Air and Noise Pollution MCQ Quiz - Objective Question with Answer for Air and Noise Pollution - Download Free PDF

Explanation:

Secondary pollutant:

• The primary pollutants often react with one another or with water vapor, aided and abetted by the sunlight, to form entirely a new set of pollutants, called the secondary pollutants. 
• These are the chemical substances, which are produced from the chemical reactions of natural or anthropogenic pollutants or due to their oxidation, etc., caused by the energy of the sun.

Examples:

1) Sulphuric acid (H2SO4)

2) Formaldehydes

3) Photochemical smog

4) Ozone

5) Peroxy Acetyl – nitrate (PAN)

Primary pollutant: 

• Pollutants are emitted directly from identifiable sources, either from natural hazardous events like dust storms, volcanoes, etc, or from human activities like burning of wood, coal, oil in homes or industries or automobiles, etc.

Examples:

1) SO2

2) CO & CO2

3) NO, NO2

4) Volatile organic compound

5) Suspended Particulate Matter (SPM)

6) Radioactive compound

7) Halogen compound

Key Points

• The National Ambient Air Quality Standards (NAAQS) in India were revised by the Central Pollution Control Board (CPCB) in 2009.
• For particulate matter of size less than 2.5 microns (PM2.5), the permissible annual average limit is 40 micrograms per cubic meter for industrial, residential, rural, and other areas.
• PM2.5 refers to fine particulate matter with a diameter of 2.5 micrometers or smaller, which can penetrate deep into the lungs and cause severe health issues.
• These standards are aimed at protecting public health, particularly sensitive groups such as children and the elderly, from the harmful effects of air pollution.
• Particulate Matter (PM): PM refers to the mixture of solid particles and liquid droplets found in the air. PM2.5 is especially harmful because it can bypass the nose and throat and reach the lungs, causing respiratory and cardiovascular issues.
• Health Impacts of PM2.5: Exposure to PM2.5 can lead to asthma, bronchitis, lung cancer, and heart diseases. Long-term exposure can reduce life expectancy.

Explanation:

Methane (CH₄) is the primary combustible component of biogas. Biogas is a mixture of gases produced through the anaerobic digestion of organic materials. The major components of biogas typically include:

1. Methane (CH₄): The most significant and combustible component, contributing to biogas's energy content.

2. Carbon dioxide (CO₂): Present in biogas but non-combustible.

3. Hydrogen sulfide (H₂S): Present in trace amounts, it can be corrosive but is not the primary combustible component.

Additional Information

1. Carbon dioxide (CO₂): Non-combustible and often makes up a large portion of biogas, but it does not contribute to the combustion properties of biogas.

2. Hydrogen sulphide (H₂S): While it can be harmful and corrosive, H₂S is not a major combustible component of biogas.

3. Butane (C₄H₁₀): Not a typical component of biogas, as biogas primarily consists of methane, not hydrocarbons like butane.

Key Points

• According to the study by Center for Science and Environment, only 5% of coal-based thermal plants meet the sulfur dioxide emission norms.
• This indicates that the majority of coal-based thermal plants are not compliant with the set environmental standards.
• Coal-based thermal plants are significant contributors to sulfur dioxide emissions, which have adverse effects on air quality and human health.
• Meeting sulfur dioxide emission norms is crucial for reducing air pollution and mitigating associated health risks.

Additional Information

• Sulfur Dioxide (SO2)
  • Sulfur dioxide is a toxic gas that is released mainly from burning fossil fuels like coal, oil, and gas.
  • It is one of the major air pollutants that contribute to acid rain, respiratory problems, and other environmental issues.
  • High concentrations of sulfur dioxide can lead to severe health problems, including lung diseases and heart complications.
  • Reducing sulfur dioxide emissions is essential for improving air quality and safeguarding public health.
• Coal-Based Thermal Plants
  • Coal-based thermal plants generate electricity by burning coal, which produces steam to drive turbines.
  • These plants are a significant source of air pollution, emitting large quantities of sulfur dioxide, carbon dioxide, and other pollutants.
  • Implementing emission control technologies and adhering to environmental norms can help reduce the harmful effects of coal-based power generation.
  • Transitioning to cleaner energy sources is vital for sustainable development and reducing the environmental footprint of power generation.
• Center for Science and Environment (CSE)
  • CSE is a public interest research and advocacy organization based in New Delhi, India.
  • It works on various environmental issues, including air pollution, water management, and sustainable development.
  • CSE conducts studies, publishes reports, and advocates for policy changes to address environmental challenges.
  • Its research and advocacy efforts aim to promote environmental awareness and drive positive changes for a healthier planet.

