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ACEEngineering College

Ankushapur, Ghatkesar, Telangana 501301 (EAMCET Code: ACEG)NAAC Accridated with ‘A’ Grade

Department of Civil Engineering

Air Pollution and Control

III Year B.Tech. (II - Sem)

Prepared by :

T. Naga Srinu, M.Tech Assistant Professor

in association with ACE Engineering Academy

ACE is the leading institute for coaching in ESE, GATE & PSUsH O: Sree Sindhi Guru Sangat Sabha Association, # 4-1-1236/1/A, King Koti, Abids, Hyderabad-500001.

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AACE Engineering College : Ankushapur, Ghatkesar, Telangana 501301 (EAMCET Code: ACEG)

UNIT -1 Syllabus:

• Air Pollution – Definitions, Scope, Significance and Episodes• Sources of Air Pollution - Natural and Artificial – Stationary and

Mobile Sources.• Air Pollutants Classifications – Primary and Secondary, Point and

Non Point, Line and Areal.

Unit Outcome:

At the end of this unit, the student is having knowledge on• Historical accidents or disasters of air pollution.• Significance of air pollution towards the atmosphere.• Categories of air pollutants with suitable examples.• Classifications of Sources of air pollutants with examples.

I. Air Pollution Definition:

Air pollution is defined as presence of one or more air contaminants in ambient (outdoor) atmosphere to be or threaten to be injurious to human life, plant life, animal life and even damage to property.

(OR) Air pollution is defined as the excessive concentration of foreign matter

in the air which adversely affects the well being of individual or causes damage to the property. It also affects plants, animals and buildings.

Unit 1 Air Pollution and Control


2 Environmental Engineering

For Micro Notes by the Student II. Scope & Significance:

Air pollution can cause death, impair health, reduce visibility, bring about vast economic losses and contribute to the general deterioration of both our cities and country-side. It can also cause intangible losses to historical monuments such as the Taj Mahal which is believed to be badly affected by air pollution.

It is therefore, a matter of great importance that engineers of all disciplines consciously incorporate in their designs sufficient constraints and safeguards to ensure that they do not contribute to atmospheric pollution. In addition, they must apply their problem-solving abilities to eliminate air pollution where it exists and restoring the natural environment for the better living of humans, plants and animals.

III. Structure of Atmosphere:

Vertical space above ground containing air is called atmosphere. The atmosphere is not infinite but it extended up to certain height above the surface of the earth forming various characteristic layers called Troposphere, Stratosphere, Mesosphere and Thermosphere. These layers are listed below with the extended distance from the surface of the ground

Name of the Zone Extended up to (km)Troposphere 0 to 12 kmStratosphere 12 to 52 kmMesosphere 52 to 92 km

Ionosphere or Thermosphere > 92km


3 Air Pollution and Control

For Micro Notes by the Student IV. Composition of Air:

Air is a mixture of gases present in the atmosphere. Major gasses

Name of the GasPercentage by Volume (%)

Nitrogen 98.09%oxygen 20.95%Argon 0.90%

Carbon di-oxide 0.032%Remaining gases Traces

Average human requires about 12 kg of air each day which is nearly 12-15 times higher than the food we take. This is why even the small concentrations of pollutants in the air become more significant in comparison to the similar levels present in the food.

V. Episodes:

Rapid advancement in industry, particularly in Europe and America led to heavy and noticeable pollution of air.01. First serious note of air pollution was taken in Meuse valley in

December 1930 a heavy fog associated with a very stable air mass, trapped emissions from neighboring industries, the residents immediately complained of respiratory trouble and many died in this episode. However, no measurement of air pollution was recorded.

02. Air pollution happened again in Donora (Pennsylvania) in October 1948 where more than half of inhabitants (living beings) of the town complained of respiratory troubles and over 20 people died. Measurement of air pollution was done in this case. Sulphur dioxide and suspended particulate matter were found to be responsible.



For Micro Notes by the Student

03. After that, the worst air pollution disaster took place in London city, resulting about 4000 deaths.

04. Greatest industrial disaster leading to toxic air pollution took place in Bhopal where extremely poisonous gas, Methyl isocyanate released from the union carbide’s pesticide manufacturing plant on 3 & 4 December 1984. Over 2500 people died (unofficial figure is much higher) and over 1,50,000 were injured in this episode.

VI. Sources of Air Pollutants:

(A) Based on Origin of Sources1. Natural sources Ex: Dust storms, Forest fires, Volcanos…etc.2. Man-Made sources Ex: Industries, Automobiles, Power plants…etc.

(B) Based on Spatial distribution of source1. Point source Ex: An Industry @ one place2. Areal source (or) Non-point source Ex: Group of industries @ one place

(C) Base on position of source w.r.t Time & Space1. Stationary source (or) Area Source (Small stationary sources and mobile sources with indefinite routes) Ex: An industry2. Mobile source (or) Line source (Mobile sources with definite routes) Ex: A truck on Highway.




