air pollution unit ii

7/31/2019 Air Pollution Unit II

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AIR POLLUTION

Defined as that quantity of pollutants which issufficient to cause injury to human being andtheir living creatures.

Air pollution can be categorized into two parts1. Primary pollutants which enter in the air

directly

2. Secondary pollutant these are created in theair from other pollutants under the influenceof electromagnetic radiation from sun


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Sources of air pollution1. Stationary combustion sources: such air pollutants are

produced mainly by burning of fuels and these maybe gaseous or particulate in nature .the largely usedfuel is coal and petroleum both are fossil fuels whichon burning produce mixture of oxides in addition toCO2 and H2O.

2. Mobile combustion source: includes automobiles,locomotives, air crafts etc.largets source of airpollution in the cities which causes about 80% of airpollution and 75% of noise pollution the major

pollutants are Carbon monoxide(77.2% highest)

Nitrogen oxide (7.7%)

Hydrocarbons (13.3%)


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Several products produced due to incompletecombustion of fossil fuels undergo photochemicalreaction with oxide of nitrogen to producephotochemical smog which contains Ozone(O3),peroxyacetyl nitrate(PAN) ,aldehydes etc. theseare often called the secondary pollutants.

3. Industrial processing and other sources: all industriesthat process organic chemicals using hightemperature release various gases causing pollution.The chemical industry are the main source of carbonmonoxide and sulphur oxides. Compound containing

chlorine and fluorine especially CFC are widely usedas propellants for aerosol can and as refrigerantsthese escape in air an cause pollution.


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Major air pollutants

I. Gaseous pollutants: are grouped into inorganic andorganic gases:

a) Inorganic gases are oxides of sulphur about 80 milliontone of SO2 per year added globally .oxides of carbon

its two common types are CO and CO2 .CO whenabsorbed into the lungs combines with haemoglobinin blood and produce carboxyhaemoglobin whichreduces the O2 carrying capacity of the haemoglobin.CO is fatal and is called silent killer. A continuous

increase of unabsorbed CO2 in atmosphere wouldhave disastrous effect on the flora and fauna anddisturb the ecological balance effect the atmosphereand result in green house effect .


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Oxides of nitrogen main source is thermal powerstation, factories ,automobiles and air craftswhere fossil fuels are used ,each tonne of coal

after burning produces 5-10 kg of nitrogen oxideand about 10 million tonnes of nitrogencontaining gases like NO and NO2 are enteringinto the atmosphere every year. Both when

combine with water to form nitrous acid /nitricacid which are highly reactive in nature. Thesealso give rise to most dangerous pollutant i.e.petrochemical smog and PAN.

Ozone is produced by chemical reaction betweenreactive organic gases and oxides of nitrogen.Ozone is a life savior if present in stratosphereand a pollutant if present in troposphere.


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b) Organic gases are aldehydes ie the thermal

decomposition of fats ,oil and glycerol

releases aldehydes in form of organic gases.They effect nasal and respiratory tract

causing irritation. Hydrocarbons which

pollute the atmosphere are methane,ethylene etc anaerobic degradation of

organic matter produces about one billion

metric tonnes of methane annually

.hydrocarbons cause irritation and injury to

mucous membrane.


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II. Particulate pollutants: these may be in formof solid particles /liquid droplets including

smoke,fogg,dust ,pollen, bacteria and fungi.It is estimated that about 8 billion solidparticles penetrate in atmosphere everyday.eg are smoke from factory chimneys

causing lung irritation asthma bronchitis etc.,photochemical smog a combination ofsmoke and fog. Biocides and pesticideschemical commonly applied in the form ofspray and are non biodegradable henceseriously effect the human health.


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Air pollution can affect our health in many ways.

Numerous scientific studies have linked air

pollution to a variety of health problemsincluding: (1) aggravation of respiratory and

cardiovascular disease; (2) decreased lung

function; (3) increased frequency and severity of

respiratory symptoms such as difficulty breathing

and coughing; (4) increased susceptibility to

respiratory infections; (5) effects on the nervous

system, including the brain, such as IQ loss andimpacts on learning, memory, and behavior; (6)

cancer; and (7) premature death.


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Effects of air pollution1. On human health: discussed in previous slides

2. On plants:SO2 pollution develop symptoms likebleached spots on leaves reduced yield etc.Oxides of nitrogen reduces the crop yield .inmany regions it is found that alfalfa issusceptible to SO2 ,tobacco to O3 .fluoridereduces the crop yield and damage leaf tissues.Chlorine develop symptoms like bleaching of

leaves.photchemical smog results into silveringand bronzing of leaves.O3 causes trees to losetheir leaves prematurely.


