Tag: air pollution and its control

Questions Related to air pollution and its control

Air entering lungs is $(1)$ Warmed $(2)$ Filtered $(3)$ Deprived of some oxygem $(4)$ Enriched with $CO _2$. What is true?

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. $1, 2, 3$ and $4$

  2. $1$ and $2$

  3. $2$ and $4$

  4. $2$ and $3$

Show answer
Correct Option: B

Photocatalysis of effluents is carried out with the help of

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. Polymeric adsorbents

  2. Titanium dioxide

  3. Resins

  4. UV radiations

Show answer
Correct Option: B
Explanation:
Photocatalysis is the reaction in presence of a catalyst that accelerates the rate of reaction which in turn, is occurring in presence of light i.e. photoreaction. Photocatalysis of effluents discharged from industries is done to remove organic pollutants from them. The catalyst used in the reaction is either zinc oxide or titanium oxide. Titanium oxide is a photocatalyst. When it is illuminated by light, an electron and positive hole pair is produced. The positive hole reacts with water to break it into hydrogen gas and hydroxyl ion whereas the negative electron reacts with oxygen to form superoxide.
So, the correct answer is 'Titanium oxide'.

In coal fired power plants, electrostatic precipitators are fitted to control emission of

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. $NO _x$

  2. CO

  3. SPM

  4. $SO _2$

Show answer
Correct Option: C
Explanation:

The electrostatic precipitators work on the principles of the electrostatic force. It consists of discharge wires and collecting plates. An application of high voltage to the discharge wires create an electric field between the wires and the plates. When the air containing the dust and suspended particulate matter like aerosols and solid particles is passed through this electrostatic field, the particles get charged and are collected onto the plate as per Coulomb's Law. This makes the air free of dust and SPM. Electrostatic precipitators are used in vehicles and coal-fired power plant to restrict the entry of dust and SPM into the atmosphere

So, the correct answer is 'SPM'

Air pollution is not reduced by

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. Using precipitators

  2. Reusing wastes

  3. Cleaning air

  4. All of the above

Show answer
Correct Option: B
Explanation:

Air pollution is caused by the release of harmful oxides of nitrogen, sulphur and carbon from the vehicular exhausts and industrial emissions primarily. Using precipitators allow the removal of dust from these emissions. Keeping the air clean by minimizing the combustion of fossil fuels, less use of vehicles, use of catalytic converters can help in reducing the air pollution. Reusing waste allows the minimal production of non-degradable waste. Hence, the correct answer is 'Reusing wastes'.

Low sulphur diesel has become available in India from

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. First April 1996

  2. First April 1997

  3. First January 1997

  4. First January 1996

Show answer
Correct Option: A
Explanation:
Sulphur is an important fuel parameter for assessing exhaust emissions. It results in the release of particulate mater in the air. The original concentration of sulphur in diesel in India used to be about 10,000 ppm which now has been reduced to about 350 ppm. This was possible because of introduction of low sulphur diesel in India on First April in 1996.
So, the correct answer is 'First April 1996'.

Unleaded petrol has been introduced in India with effect from 

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. First January, 1996

  2. First April, 1995

  3. First April, 1996

  4. First January, 1997

Show answer
Correct Option: B
Explanation:

From April 1995, mandatory fitment of catalytic converters in new petrol passenger cars sold in the four metros, Delhi, Calcutta, Mumbai and Chennai along with the supply of Unleaded Petrol (ULP) was affected. Availability of ULP was further extended to 42 major cities and it is now available throughout the country. 

So the correct answer is 'First April 1995'.

Thermal plants have installed

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. Cyclone collector

  2. Porous filters

  3. Electrostatic precipitators

  4. Adsorbents

Show answer
Correct Option: C
Explanation:
A. Cyclone collector removes particulate matter from air, water or gas stream.
B. Porous filters remove minute particles from liquids and gases.
C. Electrostatic precipitators removes the particulate matter from air as the particles are charged and get settled down when they are passed through a chamber.
D. Adsorbents remove very fine particles from air or water as the particles get stuck on the surface of adsorbents.
Thermal plants have installed electrostatic precipitators to remove the fly ash formed as a result of boiler emissions.
So, the correct answer is 'Electrostatic precipitators'.
 

In vehicles, catalytic converter are used to

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. Increase mileage

  2. Convert $CO _2$ to carbonates

  3. Increase efficiency of lead petrol

  4. Convert CO to $CO _2$

Show answer
Correct Option: D
Explanation:
Catalytic convertors consist of expensive metals like platinum- palladium and rhodium as catalysts which are fitted in the automobiles to reduce the emission of poisonous gases. When the exhaust passes through catalytic convertor, unburnt hydrocarbons get converted into carbon dioxide and water, carbon monoxide is converted to carbon dioxide and nitric oxide is converted to nitrogen gas.
So, the correct answer is 'Convert CO to CO2'.

Match the items of Column I and Column II and select the correct combinations.

Column-I Column-II
a Electrostatic precipitator p Removes gases like $SO _2$
b Scrubber q Reduces automobile emission
c Catalytic converter r Removes particulate matter
zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. a-q, b-r, c-p

  2. a-r, b-q, c-p

  3. a-r, b-q, c-r

  4. a-r, b-p, c-q

  5. a-p, b-r, c-q

Show answer
Correct Option: D
Explanation:

  • Electrostatic precipitator is used to remove particulate matter present in the air. The particulate matter are charged and passed through a chamber where they the particles lose their charge and settle down.
  • Scrubbers are used to remove gases like sulphur dioxide (SO2). The exhaust is passed though a spray of lime or water.
  • Catalytic convertors consist of expensive metals like platinum- palladium and rhodium as catalysts which are fitted in the automobiles to reduce the emission of poisonous gases. When the exhaust passes through catalytic convertor, unburnt hydrocarbons get converted into carbon dioxide and water, carbon monoxide is converted to carbon dioxide and nitric oxide is converted to nitrogen gas.
So, the correct answer is 'a-r, b-p, c-q'.

Consider statements a-c about pollution.
(a) To control air pollution all Delhi buses were asked to run on unleaded petrol by the end of $2002$.
(b) Electrostatic precipitator can remove $99\%$ of particulate matter from thermal power plant exhaust.
(c) It is possible to estimate amount of organic matter in sewage water by measuring BOD. Of the statements.

zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

  1. b and c correct

  2. a alone correct

  3. b alone correct

  4. c alone correct

  5. a and b correct

Show answer
Correct Option: A
Explanation:
  • An electrostatic precipitator is a device that removes suspended dust particles from a gas or exhaust by applying a high-voltage electrostatic charge and collecting the particles on charged plates. It can remove 99% of particulate matter from thermal power plant exhaust.
  • BOD(Biochemical oxygen demand) is a measure of, the amount of oxygen that require for the bacteria to degrade the organic components present in water/wastewater. Hence based on the BOD it is possible to estimate the amount of organic matter in sewage water.
  • Hence b and c are correct statements.
  • So, the correct answer is 'b and c correct'.