Air Pollution Sources, Effects and Standards - Air and Noise Pollution - Environmental Science & Engineering Previous Year Questions

1

2024 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2024

The environmental temperature increases by 6 °C/km with height at a particular location. The stability condition of the atmosphere at the location is ______.

A

stable

B

unstable

C

inversion

D

neutral

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2

2024 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2024

Which is/are the secondary air pollutant(s)?

A

O₃

B

HNO₃

C

CO₂

D

H₂SO₄

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3

2024 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2024

The concentration of Ozone corresponding to a mixing ratio of 120 ppbv at pressure of 1 atmosphere and temperature of 25°C is __________ µg/m³ (rounded off to 1 decimal place).
Atomic weight of oxygen = 16; R= 8.314 J/K-g.mole.

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4

2025 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2025

Consider the following statements

P : According to the National Ambient Air Quality Standards (Central Pollution Control Board, Govt. of India, notification 2009), annual time weighted average PM10 standard is more than PM2.5 standard.

Q : According to the National Air Quality Index released by Govt. of India in 2015, sub index value of PM10 can be less than that of PM2.5.

Choose the correct option from the following

A

P is TRUE; Q is FALSE

B

P is FALSE; Q is TRUE

C

P is TRUE; Q is TRUE

D

P is FALSE; Q is FALSE

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5

2025 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2025

At a pressure of 1 atmosphere and temperature of 25 °C, 365 μg m⁻³ of a pollutant corresponds to mixing ratio of 139 parts per billion (ppb). The atomic weights: C – 12, H – 1, O – 16, N – 14 and S – 32. Which one of the following options most closely represents the pollutant

A

SO₂

B

NO₂

C

O₃

D

CO

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6

2025 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2025

Which option gives the best control strategies for Dioxins and Furans in the flue gas emitted from waste incineration facilities?

A

Avoid burning polystyrene (PS) and polyethylene (PE); ensure the furnace temperature above 1000 °C; and use a bag filter for cleaning the flue gas.

B

Avoid burning polyvinyl chloride (PVC); quickly cool down the flue gas through the temperature range 400 - 250 °C; and use an activated carbon treatment for the flue gas.

C

Avoid burning food wastes; ensure the furnace temperature above 900 ± 50 °C; and use an electrostatic precipitator (ESP) for cleaning the flue gas.

D

Avoid burning metal bearing waste; ensure the flue gas temperature above 1000 °C; and use a venturi scrubber for cleaning the flue gas.

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7

2025 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2025

A boiler burns coal at a rate of 1 kg/s. If the coal has 3% sulfur content, assuming that there is no sulfur in ash, SO₂ emitted is __________ kg/day. (rounded off to nearest integer)

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8

2025 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2025

An incandescent light bulb operated for two hours per day uses 12.2 kWh of energy per month. Burning of one kg of coal generates 2 kWh of electrical energy and releases 7 g of PM₁₀. The reduction in PM₁₀ emitted per month, if this incandescent bulb is replaced with a light emitting diode (LED) bulb which consumes 1/6th of energy, is ______ g. (rounded off to one decimal place)

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9

2021 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2021

A sample of air is collected in the morning at an ambient temperature of 25 °C. The concentration of carbon monoxide (CO) in this sample is 30 ppmv (ppm by volume). The same sample is analysed later in the afternoon when the sample temperature is 35 °C. The analysis results will show the CO concentration as __________.

A

< 29 ppmv

B

> 30 ppmv

C

= 30 ppmv

D

= 29 ppmv

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10

2021 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2021

In air pollution, which of the following is/are classified as primary pollutants?

A

Carbon monoxide (CO)

B

Sulphur dioxide (SO₂)

C

Ozone (O₃)

D

Nitrogen dioxide (NO₂)

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11

2021 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2021

For any particular location, which of the following would influence the solar radiation incident on a rooftop solar water heater?

A

Heater surface temperature

B

Day of the year

C

Hot water temperature

D

Sky clearness

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12

2021 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2021

The concentration of NO₂ in the air at NTP is reported as 0.30 ppmv (ppm by volume). The concentration of NO₂ in μg/m³ is ______________ (rounded off to the nearest integer).
[At NTP, temperature = 298 K, pressure = 1 atm, and one mole of ideal gas occupies 24.45 L.]
[Molecular weight of NO₂ = 46 g/mol]

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13

2022 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2022

According to the National Ambient Air Quality Standards (Central Pollution Control Board, Govt. of India, notification 2009) which of the following statement(s) is/are correct?

