Set 1 | Important Environment Pollution MCQs

Correct Answer is C.

• Environmental pollution refers to the addition of undesirable materials into the environment making it unfit for life. Some of the major pollutants present in the environment include Carbon monoxide, carbon dioxide, Chlorofluorocarbons, Lead, etc.
• Pollutants are classified into different types depending upon origin, existence, disposal etc. They can be natural or anthropogenic based on their origin. Based on their disposal, they can be either biodegradable or non-biodegradable. Radioactive substances, Salts of heavy metals, glass, plastic, etc. are some of the examples of the non biodegradable pollutants.
• They cannot be decomposed by way of microbial actions. Ozone occurring at the ground level also acts as a pollutant. But not stratospheric Ozone rather it important for shielding the earth from the harmful ultraviolet rays of the sun. Pollutants might occur from biological sources like fungi, parasites, and pollen from plants. They are usually responsible for causing asthma and allergies.

Correct Answer is B.

• Statement 1 is true: A byproduct of coal-fired power plants is fly ash, which is fine gray powder. Aluminum silicate makes up the majority of it. Calcium oxide, silicon dioxide, and other elements are also included. The second statement, “Fly ash is lightweight, durable, and stronger,” is untrue. It is a material that can be used to fill in roads, etc.
• Therefore, one of fly ash’s most significant benefits is that it can be used in place of cement when building roads. Pollution will be reduced if fly ash is used in place of cement. Reclamation of wastelands can also be accomplished with fly ash, which is not accurate in Statement 3. It can raise crop productivity and increase the land’s ability to retain moisture.
• If improperly disposed of, it may lead to issues with air and water pollution. Before fly ash is released into the atmosphere, electrostatic precipitators are primarily used in the chimneys of coal-fired power plants to remove it.

Correct Answer is D.

• It is not true that Statement 1 states that all coal-based thermal power plants must use coal with no more than 34% ash content, as per a 2014 Environmental Ministry regulation. Removing impurities from coal before delivering it to thermal power plants was a mandate for coal producers.
• Due to the high ash content of 40–45 percent in Indian coal, thermal power plants were forced to import coal. Thermal power plants can now utilize coal, regardless of its ash content, according to a recent Ministry of Environment regulation.
• Thus, the 2014 regulation and the current regulation are at odds with each other. The amount of ash in the coal that Thermal Power Plants can currently use is therefore unlimited.

Correct Answer is C.

• The first statement is untrue: flue gas desulfurization is a technique used to take sulfur dioxide out of the gases released by fossil fuel-powered power plants. Either a wet or dry method can be used. Lime is a reactive agent that is used in dry flue gas desulfurization to separate the flue gases from the exhaust gases. Lime slurry is used in wet flue gas desulfurization to absorb pollutants from flue gasses.
• Statement 2 is untrue: One method of removing nitrogen dioxide from flue gases is selective catalytic reduction. Liquid ammonia is used as a reducing agent in this process. As a result, ammonia serves as the reacting agent while nitrogen dioxide serves as the pollutant that is eliminated during this process. It’s a costly procedure.
• Statement 3 is true: Dust and smoke particles are removed using an electrostatic precipitator. When the gas containing these is passed through the unit, it uses the force produced by the electrostatic charge to remove the dust. Statement 4 is true: A technology called scrubbers is used to extract particulate matter from gases. When a contaminated gas passes through the dry and wet packaging material, it removes the gases as well as the dust.

Correct Answer is D.

• Statements 1 and 2 are untrue: an IIT Kharagpur study found that the Indo-Gangetic Plains are a hotspot for ammonia pollution. Ammonia plays a significant role in fertilizer use and agriculture. The overuse of fertilizers contributes to the increase of ammonia in the atmosphere. It and temperature have a positive relationship.
• Increased temperature causes fertilizer to become more volatile, which increases fertilizer use and pollution levels. Fact: The Indus Basin was not mentioned in the study.
• Statement 3 is untrue: More precipitation eliminates pollutants like ammonia, hence more precipitation lowers agricultural emissions. As a result, there is a negative relationship between the total precipitation and agricultural emissions.

