Air and Air Pollution Questions in English

(A) The main difference lies in the chemical composition of the atmospheres.
Earth's atmosphere consists of a mixture of gases,primarily nitrogen $(78.08\%)$,oxygen $(20.95\%)$,carbon dioxide $(0.03\%)$,and water vapour in varying proportions.
In contrast,the atmospheres of Venus and Mars are composed primarily of carbon dioxide,accounting for about $95-97\%$ of their total composition.
This high concentration of carbon dioxide is likely a primary reason why life as we know it does not exist on Venus and Mars.

(N/A) The atmosphere acts as a blanket by performing the following functions:
$(a)$ It keeps the average temperature of the Earth fairly constant during day time and even during the course of the whole year.
$(b)$ It prevents a sudden increase in the temperature during day time.
$(c)$ It slows down the escape of heat from the surface of the Earth into outer space during night time.

(B) Winds are generated due to the unequal heating of atmospheric air by the Sun.
When air is heated,it becomes lighter and rises up,creating a region of low pressure.
Cooler air from high-pressure regions rushes in to fill this space,resulting in the movement of air,which we perceive as wind.
This process also facilitates the movement of water vapour,which eventually cools and condenses to form clouds.

(N/A) The following human activities contribute to air pollution:
$1$. Burning of fossil fuels: The combustion of coal and petroleum in vehicles and power plants releases harmful gases like $CO_2$,$SO_2$,and oxides of nitrogen into the atmosphere.
$2$. Industrial emissions: Many industries release toxic gases,smoke,and particulate matter into the air as byproducts of their manufacturing processes.
$3$. Deforestation and agricultural burning: Clearing forests and burning agricultural waste release large amounts of smoke and carbon particles,which significantly degrade air quality.

(N/A) The human activities that lead to an increase in the $CO_2$ content of the air are:
$1$. Deforestation: Trees absorb $CO_2$ for photosynthesis. Large-scale cutting of trees reduces this absorption,leading to an increase in atmospheric $CO_2$.
$2$. Combustion of Fossil Fuels: Burning coal,petroleum,and natural gas for transportation,electricity generation,and industrial processes releases significant amounts of $CO_2$ into the atmosphere.
$3$. Industrial Processes: Many industrial activities,such as cement production and chemical manufacturing,release $CO_2$ as a byproduct of their chemical reactions.

(B) The greenhouse effect is a natural process where certain gases in the atmosphere,such as $CO_2$,methane $(CH_4)$,and nitrous oxide $(N_2O)$,trap heat radiating from the Earth's surface.
These gases prevent the heat from escaping into space,which helps maintain the Earth's average temperature at a level suitable for life.
However,an excessive increase in the concentration of these greenhouse gases due to human activities leads to an abnormal rise in the Earth's temperature,a phenomenon known as global warming.

(N/A) The atmosphere is essential for life due to the following reasons:
$1$. It maintains an appropriate climate for the sustenance of life. It keeps the average temperature of the Earth steady during the day and throughout the year.
$2$. It prevents sudden increases in temperature during daylight hours.
$3$. The gases it contains are required for sustaining life on Earth. These gases include $Oxygen$,$Carbon$ $dioxide$,and $Nitrogen$.
$4$. $A$ thick layer of $Ozone$ in the stratosphere filters harmful $UV$ radiations from reaching the Earth. $UV$ rays produce harmful effects on all living organisms.

(N/A) Meteorologists collect information regarding the patterns of temperature,wind speed,air pressure,and other features that influence weather.
These data are gathered using remote sensing technology and weather forecast satellites.
This information is then compiled by meteorological departments,which prepare weather reports displayed on maps.
Finally,these reports are transmitted to the public through radio,television,and newspapers.

(A) The heat from the sun reaches the earth and warms the land and water surfaces.
These surfaces then re-radiate the absorbed heat in the form of infrared radiation,which warms the air in the atmosphere.
Therefore,the atmosphere is primarily heated by the radiation re-emitted from the land and water bodies.

