True
False. Almost all urban areas show high levels of air pollution.
True
True
False. Global warming is the most undesirable aspect of the intensified greenhouse effect.
The adverse effects of ozone depletion are as follows: Stratospheric ozone is being destroyed mainly by chlorine atoms of chlorofluorocarbon (CFC) molecules. This has created a hole in the ozone layer in the stratosphere near Antarctica. This hole allows the ultraviolet radiations of the Sun to reach the Earth's surface directly. These rays damage animal and plant life on the Earth. Ultraviolet rays even cause skin cancer and cataract in human beings.
Different laws to prevent pollution:
i. Water (Prevention and Control of Pollution) Act, 1974
ii. Air (Prevention and Control of Pollution) Act, 1981
iii. Environment (Protection) Act,1986
Different laws and rules have been made for the disposal of hazardous waste, biomedical waste, solid waste and prevention of noise pollution.
The Central Pollution Control Board (CPCB) and Maharashtra Pollution Control Board (MPCB) are government bodies which check whether organisations such as factories, industrial estates, municipalities, Zilla Parishads, Panchayat Samities and Gram Panchayats follow all the laws related to the control of pollution. Any violation is punishable under the specifications of these laws.
There are two main sources of water pollution - natural sources and man-made sources.
Natural sources of water pollution:
Because of heavy rains, minerals from the land are washed off into the rivers and then oceans. Dead animals, animal waste, ashes, chemicals of forest fires and sulphur compounds from volcanoes get washed into the nearby water sources due to rain.
Man-made sources of water pollution:
City sewage and industrial waste are the main sources of water pollution. They can be further classified into domestic sewage, industrial waste, radioactive waste, agricultural runoff, oil spills and thermal pollutants.
Biodegradable waste includes materials such as sewage which can rapidly decompose by natural processes. These pollutants can become a nuisance when added to the environment at a faster rate than they decompose.
Because a large amount of urban solid waste is paper and food waste, majority of it is biodegradable and can be buried in landfills.
Non-biodegradable waste includes materials such as polythene bags, footwear and plastic which either do not decompose or decompose slowly in the natural environment. They remain in the soil for a long period of time.
When industrial and urban wastes such as chemicals and plastics are dumped in soil, they can accumulate and interfere with life processes.
Excessive burning of fossil fuels along with deforestation and pollution, greenhouse effect and ozone depletion are the major causes of global warming.
Diseases caused by polluted water are cholera, typhoid, diarrhoea, dysentery, hepatitis, polio and jaundice.
The excessive use of fertilisers and pesticides should be avoided so that the soil does not get contaminated.
Domestic waste should not be thrown indiscriminately on the land. Instead, it should be classified into biodegradable and non-biodegradable wastes before disposal.
Biodegradable materials should be composted and converted into useful manure.
Non-biodegradable materials should be recycled and reused.
Safe disposal of biomedical waste should be practised and solid waste should be properly disposed.
Pollutants are substances which affect the normal functioning of an ecosystem and have an adverse effect on plants, animals and human beings. When pollutants are present in excess, the environment becomes toxic and unhealthy.
When toxic substances enter any water body or lie suspended in water or get deposited on the bed of the water body, the quality of water deteriorates and affects the aquatic ecosystem. This is called water pollution.
Due to human activity, high energy radioactive particles mix in air, water and soil and pollute it. This is known as radioactive pollution.
Monuments affected by acid rain:
i. Taj Mahal in India
ii. Longmen Grottoes and Leshan Giant Buddha on Mount Emei in China
iii. Acropolis of Athens in Greece
iv. Dampier Rock Complex in Australia
Air pollution has major effects on human health. They can be short-term effects or long-term effects.
Short-term effects:
Irritation of eyes, nose, mouth and throat
Infections of the respiratory tract such as bronchitis and pneumonia
Headache, nausea and allergy
Asthmatic attacks
Reduced lung functioning
Long-term effects:
Chronic pulmonary disease
Cardiovascular disease
Lung cancer
Premature death
The impact of noise pollution on the human body depends on the intensity, frequency and duration of exposure to noise.
Effects of noise pollution on the human body:
Auditory effects: Auditory fatigue and deafness
Non-auditory effects: Mental disorientation, violent behaviour, ill temper, annoyance, loss of working efficiency and interference in communication, sleep and concentration
Physiological effects: Nausea, fatigue, anxiety, cardiovascular disease, insomnia, visual disturbances and hypertension
To avoid noise pollution in the classroom, we should practise small things in the classroom.
When the teacher is not present in the classroom, all students should observe silence and not shout loudly.
Activities such as book reading, solo singing or story telling should be carried out so that the other students can maintain silence.
The monitors in the class who control the classroom should ask the teacher to punish the students who make a lot of noise.
Add curtains to the classroom.
Use cork bulletin boards for the walls.
Place sound-absorbent panels on the upper walls of the classroom.