1. Natural sources of air pollution:(i) Products from atmospheric reactions (chemical reactions like

oxidation, combinatio,polymerizatio,photochemical reactions etc.):

(ii) Aerosols-Particulates: Aerosols are finely divided solid or liquid particles of microscopic size held suspended and dispersed in atmosphere. They cause visibility reduction, soiling of surfaces, corrosion etc.

The various types of aerosols are (a) dust, (b) smoke, (c) mists, (d) fog, (e) haze, (f) fumes.

(iii) Micro-organisms: Infect plants and animals.

(iv) Pollens: Pollens are the small grains from the anthers of flowers which may cause allergic reactions.

(v) Radioactive minerals

(vi) Volcanic ash and gases

(vii) Gases and odour from swamps and marshy lands.

2. Man-made sources of air pollution:(i) Combustion of fuels: (CO2), (SO2), (NO2),etc. accumulate in the

atmosphere.

(ii) Industries: Emit undesirable gases (SO2., CO2, NO2, NH3, CO.

(iii) Thermal Power Plants: Mainly they emit Sulphur dioxide.

(iv) Automobiles: Exhaust contains carbon monoxide (CO), methane, un-burnt carbon. CO is the main source of air pollution in congested cities.

(v) Agricultural activities: Crop spraying and field burning.

(vi) Nuclear Power Plants: Emit various radioactive substances



For Micro Notes by the Student VII. Classification of air pollutants:

Air pollutants are classified according to the manner in which they are formed and this classification is primarily categorized into three distinct types(A) Based on Origin

1. Primary air pollutants2. Secondary air pollutants

(B) Based on Nature1. Organic air pollutants 2. Inorganic air pollutants

(C) Base on State of Matter1. Particulates (Aerosols)2. Gasses and vapours

1. Primary air pollutants: Pollutants are those emitted into the atmosphere as a result of some specific process and remain for a long time in the chemical form in which they are emitted.

Eg:a) Particulate matter such as dust and aerosols,b) Pollensc) Sulphur compounds (SO2, SO3, H2S) d) Nitrogen compounds (NO, NO2, NH3)e) Carbon monoxide (CO) and carbon dioxide (CO2)f) Photochemical oxidantsg) leadh) Hydrocarbonsi) Radioactive materials j) Halogen compounds (Hydrogen fluoride, hydrochloric acid)




2. Secondary air Pollutants: These are the pollutants those formed in the atmosphere as a result of

some reaction. This reaction may be photochemical or Non-photo chemical and may take place between two pollutants (or) between one pollutant and natural constituents of the atmosphere. Ex: Ozone, PAN (Peroxy Acetyl Nitrate), SMOG (smoke+fog) and acid rain. Sulphuric acid (H2SO4) is formed by simple chemical reaction between sulphur dioxide (SO2) and water (H2O) vapour. It causes acid rains.

Ozone, formaldehyde, peroxy-acetyl-nitrate (PAN), etc., are formed by photochemical reactions caused by sunlight between two primary pollutants.

3. Organic air pollutants: They are organic in nature and mainly contain carbon and hydrogen

but may also contain some other elements. Carbon monoxide and carbon dioxide are excluded from this category as these contain only carbon and oxygen but no hydrogen. Ex: HC, Chlorinated HC, aldehydes and alcohols…etc.

4. Inorganic air Pollutants: These are the most common pollutants of the atmosphere. Contaminates

in the form of simple inorganics are compounds like CO, CO2, NO2, NO, SO2, HF, H2S metals…etc.

5. Particulates (Aerosols): These are finely divided solids or liquids. The larger particles tend to

get settle quickly and are called settleable or dustfall particulates (particles more than 1µ), while the smaller particles remain suspended for a longer period are called suspended particulate matter (SPM: Particles size less than 1µ). The smallest particles may behave almost like a gas and are readily transported by wind for longer distances without being deposited. Ex: For solid particulates dusts, smoke and fumes while for liquid particulates mist and sprays.

6. Gasses: Contaminants in the form of gases behave much as the air itself, without being settled out. Ex: SO2, CO2, NOX, H2S, NH3, Cl2, HC…etc.




VIII. Characteristics of air pollutants:

(i) Sulphur dioxide (SO2): It is one of the most important air pollutant and exists where ever fossil fuels are burnt. Thermal plants produce the largest quantity of SO2.

(ii) Carbon Monoxide (CO): The automobile exhausts are the main

contributors CO. The (CO) causes asphyxia i,e., loss of consciousness as a result of too little oxygen and too much carbon dioxide in the human blood.

(iii) Hydrocarbons and Photochemical oxidants: Hydrocarbons are mainly released into the atmosphere by automobile exhausts.

(iv) Lead: It is mainly injected into the atmosphere from the automobile exhausts, particularly by the automobiles running on petrol. They cause irritation of mucous membranes of nose, throat and lungs.

(v) Oxides of Nitrogen: These are the second most abundant pollutants of air in many cities ranking next to SO2. The oxides of nitrogen are produced from air oxidation, electrical discharge and solar radiations, incineration plants, welding operation etc.