(B) The atmosphere acts as a blanket that regulates the temperature of the earth.
During the day,the atmosphere prevents a significant amount of solar radiation from reaching the surface,keeping it from becoming excessively hot.
During the night,the atmosphere traps heat and prevents it from escaping into outer space,keeping the earth warm.
If there were no atmosphere,the earth would experience extreme temperature fluctuations: it would become extremely hot during the day due to direct solar exposure and extremely cold at night due to the rapid loss of heat.

(C) Greenhouse gases are gases in the Earth's atmosphere that trap heat.
Major greenhouse gases include $CO_2$ (Carbon dioxide),$CH_4$ (Methane),$N_2O$ (Nitrous oxide),and water vapor.
Carbon monoxide $(CO)$ is generally considered a toxic air pollutant rather than a direct greenhouse gas,as it does not significantly absorb infrared radiation compared to the others.
Ammonia $(NH_3)$ is also not classified as a primary greenhouse gas.
However,in the context of standard multiple-choice questions regarding greenhouse gases,$CO$ is the most commonly cited non-greenhouse gas among the options provided.

(A) Nitrogen is the most abundant gas in the atmosphere, making up about $78\%$ of the air we inhale.
Since the human body does not have any metabolic process to utilize nitrogen gas $(N_2)$, it does not participate in cellular respiration or any other biological function.
Therefore, the nitrogen that enters the lungs during inhalation remains inert and is exhaled back into the atmosphere along with $CO_2$ and other gases during the process of exhalation.

(C) An increase in $CO_2$ levels leads to the greenhouse effect,which causes more heat to be retained by the environment and contributes to global warming.
Increased $CO_2$ can also enhance the rate of photosynthesis in many plants.
However,the abundance of desert plants is primarily limited by the scarcity of water,not by the concentration of $CO_2$.
Even with higher $CO_2$ levels,desert plants cannot thrive without sufficient water,which is a limiting factor in arid ecosystems.

(A) Low visibility during cold weather is primarily caused by the formation of smog. Smog is a mixture of smoke and fog. When unburnt carbon particles or hydrocarbons from vehicle emissions and industrial processes are suspended in the air,they act as condensation nuclei for water vapor,leading to the formation of thick fog or smog,which significantly reduces visibility.

(N/A) During the day,the land heats up faster than the sea. The air above the land gets heated quickly and starts rising,creating a region of low pressure. Consequently,the cooler air over the sea rushes into this low-pressure area,causing a sea breeze.
During the night,the land cools down faster than the sea. The air above the water remains warmer than the air over the land. Therefore,the air moves from the land towards the sea,creating a land breeze.

(B) The moon does not have an atmosphere.
Due to the absence of an atmosphere,there is no mechanism to trap heat or regulate the surface temperature during the daytime,unlike on Earth where the atmosphere acts as a blanket.
Furthermore,the lack of an atmosphere allows all the accumulated heat to escape rapidly into space during the night.
Consequently,the moon experiences extreme temperature fluctuations between day and night.

(N/A) In coastal areas, a $ \text{sea breeze} $ blows during the daytime. This $ \text{sea breeze} $ provides a consistent and ideal wind speed for flying kites. Therefore, people enjoy flying kites near the seashore.

(B) The Mathura refinery releases significant amounts of toxic gases,specifically oxides of sulphur $(SO_2)$ and nitrogen $(NO_x)$.
These gases react with moisture in the atmosphere to form sulphuric acid and nitric acid.
This results in acid rain,which reacts with the calcium carbonate $(CaCO_3)$ present in the marble of the Taj Mahal,leading to its corrosion and yellowing.

(B) Lichens are known as bio-indicators of air pollution,specifically sensitive to sulfur dioxide $(SO_2)$.
Delhi has a very high density of automobiles and industrial activities,which leads to high levels of $SO_2$ in the atmosphere.
This high concentration of $SO_2$ prevents the growth of lichens in Delhi.
In contrast,places like Manali or Darjeeling have cleaner air with significantly lower levels of $SO_2$,allowing lichens to grow abundantly.

