Unit 4: Environmental pollution - Practice Quiz

CHE110 — Environmental Studies 60 Questions
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1 Which of the following best defines environmental pollution?

Definition, types and causes of environmental pollution Easy
A. The conservation of natural resources
B. The addition of harmful substances into the environment
C. The planting of trees in urban areas
D. The natural cycling of nutrients in ecosystems

2 A substance that causes pollution is known as a:

Definition, types and causes of environmental pollution Easy
A. Catalyst
B. Nutrient
C. Solvent
D. Pollutant

3 Which gas is the main pollutant released by vehicles due to incomplete combustion of fuel?

Air pollution: effects and controls Easy
A. Helium
B. Nitrogen
C. Oxygen
D. Carbon monoxide

4 Which device is commonly used to control particulate matter in industrial chimneys?

Air pollution: effects and controls Easy
A. Air conditioner
B. Water sprinkler
C. Ceiling fan
D. Electrostatic precipitator

5 Which of the following is a common cause of water pollution?

Water pollution: effects and controls Easy
A. Rainwater harvesting
B. Discharge of untreated sewage into rivers
C. Planting aquatic plants
D. Building check dams

6 The enrichment of water bodies with excess nutrients leading to algal blooms is called:

Water pollution: effects and controls Easy
A. Sedimentation
B. Distillation
C. Eutrophication
D. Filtration

7 Which of the following is a major cause of soil pollution?

Soil pollution: effects and controls Easy
A. Organic composting
B. Mulching with dry leaves
C. Crop rotation
D. Excessive use of chemical fertilizers and pesticides

8 Which practice helps control soil pollution?

Soil pollution: effects and controls Easy
A. Using biofertilizers and organic manure
B. Spraying more pesticides
C. Dumping industrial waste on land
D. Overusing plastic sheets

9 Noise pollution is measured in which unit?

Noise pollution: effects and controls Easy
A. Newton
B. Kelvin
C. Decibel
D. Pascal

10 Which of the following is a harmful effect of noise pollution on humans?

Noise pollution: effects and controls Easy
A. Better digestion
B. Hearing loss
C. Improved eyesight
D. Stronger bones

11 Which of the following is a natural source of radiation pollution?

Radiation pollution: effects and controls Easy
A. Cosmic rays from the sun
B. Vehicle exhaust
C. Sewage water
D. Plastic bags

12 Exposure to high levels of radiation can cause which of the following?

Radiation pollution: effects and controls Easy
A. Better vision
B. Cancer
C. Faster hair growth
D. Increased immunity

13 Which of the following is considered an emerging pollutant?

Emerging pollutants Easy
A. Carbon dioxide
B. Rainwater
C. Pharmaceutical residues in water
D. Sand

14 Bursting of fireworks mainly contributes to which type of pollution besides air pollution?

Fireworks and their ill-effects Easy
A. Soil pollution
B. Water pollution
C. Thermal pollution
D. Noise pollution

15 Which gas is the main contributor to global warming?

Global warming Easy
A. Argon
B. Oxygen
C. Nitrogen
D. Carbon dioxide

16 Which of the following is a likely consequence of climate change?

Climate change Easy
A. Reduction in extreme weather events
B. Rising sea levels
C. Increase in ozone layer thickness
D. Cooling of all oceans

17 Which group of chemicals is mainly responsible for ozone layer depletion?

Ozone layer depletion Easy
A. Chlorofluorocarbons (CFCs)
B. Nitrates
C. Carbohydrates
D. Proteins

18 Acid rain is mainly caused by the emission of which gases?

Acid rain Easy
A. Sulphur dioxide and nitrogen oxides
B. Methane and hydrogen
C. Oxygen and nitrogen
D. Helium and neon

19 Which of the following is an example of biodegradable waste?

Solid waste management Easy
A. Vegetable peels
B. Plastic bottles
C. Aluminium cans
D. Glass pieces

20 The '3 R' principle of waste management stands for:

Control measures of urban and industrial waste Easy
A. Remove, Repair, Restore
B. Read, Recall, Review
C. Reduce, Reuse, Recycle
D. Reject, Reserve, Return

21 A factory releases pollutants that are not harmful themselves but react with sunlight to form toxic compounds like smog. These original pollutants are best classified as:

Definition, types and causes of environmental pollution Medium
A. Secondary pollutants
B. Primary pollutants
C. Tertiary pollutants
D. Biodegradable pollutants

22 A device used in industries removes particulate matter from exhaust gases by charging the particles and collecting them on oppositely charged plates. This device is a(n):

