Air Pollution and Control

(Elective-I)

Contents of Unit-IThe Structure of the atmosphere,

Definition and scope of AirPollution,

Scales of air pollution.

Earths atmosphere:

1) provides essential oxygen

2) provides medium for sound

3) shields solar radiation

4)has been neglected

Earths great spheresLithosphere- The lithosphere contains

all of the cold, hard solid land of theplanet's crust (surface), the semi-solidland underneath the crust, and theliquid land near the center of the planet

Hydrosphere- The hydrospherecontains all the solid, liquid, andgaseous water of the plane

Biosphere- The biospherecontains all the planet's livingthings. This sphere includes all ofthe microorganisms, plants, andanimals of Earth

Atmosphere- The atmospherecontains all the air in Earth'ssystem

AtmosphereIt is a mixture of gases that forms a layer

of about 500 km thick around the earth.

- Bottom 10-15 km (Troposphere) are most important part in terms of

Weather and Other aspects of Biogeochemical cycle

- The lowest 600 meters of Troposphere: Air Quality Studies

Composition of Air - 78% nitrogen, 21% oxygen, 1% carbon dioxide, water, other gases

Divided into four zones: - Troposphere- Stratosphere- Mesosphere- Thermosphere

Name ofregion

Height above the earths surface km

Temperature range O C

Major chemical species

Troposphere 0-11 15 to -56 O2, N2, CO2, H2O

Stratosphere 11-50 -56 to -2 O3

Mesosphere 50-85 -2 to -92 O2+and NO+

Thermosphere 85-500 -92 to 1200 O+, O2+ and

NO+

0 to 11 km

11 to 50 km

50 to 85 km

85 to 500 km

The structure of atmosphere

Definitions of air pollution

Air pollution is the introduction ofchemicals, particulate matter, orbiological materials that causeharm or discomfort to humans orother living organisms, or causedamage to the natural environmentor built environment, into theatmosphere.

Engineers joint council USA

Air pollution means the presence in theoutdoor atmosphere of one or morecontaminants, such as dust, fumes, gas,mist, odour, smoke or vapour, inquantities, with characteristics, and ofduration such as to be injurious tohuman, plant or animal life, or whichunreasonably interfere with thecomfortable enjoyment of the property

American Medical AssociationAn air pollution is the excessive

concentration of foreign matter in theair which adversely affects the wellbeing of the individuals or causesdamage to property.

Definition based on composition of air

Gas Name Chemical Formula Percent Volume

Nitrogen N2 78.08%

Oxygen O2 20.95%

*Water H2O 0 to 4%

Argon Ar 0.93%

*Carbon Dioxide CO2 0.0360%

Neon Ne 0.0018%

Helium He 0.0005%

*Methane CH4 0.00017%

Hydrogen H2 0.00005%

*Nitrous Oxide N2O 0.00003%

*Ozone and others O3 0.000004%

Another method of defining air pollution isfirst to specify the composition of clean airand then to classify all other materials orincreased amounts of those materials given incomposition of atmospheric air pollutants iftheir presence results in damage to humanbeings, plants and animals or materials.

Thus according to this definition CO,hydrogen, water vapours, ozone in aconcentration greater than 0.04 ppm(0.000004% by volume) would be airpollutants.

IS definition [IS-4167 (1966)] Air pollution is presence in ambient

atmosphere of substances, generallyresulting from the activity of man, insufficient concentration, present for asufficient time and under circumstanceswhich interfere significantly with thecomfort, health or welfare of persons orfull use or enjoyment of property.

Types of Air Pollution

Personal air exposureIt refers to exposure to dust, fumes

and gases to which an individualexposes himself when he indulgehimself in smoking

Occupational air exposureIt represents the type of exposure

of individuals to potentiallyharmful concentration of aerosols,vapors, and gases in their workingenvironment.

Community air exposureThis is most serious, complex, consists

of varieties of assortment of pollutionsources, meteorological factors, andwide variety of adverse social,economical, and health effects.

Air pollution problems may occur on three scales:

i. Micro scale

ii. Meso-scale and

iii. Macro scale.

Micro-scale problems range from those covering less than a centimeter to those the size of a house or slightly larger (few meters to 100s of meter).

Meso-scale air pollution problems are those of a few hectares up to the size of a city or county (local-to-regional ).

Macro-scale problems extend from counties to states, nations, and in the broadest sense, the globe (regional-to-continental scale)

Objective QuestionsQ1. IS _____________ gives definition of air

pollution.

Q2. The lowest _______m of troposphere are important for ___________________________ studies.

Q3. The line separating troposphere and stratosphere is known as __________________ .

Q4. Smoking causes ____________ type of exposure.

Q5. Thickness of atmosphere is about __ km.

Q6. ______________ problems range from those covering less than a centimeter to those the size of a house or slightly larger.

Q7. _____________ air pollution problems are those of a few hectares up to the size of a city or county.

Q8. ____________ problems extend from counties to states, nations, and in the broadest sense, the globe.

Theory questionsQ1. give IS definition of air pollution.

Also define air pollution based on composition of clean air..

Q2. Write a detailed note on Structure of the atmosphere.

Q3. Explain various types of exposures related to air pollution.

Q4. Explain different types of scales of air pollution