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Stratosphere zone is called ozonosphere.

Chlorofluoro carbons (CFC’s) damage the ozone layer and create holes in ozone layer.

Ultraviolet rays reaching the earth passing through the ozone hole cause skin cancer.

The warming of the earth or global warming due to re-emission of sun’s energy absorbed by the earth followed by its absorption by CO₂ molecules and H₂O vapours present in the atmosphere, near the earth’s surface and then its radiation back to the earth is called greenhouse effect. Greenhouse affects the climate. If the rate at which solar radiation are arriving the earth continues, then the entire global climate is going to change drastically.

Ultraviolet rays from the sun will reach the earth after passing through the ozone hole and cause skin cancer.

The lower regions of atmosphere in which the human beings along with other organisms live are called troposphere. It extends up to the high of ~10 KM from sea level.

Above the troposphere, between 10 and 50 km above sea level lies is called stratosphere.

UV radiation 

It prevents the harmful UV radiations to reach on earth which cause skin cancer.

It is produced due to the incomplete combustion of carbon, coal, firewood, petrol etc.

1. CO binds haemoglobin of blood to form carboxyhaemoglobin which is about 300times more stable than oxygen –haemoglobin complex. When carboxyhaemoglobin concentration increases in blood the oxygen carrying capacity is reduced. This results in headache, nervousness & cardiovascular disorder.

2.  In pregnant women who have the habit of smoking may induce premature birth, abortions, deformed babies.

The warming of earth due to the trapping of sun‟s energy by gases such as CO₂, CHs, Ozone, CFC‟S in the atmosphere. 

1. A rise in sea level 

2. Increase in heat related diseases

3. Increase in precipitation & decrease in soil moisture content etc. 

CO & CO₂ oxide of carbon.

Infrared radiations.

UV radiation

Drinking water containing moderate level of sulphatcs is harmless. But excessive concentration (>500 ppm) of suiphates in drinking water causes laxative effect.

The three main components of photochemical sinog are Hydrogen sulphide. dust and PAN.

Classical smog is otherwise called reducing smog.

Pinus tree plantation can metabolise nitrogen oxide and control photochemical smog.

ozone acts as an umbrella for the earth and prevent harmful UV radiations.

Photochemical smog is  other wise called Los angeles smog.

Oxides of sulphur, nitrogen & carbon,H₂S, Hydrocarbons etc. 

Greenhouse effect is defined as the heating up of the earth’s surface due to trapping of infrared radiations reflected by earth’s surface by the CO₂ layer in the atmosphere.

Smog, When smoke mixes with fog, it is called smog. It is of two types: 

1. Classical smog: It occurs in cool humid climate and is the result of build-up of sulphur dioxides and particulate matter from fuel combustion. It is reducing in nature.

2. Photochemical smog : It occurs in warm, dry and sunny climate and results from the action of sunlight on the nitrogen oxides and hydrocarbons produced by automobiles and factories. It is oxidizing in nature.

(iv) A is not correct but R is correct

ATMOSPHERIC POLLUTION:-

The atmosphere that surrounds the earth is not of the same thickness at different heights.Atmospheric pollution is generally studied as tropospheric and stratospheric pollution.The ozone layer prevents about 99.5%of the sun‘s UV rays.

It is a substance present in the environment in great proportion than its natural abundance and resulting in harmful damage effect.

Consequences of Ozone hole:

The ultraviolet rays entering into the earth through ozone hole leads to

(i) Increase cases of skin cancer

(ii) It affects plants, chlorophyll, proteins and causes harmful mutation in them.

(iii) Upset the heat balance of the earth

(iv) Ecological imbalance, which would adversely affect man and animals.

1. Pathogens: These are water pollutants include bacteria and other organisms. They enter water from animal excreta and domestic Sewage. Bacteria presents in human excreta causes gastrointestinal diseases (Excreta contains, Escherichia Coli and streptococcus faecalis ) 

2. Organic wastes: These are biodegradable water that pollutes water as a result run off. The presence of excess of organic wastes in water decreases the amount of oxygen held by water. This decrease in the amount of dissolved oxygen inhibits aquatic life. 

3. Chemical pollutants: These are the water soluble chemicals like heavy metals such as cadmium, mercury, nickel etc… The presence of these chemicals (above the tolerance limit) can damage the kidneys, central nervous system and liver.

When smoke with fog, it is called smog.

Smog is a mixture of smoke, dust partials and small drops of fog. 

Classical smog :--- 

a. It occurs in cool humid climate. 

b .It is a mixture of smoke, fog and sulphur dioxide. 

c. It is called reducing smog 

Photochemical smog:-- 

a.It occurs in warm dry and Climate sunny climate 

b. It is a mixture of oxides of nitrogen, formaldehyde ,acrolein and PAN. 

c. It is called oxidizing smog.

The London smog is caused during summer season and in the afternoon pant of the day when it is very hot.

SO₂ and NO₂.

PAN  and O₃ two air pollutants which forms photochemical smog.

An example for biodegradable pollutant is plant waste.

CH₃COOH acid is not present in acid rain.

One insecticide is DDT.

Present in acid rain is CH₃COOH.

PAH is carcinogenic and causes irritation in eyes and mucous membrane.

H₂SO₄ acid is most abundant in acid rain.

CO₂ causes less pollution.

Eutrophication causes reduction in dissolved oxygen.

Neem based pesticide is the most safest pesticide.

H₂O₂ is used to bleach paper

• Green chemistry is a chemical philosophy encouraging the design of products and processes that reduces or eliminates the use and generation of hazardous substances. 
• Efforts to control environmental pollution resulted in development of science for the synthesis of chemicals favorable to environment. 
• Green chemistry means science of environmentally favorable chemical synthesis.

(a) CCF : Green house effect

Methods to control environmental pollution: 

• Waste management Environmental pollution can be controlled by proper disposal of wastes. 
• Recycling A large amount of disposed waste materials can he reused by recycling the waste, thus it reduces the landfill. – 
• By substitution of less toxic solvents for highly toxic ones are used in industrial processes. By growing more trees. 
• By using fuels with lower sulphur content. 
• By control measures in vehicle emissions which are adequate.