MCQs on Environmental Problems for SSC & State PSC

Chlorofluorocarbon is the main cause of ozone depletion.

• The main cause is manufactured chemicals, refrigerants, solvents propellants, and other agents referred to as ozone-depleting substances.
• These Chlorofluorocarbons transported into the stratosphere through turbulence mixing after emitted from the surface.
• Ozone depletion is the worldwide concern over increased cancer risks and other negative impacts on the environment.
• The ozone layer prevents harmful ultraviolet wavelengths from passing through the Earth’s atmosphere.
• These wavelengths can cause cancer, sunburns, cataracts, permanent blindness, etc.
• This led to the adoption of the Montreal Protocol in 1987 which bans the production of Chlorofluorocarbon and other ozone-depleting substances.

• Water can be contaminated by physical, chemical, biological, and radiological contaminants.
• Physical contaminants are those contaminants that impact the physical appearance of physical properties of water Like sediments, suspended organic matter, etc.
• Chemical contaminants can be found in the form of elements as well as compounds.
• They can be natural or manmade. eg. nitrogen, salt, pesticides, fertilizers, bleach, metals, toxins, human or animal waste, drugs, etc.
• Biological contaminants are referred to as living microorganisms or microbes present in water like bacteria, viruses, protozoa, and parasites.
• Radiological contaminants are basically chemical elements with unbalanced protons or neutrons which makes the atoms unstable enabling it to emit ionizing radiation.
• Caesium, uranium-plutonium are some of the radiological contaminants.

Carbon dioxide is the gas that contributes maximum to the phenomena of global warming. Carbon dioxide is generated as a by product of cellular respiration as well as combustion of fossil fuels. It is also generated by human industries which leads to the global warming of the planet.

• Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth's surface, the atmosphere itself, and by clouds.
• This property causes the greenhouse effect.
• The GHGs are transparent to incoming solar radiation but are opaque to some wavelengths of heat radiated from the Earth.
• So, they trap heat, which leads eventually to a warming of the lower atmosphere. This is called the Greenhouse effect.
• The Primary GHGs are Water vapour, Carbon dioxide, Methane, and Ozone.
• Other GHGs are carbon monoxide, fluorinated gases, chlorofluorocarbons (CFCs), black carbon (soot), and brown carbon.

• Nitrogen oxides are major air pollutants, not the primary GHGs.

• Blue-green algae(BGA) are actually types of bacteria known as Cyanobacteria.
• They normally look green and sometimes may turn bluish when scums are dying.
• BGA is widely distributed all over the earth.
• While fixing carbon from CO₂, certain BGA can fix dinitrogen from the atmosphere and are called nitrogen-fixing BGA, including free-living and symbiotic forms.
• Plant cyanobionts all have two major characteristics in common:
  • The ability to differentiate both specialized nitrogen-fixing cells known as heterocysts and
  • Short, motile filaments known as hormogonia, which lack heterocysts and provide a means of dispersal for otherwise immotile.

• In simpler term, the greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat.
• When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
• Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs).
• The absorbed energy warms the atmosphere and the surface of the Earth.
• The human activities such as burning fossil fuels (coal, oil and natural gas), agriculture and land clearing - are increasing the concentrations of greenhouse gases.
• This is the enhanced greenhouse effect, which is contributed to the global warming of the Earth .
• Methane is much more potent in terms of the greenhouse effect. Its global warming impact is 25 times greater than that of carbon dioxide over a 100-year period.
• The Paris Agreement speaks of the vision of fully realizing technology development and transfer for both improving resilience to climate change and reducing GHG (Green House Gas) emissions.

Option 3 is correct, i.e. Hydrogen.

• Gases that trap heat in the atmosphere are called greenhouse gases.

• Hydrogen gas is not a greenhouse gas. While hydrogen is abundant and involved in many atmospheric processes, it does not in itself absorb and emit radiant energy within the thermal infrared range, which is characteristic of greenhouse gases.