Concept:

1. Ozone:

• Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earth's upper atmosphere and at ground level.
• Ground-level ozone is a colorless and highly irritating gas that forms just above the earth's surface. It is called a "secondary" pollutant because it is produced when two primary pollutants react in sunlight and stagnant air.

These two primary pollutants are nitrogen oxides (NOx) and volatile organic compounds (VOCs).
Its effect is as follows:

• When inhaled, ozone can damage the lungs.
• Relatively low amounts of ozone can cause chest pain, coughing, shortness of breath, and, throat irritation.
• It may also worsen chronic respiratory diseases such as asthma as well as compromise the ability of the body to fight respiratory infections.

2. Lead:

• Lead is a naturally occurring toxic metal found in the Earth’s crust. Its widespread use has resulted in extensive environmental contamination, human exposure, and significant public health problems.

Its effect is as follows:

• Exposure to high levels of lead may cause anemia, weakness, and kidney and brain damage.
• Very high lead exposure can cause death.​
• Lead can cross the placental barrier, which means pregnant women who are exposed to lead also expose their unborn children.
• Lead can damage a developing baby’s nervous system and also affect the mental growth of children.

3. Carbon monoxide:

• It is a colorless, odorless, tasteless, deadly gas. You can’t see, smell or taste it.
• Carbon monoxide is slightly lighter than air and quickly spreads throughout an entire house.

Its effect is as follows:

• Carbon monoxide symptoms mimic the flu: headaches, fatigue, nausea, dizziness, confusion, and irritability.
• Continued exposure can lead to vomiting, loss of consciousness, brain damage, heart irregularity, breathing difficulties, muscle weakness, abortions, and even death.

4. ​Sulphur Dioxide:

• Sulfur dioxide (SO2) is a gaseous air pollutant composed of sulfur and oxygen.
• SO2 forms when sulfur-containing fuel such as coal, oil, or diesel is burned.
• Sulfur dioxide also converts in the atmosphere to sulfates, a major part of fine particle pollution.

Its effect is as follows:

• Sulfur dioxide can cause respiratory problems such as bronchitis and can irritate your nose, throat, and lungs.
• It may cause coughing, wheezing, phlegm, and asthma attacks. The effects are worse when you are exercising.
• Sulfur dioxide has been linked to cardiovascular disease.

Explanation:

Noise pollution

• It is a major issue in today’s urban areas. From factories to vehicles, from machinery to daily equipment, everything produces a noise that is having a significant impact on the ambient environment as well as the health and well-being of humans.
• Recognizing the harmful effects of noise, the Indian government included measures to abate noise pollution under the Environment Protection Act, 1986. Noise pollution was one of the categories being addressed under this Act. However, in the late 1990s, the government decided to come out with separate legislation solely focusing on noise pollution. Thus was born, Noise Pollution (Regulation and Control) Rules, 2000.

Explanation:

CPCB (Central Pollution Control Board) has laid down the following permissible noise levels limitations in India for different areas:

As per Noise pollution (Regulation and control) Rules 2000 of India.

Primary pollutants:  Pollutants that are emitted directly from either natural events or from human activities are called primary pollutants.

The natural events are dust storms; volcano etc and human activities can be emission from vehicles, industrial wastes.

About 90% of global air pollution is constituted by five primary pollutants. These are

1. Carbon oxides (CO and CO₂)

2. Nitrogen oxides

3. Sulphur oxides

4. Hydrocarbons

5. Particulate matter

6. Suspended particulate matter (SPM).

Secondary pollutants: Primary pollutants when reacting with each other or from basic components of air, forms a new pollutant called secondary pollutants.

Different types of secondary pollutants include:

1. Ozone (O₃)

2. Sulfuric acid (H₂SO₄) and nitric acid (component of acid rain)

3. Nitrogen dioxide (NO₂)

4. Peroxyacyl nitrates (PAN)

Explanation:

1) Looping Plume: This occurs in a superadiabatic environment with light to moderate wind speed in the presence of large scale thermal eddies. Unstable and need higher stacks.

