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Solutions for Geography, Class 9, ICSE
Assertion (A): The rapidly increasing number of vehicles on the roads is a big source of noise pollution.
Reason (R): Increasing traffic jams in congested areas lead to repeated hooting of horns by impatient drivers causing noise pollution.
Both A and R are true and R is the correct explanation of A.
Explanation — The rapidly increasing number of vehicles on the roads is a big source of noise pollution. This is due to increased traffic jams in congested areas which leads to repeated hooting of horns by impatient drivers and cause noise pollution.
Assertion (A): Noise from construction sites is generally far worse than noise originating from factories.
Reason (R): Construction itself causes high noise emissions and the equipment used is inherently noisy.
Both A and R are true and R is the correct explanation of A.
Explanation — Noise from construction sites is generally far worse than noise originating from factories. This is because whatever construction takes place noise emissions levels are higher as well as the equipment is inherently noisy.
Assertion (A): The excessive use of chemical fertilisers creates pollution.
Reason (R): The fertilisers are used to enrich the soil.
Both A and R are true but R does not explain A.
Explanation — Chemical fertilisers contain plant nutrients such as nitrogen, phosphorous and potassium. These fertilisers are used to enrich the soil, but they also contaminate the soil with their impurities. When the fertilisers are contaminated with other synthetic organic pollutants, the water in the soil gets polluted too. Hence, excessive use of chemical fertilisers creates pollution.
(a) The main pollutants in Picture A are —
These pollutants contribute to Vehicular Air Pollution, primarily affecting air quality and human health.
Reasons —
These pollutants are emitted from the incomplete combustion of fuel in automobile engines, which is a major cause of air pollution.
Carbon monoxide is a toxic gas that reduces the oxygen-carrying capacity of the blood.
Unburned hydrocarbons such as methane, acetylene, and ethylene are volatile and contribute to smog formation.
Ethylene, in particular, undergoes chemical reactions in the presence of sunlight and nitrogen oxides (NOₓ) to form photochemical oxidants, such as ozone, which are harmful to health and the environment.
Nitrogen monoxide (NO), released during fuel combustion, reacts with oxygen to form nitrogen dioxide (NO₂), which is another harmful pollutant.
(b) The main pollutants in picture B are —
These pollutants are responsible for causing Air Pollution.
Reasons —
During the production of building materials, large quantities of dust and fine particulate matter are released into the air, especially from processes like crushing, grinding, and heating raw materials.
The smoke coming out from the factories producing contruction materials has small particles of dust, carbon, metals, other solids, liquids and radioactive materials which get mixed in smoke and pollute the air.
The combustion of fossil fuels to power machinery and kilns emits sulphur dioxide, nitrogen oxides, and carbon monoxide into the atmosphere.
These pollutants reduce air quality, cause respiratory problems, and contribute to smog and acid rain.
Three air pollutants are-
Carbon Monoxide — It is produced by gasoline fuel, motor vehicles fuel, burning of wood and coal, solid waste disposal and industrial processes.
Nitrogen Oxides — Its primary sources are motor vehicles and power generation stations, combustion of organic matters, furnace stacks and incinerators.
Hydrocarbons — These are produced by motor vehicles, industrial processes, garbage and agricultural waste.
Natural sources of air pollution produce air pollutants as a result of natural phenomena. These include volcanic eruptions, deflation of sand and dust as well as forest, or wild fires of natural vegetation, etc.
Automobile industry pollutes the atmosphere with gaseous as well as with particulate matter.
Smog is a combination of smoke and fog.
During the winter months, due to severe cold, the use of coal and fossil fuels to heat homes and for other purposes increases. These lead to the formation of smog. Smog is harmful for health as it causes asthma, bronchitis, shortness of breath, eye and nose irritation, etc. It also reduces visibility and leads to problems in traffic movement.
Radioactive pollutants are very dangerous because of the following reasons-
This is done in order to reduce noise pollution. Flyovers experience heavy vehicular traffic, which generates continuous and high levels of noise. Fiberglass sheets act as sound barriers, absorbing and deflecting traffic noise away from surrounding residential and commercial areas, thus minimizing noise pollution.
Lighting of crackers significantly contributes to Air Pollution and Noise pollution.
Air Pollution: Crackers release harmful gases like sulphur dioxide, nitrogen oxides, carbon monoxide, and particulate matter into the atmosphere. These reduce air quality and can cause respiratory issues.