(B) Fossil fuels like coal and petroleum contain small amounts of nitrogen and sulphur.
When these fuels are burnt,they produce oxides of nitrogen and sulphur.
These gases cause respiratory problems and,in the presence of rain,form acid rain.
Furthermore,the burning of fossil fuels increases the concentration of suspended particulate matter in the air,which reduces visibility.

(N/A) Dust particles remain suspended in the air and can cause various allergies and respiratory diseases in humans.
Dust affects plant growth by settling on the leaf surface and blocking the $stomata$, which interferes with photosynthesis and gaseous exchange.
Dust particles act as carriers for toxic substances, including heavy metals and harmful chemicals, which can be inhaled or deposited into the environment.

(C) While $CO_2$ is essential for photosynthesis in plants,its concentration in the atmosphere is strictly regulated by natural cycles.
When human activities like burning fossil fuels and deforestation increase the concentration of $CO_2$ beyond natural levels,it acts as a pollutant.
High levels of $CO_2$ trap heat in the atmosphere,leading to the greenhouse effect and global warming,which causes climate change and rising sea levels.

(B) Lichens are symbiotic associations between fungi and algae. They are highly sensitive to air pollution,particularly sulfur dioxide $(SO_{2})$,and are therefore used as bioindicators of air quality.

(N/A) Regularly breathing in polluted air can lead to various respiratory diseases. Two common examples are:
$1$. Bronchitis: Inflammation of the lining of the bronchial tubes.
$2$. Asthma: $A$ condition in which airways narrow and swell and may produce extra mucus.

(N/A) The primary factor responsible for the change in rainfall patterns in India is the prevailing wind patterns,specifically the monsoon winds. These winds carry moisture from the oceans to the land,and shifts in their direction and intensity significantly influence the distribution and timing of rainfall across the country.

(N/A) Regularly breathing in polluted air can lead to various respiratory and systemic health issues. Two common diseases caused by this are:
$1$. Asthma: Chronic inflammation of the airways.
$2$. Lung Cancer: Caused by the inhalation of carcinogenic particulate matter and toxic gases.
(Other examples include bronchitis,heart disease,or chronic obstructive pulmonary disease $(COPD)$).

(N/A) The two main causes for the increase in the concentration of $CO_{2}$ in the atmosphere are:
$(i)$ Deforestation: Trees and plants absorb $CO_{2}$ for photosynthesis. Large-scale cutting of forests reduces this absorption,leading to an increase in atmospheric $CO_{2}$ levels.
$(ii)$ Increased combustion of fossil fuels: The burning of fossil fuels like coal,petroleum,and natural gas for energy,transportation,and industrial activities releases large amounts of $CO_{2}$ into the atmosphere.

(N/A) Greenhouse gases are gases that trap heat in the atmosphere,contributing to the greenhouse effect.
Examples of greenhouse gases include $CO_2$ (Carbon dioxide),$CH_4$ (Methane),$H_2O$ (Water vapour),$N_2O$ (Nitrous oxide),and $O_3$ (Ozone).
Any two of these can be listed as the answer.

(A) Smog is a type of intense air pollution. The word comes from a combination of the words 'smoke' and 'fog'.
It occurs due to the presence of suspended particles like carbon particles or hydrocarbons in the atmosphere.
These particles cause visibility to be lowered,especially in cold weather,when water vapor also condenses out of the air onto these particles.

(B) The movement of air,known as wind,is primarily caused by the uneven heating of the Earth's atmosphere by the Sun.
Different regions of the Earth receive varying amounts of solar radiation due to factors like latitude,surface type (land vs. water),and topography.
This creates temperature differences,which lead to pressure differences in the atmosphere.
Air naturally moves from regions of high pressure to regions of low pressure to balance these differences,resulting in the movement of air or wind.

(A) Biodegradable pollutants are substances that can be broken down or decomposed into simpler,harmless substances by the action of microorganisms like bacteria and fungi. Examples include organic waste,food scraps,and paper.

(N/A) The primary winds responsible for bringing rain to India are:
$(i)$ South-west monsoon: This is the main rainy season in India,which brings the majority of the annual rainfall.
$(ii)$ North-east monsoon: This brings rainfall to the south-eastern parts of India,particularly during the winter months.

(N/A) The compounds of nitrogen that cause air pollution are oxides of nitrogen,specifically $NO$ (nitric oxide) and $NO_2$ (nitrogen dioxide).
These compounds are primarily released into the atmosphere through the high-temperature combustion of fossil fuels in automobiles,power plants,and industrial processes.

(A) Fossil fuels such as coal and petroleum contain small amounts of nitrogen and sulphur.
When these fossil fuels are burnt,nitrogen and sulphur are also oxidized,producing various oxides of nitrogen and sulphur.
When these oxides dissolve in rainwater,they form acids (such as nitric acid and sulphuric acid),which leads to the phenomenon known as acid rain.

(N/A) $(i)$ $CO_2$ is fixed by plants to prepare food through the process of photosynthesis.
$(ii)$ $CO_2$ acts as a greenhouse gas that traps heat in the atmosphere,which helps in maintaining the Earth's temperature suitable for life.

(N/A) During the daytime,the land heats up faster than the water. The air above the land becomes hot and rises,creating a low-pressure area. Cooler air from the sea moves towards the land to fill this space,resulting in a $sea \ breeze$.
At night,the land cools down much faster than the sea. The air above the sea remains warmer than the air above the land. This warm air above the sea rises,and the cooler air from the land moves towards the sea to replace it,which is known as a $land \ breeze$.

(N/A) The greenhouse effect is the process by which certain gases in the Earth's atmosphere trap heat from the sun,preventing it from escaping back into space and thereby warming the planet.
$(b)$ The primary greenhouse gases responsible for this effect include Carbon dioxide $(CO_{2})$,Methane $(CH_{4})$,Nitrous oxide $(N_{2}O)$,and Chlorofluorocarbons $(CFCs)$.
$(c)$ The impact of the greenhouse effect on the global climate is known as global warming,which leads to the melting of polar ice caps,rising sea levels,and significant changes in weather patterns worldwide.

(N/A) Acid rain is caused by the presence of pollutants like sulphur dioxide $(SO_2)$ and nitrogen dioxide $(NO_2)$ in the atmosphere. These gases react with water vapor in the air to form sulphuric acid and nitric acid,which fall to the ground with rain.
Damage to living organisms:
$1$. In plants: It leads to stunted growth,yellowing of leaves (chlorosis),and can eventually cause the death of the plant.
$2$. In animals and humans: It causes skin irritation,itching,respiratory problems,and can lead to long-term health issues due to the accumulation of toxic metals leached from the soil.

(N/A) The two forms of oxygen found in the atmosphere are elemental oxygen $(O_2)$ and ozone $(O_3)$.
$(b)$ Biotic components include all living organisms such as plants,animals,and microorganisms. Abiotic components include non-living physical factors such as land (soil),air,water,sunlight,and temperature.

(N/A) The primary reasons for the increase in asthmatic patients are air pollution,excessive urbanization,and industrialization,which lead to the accumulation of particulate matter and allergens in the atmosphere.
$(b)$ Sidak's mother demonstrated values such as social responsibility,proactive problem-solving,environmental awareness,and a commitment to fostering a healthy and sustainable community.
$(c)$ Other methods to reduce this problem include walking to nearby markets or workplaces,using public transport,switching to cleaner fuels like $CNG$,and ensuring regular maintenance of vehicles to reduce exhaust emissions.

(N/A) This indicates high levels of air pollution. This phenomenon is known as $Smog$.
$(b)$ In cold weather, water vapor in the air condenses around suspended particulate matter, such as unburnt carbon particles, hydrocarbons, and other pollutants, to form a thick, dark, or yellowish fog known as $Smog$.
The two gases that primarily cause acid rain are $Sulfur \text{ } dioxide$ $(SO_2)$ and $Nitrogen \text{ } oxides$ $(NO_x)$.

(N/A) The atmosphere acts as a blanket because air is a bad conductor of heat. It prevents the sudden increase in temperature during the daylight hours and slows down the escape of heat into outer space during the night,thereby keeping the average temperature of the Earth fairly steady.
$(b)$ The factors that decide the rainfall patterns are:
$1$. The direction of prevailing winds.
$2$. The presence of mountain ranges or geographical barriers.
$3$. The proximity to large water bodies like oceans or seas.
$4$. The temperature variations in different regions.

