
Rain
When water bodies are heated with solar radiation during the day,a large amount of water evaporates and goes into the air.Some amount of water vapour also goes into the atmosphere because of various biological activities such as transpiration.The air carrying water vapours also gets heated.This hot air rises up carrying water vapours with it.As the air rises,it expand and cools.This cooling causes the water vapour in the air to condense in the form of tiny droplets.

Such process of condensation of water is facilitated when dust and other suspended particles act as the nucleus for these droplets to form around.An enormous collection of tiny droplets of water appear in the form of clouds.These droplets of water,once formed,slowly grow bigger by condensation of more water droplets.When the droplets have grown big and heavy,they fall down in the form of a rain.When the temperature of air is very low,precipitation then may occur in the form of snow,sheets or hail.

Movement of air plays an important role in bringing rains in India.Due to its peninsular shape and differences in temperature and pressure,monsoon winds are prevalent in India.In summer season southwest monsoon is active while during winter season northeast monsoon is active.

Air Pollution

Air carries many undesirable substances or impurities such as carbon dioxide,carbon monoxide, Oxides of S and N,fluoride compounds,Metals(Lead,arsenic,cadmium,tin)Particulate matter.
 Air Pollution is caused by
1)Burning of fossil fuels such as coal and petroleum
2)Automobile exhaust
3)Industries,heavy metals,pesticides
4)Photo chemical smog,smoke.
These air pollutants can cause respiratory problem,high blood pressure,problems in nervous system,eye irritation,falling of leaves,Sulphur dioxide react with water in the atmosphere to form sulphuric acid.This acid is washed down by rain(Acid rain) which make the soil acidic affecting plant growth,affect fish yield,eats surfaces of building.