Noise Pollution: Loud explosions from crackers exceed safe decibel levels, causing hearing discomfort, stress, and disturbance to humans and animals.
Noise pollution refers to an unwanted sound which produces unpleasant effects and discomfort. Sound becomes unwanted when it interferes with normal activities such as sleeping, conversation or disrupts one's quality of life.
The rapidly increasing number of vehicles on the roads are a big source of noise pollution. Increasing traffic jams in congested areas lead to repeated hooting of horns by impatient drivers causing noise pollution.
The construction sites are considered as worse than factories in their contribution to noise pollution because whatever construction takes place noise emissions levels are higher as well as the equipment is inherently noisy.
In the era of fast urbanisation the demolition and the repair activities along with the huge machines used for the purposes create a great deal of noise to the annoyance of the people living near the sites of construction.
The airplanes cause noise pollution as the noise made by the jet planes is more disturbing than that of the old propeller driven aircraft because it is of far higher pitch. Jet noise is caused by the violent mixing of the jet of gases from the engine with the surrounding air. It is at maximum level during take-off when the engine delivers maximum thrust, and reduces rapidly as the aircraft climbs.
During landing, the main source of high-frequency noise is the sound made by the air compressor and turbine blades. Air crafts pass close to the ground for quite a distance during landing operation and this noise often constitutes a more sustained environmental nuisance than the intense noise of shorter duration produced during take-off. Hence, there is more noise pollution during landing as compared to during take-off.
Vehicles are mainly responsible for more than 80% of total air pollution. The major pollutants released from automobiles, locomotives, aircraft etc., include carbon monoxide, unburnt hydrocarbons and nitrogen monoxide. In the major metropolitan cities like Delhi, Mumbai and Kolkata, vehicular exhaust accounts for 75% of all CO, 45% of all hydrocarbons, 40% of all oxides and 30% of all suspended particulate matter.
Air pollution is also caused by the gaseous and volatile hydrocarbons such as methane, acetylene and ethylene. Some hydrocarbons like ethylene, which undergo chemical reactions in the presence of sunlight and nitrogen oxide form photochemical oxidants that are harmful. Fuel combustion in automobiles also produces nitrogen dioxide.
Industries such as chemical industries, paper and pulp mills, cotton mills and petroleum refineries produce most air pollution. The cement factories emit dust, which is potential health hazard. The smoke coming out from the factories has small particles of dust, carbon, metals, other solids, liquids and radioactive materials which get mixed in smoke and pollute the air.
The burning of sulphur in coal or heavy oil in thermal power plants releases sulphur dioxide in the air. Sulphur dioxide combines with oxygen and water to form sulphuric acid in the atmosphere which is a health hazard. Besides, it produces acid rain.
Three air pollutants are-
Man uses water for drinking, preparation of food, bathing, for cleaning the house, etc. Most of the used water is drained out through municipal drains and poured into a river or lake. Domestic waste water that is mixed with other wastes such as plastic, detergents, animal dung and human faecal material is known as municipal waste.
Many detergents and fertilisers contain phosphates. When phosphates are discharged into waterways, their remnants promote rapid growth of algae. Such enrichment process is known as eutrophication. Aquatic weeds multiply rapidly in many water bodies. They interfere with fishing, navigation and irrigation.
Many detergents contain phosphates. When phosphates are discharged into waterways, their remnants promote rapid growth of algae. Such enrichment process is known as eutrophication. Aquatic weeds multiply rapidly in many water bodies. They interfere with fishing, navigation and irrigation.
Industries dealing with chemicals, pulp and paper, food processing, etc. produce waste material such as heavy metals or synthetic organic compounds. These reach water bodies either through direct discharge or by leaching from waste dumps. Among the heavy metals, cadmium, lead, mercury, copper, chromium etc., get into water.
The industrial waste mixed with water makes it poisonous and unhygienic. It may also cause various diseases in humans and animals, if consumed without treatment.
The two main sources of radioactive pollution are-
Yes, I agree that of all the different types of pollution, noise pollution is the most subtle as we often tend to overlook noise pollution in comparison to other kinds of pollution. Noise pollution has the following harmful effects:
The statement "Pollution in the cities is the price of growing affluence" reflects a commonly observed phenomenon in urban areas. Some examples to support the statement are as follows: