Earth's Atmosphere: A Detailed Overview
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ATMOSPHERE
D
R
. S
HAKHA
S
HARDA
I
NTRODUCTION
Layer of gases surrounding the Earth
Held due to gravitational pull
Height of atmosphere from sea level
is 1600 km
Derived from Greek word “
atmos
”
means vapour
Composition of atmosphere
major : water vapours (most
variable component) N; 78% (largest
proportion) and O
2
; 21%
minor : Ar; 0.9, CO
2
; 0.03%
trace : Ne, He, Xe, Rn etc.
S
TRUCTURE
OF
A
TMOSPHERE
Troposphere
lowest layer (layer closest to man)
Greek word: tropos; mixing
distance: 8 kms from poles; 18kms from equator
temperature decreases with increasing altitude (+lapse
rate)
turbulent region, climate changes, cloud formation,
regulates weather, lightening, thundering , sound
transmission
twilight of dusk and dawn, medium of flight
pollination of seeds, fruits, seeds and spores
Circulation of biogeochemical cycles(CO
2,
O
2,
H
2
O, N)
Tropopause
: transition zone between troposphere and
stratosphere, winds move in horizontal direction (jet
streams: 480kms/hr)
C
ONTD
---
Stratosphere
second layer: 16-55 kms
ozone layer: 25 km from mean sea
level (protects from harmful UV
radiations)
temperature increases with height
(negative lapse rate)
no mixing: free of clouds
long distant flights
Stratopause:
boundary between
stratosphere and mesosphere
C
ONTD
---
Mesosphere
55-80 kms :middle atmosphere
temperature decreases with height
meteors burns up
coldest layer
Mesopause:
boundary between
mesosphere and thermosphere
C
ONTD
---
Thermosphere
80-500 kms.
temperature increases with height
telecommunication services
phenomenon of Auroras ( colorful light
display which can be seen almost
every night by people near poles)
o
Exosphere
Up to infinity
C
ONTD
---
Study of troposphere and
stratosphere is called
Meteorology.
Study of mesosphere and
thermosphere is called
Aerology
Atmospheric pressure:
Barometer
Temperature :
Thermometer
Wind :
Anemometer
Atmospheric humidity:
paper
strip hygrometer
A
IR
POLLUTION
WHO (World Health Organization)
the presence of materials in air in
such concentration which are harmful to
man and environment is known as air
pollution.
Sources
Natural
: e.g. Volcanic eruptions,
forest fires
Man-made
: e.g.combustion,
industrial processes, agricultural
activities, household activities
T
YPES
OF
AIR
POLLUTANTS
Primary pollutants
remain as such in air : CO,NO,
SO
2
, HC, CO
2,
NO
2,
SPM and CFC
Secondary pollutants
formed due to chemical reactions
among
primary pollutants : ozone,
smog, acid rain
14 out of 20 most polluted cities of the world are
in India and four out of these are in Punjab. NCR
the most polluted region of the world where
during smog each one inhales toxins equal to 30
cigarettes a day
O
XIDES
OF
CARBON
CO
: incomplete combustion
•
hypoxia : O deficiency
•
anoxia : CO poisoning
CO
2
: complete burning
•
ocean acidification
•
green house effect: CO
2
, CH
4
N
2
Oand CFC’s (Green House Gases)
•
global warming
GREEN HOUSE EFFECT
O
XIDES
OF
SO
2
Cause acid rain
Leads to chlorosis (yellowing of leaves)
and necrosis ( death of tissues)
Discoloration of buildings
Irritation in eyes
Asthma
Kills fishes
Mutagenic properties
O
X
I
D
E
S
O
F
N
O
2
Photochemical smog
PAN (Peroxy Acyl Nitrate)
Acid rain
Corrosion of metals
Fading of textiles
Necrosis, defoliation
Eye irritation, lung odema, blood
congestion
Injury to lungs, liver and kidneys
SPM (S
USPENDED
P
ARTICULATE
M
ATTER
)
•
Cotton dust : Bysinosis/ Pneumoconiosis
•
Stone grinding : Silicosis
•
Iron mills : Siderosis
•
Pollen grains : Hay fever
Others:
VOC’s ( Volatile Organic Compounds) :
benzene,
toluene, xylene
Carcinogenic
Leukemia
S
ECONDARY
P
OLLUTANTS
Acid rain ( Nitric acid and Sulphuric
Acid)
term coined by Robert Angus Smith,
1872
pH less than 5.4 (Acid Rain)
West Virginia, Washington D.C. : pH 1.2
Taj Mahal (India)
Dead lakes (Norway, Sweden, Germany,
U.S.A.)
