Subject: environmental engineering Topic: Air pollution

Prepared By:Kansara Abhishek 151103106007Kotila Jayveer 151103106008Mistry Aditya 151103106009Pandya Dhrumil151103106010Patel Kajal 151103106011

Guided by:Assi. Prof. Mamta Patel

Civil Engg. Dept.

AIR POLLUTION Air pollution is defined as the presence of unwanted and undesirable foreign

particles and gases in the air which ay have adverse effects on human beings, animals,plants,vegetations and important structures.

POLLUTANT Any substance present in the environment in harmful concentration which adversely

alters the environment by damaging the growth rate of a species and by interfering with the food chains is toxic and affects the health, comfort and property etc. is considered as a pollutant.

COMPOSITION OF AIR

ATMOSPHERE AND ITS STRUCTURE Atmosphere:- The gaseous layer surrounding the

earth is known as atmosphere. The atmosphere is the life supporting mantle,

surrounding the earth. The atmosphere surrounds the earth up to 700 km,

atmosphere is subdivided as

Troposphere:- ( 0 To 12 Km) Contains 75 % of the gases in the atmosphere. This is where we live and weather occurs.

Stratosphere:- (12 – 50 Km) this layer contains ozone layer. Ozone acts as a shield for the earth’s surface. It absorbs ultraviolet radiations from the sun. This causes temperature increase in the upper part of the layer.

Mesosphere:- ( 50 to 80 Km) This is the coldest region of the atmosphere. This layer protects the earth from meteoroid. They burn up in this area.

Thermosphere:- ( 80 Km and above) The air is very thin in this region. Thermosphere means “Heat Sphere”. The temperature is very high in this region

This layer contains:- (a) Ionosphere:-This is the lower part of the thermosphere. It extends from 80 Km –

550 Km. This layer generally helps in radio communication.

(b) Exosphere:- The upper part of the thermosphere. It extends from 550 km and above. Air is very thin here this is the area where satellite orbits the earth.

STRUCTURE OF ATMOSPHERE

AMBIENT AIR QUALITY STANDARDS

* Ministry of Environment and Forests, Government of India notification,1994** Particle size less than 10 µm

CLASSIFICATION OF AIR POLLUTANTS

Air pollutants

Based on Origin Based on states of matter

Based on presence in environment

Particulate air

pollutantsGaseous air pollutants

Secondary air

pollutantsPrimary air pollutants

Indoor air pollutants

Outdoor air pollutants

ACCORDING TO ORIGIN (a) Primary Pollutants

(b) Secondary Pollutants

PRIMARY POLLUTANTS:- Primary pollutants are those which are directly emitted from identifiable source

These pollutants are emitted directly to the atmosphere. e.g.

(a) Particulate matter

(b) Oxides of Sulphur

(c) Oxides of Nitrogen

(d) Carbon Monoxide

(e) Radioactive Compounds

SECONDARY AIR POLLUTANTS:- Secondary air pollutants are those which are produced in the air by the reaction of two or more primary pollutants.

e.g. Ozone Formaldehyde Photochemical smog Peroxy acetyl nitrate (PAN)

CLASSIFICATION BASED ON STATES OF MATTER

1. Gaseous air pollutants 2. Particulate air pollutants

GASEOUS AIR POLLUTANTS Gaseous air pollutants are those air pollutants which are found in the gaseous state at

normal temperature and pressure in the atmosphere. The most common gaseous air pollutants are:

Carbon monoxide Carbon dioxide Nitrogen oxides Sulpher oxides Hydrocarbons etc.

PARTICULATE AIR POLLUTANTS These may be liquid or solid. The particulate matter are identified as aggregates which are

larger than 0.002 µ but smaller than 500 µ Dust (1 To 10,000 µ) : Small solid particles resulting from break up of large masses through

processes such as crushing, grinding or blasting. Smoke ( 0.5 To 1 µ) Consist of finely divided solid particles produced by incomplete

combustion of organic particles such as coal, wood, or tobacco. Mist ( 0.1 To 10 µm) :- These are liquid particles formed by condensation of vapor. Fog (1 to 40 µ ):- High concentration of mist is called as fog. It is dispersion of liquid

particles in air. Fumes ( 0.03 to 0.3 µ ):- Fine solid particles formed by the condensation of vapors of solid

material. The fumes are generally emit from melting operations. Ash ( 1 to 1000 µ ):- fine, noncombustible particles are known as fly ash. Spray (10 to 1000 µ):- Liquid particles formed by automation.

CLASSIFICATION BASED ON PRESENCE IN ENVIRONMENT

1. Indoor air pollutants 2. Outdoor air pollutants

INDOOR AIR POLLUTANTS The air pollutants which are generated from households are called indoor air

pollutants. Cleaning agents Mosquito repellents Pesticides Cigarette smoke Gases from stoves etc.

Outdoor air pollutants

The air pollutants which are generated outside the buildings are called outdoor air pollutants. Automobile pollutants Industrial pollutants Mining pollutants Natural emissions from decaying matter and animals etc.