Air pollution: effects and controls Medium
A. Cyclone separator
B. Wet scrubber
C. Electrostatic precipitator
D. Fabric bag filter

23 Carbon monoxide (CO) is dangerous to humans mainly because it:

Air pollution: effects and controls Medium
A. Binds to hemoglobin more strongly than oxygen
B. Dissolves in blood to form carbonic acid
C. Reacts with skin to cause burns
D. Directly damages lung tissue on contact

24 A lake shows heavy algal growth, low dissolved oxygen, and fish deaths after receiving fertilizer runoff. This process is called:

Water pollution: effects and controls Medium
A. Biomagnification
B. Eutrophication
C. Bioremediation
D. Acidification

25 A high Biochemical Oxygen Demand (BOD) value in a water sample indicates:

Water pollution: effects and controls Medium
A. High concentration of dissolved oxygen
B. Safe and clean drinking water
C. Low bacterial activity present
D. High level of organic pollution

26 Repeated use of chemical pesticides on farmland often leads to a long-term problem because these chemicals:

Soil pollution: effects and controls Medium
A. Rapidly evaporate into the air
B. Convert into harmless nutrients
C. Persist and accumulate in the soil
D. Immediately dissolve and wash away

27 The intensity of sound is measured on a logarithmic scale. An increase from 60 dB to 90 dB represents an increase in intensity by a factor of:

Noise pollution: effects and controls Medium
A. 30
B. 500
C. 1000
D. 100

28 Planting dense rows of trees and shrubs along a highway helps control noise pollution primarily by:

Noise pollution: effects and controls Medium
A. Increasing the speed of sound
B. Amplifying low-frequency noise
C. Absorbing and deflecting sound waves
D. Converting noise into heat energy

29 Which of the following is a natural source of background radiation exposure?

Radiation pollution: effects and controls Medium
A. Radon gas from soil and rocks
B. Television and mobile screens
C. Nuclear power plant leaks
D. X-ray machines in hospitals

30 Microplastics are considered emerging pollutants of concern mainly because they:

Emerging pollutants Medium
A. Decompose quickly in seawater
B. Neutralize other water pollutants
C. Enter food chains and are hard to remove
D. Dissolve completely in water

31 The colorful sparks and smoke from fireworks release harmful heavy metals into the air. The green color in fireworks is typically produced by compounds of:

Fireworks and their ill-effects Medium
A. Barium
B. Sodium
C. Copper
D. Strontium

32 Which gas contributes the largest share to human-induced global warming despite others being more potent per molecule?

Global warming Medium
A. Methane ()
B. Chlorofluorocarbons (CFCs)
C. Nitrous oxide ()
D. Carbon dioxide ()

33 Melting of polar ice caps accelerates warming through a feedback loop because ice normally:

Climate change Medium
A. Absorbs and stores heat energy
B. Reflects sunlight back to space
C. Blocks ocean currents completely
D. Releases greenhouse gases

34 Chlorofluorocarbons (CFCs) deplete the ozone layer because in the stratosphere they release:

Ozone layer depletion Medium
A. Fluorine gas that reflects ozone
B. Chlorine atoms that destroy ozone
C. Oxygen atoms that form ozone
D. Carbon atoms that absorb ozone

35 The international agreement specifically aimed at phasing out ozone-depleting substances is the:

Ozone layer depletion Medium
A. Montreal Protocol
B. Paris Agreement
C. Basel Convention
D. Kyoto Protocol

36 Acid rain is primarily caused by the atmospheric conversion of which two gases into acids?

Acid rain Medium
A. and
B. and
C. and
D. and

37 Acid rain harms agriculture most directly by:

Impacts on human communities and agriculture Medium
A. Adding nitrogen fertilizer to crops
B. Increasing soil fertility rapidly
C. Raising the soil pH sharply
D. Leaching nutrients from the soil

38 The 1984 Bhopal Gas Tragedy in India was caused by the leakage of which toxic gas?

Case studies on pollution Medium
A. Chlorine gas
B. Carbon monoxide
C. Sulfur dioxide
D. Methyl isocyanate (MIC)

39 Minamata disease, a famous pollution case study in Japan, was caused by consuming seafood contaminated with:

Case studies on pollution Medium
A. Mercury
B. Arsenic
C. Lead
D. Cadmium

40 In the waste management hierarchy, which option is considered the most preferred approach?

Solid waste management Medium
A. Recycle the materials
B. Incinerate the waste
C. Reduce (source reduction)
D. Landfill disposal

41 An electrostatic precipitator (ESP) in a coal power plant achieves 98% collection efficiency for fly ash, but stack monitoring still shows high fine-particle () emissions relative to total mass captured. What is the most likely explanation?

