Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

Unit 1
Air pollution: composition and structure of atmosphere, global implications of
air pollution, Classification of air pollutants: particulates, hydrocarbon, carbon
monoxide, oxides of sulphur, oxides of nitrogen and photochemical oxidants.
Indoor air pollution.
Effects of air pollutants on humans, animals, property and plants.

Composition of Atmosphere
Different types of gases, water vapour, and dust particles make up the Earth’s atmosphere
composition.
 Gases of the Atmosphere
The composition and structure of atmosphere is made up
of a variety of gases, such as water vapour and dust
particles. The two major gases in the atmosphere are
nitrogen and oxygen. These two gases account for 99%
of it. The remaining gases in the atmosphere include
argon, carbon dioxide, neon, helium, hydrogen, etc. The
proportion of gases fluctuates in the upper layers of the
atmosphere to the point where oxygen is almost non-
existent at altitudes of 120 km.
 Oxygen
Despite accounting for only 21% of the total volume of the composition and structure of the
atmosphere, oxygen is an essential gas component. All living things take in oxygen. Oxygen can also
interact with other elements to generate useful compounds like oxides. Also, without oxygen, burning
is impossible.
 Nitrogen
Nitrogen makes up about 78% of the entire volume of the atmosphere. It’s a moderately innocuous gas
found in almost every organic substance. Nitrogen’s primary purpose is to control combustion by
diluting oxygen. It also aids in the decomposition of many substances indirectly.
 Carbon Dioxide
A very important gas in meteorology, Carbon dioxide can only be found up to 90 kilometres below the
Earth’s surface. It is transparent to insolation (incoming solar energy) but impervious to outgoing
terrestrial radiation. The greenhouse effect is mostly caused by carbon dioxide. When the volume of
other gases in the earth’s atmosphere composition remains constant, the volume of carbon dioxide in
the atmosphere has risen in recent decades, owing primarily to the combustion of fossil fuels. The
fundamental cause of global warming is the increase in carbon dioxide levels.
 Ozone Gas
Another essential element of the earth’s atmosphere composition is ozone, which is found primarily
between 10 and 50 kilometres above the Earth’s surface. There is very little ozone gas in the
atmosphere. It only affects the ozone layer, yet it is extremely significant. It protects living things by
absorbing the Sun’s UV radiation. There would have been no living beings or plants on the Earth’s
surface if there was no ozone gas in the atmosphere.
 Water Vapour
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
Evaporation of moisture and water from water bodies, plants, and soil cover provides atmospheric
vapour. The amount of vapour in the atmosphere varies from 0% to 5% by volume. It is temperature-
dependent, and as a result, it diminishes from the equator poleward as the temperature drops towards
the poles. The amount of vapour in the atmosphere decreases as it rises. Up to a height of 5 km, more
than 90% of the total atmospheric vapour is detected. Clouds, fog, dew, rainfall, frost, hailstorm, ice,
snowfall, and other types of condensation and precipitation are caused by the amount of moisture in
the atmosphere.
 Dust particles
Dust particles are most commonly found in the atmosphere’s lower levels. Sand, smoke-soot, sea salt,
ash, pollen, and other particles contain these particles. Due to dry winds, dust particles are found in
higher densities in temperate and subtropical regions than equatorial and polar regions. These
particulates aid the condensation of water vapour. Water vapour condenses in droplets around these
dust particles during condensation, resulting in clouds.

Structure of the Atmosphere

Composition, density, pressure, and temperature differences describe the composition of the
atmosphere into layers. It is broadly separated into two levels based on its composition and structure of
the atmosphere:
The structure of the atmosphere can be divided into five layers based on temperature:

