gives a detailed account on the varying causes of pollution-air and water (as guided by the oxford science text of class 8).

4. PERCENTAGE OF AIR IN ATMOSPHERE :-
NITROGEN-78.08%,OXYGEN-20.95% & others -0.97%

5. AIR – POLLUTION-
THE PRESENCE OF CHEMICALS IN THE AIR IN QUANTITIES
HARMFULL TO HUMAN HEALTH AND THE ENVIRONMENT
IN WHICH THEY LIVE IS KNOWN AS AIR- POLLUTION.
NOW WE MOVE ONTO THE COMMON AIR-POLLUTANTS AND THEIR MAJOR
SOURCES ON THE NEXT SLIDE COMING UP:-
-PARTICULATE MATTER -OXIDES OF SULPHUR AND NITROGEN
-CLOROFLUROCARBONS -CO2&CARBON MON OXIDE

6. 1

7. 2.

8. 3.

9. 4.

11. AN INCREASE IN THE AMOUNT OF CO2
AND CERTAIN OTHER GASES IS
RESPONSIBLE FOR A PHENOMENON
KNOWN AS GLOBAL –WARMING.
GREEN HOUSE-EFFECT IS THE
PHENOMENONWHEREBY THE EARTH’S
ATMOSPHERE TRAPS THE SOLAR RADIA
–TION BECAUSE OF THE PRESCENCE OF
GASES SUCH AS CO2,WATER VAPOUR,
METHANE ETC.

12. 2.THE EARTH’S SURFACE RADIATES HEAT TO THE ATMOSPHERE
SOME OF WHICH ESCAPES INTO THE SPACE.GREENHOUSE
GASES SUCH AS CO2 & METHANE ABSORB SOME OF THE HEAT
& SEND IT BACK TO EARTH.
1.SUNLIGHT PENET -
RATES THE ATMOS –
PHERE & WARMS
THE EARTH’S
SURFACE.
3.WHEN THE CONCENTRATION OF GREEN HOUSES INCREASES
IN THE ATMOSPHERE ,MORE HEAT IS TRAPPED NEAR THE
EARTH’S SURFACE.THIS RESULTS IN A RISE IN THE EARTH’S
SURFACE TEMPERATURE.

13. CAUSES POSSIBLE EFFECTS
*DEFORESTATION. *INCREASE IN EARTH’S
SURFACE TEMPERATURE
*BURNING OF FOSSIL FUELS. *MELTING OF POLAR ICE CAPS
*RELEASE OF METHANE DUE
TO THE BREAK DOWN OF
ORGANIC MATTER.
*RISE IN GLOBAL SEA-LEVEL
RESULTING IN THE FLOODING
OF LOW LYING COASTAL
REGIONS

14. AIR POLLUTANTS SUCH AS OXIDS OF
SULPHUR & NITROGEN REACT WITH
O2 & WATER VAPOUR OF THE
ATMOSPHERE ,THEY EVANTUALLY
FORM DILUTE SOLUTIONS OF H2SO4,
&HNO3.THESE ACIDS MIX WITH RAIN
WATER & COME DOWN IN THE FORM OF
RAIN WATER .

17. -PHOTOCHEMCALSMOG IS SAID TO HAVE AN ADVERSE
IMPACTON PLANT GROWTH BECAUSE IT FORMS A LAYER ON
LEAVES &,ALONG WITH DUST ,BLOCKS SUNLIGHT FROM
BEING ABSORBED BY THR LEAF SURFACE.THIS LAYER BLOCKS
THE ABSORPTION OF CO2 BY THE LEAVES AND ALSO AFFECTS
THE FUNCTIONING OF THE STOMATA ,THEREBY REDUCING
THE RATE OF PHOTSYNTHESIS.
-ACID RAIN DAMAGES PLANTS AND CAN ALSO CAUSE
PREMATURE LEAF FALL.