• On the other hand, Ozone (A), Nitrous oxide (B), and Water vapor (C) are all considered greenhouse gases because they can absorb and emit radiant energy within the thermal infrared range. This property causes the greenhouse effect, in which these gases capture heat in the Earth's atmosphere, leading to global warming.

Carbon dioxide (CO₂):

• It enters the atmosphere through burning fossil fuels solid waste, trees, and other biological materials.
• Carbon dioxide is removed from the atmosphere, when it is absorbed by plants as part of the biological carbon cycle.

Methane (CH₄):

• 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.

Nitrous oxide (N₂O):

• Nitrous oxide is emitted during agricultural and industrial activities, combustion of fossil fuels and solid waste, as well as during the treatment of wastewater.
  

Fluorinated gases:

• Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes.

• The presence of Chlorofluorocarbons is majorly responsible for the depletion of the ozone layer in the atmosphere.
• The depletion of the ozone layer results in an increase in the earth's atmospheric temperature.
• The stratosphere is located above the troposphere and below the mesosphere.
• The ozone layer found in the stratosphere helps protect us from ultraviolet radiation (UV) from the sun by blocking UV radiation from reaching the Earth’s surface.
• CFCs are long-lived chemical compounds that eventually rise into the stratosphere, where they are broken apart by the Sun’s ultraviolet radiation, releasing chlorine atoms that go on to destroy ozone molecules.

• Northern Aravlli has acute ecological crises due to illegal mining.
• Though the Supreme Court banned mining in the range in 2002, unless cleared by the Union Ministry of Environment, Forest and Climate Change (MoEFCC), illegal mining has continued, sometimes on a scale even larger than that of legal mining operations.
• A 2018 report by Supreme Court-appointed Central Empowered Committee (CEC) says that 25 percent of the Aravalli range has been lost due to illegal mining in Rajasthan since 1967-68.
• 10,300 hectares (ha) have been affected outside the lease boundary in the 15 districts where 80 percent of the Aravallis are located.
• Loss of a great number of flora and fauna like leopards, striped hyenas, golden jackals, nilgais, palm civets, wild boar.

Aravalli range & hilly tract can be divided into the following four parts.

• North Eastern Hills:
  • Districts - Jaipur, Sikar, Khetri, Alwar, Sawai Madhopur
  • Average Height - 300 m to 670 m
  • Valleys between the hills are wide & in some cases stretch for many kilometres.
  • Flattered hilltops - form a small plateau.
  • To the east & north - it merges with Ganga - Yamuna plain
  • Lake - Sambhar, Ramgarh, Pandupole
  • Highest Peak - Raghunathgarh 1055 m in Sikar
• Central Aravalli Range:
  • Districts - Ajmer, Jaipur South Part of Tonk
  • Height/Elevation - 700 m
  • Depth of valley - 550 m
  • Highest Peak/elevation - 799 m in Rajgarh.
• The Mewar Rocky Region:
  • Districts - Udaipur, Rajsamand, Dungarpur, Sirohi, Bhilwara and Chittorgarh
  • Area - 17007 Sq. Km
  • Location - It is located from South East to South East
  • Average Height - 1225 m
  • The highest portion of the Aravalli range lies between the forts of Kumbhalgarh & Gogunda in the form of plateau locally known as ‘Bhorat’.
  • The altitude of Bhorat - 1225 m
  • Bhorat plateau is one of the highest tablelands of Aravalli.
• The Abu Block:
  • District - Abu, Sirohi
  • Area - 5180 Sq. Km
  • Location - West to Abu in Sirohi
  • Sea Level - 1200 m
  • It has been separated from the main Aravalli range by the wide valley of the West Banas.

