All questions of Environmental Pollution for BPSC (Bihar) Exam

Correctly Matched Terms and their Descriptions:

1. Arresters - These are used to separate particulate matters from contaminated air
2. Scrubbers - These are used to clean air for both dusts and gases by passing it through a dry or wet packing material

Explanation:

The given statements are related to air pollution control devices. The first statement is about Arresters and describes their function, which is to remove particulate matter from contaminated air. The second statement is about Scrubbers, which clean air by passing it through dry or wet packing material. Both of these statements are correctly matched with their respective devices.

Hence, option 'C' is the correct answer.

Water Pollution and Biochemical Oxygen Demand (BOD)

Introduction:
Water pollution is a significant environmental issue that poses a threat to the health and well-being of humans and ecosystems. Organic wastes, such as sewage, agricultural runoff, and industrial effluents, can contribute to water pollution. Biochemical Oxygen Demand (BOD) is a crucial parameter used to measure the extent of water pollution caused by organic wastes.

Statement 1: Water pollution by organic wastes is measured in terms of Biochemical Oxygen Demand (BOD).
This statement is correct. Biochemical Oxygen Demand (BOD) is a widely used parameter for measuring the level of organic pollution in water bodies. BOD helps to determine the amount of oxygen required by microorganisms to break down the organic matter present in the water.

Statement 2: BOD is the amount of dissolved oxygen needed by bacteria in decomposing the organic wastes present in water.
This statement is correct. BOD quantifies the amount of oxygen consumed by bacteria and other microorganisms as they decompose the organic matter in the water. Bacteria require oxygen to carry out biological processes involved in breaking down the organic wastes, and BOD helps to estimate this oxygen demand.

Statement 3: It is expressed in milligrams of oxygen per liter of water.
This statement is correct. BOD is typically expressed in milligrams of oxygen required per liter of water (mg/L). It represents the amount of oxygen needed by microorganisms to oxidize the organic compounds present in the water.

Conclusion:
All three statements are correct. Water pollution caused by organic wastes is measured using Biochemical Oxygen Demand (BOD), which represents the amount of dissolved oxygen required by bacteria and other microorganisms to decompose the organic matter in the water. BOD is expressed in milligrams of oxygen per liter of water, providing a quantitative measure of water pollution. Monitoring BOD levels is essential for assessing the impact of organic pollution and implementing effective pollution control measures.

• Photochemical smog (smog) is a term used to describe air pollution that is a result of the interaction of sunlight with certain chemicals in the atmosphere.
• One of the primary components of photochemical smog is ozone.
• Ground-level ozone is formed when vehicle emissions containing nitrogen oxides (primarily from vehicle exhaust) and volatile organic compounds (from paints, solvents, printing inks, petroleum products, vehicles, etc.) interact in the presence of sunlight.

Effects of Soil Pollution on Agriculture:

Increased salinity:
- Soil pollution can lead to an increase in salinity levels in the soil, making it unsuitable for plant growth.
- High salinity can hinder the absorption of water and essential nutrients by plants, ultimately affecting their growth and productivity.

Loss of soil and nutrients:
- Soil pollution can result in the loss of soil structure and fertility due to the accumulation of harmful chemicals and pollutants.
- This can lead to a decrease in the availability of essential nutrients for plant growth, affecting crop yields and overall agricultural productivity.

Incorrect Statement:
Increased nitrogen fixation:
- Soil pollution does not lead to an increase in nitrogen fixation. Instead, it can disrupt the nitrogen cycle and negatively impact soil health and fertility.

Therefore, the correct statements regarding the effects of soil pollution on agriculture are:
- Increased salinity
- Loss of soil and nutrients

Hence, the correct answer is option 'A'.

DDT, Salts of heavy metals, Radioactive substances are some of the examples of non-biodegradable pollutants.

**Answer:**

The correct statement out of the given options is **2 only**. Let's understand why this is the correct answer.

1. **Statement 1: It releases mainly from air-conditioning systems and refrigeration.**
This statement is incorrect. Ozone is not released mainly from air-conditioning systems and refrigeration. Ozone is a naturally occurring gas in the Earth's atmosphere. It is formed primarily in the upper atmosphere, or stratosphere, through a process involving the interaction of sunlight with oxygen molecules. Ozone is also produced by lightning and certain chemical reactions. It acts as a protective layer against harmful ultraviolet (UV) radiation from the sun.

2. **Statement 2: Vehicles and industries are the major source of ground-level ozone emissions.**
This statement is correct. Ground-level ozone is formed by the reaction of nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. The primary sources of these pollutants are vehicles and industries. Vehicle emissions, including exhaust and evaporation from fuel, contribute to the release of nitrogen oxides and volatile organic compounds. Industries, especially those involved in manufacturing, power generation, and chemical production, also emit significant amounts of these pollutants.

Ground-level ozone is a harmful air pollutant and a major component of smog. It can have detrimental effects on human health, particularly for individuals with respiratory conditions such as asthma. It can also damage crops, forests, and other vegetation.

To summarize, ozone is not released mainly from air-conditioning systems and refrigeration (statement 1 is incorrect). Vehicles and industries are indeed the major sources of ground-level ozone emissions (statement 2 is correct). Therefore, the correct answer is **option B: 2 only**.

• Alpha particles can be blocked by a piece of paper and human skin.
• Beta particles can penetrate through the skin, while can be blocked by some pieces of glass and metal.