(N/A) Glass allows short-wave solar radiation to enter but traps long-wave infrared radiation (heat) reflected from the interior,leading to an increase in temperature inside the enclosure.
$(b)$ Cold countries use this phenomenon,known as the greenhouse effect,to build glass houses (greenhouses) that trap heat,allowing them to grow tropical plants even in freezing external temperatures.
$(c)$ Carbon dioxide $(CO_{2})$ or Methane $(CH_{4})$.

(N/A) $(i)$ Burning of wood.
$(ii)$ Combustion of coal and petroleum fuels.
$(iii)$ Use of chemicals in the form of fertilizers and pesticides.

(N/A) The Mathura refinery releases oxides of nitrogen and sulphur into the atmosphere. These gases react with water vapor to form acid rain,which causes the corrosion of the marble of the Taj Mahal.
$(b)$ Lichens are highly sensitive to sulphur dioxide $(SO_2)$ pollution. Delhi has high levels of air pollution due to industrial activities and vehicular emissions,which prevents the growth of lichens. In contrast,places like Manali and Darjeeling have cleaner,humid environments that are suitable for lichen growth.
$(c)$ Smog is a combination of smoke and fog particles in the atmosphere.
Harmful effects of smog:
$(i)$ It significantly reduces visibility,which disrupts road and air traffic.
$(ii)$ It causes severe respiratory and breathing problems in humans.

(N/A) Burning of fossil fuels releases gases such as $CO$, $CO_2$, $SO_2$, $NO_2$, and unburnt carbon particles or hydrocarbons, commonly known as suspended particulate matter.
$(i)$ The presence of $CO_2$ in large quantities leads to global warming.
$(ii)$ The presence of $SO_2$ and $NO_2$ in large quantities causes acid rain, which damages crops and buildings made of marble.
$(b)$ Dust is considered a pollutant because:
$(i)$ It reduces visibility and acts as condensation nuclei for water vapor, leading to the formation of smog.
$(ii)$ Inhalation of dust-laden air increases the incidence of respiratory allergies, lung cancer, and cardiovascular diseases.

(N/A) Biodegradable substances are those that can be broken down into simpler,harmless substances by biological processes (decomposers). They do not cause long-term pollution. Example: Organic waste.
Non-biodegradable substances are those that cannot be broken down by biological processes. They persist in the environment and cause significant pollution. Example: Plastic.
$(b)$ Acid rain contains high concentrations of sulfuric and nitric acids. When it falls on the 'Taj Mahal',it reacts with the calcium carbonate $(CaCO_3)$ present in the marble,leading to its corrosion and the formation of pits,which causes the monument to lose its luster and structural integrity.
$(c)$ Smog is a type of air pollution that is a mixture of smoke and fog. It often forms in industrial areas or cities with high vehicular traffic.

(N/A) The percentage of oxygen in the atmosphere is approximately $21 \%$.
Two compounds of oxygen found in nature are water $(H_2O)$ and carbon dioxide $(CO_2)$.
Three processes in which oxygen is used up in the atmosphere are:
$(i)$ Respiration: Living organisms consume oxygen to break down glucose and release energy.
$(ii)$ Combustion: Burning of fuels requires oxygen to proceed.
$(iii)$ Formation of oxides of nitrogen: During lightning,nitrogen reacts with oxygen to form nitrogen oxides.

(N/A) The three primary processes in which oxygen is used are:
$1$. Combustion: Oxygen is essential for the burning of fuels.
$2$. Respiration: Living organisms use oxygen to break down glucose and release energy.
$3$. Formation of oxides of nitrogen: Oxygen reacts with nitrogen during high-temperature processes (like lightning or internal combustion engines) to form nitrogen oxides.

(N/A) $(i)$ Some bacteria are poisoned by elemental oxygen.
$(ii)$ The process of nitrogen fixation by bacteria,such as the enzyme nitrogenase,is inhibited by the presence of oxygen.