• Negative aspects of development:
  • ​Creative Destruction:
    • ‘Creative destruction is the creation of natural social tension. Because widespread structural transformations often accompany the growth and development of an economy, some relationships which may have been previously established could be destroyed. Eg. Displacement and Rehabilitation of masses, Degradation of natural resources
  • Environment pollution:
    • ​Increased pollution has also been cited as a downside of economic growth. The World Bank (2014) states that while many people have benefited from an improved quality of life due to economic growth, these gains have not been even, and economic growth usually has negative environmental consequences.
  • Health Challenges:
    • ​Health systems currently face complex challenges due to new pressures such as ageing populations, an increase in the occurrence of chronic illnesses, and an intensive use of health technologies which, while essential, are also expensive.
  • Politics and Development:
    • ​Development concerns the diffusion of norms and ideas, and the confrontation between modernity, tradition, secularization, religion and identities.
    • This included development cooperation, international organisations, transnational activism, migration, peacebuilding, women’s empowerment, labour rights/decent work, sustainable development, corruption and global health. During the mid 80's decade of the twentieth century, This Negative aspect of Development was not given importance.

• Greenhouse gases such as methane and carbon dioxide in the atmosphere prevent the rays of the Sun reflected from the Earth’s surface to escape the atmosphere thus trapping the radiations.
• The trapped radiations warm the Earth’s atmosphere, causing increases in the global temperature. This is called the greenhouse effect.
• Because of the increase in temperature, icy bodies start melting and increase the sea level.
• Water vapor, carbon dioxide, methane, and other trace gases in Earth's atmosphere absorb the longer wavelengths of outgoing infrared radiation from Earth's surface.
• These gases then emit infrared radiation in all directions, both outward toward space and downward toward Earth.

Explanation:

• Eutrophication refers to the addition of artificial or non-artificial substances, such as nitrates and phosphates, through fertilizers or sewage, to a freshwater system.
• It can be anthropogenic or natural.
• It leads to an increase in the primary productivity of the water body or “bloom” of phytoplankton.
• The overgrowth causes the loss of oxygen in the water leading to severe reductions in fish and other animal populations.
• Eutrophication escalates rapidly when high nutrients from fertilizers, domestic and industrial wastes, urban drainage, detergents and animal, sediments enter water streams.
• When the process of Eutrophication is increased by human activities, it is called cultural Eutrophication.

Effects:

They can have a large impact on the health of rivers and estuaries such as increased production of algae and aquatic plants, depletion of fish species, general deterioration of water quality.

• Acid rain: Emission of sulphur dioxide and nitrogen oxide into the atmosphere which reacts with water molecules and produces acid.
• Rhodium: It is used in a catalytic converter to reduce the level of hydrocarbons in vehicle emissions.
• Montreal protocol: It is an international treaty organization for climate change. Its main objective is to protect the ozone layer depletion.
• Carbon dioxide: It is the main cause of Global warming which is released into the atmosphere by two processes, among which, first is a natural process like respiration, and volcanic eruption and the other one is by human activity like deforestation, burning fossil fuels etc.

• Air quality indices have been created in different countries for the measurement of air quality.
  • These indices measure the air quality in the country and indicate whether the amount of nitrogen dioxide, carbon monoxide, and sulfur dioxide in the air exceeds the criteria set by the World Health Organization or not.
  • India uses the National Air Quality Index (AQI), Canada uses the Air Quality Health Index, Singapore uses the Pollutant Standards Index and Malaysia uses the Air Pollution Index.
  • There are many cities including Beijing, Paris where 'pollution emergency' is declared.
  • However, India also declared the same in November 2019.
• What is Air Quality Index?
  • The National Air Quality Index (AQI) in India was launched on 17 September 2014 in New Delhi under the Swachh Bharat Abhiyan by Environment Minister Shri Prakash Javadekar.
  • The air quality index is composed of 8 pollutants - PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Pb).
  • The Air Quality Index measures the quality of air. It shows the amount and types of gases dissolved in the air. There are 6 categories of air that have been created in this air quality index.
  • These categories are based on air quality.
  • These categories are; good, satisfactory, moderate, poor, very poor, and severe.
  • As the air quality deteriorates, so does the ranking of air from good to bad than very poor to severe.
• Air pollution means the amount of Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), and Carbon Monoxide (CO) in the air exceeds the criteria set by the World Health Organization (WHO).
  • In cities like Delhi, the main components of air pollution are the PM 2.5 and PM 10 particles that are present in the air. When the level of these particles rises in the air, they cause difficulty in breathing, irritation in the eyes, etc.
  • According to the Berkeley, Earth science research group; breathing in air with a PM2.5 content of between 950 to 1,000 is like smoking 44 cigarettes a day.