A

SO₂ and NO₂ have annual average standards; while O₃ and CO have eight hour average standards.

B

SO₂ and CO have annual average standards; while O₃ and NO₂ have eight hour average standards.

C

SO₂ and CO have eight hour average standards; while O₃ and NO₂ have hourly average standards.

D

SO₂ and NO₂ have 24 hour average standards; while O₃ and CO have hourly average standards.

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14

2022 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2022

Consider the figure shown below for three different cases:

Which of the following statement(s) is/are correct for surface level emissions, given the environmental temperature?

A

Case P represents unstable atmosphere and results in higher dispersion of emissions.

B

Case Q represents subsidence inversion and results in higher dispersion of emissions than Case P.

C

Case Q represents elevated inversion and results in lower dispersion of emissions than Case P.

D

Case R represents subsidence inversion and results in lower dispersion of emissions than Case P.

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15

2023 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2023

Which of the following is true according to the Central Pollution Control Board (CPCB), Government of India’s notification issued in the year 2009?

A

24 hour averaged standard for PM_2.5 in ambient air is 60 µg/m³; 24 hour averaged standard for PM₁₀ in ambient air is 100 µg/m³

B

24 hour averaged standard for PM_2.5 in indoor air is 60 µg/m³; 24 hour averaged standard for PM₁₀ in ambient air is 100 µg/m³

C

24 hour averaged standard for PM_2.5 in ambient air is 60 µg/m³; 24 hour averaged standard for PM₁₀ in indoor air is 100 µg/m³

D

24 hour averaged standard for PM_2.5 in indoor air is 60 µg/m³; 24 hour averaged standard for PM₁₀ in indoor air is 100 µg/m³

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16

2023 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2023

Which of the following statements is/are NOT true?

A

Urban heat island effect in a city can be reduced by increasing trees and vegetation cover in the city.

B

Urban heat island intensity is affected by PM2.5 concentrations in a city.

C

Urban heat island intensity increases due to installation of reflective roofs in a city.

D

In comparison with the non-urban areas, urban heat island effect raises night-time temperatures more than daytime temperatures in cities.

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17

2023 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2023

An industry with an effective stack height of 80 m emits 1200 g/h of CO. The windrose plotted using the meteorological data at the top of the stack, and the relation between dispersion coefficients and wind direction are given below:

Wind Direction	Dispersion coefficients (in m)
	Crosswind direction	Vertical direction
Northeast	50	20
North	45	30
Northwest	40	35
East	45	30
Southeast	55	35
South	60	40
Southwest	65	45
West	70	50

During the maximum duration of the year, the ground level PM_2.5 concentration at the downwind distance of 2 km (at the plume centerline) from the stack is __________ (in μg/m³, rounded off to two decimal places).

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18

2026 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2026

The general atmospheric composition of gases in the decreasing order is ______.

A

N2 > O2 > CO > CO2 > NH3

B

N2 > O2 > CO2 > CO > NH3

C

N₂ > CO₂ > O₂ > NH₃ > CO

D

N2 > CO2 > NH3 > CO > O2

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19

2026 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2026

Which ONE of the following options CORRECTLY matches the atmospheric stability conditions with plume conditions/ behaviours given in the table?

Atmospheric Stability Conditions	Plume Conditions/ Behaviours
(P) Strong instability	(i) Fanning plume
(Q) Neutral stability	(ii) Fumigation
(R) Surface inversion	(iii) Coning plume
(S) Aloft inversion	(iv) Looping plume

A

(P) - (i); (Q) - (ii); (R) - (iii); (S) - (iv)

B

(P) - (iv); (Q) - (iii); (R) - (i); (S) - (ii)

C

(P) - (iii); (Q) - (iv); (R) - (ii); (S) - (i)

D

(P) - (ii); (Q) - (i); (R) - (iv); (S) - (iii)

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20

2026 · Environmental Science & Engineering · Air and Noise Pollution · Air Pollution Sources, Effects and Standards

Environmental Science & Engineering (ES) 2026

The mixing ratio of CO₂ at a pressure of 1 atm and at 300K is reported as 340 ppmv.
Considering ideal gas conditions, the equivalent concentration of CO₂ in air is ______ mg/m³ (rounded off to two decimal places).
The molecular weight of CO₂ = 44 g/mol
Universal gas constant = 8.314 J/mol-K

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