19. -CARBON MONOXIDE IN THE AIR EASILY COMBINES WITH THE
HAEMOGOBLIN IN THE BLOOD AND HAMPERS THE TRANSPORT OF
OXYGEN WITHIN OUR BODY,WHICH CAN LEAD TO
DROWSINESS,HEADACHE,DIZZINESS & NAUSEA.
-EXPOSURE TO HIGH LEVELS OF SUSPENDED
PARTICULATE MATTER ,SULPHUR DIOXDE,OXIDES OF
N2O,AND OTHER AIR POLLUTANTS IRRITATES THE EYES
,NOSE ,THROAT & LUNGS.YEARS OF EXPOSURE TO THESE
CHEMICALS CAN LEAD TO RESPIRATORY DISEASES SUCH
AS LUNG CANCER ,ASTHMA & BRONCHITES.

20. -USE OF UNLEADED PETROL SHOULD BE ENCOURAGED
-THE EXHAUST GASES IN VEHICLES SHOULD MADE TO PASS
THROUGH THE CATALYTIC CONVERTER WHICH CON VERTS
HARMFULL CARBON MONOXIDE & NITROGEN OXIDES TO
HARMLESS CO2,NITROGEN OXIDE & H2O,BEFORE RELEASING
THE EXHAUST INTO THE AIR.

21. -LESS POLLUTING SUBSTANCE SUCH AS CNG SHOULD BE USED
-REGULAR POLLUTION CHECK SHOULD BE MADE MANDATORY
FOR ALL VEHICLES
-COAL SHOULD BE MADE FREE OF SULPHUR BEFORE BEING
BURNT IN POWER PLANTS.ONLY LOW-SULPHUR COAL
SHOULD BE USED FOR BURNING.

22. -LESS POLLUTING ENERGY
RESOURCES SUCH AS
HYDROELECTRICITY,NUCLEAR
ENREGY SHOULD BE USED.
-USE OF PUBLIC TRANSPORT SHOULD BE ENCOURAGED

24. 1.

25. 2.

26. 3.

27. 4.

28. -INDUSTRIAL WASTES DISCHARGED INTO THE WATERS
CONTAIN A LOT OF TOXIC SUBSTANCES THAT MAKE WATER
UNFIT FOR DRINKING & BATHING.
-UNTREATED DOMESTIC SEWAGE WHEN DISCHARGED INTO
WATER BODIES ,BECOMES A BREEDING GROUND FOR A NO.
ORGANISMS THAT CAUSE WATER – BORNE DSEASES.

29. -OIL SPILLS ARE VERY HARMFUL TO AQUATIC
ANIMALS , WHICH LEAD TO DESTRUCTION OF
MARINE LIFE. MOREOVER,
THE CLEANING UP PROCESS ALSO TAKE A LOT OF
DAMAGE TO THE MARINE LIFE.
-IGNITION OF ARMS AND MERCURY RELEASE A LARGE
AMOUNT OF MERCURY.WHEN WATER CONTAMINATED WITH
MERCURY IS USED FOR DRINKING BY ANIMALS AND HUMAN
BEINGS IT CAN CAUSE NUMBNESS TO LIMBS,LIPS & TONGUE.
IT CAN ALSO LEAD TO BLURRED VISION & MENTAL
DISORDERS.
-THE WASTE WATERS RELEASED BY FACTORIES &
INDUSTRIES AND THE FERTILIZER RICH RUN-OFFS FROM
THE AGRICULTUREFIELDS IS RICH IN ORGANIC-MATTER.

30. THE ENTRY OF NUTRIENT-RICH WATERRESULTS IN A THICK
GROWTH OF ALGAE,CALLED ALGAL BLOOM,AND MANY
OTHER WEEDS.SOON THESE PLANTS COVER THE ENTIRE
SURFACE OF WATER .THIS IS CALLED
EUTROPHICATION MAY BE
DEFINED AS THE
THE ALGAE USE UP
A LOT OF OXYGEN THAT THE
OTHER AQUATIC ANIMALS DIE
DUE TO LACK OF IT.
ALGAL
BLOOMS
SHUTS OUT
THE
SUNLIGHT.
LIMIT OF
LIGHT
PENETRA
-TION
DEAD WATER
NO LIVING
AQUATIC PLANT
OR ANIMAL
LIFE.