• Greenhouse gas:
  • A greenhouse gas is a gas that absorbs and emits infrared radiation.
  • They absorb infrared energy (heat energy) emitted from the earth’s surface and reradiates it back to the earth’s surface.
  • The Primary GHGs are:
    • Water vapour
    • Carbon dioxide
    • Methane
    • Nitrous oxide
    • Ozone
  • Other GHGs are fluorinated gases, chlorofluorocarbons (CFCs), and black carbon (soot).

Mistake Points

• Argon is not a greenhouse gas.
• Argon is a noble gas that is chemically inert.

• The 'Rat-Hole Mining’ was prevalent in the north-east states until it was declared illegal by the National Green Tribunal.
• The National Green Tribunal had ordered an interim ban on Rat-Hole Coal Mining in Jaintia Hills of Meghalaya on 17^th April 2014.
• Coal reserves are predominantly found in north-east regions like Assam and Meghalaya.
• Rat-Hole Mining is a primitive and hazardous method of mining for coal.
• Rat-Hole Mining is done with tunnels that are only 3-4 feet in diameter, leading to pits ranging from 5-100 sq. mt deep.
• In Rat-Hole Mining the coal is taken out manually, loaded into a bucket, and dumped on a nearby un-mined area.
• It was banned soon after a petition submitted on pollution issues in the Kopili river due to the acidic discharge from the mines.
• The studies conducted by the North-Eastern Hill University, Shillong says that the Kopili river has turned acidic due to the discharge of acidic water from mines and the leaching of heavy metals.
• Even after the ban, the practice continues unabated.
• Water from rivers and streams in the mining area will gradually become unfit for drinking and irrigation and is toxic to plants and animals.

• Carbon dioxide is a natural byproduct of animal and plant respiration but is also caused by human activities like fossil fuel burning, deforestation, and biomass burning.
• Carbon dioxide is an abundant greenhouse gas and the increased concentration of carbon dioxide in the air is believed to cause Global warming.
• Acid rain is caused by an increase in the atmospheric concentration of Sulphur dioxide and Nitrogen oxides.
• Ignition is the electrical system in an engine that causes the fuel to burn or explode in order to start the engine.

• The Air Quality Index measures the quality of air.
• When the AQI level (air quality index) is below 50, people are breathing fresh, clean air.
• The National Air Quality Index (AQI) was launched in New Delhi in September 2014, under the Swachh Bharat Abhiyan.
• The air quality index is composed of 8 pollutants: PM10, PM2. 5, Ozone (O₃), Sulphur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), lead (Pb) and ammonia (NH₃)
• Air Quality Index doesn’t include carbon dioxide and methane.

Explanation:

• Marble cancer is the corrosion of statues and buildings made up of marbles by the action of nitric acid or sulphuric acid.
• It also happens because of acid rain. This rain corrodes the marble monuments by dissolving the calcium and making salt.
• Yellowing of Taj Mahal is one of the examples of marble cancer.
• It is also known as Stone cancer.
• The pollutants present in acid rain reacts with the stone to change their colour.