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
Troposphere : The troposphere is the lowest layer of the atmosphere, extending from the Earth's
surface to an altitude of about 12 kilometers (7.5 miles). It is the layer where most of the weather
occurs, including clouds, precipitation, and wind. The temperature in the troposphere decreases with
altitude.
Stratosphere: The stratosphere is the second layer of the atmosphere, extending from the top of the
troposphere to an altitude of about 50 kilometers (31 miles). The temperature in the stratosphere
increases with altitude due to the presence of ozone, which absorbs ultraviolet radiation from the sun.
Mesosphere : The mesosphere is the third layer of the atmosphere, extending from the top of the
stratosphere to an altitude of about 80 kilometers (50 miles). The temperature in the mesosphere
decreases with altitude. Meteors often burn up in this layer.
Thermosphere : The thermosphere is the fourth layer of the atmosphere, extending from the top of the
mesosphere to an altitude of about 600 kilometers (373 miles). The temperature in the thermosphere
increases with altitude due to the absorption of solar radiation.
Exosphere : The exosphere is the outermost layer of the atmosphere, extending from the top of the
thermosphere to an altitude of about 10,000 kilometers (6,214 miles). The air in the exosphere is very
thin and consists mostly of hydrogen and helium.
In addition to these five layers, the atmosphere can also be divided into different regions based on its
electrical properties. For example, the ionosphere is a region of the atmosphere that extends from the
upper mesosphere to the top of the thermosphere. It is characterized by the presence of free ions and
electrons.
The structure of the atmosphere is important for a number of reasons. It helps to protect life on Earth
from harmful radiation from the sun. It also plays a role in regulating the Earth's climate and weather

Global implications of air pollution

Effect on Atmosphere i. It is found increment in the temperature in extreme industries, motor
vehicles, heat and gases emitted from AC and dense populated urban
region.
ii. Gradually this temperature forms heat island on increasing.
iii. When smoke and dust covers the sky in plentiful quantity, the heat
obtained from the sun goes back into the space on being reflected
bysmoke and dust.
iv. Due to this there is a fall in temperature and it causes the danger of
snow fall.
2. Depletion of Ozone i. In the atmosphere, 12 km above from the earth, ozone layer in
Layer : stratosphere is disarranged which prevents ultraviolet rays by 99%.
ii. Generally, refrigerators, fire brigades, CFC (chlorofluorocarbon) gas
used in AC, harm the ozone layer mostly.
iii. In 1985, British scientists discovered ozone hole.
iv. They find 2 % shortage in the thickness of Ozone layer; this
depletion is a symbol of danger.
v. The depletion is going on, that day is not so far harmful ultraviolet
rays
will demolish everything. So it is quite necessary to ban CFC gases
completely.
3. Green House Effect i. In the atmosphere, there are plenty of some gases which are heat

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
: absorber due to these, the temperature of the earth increases.
ii. In some decades, such a situation will rise, the temperature of the
earth
will increase from 5°C to 7°C because of which glaciers will start
melting
and the level of water in the sea will increase and the coastal regions will
sink in the water.
iii. The average temperature of the earth is 15°C which can increase up
to
30°C.
iv. So, we call these gases (CO2, CH4, N2O, CFC, and SF6) as green
house
gases. Green house effect places due to green house gases.
Acid Rain : i. Refineries, metals-melting industries, sulphur dioxide, nitrogen
dioxide
produced on burning coal and petrol, SO2 reacting with H2O present in
atmosphere in the sunlight forms sulphuric acid (H2SO4) and it rains as
acid rain because SO2 cannot stay in gaseous state for a long time :
2SO2 + 2H2 + O2  2H2SO4
ii. Sulphuric acid harms the soil and plants mostly.
iii. Acid rain has bad effect on rail-lines, buildings, bridges mostly.
iv. When the value of pH is less than 5, then the rain is called acid rain.
Smog : i. Smog is a problem in most large cities.
ii. It is caused by emissions from industry, motor vehicles, domestic
wood combustion and other sources, accumulating under
certainmeteorological conditions.
iii. Smog is a combination of smoke and fog.
iv. The infamous London fogs about 4,000 deaths were attributed to the
severe fog of 1952 were smog of this type.
There are mainly two types of smog :
1. Industrial smog.
2. Photo-chemical Smog :
i. Light energy (UV).
ii. Hydrocarbons/VOCs (from fossil fuel combustion).
iii. NOx (from fossil fuel combustion).
iv. Often contains ozone (O3
Effect of Air Pollution i. Effect on Living Organisms and Plants :
on Living Organisms a. Sulphur-dioxide, nitrogen dioxide and carbon mono-oxide
and Non-living (SO2, NO2, CO) present in the atmosphere are very harmful.
Organism : b. These gases produce (cause) various types of diseases as: diseases
related to lungs, eyes, respiration, heart, bones, teeth etc.
c. The smoothness of plants and leaves start ending. It causes the
danger of cold (ice) and worms.
ii. Effect on Non-living Organisms :
a. Atmospheric pollution equally affects not only living organisms but
also non-living organisms.
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
b. Due to this vehicles, building are destroyed which are in the contact
of atmosphere directly.
c. The main reasons for this are acid rain and green house gases.