SOURCES OF AIR POLLUTION The sources of air pollution may be classified into two groups: 1. Natural sources 2. Man made sources

NATURAL SOURCES The following are the different forms of natural sources:

Atmospheric reactions Volcanic eruptions Forest fires Dust storms, electric storms Salt spray form oceans Microorganisms Radioactive substances

Man made sources Combustion of fuel Automobile exhaust Industries Thermal and nuclear power plants Agricultural activities Construction materials System of sanitation Mining Nuclear explosions Air crafts Waste water treatment plants

MAJOR AIR POLLUTANTS – SOURCES AND EFFECTS

OXIDES OF NITROGEN Oxides of Nitrogen Include 4 gaseous compound:- Nitric oxide ( NO),

Nitrogen dioxide (NO2), Nitrous Oxide (N) Nitrogen penta oxide (N2O5)

In air pollution, Nitric oxide (NO) and Nitrogen dioxide are of prime concern. The sources of this pollutants are Industrial Processes, automobile exhausts.

HYDROCARBON Organic compounds containing only carbon and hydrogen are classified as

Hydrocarbons. They are of 2 types. (a) Aliphatic hydrocarbon (b) Aromatic hydrocarbon Hydrocarbon present in the atmosphere in the atmosphere from both natural and

man made sources. The major sources of hydrocarbon is burning of gasoline and industrial processes.

EFFECTS OF SOME COMMON AIR POLLUTANTS

Particulate Matter:-

EFFECTS ON HUMAN:- The pollutants of size less than 1 µ causes lung damage Asbestos fibers causes cancer Lead from automobile exhaust affects brain It causes several respiratory diseases Silica , arsenic, dust causes cancer

EFFECTS OF AIR POLLUTION ON HUMANS

EFFECTS ON PLANTS:- Deposition of particulate matter containing toxic metals affects the growth of plants The particulate matter after deposition on plant leaves block stomata opening of plants

and reduce plant growth. The particulate matter with acid rain, reduces pH of the soil which makes the infertile.

EFFECT ON MATERIAL: The particulate matter causes damage to building The corrosion is enhanced It causes cracks and fading of pointed surface Particulates accumulate on the soil and reduces fertility of soil.

CARBON MONOXIDE

EFFECTS ON HUMANS:- The high concentration of co can cause death The combination of co and hemoglobin leads to the formation of

carboxylhaemoglobin (cohb) reduces the oxygen carrying capacity of blood. At concentration of 100 ppm people experience dizziness and headache. The cigarette smoke contains 400 to 450 ppm co the percentage of cohb in blood

of cigarette smokers increases with increase in smoking. At concentration of 750 ppm of co it will cause death.

EFFECTS ON PLANTS:- CO reduces nitrogen fixing capacity of bacteria. Which affects the plant

growth. High concentration of causes leaf drops, reduces the size of leaf and

ageing.

EFFECTS ON MATERIALS:- Carbon monoxide appears to have no detrimental effect on materials.

OXIDES OF SULPHUR EFFECTS ON HUMAN HEALTH:- It causes irritation of eyes and respiratory tracts. Increase in SO2 concentration in the atmosphere, may lead to lung cancer

SO2 may obstruct breathing

SO2 leads to the formation of H2 SO4 which is 20 times more irritant than SO2

EFFECTS ON PLANTS:- The low concentration for long period may cause discoloration of leaves SO2 affects the growth of plants

At high concentration the leaf tissues gets damaged. H2SO4 is extremely toxic to plants and soil fertility.

EFFECTS ON MATERIALS:- The sulphuric acid will attack building materials containing carbonates. This will

form CaSO4 the CaSO4 gets easily washed away leaving discolored surface

Paper absorb SO2 causing the paper to become brittle

Leather looses the strength and flexibility.

OXIDES OF NITROGEN

Effects on Human Health:- Nitric Oxide reduces the Oxygen carrying capacity of blood.

Nitrogen dioxide causes irritation of lungs

High level of NOx causes pneumonia, lung cancer, oxygen deficiency.

NOx causes irritation of respiratory system, nervous system and digestive tracts.

NOx is extremely dangerous to human health.

EFFECTS ON VEGETATION:- NO2 and primary pollutants can damage plant tissues

High concentration of NO Causes Damage to leaves.

Secondary Pollutants such as smog, O3 may damage the vegetation

EFFECTS ON MATERIALS:- Nitric acid causes corrosion to metal surface

NO2 fades the color of clothes

NO2 causes cracking of rubber

HYDROCARBON EFFECTS ON HUMAN HEALTH:- Aromatic hydrocarbon may lead to cancer Inhalation of hydrocarbon causes irritation of respiratory tract. Methane creates narcotic effects on human beings Most of the hydrocarbon are carcinogenic to lungs

EFFECTS ON VEGETATION:- HC affects plant growth Discoloration of leaves

EFFECTS ON MATERIALS:- It causes discoloration of materials Material becomes less elastic and more brittle.

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