• Acid rain: Acid rain is a byproduct of a variety of human activities that emit the oxides of sulphur and nitrogen in the atmosphere.
• Burning of fossil fuels (which contain sulphur and nitrogenous matter) such as coal and oil in power stations and furnaces or petrol and diesel in motor engines produce sulphur dioxide and nitrogen oxides. SO2 and NO2 after oxidation and reaction with water are major contributors to acid rain.
• \(2\;SO_2 (g) + O_2 (g) + 2\;H_2O (l) → 2\;H_2SO_4 \;(aq) \)
• \(4\;NO_2 (g) + O_2 (g)+ 2\;H_2O (l) → 4\;HNO_3 (aq)\)
• They mixed with clouds and form acids.
• Acid rain is harmful for agriculture, trees and plants as it dissolves and washes away nutrients needed for their growth.

• Hydrogen fuels would produce minimum environmental pollution.
  • When hydrogen burns it becomes water vapour.
  • There are no carbon or other compounds released into the atmosphere.
  • There are various compounds including carbon dioxide and carbon monoxide released when other fuels are burnt.
  • Hydrogen is the chemical element with the symbol H and atomic number 1.
    • Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass.
• Hence, option 1 is correct.

• Coal:
  • Coal on burning comes in oxygen, the chemical energy is converted into thermal energy that is heated.
  • It is composed mostly of carbon and hydrocarbons, which contain energy that can be released through combustion.
  • But it also gives carbon dioxide and methane in the environment.
• Diesel:
  • The petroleum fuels burn to give carbon dioxide, water and nitrogen.
  • Diesel is a type of engine that produces enough heat to burn fuel and power a vehicle.
  • combustion of fuel gives these harmful gases which when released into the environment will pollute it.
• Kerosene:
  • It is the combustible hydrocarbon derived from petroleum, a fuel.
  • It is a transparent liquid fuel with a mixture of hydrocarbon chains 6 to 16 carbon atoms in length.
  • so it will also give carbon dioxide and nitrogen to pollute the environment.

• Carbon Dioxide, carbon monoxide and Methane are harmful to the environment as well as life existing on earth.
  • Their high exposure causes suffocation, dizziness, weakness, loss of coordination.
  • carbon dioxide is the greenhouse gas which leads to increased temperature on the earth.

Solar energy:

• Energy harnessed from the sun directly is called solar energy.
• It is used to generate electricity with solar cells.
• Solar energy is a clean source of energy and hence does not produce atmospheric pollution.

Nuclear energy:

• It originates from the splitting of uranium atoms, a process called fission.
• This generates heat to produce steam, which is used by a turbine generator to generate electricity.
• It is a non-renewable resource of energy.

Renewable resources:

• Renewable resources of energy are those that can be replenished or renewed naturally over time. As they are clean sources of energy they does not produce air pollution.
• Air, water, wind, solar energy, biogas, Hydrogen, etc are all renewable resources of energy.
• Wind energy: Energy generated due to windmills.
• Hydrogen: Energy generated with the use of hydrogen or/and hydrogen-containing compounds has minimum pollution and produces maximum energy on burning.
• Biogas: It is a mixture of gases such as methane, carbon dioxide, hydrogen, etc and is obtained by the decomposition of animal and plant wastes.

Non-renewable resources:

• Fossil fuels like coal and petroleum are non-renewable resources of energy. Nonrenewable energy typically releases carbon dioxide, methane, and other gasses into the atmosphere.
• They are found deep inside the earth and are made by natural processes over many years.
• Examples of fossil fuels are coal, petroleum, natural gas, etc.

• The groundwater utilization is very high in the states of Punjab, Haryana, Rajasthan, and Tamil Nadu.
• Gujarat, Uttar Pradesh, Bihar, Tripura, and Maharashtra are utilizing their groundwater resources at a moderate rate.
• States like Chhattisgarh, Odisha, Kerala utilize only a small proportion of their groundwater potentials.

• The total replenishable groundwater resources in the country are about 432 cubic km.
• The Ganga and the Brahmaputra basins have about 46% of the total replenishable groundwater resources.
• The level of groundwater utilization is relatively high in the river basins lying in the north-western region and parts of south India.