Air Pollution : “Pollution is an undesirable change in the physical, chemical or biological

characteristic of air, water and soil that may harmfully affect the life or create a potential life hazard of
any living organism especially for man.”, OR, “Pollution is an unwanted alteration to the Earth’s
natural resources, usually with a negative impact on human health or life style.”

According to WHO (World Health Organisation) :

“Air pollution results mainly from gaseous emissions of industry, thermal power stations automobiles
domestic combustions, smoke from the fire etc. From the different sources of air pollution, a variety of
pollutants are released into atmosphere”. Our atmosphere covers the earth as a blanket in which there
is the combination of various gases which protects living beings from Ultraviolet Radiations. This
atmosphere helps in spreading radio waves as a medium.

Household (Indoor) Air Pollutions

Indoor air pollution is created by the release of harmful pollutants inside. These can include fine
particulate matter, carbon monoxide, and various other toxins. Indoor air pollution is a big problem in
developing countries, where people often burn fuels indoors for cooking and heating. It is also a
concern for people living in energy-efficient homes. These properties tend to be relatively airtight,
meaning that the air inside can quickly become stagnant and pollutant levels can rise rapidly.
• Second hand Smoke
• Pesticides
• Mold
• Your Pet Cat and/or Dog
• Fireplaces, Gas Stoves, Cars and Trucks
• Furniture in Your Living Room, Kitchen,
or
• Beauty Products
• Nonstick Pots and Pans
• Household Cleaners
• Home Computer Printer/Fax Machine
• Household Paints and Finishes
• Radon
• Pillows, Cushions,
• Crumbling Paint and Paint
• Asbestos Flooring, Shingles, Siding, and
• Rotten Food – Food will rot –plain and simple
Mitigation

Proper ventilation
One of the main ways to reduce indoor air pollution is by ensuring proper ventilation. Proper
ventilation helps remove polluted indoor air and replace it with fresh, clean air from outside.
When indoor spaces are not adequately ventilated, pollutants can build up to dangerous levels. This is
especially a concern in homes that are sealed tight to conserve energy.
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
Inadequate ventilation can also lead to a build-up of carbon dioxide, which can cause health problems,
including headaches, dizziness, and fatigue.
Use HEPA filters
High-efficiency particulate air (HEPA) filters can reduce indoor pollution, effectively removing
pollutants like mold spores, pet dander, dust mites, and tobacco smoke. In fact, HEPA filters remove
99.97% of airborne particles that are 0.3 microns or larger from the air that passes through it.
The filters can be used in various ways, including in vacuums, air purifiers, and in heating and air
conditioning systems.
Use green cleaners
Many conventional cleaning products contain harmful chemicals that cause indoor air pollution. To
avoid this, choose green cleaners made with natural ingredients like white vinegar, baking soda, borax,
citrus fruit, and essential oils.
These natural ingredients are safe for indoor use and are effective at cleaning surfaces and removing
dirt, dust, and grime.
Keep indoor spaces clean and dry
Keeping indoor space clean and dry can help reduce indoor air pollution. This is especially important
in areas where mold and mildew tend to grow, such as in the kitchen and bathroom. Additionally, it's
crucial to promptly repair any leaks or water damage to prevent mold and mildew from growing.
Indoor plants
Keeping indoor plants is an effective way to reduce indoor pollutants. Indoor plants help to purify the
air by absorbing contaminants and releasing oxygen. Additionally, indoor plants help to improve
indoor air quality by increasing humidity and reducing dust levels.
Choose low-emitting building materials and furnishings
When building or renovating indoor spaces, choosing low-emitting building materials and furnishings
is important. These materials and furnishings emit lower levels of volatile organic compounds (VOCs),
harmful chemicals that can pollute indoor air.
Some low-emitting materials and furnishings include bamboo, wool carpets, and latex paint.
Use air purifiers
An air purifier can provide protection against indoor air pollution, eliminating pollutants like dust,
pollen, mold spores, and pet dander. They can also remove VOCs, carbon monoxide, and other
harmful chemicals.

Source of Environmental Pollution

1. Natural Pollution: i. Since these types of pollution are caused by natural processes, they cannot be
halted. However, they can be managed at the right moment through prediction.
ii. Examples include a landslide, volcanic eruption, a hurricane, etc.

They can be split into three categories based on their nature:

i. Bio-degradable Pollutants: These are pollutants that are easily broken down by temperature, air,
humidity, bacteria, or animals. Examples include garbage produced by people in their daily lives,
cardboard taken from homes, vegetables, contaminated water, etc. They are part of a group of
contaminants that degrade naturally.

ii. Slow biodegradable pollutants: These pollutants can persist in their original form for a very long
time since they do not naturally breakdown quickly, such as plastic, which can last up to 1500 years
before decomposing.
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

iii. Non-degradable Pollutants: These pollutants have been causing harm for decades by lingering in
the atmosphere. Atomic and radioactive waste made of lead (Pb), mercury (Hg), and aluminum (Al)
are contained in this.

Classification of Air Pollutants

1. Physical Air Pollutants : There are many factors under physical air pollutants :
i. Smell of waste substances from homes.
ii. Heat emitted from radioactive radiation.iii. Smoke produced from industrial workshop, domestic
chimneys.
2. Biological Air Pollutants : Biological pollutants consist of decomposition of wastes from crops and
the smell generated from decomposing of dead animals.

3. Chemical Air Pollutants : It consists of gases produced from chemical fertilizers, and harmful
gases from industrial workshop as (CO2, CO, SO2) etc.

Sources of Man-made Pollution :

1. Transportation: i. One of the main sources of air pollution is transportation.
ii. The greatest single source of pollutants such hydrocarbons, nitrogen dioxide, and carbon monoxide
is likely transportation.
iii. Other dangerous emissions include the secondary production of ozone, lead, benzene, arsenic,
aldehydes, sulphates, and particle matter.
iv. The gasoline contains 4 g/L of lead, which is more than other countries are allowed to allow.
v. The number of vehicles on the road in the country has dramatically increased recently.

2. Industrial Processes:
i. India's major industries are situated close to the country's major cities.
ii. Because many companies are located close to residential areas, whatever pollutants they emit are
distributed and eventually deposit in the neighbourhoods, having a significant negative influence on
the health of the occupants.
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

iii. Sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), methane (CH4), volatile
organic compounds (VOC), and particulate matter are typical examples of industrial emissions.

iv. The majority of emissions come from industrial activities such the production of cement, fertilizer,
and synthetic rubber, as well as pulp and paper milling, chemical plants, and petroleum refineries.
v. Smelters, brass works, secondary lead plants, coal combustion, and other facilities that use heavy
metals (lead, mercury, cadmium, etc.) produce these pollutants.

3. Industrial and Non-industrial Fugitive Processes :

Process fugitive particles are not released from a defined place, such as a stack, in industrial or non-
industrial fugitive processes.
ii. Wind erosion of stored piles and unpaved roads is the cause of industrial fugitive dust emissions.
iii. Industry-related processes such material handling, loading, and transfer operations are the cause of
fugitive emissions.
iv. Fugitive emissions of pollutants, primarily methane, are produced during the mining,
transportation, and storage of coal.
v. When fuels like gasoline and natural gas evaporate from storage tanks while being transported from
one tank to another, volatile hydrocarbons evaporate.
vi. Traffic entrapment of dust from publicly paved and unpaved roads, crop cultivation, building, and
fires are the main causes of non-industrial fugitive emissions.

4. The Energy Production :

i. The majority of the energy used in India is produced by burning carbon-based fuels like coal,
petroleum, and wood.
ii. Over 90% of people living in rural areas rely on wood fuel as their primary energy source.
iii. The residential sector uses around 52% of the energy, followed by the productive sector at about
31%, and the transport sector at about 11%.

5. Waste Management :
i. One of the main causes of air pollution is the treatment of toxic wastes.
ii. Burning dumps reduces waste volume and eliminates dangerous organic materials, but it can also
release enormous amounts of particulate matter, which includes unburned trash and unpleasant odors.
iii. Burning garbage can release a lot of hazardous substances into the air, especially if it contains
industrial chemicals, tires, and petroleum-based wastes.
iv. In addition, poorly managed incineration of household, medical, and industrial waste can produce
highly harmful emissions of particulate matter, such as dioxins, hydrochloric acid, and heavy metals.
v. Residential waste burning additionally contributes to global emissions.