Stone leprosy
P
HOTOCHEMICAL
S
MOG
(
FOG
+
SMOKE
)
1946 (Los Angeles, U.S.A.)
Brown haze
Automobiles exhaust
NO
2
PAN (Peroxy Acyl Nitrate)
R
EDUCING
S
MOG
/ C
LASSICAL
SMOG
1952 (London)
Blackish grey
Burning of coal
SO
2
Killed 4000 people in
London
O
ZONE
H
OLE
/ D
EPLETION
OF
O
ZONE
LAYER
Thinning of ozone layer (Farman et al, 1985)
Formed by the interaction of sunlight with NO
x
(
oxides of Nitrogen) and VOC’s (Volatile Organic
Compounds)
Maximum thinning of ozone layer is during
spring season
The thickness of ozone is measured in Dobson
Unit (DU); 1DU = 1ppb
Major hole was seen over Antarctica (South Pole)
and minor hole over Greenland (North Pole);
September 2003.
C
ASE
STUDIES
Bhopal Gas Tragedy, 3
rd
Dec, 1984
MiC (Methyl Isocyanate) and Phosgene
Chernobyl Nuclear Disaster, 1986;USSR
Sevoso Episode, 1976;Italy
Three Mile Island Nuclear Disaster, 1979;
U.S.A
Hiroshima and Nagasaki (1945) during
World War II
Bhopal Gas tragedy
Three mile island
CONTROL OF AIR POLLUTION
Control of Particulate
Emissions
Gravity settlers: settling of SPM with force of gravity
Cyclone Separators: separation of particulates through
centrifugal motion from a gas stream
Impinger: consists of bubble tubes for collecting particulates
into a liquid medium
Wet Scrubbers: collecting the particulates in a scrubbing liquid
Electrostatic Precipitator (ESP): use an electrostatic field o
induce a charge on particulates to remove them
Bag Filters: large sized porous bags for filtering the
particulates under pressure.
C
ONTROL
OF
A
IR
P
OLLUTION
Control of
Vehicular
Emissions
Catalytic converters
Unleaded petrol
Use of CNG
Biodiesel (Jatropa)
Control of Gaseous
/Industrial Emissions
Tall Chimneys
Absorption(within the surface)
Adsorption (on the surface)
Condensers
Desulphurization
Raprenox (Rapid Removal of NO
X
)
Catalytic Converters
Incinerators
The Earth's atmosphere is a vital layer of gases that encircles our planet, providing the necessary conditions for life to thrive. It consists of several distinct layers, each with unique characteristics and functions. From the troposphere closest to the surface to the thermosphere extending to great heights, this comprehensive guide delves into the composition, structure, and significance of each atmospheric layer. Explore the role of the ozone layer, the effects of temperature variation, and intriguing phenomena like auroras as we unravel the mysteries of our atmospheric realm.
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Presentation Transcript
ATMOSPHERE DR. SHAKHA SHARDA
INTRODUCTION Layer of gases surrounding the Earth Held due to gravitational pull Height of atmosphere from sea level is 1600 km Derived from Greek word atmos means vapour Composition of atmosphere major : water vapours (most variable component) N; 78% (largest proportion) and O2; 21% minor : Ar; 0.9, CO2; 0.03% trace : Ne, He, Xe, Rn etc.
Structure of Atmosphere (Sutcliffe : 1966)
STRUCTUREOF ATMOSPHERE Troposphere lowest layer (layer closest to man) Greek word: tropos; mixing distance: 8 kms from poles; 18kms from equator temperature decreases with increasing altitude (+lapse rate) turbulent region, climate changes, cloud formation, regulates weather, lightening, thundering , sound transmission twilight of dusk and dawn, medium of flight pollination of seeds, fruits, seeds and spores Circulation of biogeochemical cycles(CO2, O2, H2O, N) Tropopause: transition zone between troposphere and stratosphere, winds move in horizontal direction (jet streams: 480kms/hr)
CONTD--- Stratosphere second layer: 16-55 kms ozone layer: 25 km from mean sea level (protects from radiations) temperature increases with height (negative lapse rate) no mixing: free of clouds long distant flights Stratopause: boundary between stratosphere and mesosphere harmful UV
CONTD--- Mesosphere 55-80 kms :middle atmosphere temperature decreases with height meteors burns up coldest layer Mesopause: boundary between mesosphere and thermosphere
CONTD--- Thermosphere 80-500 kms. temperature increases with height telecommunication services phenomenon of Auroras ( colorful light display which can be seen almost every night by people near poles) o Exosphere Up to infinity
CONTD--- Study stratosphere Meteorology. Study thermosphere is called Aerology Atmospheric pressure: Barometer Temperature : Thermometer Wind : Anemometer Atmospheric humidity: paper strip hygrometer of troposphere is and called of mesosphere and
AIRPOLLUTION WHO (World Health Organization) the presence of materials in air in such concentration which are harmful to man and environment is known as air pollution. Sources Natural: e.g. Volcanic eruptions, forest fires Man-made: e.g.combustion, industrial processes, agricultural activities, household activities
TYPESOFAIRPOLLUTANTS Primary pollutants remain as such in air : CO,NO, SO2, HC, CO2, NO2, SPM and CFC Secondary pollutants formed due to chemical reactions among primary pollutants : ozone, smog, acid rain
14 out of 20 most polluted cities of the world are in India and four out of these are in Punjab. NCR the most polluted region of the world where during smog each one inhales toxins equal to 30 cigarettes a day
OXIDESOFCARBON CO: incomplete combustion hypoxia : O deficiency anoxia : CO poisoning CO2: complete burning ocean acidification green house effect: CO2, CH4 N2Oand CFC s (Green House Gases) global warming
OXIDESOF SO2 Cause acid rain Leads to chlorosis (yellowing of leaves) and necrosis ( death of tissues) Discoloration of buildings Irritation in eyes Asthma Kills fishes Mutagenic properties
OXIDESOF NO2 Photochemical smog PAN (Peroxy Acyl Nitrate) Acid rain Corrosion of metals Fading of textiles Necrosis, defoliation Eye irritation, congestion Injury to lungs, liver and kidneys lung odema, blood
SPM (SUSPENDED PARTICULATE MATTER) Cotton dust : Bysinosis/ Pneumoconiosis Stone grinding : Silicosis Iron mills : Siderosis Pollen grains : Hay fever Others: VOC s ( Volatile Organic Compounds) : benzene, toluene, xylene Carcinogenic Leukemia
SECONDARY POLLUTANTS Acid rain ( Nitric acid and Sulphuric Acid) term coined by Robert Angus Smith, 1872 pH less than 5.4 (Acid Rain) West Virginia, Washington D.C. : pH 1.2 Taj Mahal (India) Dead lakes (Norway, Sweden, Germany, U.S.A.) Stone leprosy
PHOTOCHEMICAL SMOG (FOG+SMOKE) 1946 (Los Angeles, U.S.A.) Brown haze Automobiles exhaust NO2 PAN (Peroxy Acyl Nitrate)
REDUCING SMOG/ CLASSICALSMOG 1952 (London) Blackish grey Burning of coal SO2 Killed 4000 people in London
OZONE HOLE/ DEPLETIONOF OZONE LAYER Thinning of ozone layer (Farman et al, 1985) Formed by the interaction of sunlight with NOx (oxides of Nitrogen) and VOC s (Volatile Organic Compounds) Maximum thinning of ozone layer is during spring season The thickness of ozone is measured in Dobson Unit (DU); 1DU = 1ppb Major hole was seen over Antarctica (South Pole) and minor hole over Greenland (North Pole); September 2003.
CASESTUDIES Bhopal Gas Tragedy, 3rd Dec, 1984 MiC (Methyl Isocyanate) and Phosgene Chernobyl Nuclear Disaster, 1986;USSR Sevoso Episode, 1976;Italy Three Mile Island Nuclear Disaster, 1979; U.S.A Hiroshima and Nagasaki (1945) during World War II
Three mile island Bhopal Gas tragedy
CONTROL OF AIR POLLUTION Control of Particulate Emissions Gravity settlers: settling of SPM with force of gravity Cyclone Separators: separation of particulates through centrifugal motion from a gas stream Impinger: consists of bubble tubes for collecting particulates into a liquid medium Wet Scrubbers: collecting the particulates in a scrubbing liquid Electrostatic Precipitator (ESP): use an electrostatic field o induce a charge on particulates to remove them Bag Filters: large sized porous bags for filtering the particulates under pressure.
CONTROLOF AIR POLLUTION Control of Gaseous /Industrial Emissions Tall Chimneys Absorption(within the surface) Adsorption (on the surface) Condensers Desulphurization Raprenox (Rapid Removal of NOX ) Catalytic Converters Incinerators Control of Vehicular Emissions Catalytic converters Unleaded petrol Use of CNG Biodiesel (Jatropa)