• Smog is basically derived from the merging of two words-smoke and fog.
• Secondary pollutants are pollutants which form in the atmosphere. These pollutants are not emitted directly from a source.
• Smog is a secondary pollutant.
• Smog is a yellowish or blackish fog formed mainly by a mixture of pollutants in the atmosphere which consists of fine particles and ground-level ozone.
• It occurs mainly because of air pollution.
• Today, most of the smog we see is photochemical smog.
• Photochemical smog is produced when sunlight reacts with nitrogen oxides and at least one volatile organic compound (VOC) in the atmosphere.
• These VOC, SO₂, and NO_x are called precursors.
• The main sources of these precursors are pollutants released directly into the air by gasoline and diesel-run vehicles, industrial plants and activities, and heating due to human activities.
• During the winter months when the wind speeds are low, it helps the smoke and fog to become stagnate at a place forming smog and increasing pollution levels near the ground closer to where people are respiring.
• It hampers visibility and disturbs the environment.

• The water pollution in the rivers is measured by the amount of dissolved oxygen.
• Dissolved oxygen (DO) is a measure of how much oxygen is dissolved in the water.
• Dissolved oxygen (DO) is the amount of oxygen available to living aquatic organisms.
• The amount of dissolved oxygen indicates its water quality.

• Biodegradable substances are capable of being decomposed by bacteria or other living organisms and thereby avoiding pollution.
• Non-biodegradable substances stay in the environment for thousands of years. They may end up getting in the food chain and cause various health issues to the animals that are in that food chain.
• Most of the polymers (like nylon), hydrocarbons (like crude oil) are non-biodegradable substances.
• Glass also stays in the environment for a very long period of time.
• Farmyard manure is a biodegradable substance.

Farmyard manure

• Farmyard manure is a fertilizer composed of waste products, typically dung and urine, produced by farm animals.
• The waste products contain a wealth of nutrients, including nitrogen which is the extremely important element that plants need.
• It is a valuable soil improver that enhances and restores a range of natural properties of the soil; increases soil fertility.
• It adds humus and slow-releasing nutrients to the soil.

• Depletion of the ozone layer is mainly due to Chlorofluorocarbons.
• Chlorofluorocarbons. are synthetic chemicals that are used as refrigerants and in fire extinguishers.
• Ozone depletion occurs when chlorofluorocarbons (CFCs) and halon gases formerly found in aerosol spray cans and refrigerants are released into the atmosphere.
• CFCs and halons cause chemical reactions that break down ozone molecules, reducing ozone's ultraviolet radiation absorbing capacity.

• Carbon monoxide:-
  • Carbon monoxide leads to air pollution. It causes harm to humans by combining with haemoglobin, thus affecting the O₂ carrying capacity of the blood.
• Methane​
  • Methane is a greenhouse gas, released from power stations, chemical industries, etc.

• Fly ash is produced due to the combustion of coal and other industrial boilers.
• It is usually produced from coal-based power plants.
• It is one of the major sources of water and air pollution.
• It is having the potential to get airborne because of its small size and lightweight.
• It consists of a high amount of toxic and heavy metals which is reducing the recharging of groundwater.

• The greenhouse effect is a warming of Earth's surface and troposphere (the lowest layer of the atmosphere) caused by the presence of water vapour, carbon dioxide, methane, and certain other gases in the air.
• Of those gases, known as greenhouse gases, water vapour has the largest effect.
• Thus, there is an increase in the average temperature of the earth. Hence, Option 2 is related to Global Warming.
• Global Warming incidence is related to the increased influx of UV rays, which can induce skin cancer. Hence, Option 3 is also related to Global Warming.
• Carbon dioxide traps the heat and stops it from escaping the earth's atmosphere, thus leading to an increase in the temperature of the earth. This phenomenon is thus related to Global Warming.

• Eutrophication is characterized by excessive plant and algal growth due to the increased availability of one or more limiting growth factors needed for photosynthesis such as sunlight, carbon dioxide, and nutrient fertilizers.
• It is NOT directly related to Global Warming.

• Smog is a secondary pollutant, which has made up of Smoke and Fog.
• Traditionally, the smog has resulted from large amounts of coal burning in an area caused by a mixture of smoke and sulfur dioxide.
• Nowadays, the Vehicle emissions and Industrial emissions that are acted on in the atmosphere by ultraviolet light from the sun to form secondary pollutants that also combine with the primary emissions to form photochemical smog.
• The major chemical pollutants in Photochemical smog are NO, NO₂, volatile organic compounds, Ozone, and PAN (Peroxyacetyl Nitrate).
  • NO₂ decreases visibility due to yellowish colour.
• Hence option 1 is correct.

• State of Global Air 2020 Report:
  • According to it, India faced the highest per capita pollution exposure (83.2 μg/cubic metres) in the world.
    • In 2019, over 116,000 infants in India died within a month after birth due to exposure to severe air pollution.
    • The report also suggests exposure to polluted air during pregnancy is linked to low weight and premature birth.
    • Further, it noted that long-term exposure to outdoor and household air pollution contributed to over 1.67 million annual deaths from stroke, heart attack, diabetes, lung cancer, chronic lung diseases, and neonatal diseases in India in 2019.
• Pollutants Causing Effect on Health
  • Pollutants with the strongest evidence for public health concern include particulate matter (PM), Ozone (O₃), Nitrogen dioxide (NO₂) and Sulphur dioxide (SO₂).
  • These pollutants are capable of penetrating deep into lung passageways and entering the bloodstream causing cardiovascular, cerebrovascular and respiratory impacts.

Explanation:

• The photochemical reaction is caused by the absorption of energy in the form of light. The word smog is formed of smoke and fog.
• Photochemical smog is the major contributor to air pollution and is composed of primary and secondary pollutants.
• Primary being the nitrogen oxides and volatile organic compounds.
• Unsaturated hydrocarbons are those that have double or triple covalent bonds between adjacent carbon atoms. e.g., Ethylene, Gasoline and natural gas are the major sources of unsaturated hydrocarbon.
• The emitted sulphur dioxide is oxidized in the troposphere thereby forming sulphuric acid which on mixing with water forms the component of acid rain.

So, the SO₂ does not contribute to the formation of Photochemical fog.

• All forest fires emit carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, and particulate matter.
• Particulates are mixtures of soot, tars, and volatile organic substances, either solid or liquid, are emitted in large quantities from forest fires.
• The particulates can be smaller than 2.5 micrometers in diameter (PM 2.5), if deeply inhaled into the lungs, can damage lung tissues and cause respiratory and cardiovascular problems.
• Nitrogen oxides are released at temperatures greater than 1,500 degrees centigrade. Therefore, nitrogen oxides are released in significant quantities only during the most severe fires.
• Carbon monoxide, which is a poisonous gas, can be emitted in large amounts during forest fires.
• Volcanic eruptions release sulfur gases. These gases combine with the water vapor released by the eruption and the water vapor in the atmosphere to form sulfurous and sulfuric acid.

• Byssinosis is a rare lung disease.
  • It’s caused by inhaling hemp, flax, and cotton particles and is sometimes referred to as brown lung disease.
  • It’s a form of occupational asthma.
• In the United States, byssinosis occurs almost exclusively in people who work with unprocessed cotton.
  • People who open bales of cotton during the first stage of processing are at the highest risk.
  • There’s also a type of byssinosis called grain worker’s lung that appears in people who work with grains.
• Patients with byssinosis usually have difficulty with cough and feelings of chest tightness.
  • Some develop “Monday fever” when they are exposed to the dust as they return to work after a break.
• The symptoms improve over the course of the week and usually cause no long-term effects if the exposure is stopped.
  • However, permanent damage and difficulty in breathing can occur with continued exposure.
  • Most people with symptoms have had exposure for more than 10 years.
• Hence the option 2 is correct.