6. Agricultural Activities :
i. Agriculture is a significant part of the Indian economy, and pollution is emitted from a variety of
sources.
ii. A significant source of hydrocarbons and particulate matter is burning crop residue.
iii. Livestock produce ammonia and methane. Burning savanna emits a lot of
Nitrogen oxides (NOx), methane (CH4), along with significant levels of carbon monoxide (CO).
iv. Enteric fermentation and manure management produce methane.
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
v. Other smaller sources of pollution include dusting, using herbicides, and spraying insecticides on
the crops.

Effects of Air-Pollutants on Materials and Services

1. In addition to harming paper and cloth, air pollutants have degrading implications for metallic
surfaces, surfaces made of glass, painted surfaces, stones for construction, rubber surfaces, etc.
2. Acidic fumes are created when water vapor and oxides of nitrogen and sulphur react in the
atmosphere, attacking and harming metal surfaces. This problem has been particularly serious for the
computer, switch gear, and telecommunication industries.
3. Fluorine is exceptionally reactive and can even etch glass in windows and other surfaces at high
ambient quantities.
4. The surrounding air's hydrogen sulfide (H2S) combines with the lead oxide in white paint to create
lead sulphate, which causes white painted surfaces like doors, windows, and building walls to
gradually take on a brownish color.
5. Power dissipation from high voltage electric cables was observed to be another distinctive effect of
air pollution on electric cables and electricity poles.
6. High tension lines began to leak as a result of the deposition of particles that are good electrical
conductors on the insulators on electrical poles.
7. The financial loss brought on by air pollution due to the faster degradation of materials and aesthetic
things, such as the exteriors of buildings, statues, memorials, or horticulture plantings; or the expense
of materials or service loss; is extremely difficult to measure.

Effects of Air-Pollutants on Live-Stock Animals:

1. When farm animals consume plants, grasses, fodder, and other vegetation tainted by air pollution,
detrimental health consequences on the animals' health result.
2. Fluorine, arsenic, and lead are contaminants that harm livestock.
3. These pollutants are either produced by local industry or by spraying and dusting.
4. Fluorine emerges as the greatest pollutant among these because it has been discovered that sheep
and cattle are more vulnerable to fluorine consumption.
5. Even if the polluted plants do not exhibit any visible evidence of damage, calves that graze on them
may get fluorosis.
6. Arsenic poisoning can cause cattle to eat contaminated vegetation, which can cause symptoms
including salivation, thirst, vomiting, drowsiness, a feeble and regular pulse, and irregular breathing.
Arsenic from sweeps and insecticide spritzes falling on plants can also accumulate by the plants.
7. Smelters, coke furnaces, and other industries that use coal as a fuel cause lead to be released into the
atmosphere.
8. Lead is accumulated within the vegetation as a result of the lead fumes that the vegetation absorbs
from the air.
9. Livestock animals that consume lead-contaminated vegetation may get lead poisoning, which can
result in symptoms like being unable to stand up straight, swaying, and prostration, among others, in
addition to total loss of appetite, digestive system paralysis, and diarrhea.

Effects of Air-pollution on Plants :

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
1. Air pollutants have negative effects on both plants and animals in addition to having a negative
impact on human health.
2. Fluorine is the most prevalent air contaminant that seriously harms plants.
3. In addition to some clay baking processes, fluorine is released from facilities that make aluminum,
glass, phosphate fertilizers, etc.
4. Fluorine levels more than around 0.3 g/m3 have phytotoxicological effects on plants.
5. Plant damage is frequently seen on the fruit or the flower, both of which greatly reduce the crop's
worth.
6. The most noticeable harm from general air pollutants, such as SO2, HF, HCl, CI2, O3, NO3, NH3,
Hg, H2S, H2N, PAN, herbicides, smog, etc., to plants and vegetation occurs in the leaf structure.
Pollutants clog the stomata of the leaf, reducing the intake of CO2, which negatively affects
photosynthesis.
7. These negative effects can vary from a slowing of the plant's growth to its complete demise.
8. Even while the plants may not even exhibit any signs of damage, low quantities of pollutants like
fluorine and heavy metals like arsenic, lead, mercury, cadmium, and others can be exceedingly
dangerous to cattle and other animals grazing on these vegetations.