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Oil spill responders trying to recover oil from a

marsh


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Jakartas rain highly acidic: Expert

The Jakarta Post, Jakarta | Tue, 01/17/2012

7:29 PM A scientist has said that the rain thatfalls in the capital is highly acidic because ofthe large quantity of pollutants in the air. "Thethickness of the acid is strongly related to how

close the rain is to air pollution sources likethe thousands of factories near Jakarta. InJakartas case, they are close enough,

Indonesian Institute of Sciences water andclimate change expert Heru Santoso said onTuesday as quoted by Antara news agency.


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Pollution, loss of habitat drive away feathered guestsHamari Jamatia, Hindustan Times

New Delhi, February 02, 2012

The high pollution level in the Yamuna, continuous destruction of naturalhabitat and inconsistent winter have made many migratory birds 21 of the27 major species skip the city this year.Endangered species like paintedstorks, black-headed ibis and ferruginous pochards have come in fewnumbers, says the Asian Waterbirds Census (AWC). Of the various stretchesof the Yamuna between Wazirabad barrage and the point where it leaves the

Capital, the Okhla Bird Sanctuary has fared better with 58 of the 75 local andmigratory species being lightedThose who did not show up include temmincks stint, Indian cormorant,greater flamingo and great white pelican. Also, the numbers of severalspecies of ducks and storks bar-headed geese, northern shoveler, northernpintail and red-wattled lapwing have witnessed a sharp decline at Okhla, thecensus said. From the other stretches of Yamuna, the species that havemissed the city include red-crested pochard, common coot, spot-billed duckand little cormorant.
http://www.hindustantimes.com/StoryPage/Print/805397.aspxhttp://www.hindustantimes.com/Search/search.aspx?q=Hamari%20Jamatia&op=Storyhttp://www.hindustantimes.com/StoryPage/Print/805397.aspxhttp://www.hindustantimes.com/Search/search.aspx?q=Hamari%20Jamatia&op=Storyhttp://www.hindustantimes.com/Search/search.aspx?q=Hamari%20Jamatia&op=Storyhttp://www.hindustantimes.com/Search/search.aspx?q=Hamari%20Jamatia&op=Storyhttp://www.hindustantimes.com/StoryPage/Print/805397.aspx


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3. On animals: the general effects of airpollution on animals are similar to those as

human.4. On material :the acid rain and the products

of photochemical smog cause considerableeffect on metal and buildings, air pollutantsdamage historical monuments e.g. Taj Mahalof Agra is endangered due to SO2 pollutionproduced by Mathura refinery,SIU and

locomotive exhausts. Books and papers turnyellow due to SO2 pollution, hydrogen sulfidedecolorizes silver and lead paints.


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5. On climate: the release of green house gasesfrom various sources are causing rise in global

temperature (global warming),an increase ofglobal temperature by 2-3 degree Celsius maylead to melting of glacier ,flooding of low lyingcoastal plains,increse in flow of rivers and

change in rainfall pattern. Freon gas fromaerosol sprays and nitrogen oxide in atmospheredepletes ozone layer.

6. Aesthetic insults: a dust hanging smoke causes

poor visibility smoke and foul smelling odoursemitted by factories,automobiles,drain andgarbage dumps make urban life unpleasant.


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Control of air pollution Some important measures to reduce or minimize the

air pollution are:

1. Use of purified petrol :use of purified unleaded andgood quality of petrol reduces the level of sulphar andlead oxide in auto mobile exhausts.

2. Modernization of industries: the industrial machineand vehicle engine should be made energy efficient .

3. Installation of air treatment plant: large number oftreatment plants for air purification must be installed.

4. Use of alternative energy source: commonalternatives are wind, water and sun. Automobileindustry should manufacture battery operated andsolar operated vehicles.


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5. Treatment of emission: the emission fromfactories and industries should be treated by

various techniques before releasing into theatmosphere e.g. gravitational settlingchambers, cyclone seperator,wet and gasscrubbers, catalytic combustion etc.

6. Plantation of tree:

7. Change in life style: could be use of energymore efficiently, use of alternative source of

energy, plantation of tree as green belt, carpooling checking the undesirable burning ofvegetation.


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8. Enforcement of air prevention and control

pollution act 1981

9. Environmental education


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Functions of Central Pollution Control Board :

Advise the Central Government on matters relating to

pollution;

Coordinate the activities of the State Boards;

Provide Technical assistance to the State Boards, carry out

and sponsor investigations and research relating to control of

pollution;

Plan and organize training of personnel;Collect, compile and publish technical and statistical data,

prepare manuals and code of conduct.

To lay down standards;

To plan nation wide programme for pollution control


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What are the steps taken to control vehicular pollution?

The following steps are taken:Establishment of Ambient Air Quality Monitoring

throughout India

Notification of Ambient Air Quality Standards under

Environment (Protection) Act.

Notification of vehicular emission norms for year 1990-91,1996, 1998, 2000, 2001

Improving fuel quality by phasing out lead from gasoline,

reducing diesel sulphur, reducing gasoline benzene, and etc.

Introduction of alternate fuelled vehicles like CNG/LPG.Improvement of public transport system.

Public awareness & campaigns.

air pollution unit ii

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