2) Trapping Plume: When the inversion layer exists above the emission source as well as below the source. Emitted plume will neither go up nor go down and would be trapped in between and thus termed as trapping plume.

3) Coning Plume: When wind velocity is high and sub-adiabatic conditions exist (ELR < ALR). The environment is highly stable.

4) Fanning Plume: Under extreme inversion conditions. The emission will spread only horizontally.

5) Lofting Plume: When there is a strong super-adiabatic condition above the surface inversion. Such plume has minimum downward mixing as its downward motion is prevented by inversion.

6) Fumigating Plume: When an inversion occurs above the top of the stack and a super-adiabatic condition prevails below the stack.

7) Neutral Plume: Upward vertical rise when ELR=ALR.

Concept:

Air pollutants:

Pollutants are classified in different ways. According to origin pollutants are two types.

1). Primary pollutants:

• These are directly emitted from the sources in the atmosphere in a harmful form.
• They can be natural (volcanic eruptions or fires, for example) or of anthropogenic origin (carbon monoxide from vehicles).

2). Secondary Pollutants:

• These are derived from primary pollutants due to chemical or photochemical reactions in the atmosphere they become hazardous after reaction in the air. 
• The best known of the secondary pollutants is certain gases that are synthesized by photochemical reactions in the lower atmosphere.
• The primary emitted chemicals in these reactions are hydrocarbons and gaseous oxides of nitrogen such as nitric oxide and nitrogen dioxide. 
• Its origin lies in the interactions between the primary emissions in the atmosphere.

Examples of primary and secondary air pollutants:

Green House Gases:

Gases that trap heat in the atmosphere are called greenhouse gases. Major Greenhouse Gases are:

1. Carbon Dioxide: Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or "sequestered") when it is absorbed by plants as part of the biological carbon cycle.

2. Methane: Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.

3. Nitrous Oxide: Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.

4. Fluorinated Gases: Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting Substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases ("High GWP gases").

(i) CO2 → 60%

(ii) Chlorofloro Carbon (CFC) → 14%

(iii) Methane (CH4) → 20%

(iv) Nitrous Oxide (N2O) → 6%

Explanation:

Gravitational Settling Chambers:

• Settling chambers in air-pollution control systems provide enlarged areas to minimize horizontal velocities and allow time for the vertical velocity to carry the particle to the floor.
• The emitted smokes, when made to pass through a settling chamber, drop some of their larger sized particles in the chamber as per Stoke’s Law. The largest size particle (d) that can be removed with 100% efficiency in such a chamber of length L and height H is given by

​\(d=C.\sqrt{\frac{18μ .{{v}_{h}}.H}{g.L.{{\rho }_{p}}}}\)

Where, V_h = Horizontal velocity of gas passing through the chamber

Electrostatic Precipitators:-

• In electrostatic precipitators, the emitted gas flue gas is passed through a highly ionized atmosphere high-voltage field; and in that zone particulates get electrically charged and get separated from the gaseous stream with the help of electrostatic forces. Fine particles up to 1 μm wet or dry can be removed easily in an electrostatic pressure.
• Four basic steps required in the operation of a high-voltage single-stage electrostatic precipitator:

Cyclone collector:

• This is a closed chamber, in which the inlet velocity of the gas (smoke) is transformed into a spinning vortex, which helps to throw out the particles under the generated centrifugal force. The particles then slide down the chamber walls into the hopper from where they come out.

Spray tower:

• A spray tower (or spray column or spray chamber) is a gas-liquid contactor used to achieve mass and heat transfer between a continuous gas phase (that can contain dispersed solid particles) and a dispersed liquid phase.

Explanation:

Air quality index (AQI)

• It is a table Developed by EIA (Environmental Protection Agency).
• Provide regular citizens with accurate, up-to-date, and easily understandable information about daily levels of air pollution.
• AQI is an index for reporting air quality on a daily basis.
• Pollutants considered for AQI are SO2, O3, CO, NO2, PM2.5, PM10, ammonia (NH3), and lead (Pb)
• AQI is divided into 6 categories 

Concept:

IS:4954-1968:- Recommendations for Noise Abatement in Town Planning

The acceptable noise levels for outdoor and indoor levels in different types of residential areas is given in below table:

The acceptable noise levels for indoor levels in different types of residential areas is given in below table: