Air pollution : Definition and sources (automobiles,industries,domestic sources and miscellaneous)
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5. Air pollution
๏ The phenomenon called โpollutionโ is an inescapable
consequence of the presence of man and his activities.
๏The term โair pollutionโ signifies the presence in the
ambient (surrounding)atmosphere of substances (e.g.
gases ,mixture of gases , particulated matter) generated
by the activity of man in the concentrations that interfere
with human health , safety or comfort , or injurious to
vegetation and animals and other environmental media
resulting in chemicals entering the food chain or being
present in drinking water and there by constituting
additional source of human exposure .
6. ๏ The direct effect of air pollutants in plants ,
animals and soil can influence the structure
and function of ecosystems, including self
regulation activity , thereby affecting the
quality of life .
๏ In the past air pollution meant smoke
pollution but today air pollution has become
more subtle and recognizes no geographical
or political boundaries .
๏Air pollution is one of the present-day
health problems throughout the world.
7. ๏Most air polluted country in the
world is Pakistan recently .
๏ But before Pakistan , China was the
most air polluted country.
8. ๏Undesirable change in the air
๏ Entry of air pollutants ( foreign materials)
like smoke, harmful gas etc in the Clean and
fresh environment
๏Production of pollutants by the
activities of man
Summary
๏ Results in the harmful effects to human
health including plants and animals .
9. Sources of air pollution
The main sources of air pollution are
as follows:
1) Automobiles
2) Industries
3) Domestic sources
4) Miscellaneous
10. Details
1)Automobiles
๏ Motor vehicles are the major source of air
pollution in urban areas
๏ They emit hydrocarbons, carbon monoxides,
lead, nitrogen oxide and paticulate matters.
๏ Diesel engines, when misused are capable of
emitting black smoke and malodorous fumes
11.
12. Mechanism of air pollution by automobiles
๏ In presence of sunlight ,
certain of hydrocarbons and oxides of
nitrogen may be converted in the atmosphere
into โ photochemical โ pollutants of
oxidizing
nature .
๏ Sulphur dioxide : Sulphur dioxide from
vehicle combines with water to form sulphuric
acid and gaseous form of this acid remains in
air and causes pollution of air.
๏ Lead : combustion of leaded petrol produces
lead and all lead are emitted into the atmosphere
causing air pollution .
13. ๏Nitrogen dioxide : It emitted from vehicles are
released in the atmosphere and itโs concentration in
the atmosphere increases resulting air pollution.
๏Particulate matter : The dust and smoke from
vehicle also forms particulate matter which are
released into the environment causing air
pollution.
Contdโฆ.
๏ Carbonmonoxide (CO) : It is the product of
incomplete combustion of carbon. Estimates of
man-made CO emission vary from 350 -600 milion
tonnes per annum. Itโs concentration in urban areas
depend upon traffic and weather conditions. Itโs
increase concentration in atmosphere results air
pollution.
14. 2) Industries
๏They emit large amount of
pollutant into the
atmosphere
๏Combustion of fuel to
generate heat and power
produces smoke, sulphur
dioxide, nitrogen oxides and
the fly ash.
15. ๏Petro chemical industries
generate hydrogen fluoride,
hydrochloric acid and
organic halides
๏Many industries discharge
carbon monoxide, carbon
dioxide, ozone, hydrogen
sulphide and sulphur
dioxide
For example
Brick factories of Bhaktapur and herbal industry
of Jadibuti produces high amount of harmful
gases causing air pollution.
16. Mechanism of air pollution by
industries
๏Industries discharge their wastes from high
chimneys at high temperature and high
speed which are released into the
environment without any treatment of
harmful gases.
17. 3) Domestic sources
๏ Domestic combustion of coal , wood or oil is a
major source of smoke , dust , sulphur dioxide
and nitrogen oxides.
๏The most direct and important source of air
pollution affecting the health of many people is
tobacco smoke.
* Note : The london disaster of air pollution in
1952 in which thousands had died was due to
domestic coal burning.
18.
19. Mechanism of air pollution by domestic
sources
๏ Harmful substances produced from
domestic sources are released into the
atmosphere and pollute the air.
๏ Tobacco smoke may be inhaled by the
people who do not smoke and this process is
called โPassive Smokingโ
20. ๏ These comprise
burning refuse ,
incinerators , grasses of
forest , tires of vehicles
etc
4) Miscellaneous
21. ๏ It also comprise pesticide
spraying , natural sources (
e.g. wind borne dust , fungi,
molds , bacteria ).Pesticides
contain harmful hydrocarbon
contents which cause air
pollution when released in
the environment.
๏ It also comprise pesticide
spraying , natural sources (
e.g. wind borne dust , fungi,
molds , bacteria ).Pesticides
contain harmful hydrocarbon
contents which cause air
pollution when released in
the environment.
22. ๏ Nuclear energy programmes also come
under it. During nuclear activities green
house gases and radioactive wastes
(plutonium , uranium )are produced and
released without proper disposal in the
environment causing air pollution .
24. Major Air Pollutants and their sources
Sources
๏ Oxides of
nitrogen
Automobile exhaust, gas
stove and heaters , wood-
burning stoves, kerosene
space heaters
๏ Hydrocarbons Automobile exhaust and
cigarette smoke
๏ Ozone
Automobile exhaust , high
altitude aircraft cabins
To be continue
25. ๏ Sulphur
dioxide
Power plants ,
smelters , oil refineries
, kerosine space
heaters
๏ Lead Automobile exhaust
using leaded gasoline
Contdโฆโฆ