Effects of air pollution on human health

1. Suspended Particular Matter :
i. Consequences on breathing and respiratory systems; deterioration of present respiratory and
cardiovascular disorders; modification of the body's defense mechanisms against foreign substances;
injury to lung tissues; carcinogenic effects; and early mortality (stillbirths).
ii. Children and the elderly are the most sensitive.
2. Sulphur Dioxide (SO2) :
i. Breathing issues, respiratory disorders, weakened lung defenses, aggravated respiratory and
cardiovascular conditions, and mortality.

ii. People with chronic lung and cardiovascular conditions, including asthmatics, are sensitive to SO2
exposure.
3. Carbon Mono-oxide (CO) :
i. Because CO decreases oxygen delivery to organs and tissues, persons with cardiovascular disease
are most at risk for health problems.
ii. CO reduces physical dexterity, mental acuity, and visual perception at high concentrations.
4. Nitrogen Oxide (NOx) :
i. NO is a key component in the creation of tropospheric ozone.
ii. NO2 weakens resistance to respiratory infections, irritates the lungs, and promotes bronchitis and
pneumonia.
iii. Asthmatics are particularly vulnerable, which makes them more vulnerable to viral assaults.
5. Lead :
i. Seizures, mental impairment, and behavioral issues may all occur from high lead exposure.
ii. Low doses can cause central nervous system abnormalities in fetuses, newborns, and children in
particular. Heart disease and excessive blood pressure may be caused by lead uptakes.
6. Ozone (O3) :
i. Ozone causes chest pain, pulmonary congestion, coughing, and sneezing as well as a reduction in
lung function.
ii. It might impact both healthy individuals and those with compromised respiratory systems.
Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM
 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution
7. Carbon Dioxide (CO2) : As concentrations rise over time, a greenhouse effect results, causing
climate change and global warming.
8. Nuclear Waste : Causes diseases, mutations, and fatalities by contaminating places with
radioactivity.

Forms of air pollutants

Air pollutants can be in a variety of forms, including:
 Gases: Gaseous pollutants include carbon monoxide (CO), nitrogen dioxide (NO2), sulfur
dioxide (SO2), ozone (O3), and volatile organic compounds (VOCs). Gases are the most
common form of air pollution.
 Particulate matter (PM): PM is a mixture of solid particles and liquid droplets found in the air.
Some common sources of PM include car emissions, dust, smoke, and pollen. PM can be
classified by size, with PM2.5 (particles with a diameter of 2.5 micrometers or less) being the
most harmful to human health.
 Biological pollutants: Biological pollutants include bacteria, viruses, and allergens. Biological
pollutants can cause a variety of health problems, including respiratory infections, allergies,
and asthma.
 Vehicle emissions: Vehicle emissions are a major source of air pollution, particularly in urban
areas. Vehicle emissions include CO, NO2, and PM.
 Industrial emissions: Industrial emissions are another major source of air pollution. Industrial
emissions can include a variety of pollutants, including SO2, NO2, PM, and VOCs.
 Power plants: Power plants that burn fossil fuels emit a variety of air pollutants, including SO2,
NO2, CO2, and PM.
 Agriculture: Agricultural activities, such as livestock farming and crop production, can emit a
variety of air pollutants, including ammonia, methane, and PM.
 Residential emissions: Residential emissions can include pollutants from cooking, heating, and
wood burning.

Air pollution control

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM

 Air and Noise Pollution |KCE-057| Unit 1 : Air Pollution

Primary pollutants: Pollutants that enter directly from the sources into the atmosphere are called primary
pollutants.

Secondary pollutants: Pollutants that are formed due to interactions between primary air pollutants and other
atmospheric components are called secondary pollutants. These interactions can be physical or chemical.

Primary pollutants Secondary pollutants

Have a direct effect on the environment and organisms

Highly reactive when photochemical agents are
and have an indirect effect by being involved in the
involved in their formation.
formation of secondary pollutants.

2. These are difficult to control. because

2. Can be controlled by controlling man-made activities
understanding the reactions involved in secondary
causing pollution.
pollutants formation is difficult.

3. For Example -

Particulate matter like aerosols, soot, dust, etc. 3. For Example -

HydrocarbonsHCs. Acid rain.

Sulphur dioxideSO2 Photochemical smog.

Nitrogen oxideNOx. Peroxyacetyl nitratePAN.

Carbon monoxideCO.

***

Er. Neha Singh | Assistant Professor | Department of Civil Engineering |SRMCEM