• According to the paradigm, transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems.
• The Earth system process boundaries mark the safe zone for the planet to the extent that they are not crossed.
• Hence option 1 is correct.

• In 2009, a group of 28 internationally renowned scientists proposed to identify the nine processes that regulate the stability and resilience of the Earth system.
• The scientists proposed quantitative planetary boundaries within which humanity can continue to develop and thrive for generations to come.
  • Crossing these boundaries increases the risk of generating large-scale abrupt or irreversible environmental changes.
  • Since then the planetary boundaries framework has generated enormous interest within science, policy, and practice.
• The planetary boundary is a concept involving Earth system processes that contain environmental boundaries.
  • It was proposed in 2009 by a group of Earth system and environmental scientists, led by Johan Rockström from the Stockholm Resilience Centre and Will Steffen from the Australian National University.

• Secondary pollutants are not emitted directly from a source like the primary pollutant.
  • Secondary pollutants are pollutants formed from the combination of primary pollutants with some other compound in the atmosphere.
  • Examples of secondary pollutants are Ozone, PAN (Peroxy acetyl nitrate), Smog, and Secondary particulate matter.
• Ozone is a highly reactive allotrope of Oxygen.
  • Chemical formula: O₃.
  • Ozone is present in the Stratosphere.
  • Ozone will absorb most of the ultraviolet (UV) radiation emitted by the Sun.
  • Chlorofluorocarbons (CFCs) is one of the main substance that causes ozone depletion.
• Sulfur dioxide is a toxic gas responsible for the smell of burnt matches.
• Carbon monoxide is a toxic gas produced from the partial oxidation of carbon-containing compounds.

• Greenhouse gases(GHGs) are a group of compounds that are responsible for absorbing heat (longwave radiation) in the atmosphere, keeping the Earth's surface warmer by allowing direct sunlight (relative short wave energy) to reach the Earth’s surface.
• Most Prominent Green House Gases:
  • Water vapour
  • Carbon Dioxide, CO2
  • Methane, CH4
  • Nitrous Oxide, N₂O (and NOT Nitrogen Oxide)
  • Ozone, O3
• Other GHGs are carbon monoxide, fluorinated gases, chlorofluorocarbons (CFCs), black carbon (soot), and brown carbon.
• Amongst all the greenhouse gases, only water vapour can absorb both incoming (UV) and outgoing (infrared) radiation.
• If GHG emissions remain unchecked, by the end of this century, the global temperatures may increase by 5^oC, causing global warming.

Explanation:

Persistent organic pollutants (POPs) are persistent, mainly lipid-soluble chemicals which bioaccumulate in fatty tissues and are biomagnified up the food web, and pose a risk to human health and the environment.

• Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochlorine.
• Originally developed as an insecticide, it became infamous for its environmental impacts.

So, DDT is a Persistent Organic Pollutant (POP).

• Incineration is a waste treatment process that involves the combustion of waste materials. Incineration and other high-temperature waste treatment systems are described as "thermal treatment".
• Incineration of waste materials converts the waste into ash, flue gas, and heat. The ash is mostly formed by the inorganic constituents of the waste and may take the form of solid lumps or particulates carried by the flue gas. The flue gases must be cleaned of gaseous and particulate pollutants before they are dispersed into the atmosphere. In some cases, the heat that is generated by incineration can be used to generate electric power.
• Incineration with energy recovery is one of several waste-to-energy technologies such as gasification, pyrolysis, and anaerobic digestion. While incineration and gasification technologies are similar in principle, the energy produced from incineration is high-temperature heat whereas combustible gas is often the main energy product from gasification. Incineration and gasification may also be implemented without energy and materials recovery.