Air pollution: effects and controls Hard
A. Fine particles carry no electrical charge and are chemically inert to the field
B. ESPs are designed only to capture gaseous pollutants, not particulates
C. ESP collection efficiency drops sharply for the smallest particle sizes, which carry disproportionate number but low mass
D. The 98% figure refers only to the mass captured after the particles leave the stack

42 A lake receiving treated sewage shows a sudden fish kill during a hot, still summer night despite low daytime BOD readings. Which mechanism best explains the timing?

Water pollution: effects and controls Hard
A. Cooler night temperatures increase oxygen solubility and cause gas-bubble disease
B. BOD is highest at night because bacterial decomposition halts during daylight
C. Nighttime respiration by algae and bacteria depletes dissolved oxygen without daytime photosynthetic replenishment
D. Increased daytime photosynthesis raises oxygen to toxic supersaturation levels overnight

43 Rainwater with dissolved in equilibrium has a pH near . A sample measures pH . Approximately how many times more acidic (higher ) is this sample than normal rain?

Acid rain Hard
A. About 14 times
B. About 140 times
C. About 25 times
D. About 1.4 times

44 Why does the ozone hole form most severely over Antarctica in early spring rather than year-round or over the tropics?

Ozone layer depletion Hard
A. Antarctic ozone is naturally thinner because of the continent's high altitude
B. The tropics receive too little UV radiation to break down ozone molecules
C. Chlorofluorocarbons are heavier than air and settle only over the poles
D. Polar stratospheric clouds form in the extreme winter cold and activate chlorine, which destroys ozone rapidly when spring sunlight returns

45 Two gases are released in equal masses: methane and carbon dioxide. Over a 20-year horizon methane has a global warming potential (GWP) of about 84, but over 100 years it falls to about 28. What best explains this decline?

Global warming Hard
A. Methane has a short atmospheric lifetime, so its warming effect concentrates in early years and diminishes over longer horizons
B. Methane is gradually converted into a more powerful greenhouse gas over time
C. Carbon dioxide is removed from the atmosphere faster than methane over a century
D. GWP values decrease because methane's radiative efficiency increases with time

46 In the integrated waste management hierarchy, why is 'source reduction' ranked above 'recycling' even though both reduce landfill volume?

Solid waste management Hard
A. Source reduction is the only method that generates saleable recovered materials
B. Recycling produces more greenhouse gases than landfilling in all cases
C. Source reduction avoids the energy, material, and pollution costs of producing, collecting, and reprocessing waste entirely
D. Recycling cannot be applied to any post-consumer packaging material

47 Two machines each produce individually. When operated together, what is the approximate combined sound level, and why isn't it ?

Noise pollution: effects and controls Hard
A. About , because decibel values add arithmetically
B. About , because sound levels add as the square root of the sum
C. About , because decibels are logarithmic and doubling intensity adds only
D. About , because identical sources cannot increase the total level

48 A radioactive isotope used in a leaked source has a half-life of 30 years. Approximately what fraction of the original activity remains after 120 years?

Radiation pollution: effects and controls Hard
A.
B.
C.
D.

49 The Bhopal Gas Tragedy (1984) resulted from the release of methyl isocyanate (MIC). Which combination of failures most directly turned a storage problem into a mass-casualty disaster?

Case studies on pollution Hard
A. Water entered an MIC tank triggering a runaway exothermic reaction while safety systems (scrubber, flare, refrigeration) were non-functional
B. A deliberate explosion ignited stored pesticides that were otherwise safely contained
C. An earthquake ruptured all storage tanks simultaneously overwhelming the flare tower
D. MIC leaked slowly over months and accumulated in groundwater before igniting

50 A persistent organic pollutant with a bioconcentration factor (BCF) of 5,000 is present at in lake water. Assuming BCF applies directly, what is its expected concentration in fish tissue?

Water pollution: effects and controls Hard
A.
B.
C.
D.

51 A temperature inversion over a city traps pollutants near the ground. Which vertical temperature profile defines an inversion and explains the trapping?