The following steps should be adopted to minimise the bursting of fire crackers in festivals and procession:
Bursting fire crackers should be strictly avoided because they cause noise and air pollution.
If necessary, noiseless crackers or eco-friendly variety of crackers can be used.
Fire crackers should not be burst near hospitals and other silence zones.
Bursting fire crackers should be banned after 10 p.m.
The following measures can help to reduce the use of fossil fuels:
Instead of fossil fuels, gobar gas should be used in villages where animal dung is available in plenty.
Biogas plants should be installed in the farms of villages as this will help in reducing the use of fossil fuels.
Solar cookers can also be made available for village kitchens so that the use of fossil fuels is reduced.
Conventional energy sources like solar energy and wind energy should be used to obtain energy instead of non-conventional energy sources.
The following practices should be adopted to avoid pollution of land when you go for a picnic:
Do not throw garbage here and there at the picnic spot as it spoils natural beauty.
Paper plates, bottles, cans and plastic bags should not be thrown indiscriminately.
Collect all the garbage and dispose it in dustbins. If dustbins are not there, carry the garbage home and then dispose it in the dustbin at home.
Do not spoil walls by writing your names or by scratching on them.
If possible, use paper bags and avoid the use of polythene bags.
The following measures can help to minimise the level of air pollution in your locality:
We should plant trees along the roadside, gardens, parks and open grounds in your locality.
Activities causing pollution should be avoided, e.g. burning of garbage or throwing garbage in the open.
A particular place can be provided for garbage collection. It has to be ensured that the garbage is disposed of on a daily basis.
Awareness should be created for the use of eco-friendly, conventional energy sources like solar energy, wind energy etc.
The following measures should be taken to avoid noise pollution in silent zones:
Loudspeakers should never be used in silent zones.
Honking of horns should be banned.
Bursting of noisy crackers should be prohibited.
Silent zone sign boards should be put up in these areas.
The following practices should be adopted to minimise electricity consumption at home:
i. Switch off the fans, lights and bulbs when not in use.
ii. Use of CFL should be encouraged.
iii. Avoid using air conditioners whenever possible.
iv. Allow sunlight and fresh air to enter the house in order to reduce the use of electricity during the day time.
v. Use solar water heaters instead of electrical heaters.
Differences between degradable and non-degradable pollutants:
Degradable pollutants
Non-degradable pollutants
1.
Degradable pollutants can degrade on their own over a period of time.
Non-degradable pollutants cannot degrade on their own.
2.
They are acted upon by microorganisms and are converted to inorganic substances.
They are not acted upon by microorganisms and so exist in the complex form only.
3.
They do not get accumulated in nature.
They get accumulated in nature and persist for a long time.
4.
They emit foul odour when they are being decomposed.
They do not emit foul odour as they are not decomposed.
5.
Examples: Vegetables, fruits, organic matter
Examples: Metals, plastic, glass
Differences between primary and secondary pollutants:
Primary pollutants
Secondary pollutants
1.
Primary pollutants are emitted directly from the source.
Secondary pollutants are not emitted directly from the source but are formed due to chemical reactions.
2.
They are found in the atmosphere in the form they are emitted.
They are found as products of chemical reaction between the atmospheric constituents and primary pollutants.
3.
Ash, smoke, dust, oxides of carbon, sulphur and nitrogen are primary pollutants.
SO3, O3, ketones and hydrogen cyanide are secondary pollutants.
Acid rain
Acid rain is rainwater mixed with harmful concentration of nitric acid and sulphuric acid.
Burning of fossil fuels releases oxides of sulphur and nitrogen into the air. These oxides dissolve in rainwater and react with it forming sulphurous acid, sulphuric acid, nitrous acid and nitric acid. When this acidic rainwater falls on the ground, it is called acid rain.
Acid rain causes harm to plants as it increases the acidity of the soil.
Increase in the acidity of water bodies damages aquatic life.
Acid rain corrodes buildings, statues, monuments and bridges.
Eutrophication
When inorganic plant nutrients such as nitrates and phosphates enter water bodies, either naturally or due to human activity, they cause eutrophication.
Eutrophication occurs because of the discharge of domestic sewage, industrial effluents and fertilisers from agricultural fields into water bodies.
These promote excessive growth of phytoplankton and algae. When the algae die, oxygen is used for their decomposition. This results in depletion of oxygen.
The bloom of algae further blocks the penetration of oxygen, light and heat into the water body. As a result, most of the aquatic animals die causing more decomposition and more eutrophication.
Oil spills
Oil spills are the accidental release of crude oil into a water body.
Oil can be from a tanker, offshore drilling rig or by underwater wells and pipelines.
Oil spills are very harmful to marine life and the environment.
Oil spills may occur because of a collision of ships in the ocean.
On 7th August 2010, the cargo vessel MSC Chitra collided with MV Khalijia III outside Mumbai harbour resulting in the spillage of 800 tonnes of oil.