Correct Answer is C.

• Statement 1 is untrue: The amount of oxygen that is utilized by the decomposers in the waterbody to carry out the breakdown of these wastes lowers the dissolved oxygen (DO) of the water when organic and inorganic wastes are present. Aquatic organisms need oxygen to survive. Therefore, the existence of organic matter serves as a key determinant of the aquatic ecosystem’s quality.
• The second statement is true: biological oxygen demand describes the quantity of oxygen required by the bacteria in the water to break down the organic matter. The oxygen needed for the organic and inorganic matter in the water to break down is referred to as the chemical oxygen demand.
• The amount of dissolved oxygen is less and the oxygen’s availability for respiration is decreased the higher the chemical oxygen demand. The third statement is untrue: Several factors influence the amount of dissolved oxygen in a body of water. It includes surface water movement, organic waste breakdown, respiration by organisms, and photosynthesis.

Correct Answer is B.

• Burning crop residue left over after wheat and paddy crops are harvested is referred to as stubble burning. The field is prepped for the upcoming season by it. During the winter months, one of the main causes of pollution in and around Delhi is stubble burning. Several factors contribute to the burning of stubble in fields, such as the use of combine harvesters that leave behind small residues.
• Because they are hard to gather, these residues are typically burned. Burning the residue is the simplest solution because intensifying the crop necessitates clearing the ground right away for the following crop. Transplanting paddy is not the sole cause of the stubble burning.
• Another way to prevent stump burning would be to increase crop diversification and cultivate short-duration rice varieties, which would increase the window for field clearance. To avoid burning stubble, the Happy Seeder Machine is a tractor-operated device that directly sows wheat. It also boosts the crop’s productivity.

Correct Answer is D.

• In order to clean up a polluted site, bioremediation uses naturally occurring or purposefully introduced microorganisms to consume and degrade environmental pollutants. It could be in-situ or ex-situ. Microbes in the contamination site break down the material in-situ, whereas exsitu bioremediation breaks down the material outside the contamination site.
• Techniques like bioventing, bioaugmentation, and biosparging are part of the in-situ method. Therefore, Statement 1 is false: In bioaugmentation, the contaminated site is invaded with microorganisms to hasten the degradation process.
• The second statement is untrue: bioremediation is an economical and environmentally friendly method of causing the pollutants in the environment to degrade. Nevertheless, the method is only effective when dealing with degradable compounds. It is not applicable to non-degradable compounds.

Correct Answer is D.

• Statement 1 is untrue: When atmospheric moisture combines with sulfur and nitrogen oxides, acid rain is produced. In addition to seriously harming man-made structures, it also destroys terrestrial and aquatic plants. In contrast to other areas, some are more vulnerable to acid rain.
• They are primarily found in industrialized areas and in mountainous areas that experience heavy precipitation. They can also be found in mountainous regions with poor soils. It is false to say that rainwater is deemed acidic if its pH is lower than 5 points, which corresponds to the pH of typical rainfall.
• Both wet and dry deposition of it are present in the atmosphere. In the event that atmospheric acids fall as rain, snow, mist, etc. That’s called wet deposition. It is referred to as dry deposition if it blows in a dry area from one location to another.

Correct Answer is A.

• The first statement—that acid rain seriously damages forests, lakes, rivers, deserts, and nearly all ecosystems and their inhabitants—is true. Similarly, the concentrations of acids in lakes can also vary. The lakes may become more acidic due to natural processes as well as human activity. The concentration of dissolved organic carbon is high in naturally acidified lakes.
• Conversely, the concentration of organic carbon is low in anthropogenically acidified lakes. Statement 2 is true: The humic content in naturally acidified lakes causes them to appear yellow or brownish rather than transparent. In contrast, the lakes that have been acidified by humans seem translucent and have extremely clear waters.
• Statement 3 is untrue: Although naturally acidified lakes are well-balanced, artificially acidified lakes are not well-balanced, with certain aquatic species absent or present in very small amounts. On the other hand, there is a wealth of aquatic life in the naturally acidified lakes.