IX. SMOG (Smoke + Fog)

Smog is a synchronym of two words – i.e., Smoke and Fog. Smog can be of two types, Photo chemical or Coal induced.

Photo chemical fog is bounded to highly motorized areas in metropolitan cities. It occurs under adverse meteorological conditions when the air movement is restricted. Smog is caused by the interaction of some hydrocarbons and oxidants under the influence of sunlight giving rise to dangerous Peroxy acetyl nitrate (PAN). Smog reduces visibility, causes eye irritation and damage to vegetation.



For Micro Notes by the StudentPrevious JNTU Questions (Subjective)

1. Define air pollution.2. Write about scope of air pollution.3. Classify air pollutants into different categories indicating their sources.4. Distinguish between primary and secondary air pollutants with examples.5. What are primary air pollutants? Give two examples.6. Differentiate point sources and area sources of air pollutants.7. Define air pollution and differentiate between natural and anthropogenic

air pollution.Model Questions:5. Write about significance of air pollution.6. List our and explain about classification of air pollutants.7. Discuss briefly about the sources of air pollution.8. What is meant by Smog? Discuss its causes and effects.9. Write short notes on (a) Aerosols (b) Smog

Previous JNTU Questions (Objective)

01. The Pollution Standard Index (PSI) scale has span from (a) 0-200 (b) 0-300

(c) 0-400 (d) 0-500

02. Which of the following is an organic gas (a) Hydrocarbons (b) Aldehydes (c) ketones (d) Ammonia

03. Which of the following is/are inorganic gas (es) (a) Carbon monoxide (b) Hydrogen sulphide

(c) Chlorine (d) All the above




04. The major contributor of Carbon monoxide is (a) Motor vehicle (b) Industrial processes

(c) Stationary fuel combustion (d) None the above

05. Ozone is found in ___________

06. The principal source of volatile organics (Hydrocarbons) is ______________

07. The function of automobile catalytic converter is to control emissions of__________

08. The boiler flue gas is source of __________

09. What is UNCED__________

KEY

01. (d) 02. (d) 03. (d) 04. (a)

05. Stratosphere

06. Industrial Processes

07. Carbon monoxide and Hydrogen

08. Nitrogen Oxide

09. United Nations Conference on Environment and Development



For Micro Notes by the StudentPrevious Gate Questions

01. Most of the weather phenomenon take place in the (a) Stratosphere (b) Mesosphere (c) Troposphere (d) Ionosphere

02. Two primary air pollutants are (GATE-07)(a) sulphur oxide and ozone (b) nitrogen oxide and peroxyacetyl nitrate.(c) sulphur oxide and hydrocarbon (d) ozone and perodyacetyl nitrate

03. Consider four common air pollutants found in urban environments, NO, SO2 Soot and O3. Among these which one is the secondary air pollutant (GATE-11)

(a) O3 (b) NO (c) SO2 (d) Soot

KEY 01. (c) 02. (c) 03. (a)

Previous ESE Questions

01. Which one of the following pollutant (or) pairs of , pollutants is formed due to photochemical reactions. (ESE-10)

(a) CO alone (b) O3 and PAN (c) PAN & NH3 (d) NH3 & CO

KEY01. (b)



For Micro Notes by the Student TSPSC Objective Questions

01. The most significant gaseous air pollutant is (a) Carbon dioxide (b) oxygen (c) sulphur dioxide (d) nitrogen

02. The primary air pollutant which is formed due to incomplete combustion of organic matter is

(a) methane (b) sulphur dioxide (c) ozone (d) carbon monoxide

03. Among the following, the only secondary pollutants (a) sulphur dioxide (b) ozone (c) hydrocarbons (d) hydrogen Sulphide04. The most significant primary gaseous pollutant found in automobile

exhausts is (a) CO (b) CO2 (c) SO2 (d) NO2

05. Sulphur dioxide is contributed to the atmosphere mainly from (a) thermal power plants (b) automobile exhausts (c) nuclear power plants (d) incineration plants

06. The chemical compounds which are mainly responsible for producing smog are

(i) hydrocarbons (ii) oxides of nitrogen (iii) oxides of sulphur (a) only (i) and (ii) (b) only (i) and (iii) (c) only (ii) and (iii) (d) (i), (ii) and (iii)

07. The secondary pollutant among the following is (a) sulphur dioxide (SO2) (b) methane (CH4) (c) Carbon monoxide (CO) (d) peroxy-acetyl-nitrate(PAN)




08. The major photo chemical oxidant is (a) hydrogen peroxide (b) ozone (c) nitrogen oxides (d) peroxy-acetyl-nitrate(PAN)

KEY

01. (c) 02. (d) 03. (b) 04. (a) 05. (a)

06. (d) 07. (d) 08. (b)




Animation Video lectures QR codes

Air Pollution Introduction and Overview

Documentary on Bhopal Gas Tragedy by Nat Geo

Air Pollution @ Delhi (One Day Tour)

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