31. -BATHING AND WASHING CLOTHS IN WATER
BODIES SHOULD 0BE AVOIDED.
-DOMESTICS AND INDUSTRIAL SEWAGES
SHOULD BE TREATED TO REMOVE TOXIC
SUBSTANCES BEFORE BEING RELEASED
INTO WATER BODIES

32. -POLLUTION –CONTROL RULES ENFORCED BY THE
GOVERMENTSHOULD BE FOLLOWED STRICTLY
-USE OF ECO-FRIENDY FERTILIZERS & HERBICIDES
SHOULD BE ENCOURAGED

33. THE WATER SUITABLE FOR DRINKING BY HUMAN
BEINGS IS KNOWN AS
-BE TRANSPARENT,COLOURLESS AND ODOURLESS.
-CONTAIN SUFFICIENT AMOUNTS OF SALTS & OXYGEN
-BE FREE FROM HARMFUL CHEMICALS AND MICRO-
ORGANISMS

34. 1.WATER COLLECTED FROM
THE RIVER IS MADE FREE OF
LARGE PIECES OF DIRT &
PUMPED INTO RESORVOIRS.
2.WATER IS ALLOWED TO STAND IN
LARGE TANKS SO THAT SUSPENDED
IMPURITIES SETTLE DOWN.THIS IS
CALLED SEDIMENTATION.
3.WATER IS PASSED
THROUGH
FILTER BEDS TO REMOVE ALL
OTHER
INSOLUBLE IMPURITIES.THIS IS
CALLED FILTRATION.
4.WATER IS CHLORINATED TO KILL
ANY HARMFULL MICRO ORGANISM
THATIS PRESENT AT THIS STAGE.
5.WATER IS
SUPPLIED
TO HOMES &
FACTORIES
BY HUGE WATER
MAINS

38. BOILING-BOILING WATER IS ONE OF THE EASIEST WAY OF
PURIFYING WATER.IT IS, HOWEVER VERY IMPORTANT THAT
WATER IS BOILED AT 100C FOR AT LEAST 10-15 MINUTES TO
KILL HARMFULL MICRORGANISMS.
ADDITION OF CHEMICAL TABLETS-CHEMICALS LIKE CHLORINE
TABLETS AND POTTASIUM PERMAGNATE CAN BE ADDED TO
WATER FROM WELLS AND WATER TANKS TO KILL HARMFULL
MICRO –ORGANISMS & GERMS.

39. USE OF ELECTRIC WATER FILTERS-THEY HAVE A MICRO
POROUS FILTERS, CARBON & A SOURCE OF ULTRAVIOLET
RADIATION. THE MICRO PORUS FILTER STRAINS OUT
PHYSICAL IMPURITIES PRESENT IN THE WATER SUCH AS DUST,
RUST etc. CARBON ABSORBS ORGANIC IMPURITIES &
REMOVES UNWANTED TASTE & ODOUR. ULTRA VIOLET
RADIATION KILLS MICRO ORGANISMS.

40. BOTANISTS AND MANY COMMERC
-IAL PLANT GROWERS USE GREEN
HOUSE GASES FOR GROWING PLA
-NTS IN COLD CLIMATE CONDTION
-S THE TEMPRATURE INSIDE A GRE
-EN HOUSE IS HIGHER THAN THE
TEMPRATURE OUTSIDE BECAUSE
THE SOLAR INTERIORS OF THE
GREENHOUSE IS REMMITED INTO
THE GREEM HOUSE, THUS
KEEPING IT WARM.THIS IS WHAT
HELPS PLANT GROW.
ALTHOUGH 75% OF EARTH’S SURFACE
IS COVERED WITH WATER, A MERE
0.01% OF THIS WATER IS AVAILABLE
FOR HUMAN CONSUMPTION .THIS IS
BECAUSE THE WATER PRESENT IN
THE OCEANS & SEAS ARE SALTY
AND, HENCE CANNOT BE USED FOR
DRINKING. IN ADDITION, MOST OF
THE FRESH WATER IS FROZENIN THE
GLACIERS & POLAR ICE CAPS AND
IS,THEREFORE NOT ACCESABLE.
WORD HELP

41. WATER POLLUTION WAYS TO REDUCE POLLUTION
AIR POLLUTION