Air pollution: effects and controls Hard
A. Temperature increases then decreases, pushing pollutants upward into the stratosphere
B. Temperature increases with altitude, so cooler dense air below cannot rise to disperse pollutants
C. Temperature stays constant with altitude, allowing free horizontal winds only
D. Temperature decreases sharply with altitude, causing rapid vertical mixing

52 Phytoremediation is proposed to clean a lead-contaminated site. What is the key limitation that distinguishes lead cleanup from organic-contaminant phytoremediation?

Soil pollution: effects and controls Hard
A. Plants cannot take up lead at all because it is insoluble in every soil condition
B. Lead is rapidly broken down by root enzymes into harmless mineral forms
C. Lead volatilizes from leaves, simply transferring the problem to the air
D. Lead is an element that plants can only accumulate, not degrade, so the harvested biomass becomes hazardous waste needing disposal

53 Why are pharmaceuticals and personal care products (PPCPs) considered problematic 'emerging pollutants' even at nanogram-per-litre concentrations?

Emerging pollutants Hard
A. They are only harmful at very high industrial-spill concentrations
B. Conventional treatment plants aren't designed to remove them, and continuous exposure can cause biological effects like endocrine disruption and antibiotic resistance
C. They rapidly break down into oxygen and water, depleting dissolved gases
D. They bind permanently to soil and never reach aquatic systems

54 The colors in fireworks come from metal salts, some of which pose health and environmental hazards. Which pairing of colorant and its principal concern is correct?

Fireworks and their ill-effects Hard
A. Copper salts produce red and are the primary source of radioactive fallout
B. Barium salts produce green and are toxic, causing respiratory and gastrointestinal effects
C. Strontium salts produce blue and release ozone-depleting halogens
D. Sodium salts produce green and are the main cause of acid rain from fireworks

55 Melting Arctic sea ice is often cited as a positive feedback loop accelerating warming. Which mechanism correctly describes this feedback?

Climate change Hard
A. Loss of reflective ice exposes darker ocean that absorbs more solar radiation, causing further warming and more melting
B. Exposed ocean reflects more sunlight than ice, but the released freshwater traps heat
C. Sea-ice melt increases planetary albedo, which paradoxically raises temperatures
D. Melting ice releases stored oxygen that intensifies the greenhouse effect

56 A pollutant discharged into a river breaks down naturally within days into harmless products, while another persists for decades and accumulates in tissues. How are these classified?

Definition, types and causes of environmental pollution Hard
A. The first is a point-source pollutant; the second is a non-point-source pollutant
B. Both are secondary pollutants differing only in concentration
C. The first is a primary pollutant; the second is a secondary pollutant
D. The first is biodegradable (non-persistent); the second is non-biodegradable (persistent)

57 Photochemical smog and classical (London-type) smog differ fundamentally in chemistry. Which statement correctly contrasts them?

Air pollution: effects and controls Hard
A. Photochemical smog is oxidizing and forms in warm sunlight from and hydrocarbons; London smog is reducing and forms in cold moist air from and smoke
B. Photochemical smog is reducing and forms at night; London smog is oxidizing and needs sunlight
C. Both require sunlight and are dominated by sulphur dioxide and soot
D. Photochemical smog forms from oxidation while London smog forms from ozone

58 A firm evaluates incineration versus sanitary landfilling for municipal waste. Which trade-off is most accurate?

Control measures of urban and industrial waste Hard
A. Landfilling reduces waste mass more than incineration and eliminates methane risk
B. Incineration produces no residues and no emissions; landfilling is the only method generating usable energy
C. Both methods produce identical environmental impacts, so cost is the only factor
D. Incineration drastically reduces waste volume and can recover energy but emits air pollutants and toxic ash; landfilling is cheaper but consumes land and generates methane and leachate

59 Prolonged irrigation with poor drainage in arid regions often reduces crop yields over time. What is the primary mechanism?

Impacts on human communities and agriculture Hard
A. Excess irrigation permanently increases soil organic carbon, blocking root growth
B. Salinization: evaporation concentrates dissolved salts at the surface, raising soil salinity and osmotic stress on crops
C. Irrigation water cools the soil below the temperature needed for germination
D. Repeated irrigation leaches all nutrients so quickly that salts never accumulate

60 During conventional sewage treatment, which sequence correctly matches the treatment stages to their principal functions?

Water pollution: effects and controls Hard
A. Primary uses microbes for organics; secondary disinfects; tertiary settles solids physically
B. Primary removes nutrients chemically; secondary settles solids; tertiary adds organic load
C. Primary disinfects with chlorine; secondary removes grit; tertiary aerates the influent
D. Primary removes settleable solids physically; secondary uses microbes to degrade organic matter; tertiary removes nutrients and pathogens