Chapter 17 Air resources
? The atmosphere layer is very thin
compared to the size of the Earth.
17.1 The Earth’s atmosphere is a mixture of gases.
Our atmosphere is a result of actions of both heat
and gravity
(a) Atmosphere with gravity but no
solar heat,molecules lie on the
earth’s surface
(a) Atmosphere with solar heat but
no gravity, molecules escape into
outer space
(a) Atmosphere with solar heat and
gravity, molecules reach high
altitudes but are prevented from
escaping into outer space
Fig 17.1 our atmosphere is a result of the
actions of both solar heat and gravity
Atmosphere is divided into layers.
Fig 17.2 the two
lowest atmospheric
layers-troposphere
and stratosphere
17.2 Human activities have increased air pollution
? Volcano
Fig 17.3 the cloud of sulfur dioxide generated by the June 15,1991,
eruption of Mount Pinatubo reached India in four days,(the black
strips are where satellite data are missing.) by July 27,the sulfur
dioxide cloud had traveled around the globe
Aerosol (烟、雾、气凝胶 ) and particulates facilitate
chemical reactions involving pollutants
Aerosol
Fig 17.4 (a) micrograph of aerosols in the atmosphere,(b) an aerosol is the site of many
chemical reactions involving pollutants,Water surrounding the solid particle attracts
airborne molecules that them readily react in aqueous solution before being released back
into the atmosphere
Removal of Aerosol and particulates
Fig 17.5 during scrubbing
of industrial gaseous
effluents,a fine mist of
water captures and
removes solid particles
that have diameters as
small as 0.001 millimeter,
Fig 17.6 (a) particulates in
industrial gaseous
effluents become
negatively charged by an
electrode and are attracted
to the positively charged
wall of the electrostatic
precipitator, Once it
touches the wall,a
particulate loses its
charge and falls into a
collection bin,(b)
smokestacks with and
without electrostatic
precipitators
Without electrostatic
precipitator
With electrostatic
precipitator
To collection bin
electrode
particles
voltage(+) (-)
Gas and
suspende
d particles
Gas
There are two kinds of smog,Industrial and
photochemical
Industrial smog,sulfur dioxide and sulfuric acid
Photochemical smog,nitrogen oxides,ozone and
hydrocarbons from internal combustion engine.
Catalytic converters reduce automobile emissions
Fig 17.8 the average
daily concentration of
nitrogen monoxide,
nitrogen dioxide,and
ozone in Los Angeles
*ppm = parts per million
night sunrise noon sunset night
NO
,N
O 2
,O
3(p
pm
)
17.3 Stratospheric ozone protects the Earth from
UV radiation
? O3 + UV O3 + heat
Fig 17.17 false-color image
of ozone levels over the
Northern Hemisphere,
recorded by NASA’s total-
ozone mapping
spectrometer (TOMS),Blue
and purple areas are areas
of ozone depletion; red and
green areas are areas of
higher-than-normal ozone
levels.
17.4 Air pollution may result in global warming
Fig 17.18 glass acts as
a one-way valve,letting
visible light in and
preventing infrared
energy from exiting.
Fig 17.19 the greenhouse effect in
the earth’s atmosphere,Visible light
from the sun is absorbed by the
ground,which then emits infrared
radiation,Carbon dioxide,water
vapor,and other greenhouse gases
in the atmosphere absorb and re-
emit heat that would otherwise be
radiated from the earth into space
Long-wavelength
infrared radiation is
not transmitted out
through the glass
and is trapped inside
Short-wavelength visible light
from the sun is transmitted
through the glass
Atmospheric carbon dioxide is a greenhouse gas
Increased emission from carbon dioxide is mainly from
burning of fossil fuel and deforestation.
The potential effects of global warming are uncertain
levels of atmospheric carbon dioxide and global
temperatures appear to be closely related to each other
? The atmosphere layer is very thin
compared to the size of the Earth.
17.1 The Earth’s atmosphere is a mixture of gases.
Our atmosphere is a result of actions of both heat
and gravity
(a) Atmosphere with gravity but no
solar heat,molecules lie on the
earth’s surface
(a) Atmosphere with solar heat but
no gravity, molecules escape into
outer space
(a) Atmosphere with solar heat and
gravity, molecules reach high
altitudes but are prevented from
escaping into outer space
Fig 17.1 our atmosphere is a result of the
actions of both solar heat and gravity
Atmosphere is divided into layers.
Fig 17.2 the two
lowest atmospheric
layers-troposphere
and stratosphere
17.2 Human activities have increased air pollution
? Volcano
Fig 17.3 the cloud of sulfur dioxide generated by the June 15,1991,
eruption of Mount Pinatubo reached India in four days,(the black
strips are where satellite data are missing.) by July 27,the sulfur
dioxide cloud had traveled around the globe
Aerosol (烟、雾、气凝胶 ) and particulates facilitate
chemical reactions involving pollutants
Aerosol
Fig 17.4 (a) micrograph of aerosols in the atmosphere,(b) an aerosol is the site of many
chemical reactions involving pollutants,Water surrounding the solid particle attracts
airborne molecules that them readily react in aqueous solution before being released back
into the atmosphere
Removal of Aerosol and particulates
Fig 17.5 during scrubbing
of industrial gaseous
effluents,a fine mist of
water captures and
removes solid particles
that have diameters as
small as 0.001 millimeter,
Fig 17.6 (a) particulates in
industrial gaseous
effluents become
negatively charged by an
electrode and are attracted
to the positively charged
wall of the electrostatic
precipitator, Once it
touches the wall,a
particulate loses its
charge and falls into a
collection bin,(b)
smokestacks with and
without electrostatic
precipitators
Without electrostatic
precipitator
With electrostatic
precipitator
To collection bin
electrode
particles
voltage(+) (-)
Gas and
suspende
d particles
Gas
There are two kinds of smog,Industrial and
photochemical
Industrial smog,sulfur dioxide and sulfuric acid
Photochemical smog,nitrogen oxides,ozone and
hydrocarbons from internal combustion engine.
Catalytic converters reduce automobile emissions
Fig 17.8 the average
daily concentration of
nitrogen monoxide,
nitrogen dioxide,and
ozone in Los Angeles
*ppm = parts per million
night sunrise noon sunset night
NO
,N
O 2
,O
3(p
pm
)
17.3 Stratospheric ozone protects the Earth from
UV radiation
? O3 + UV O3 + heat
Fig 17.17 false-color image
of ozone levels over the
Northern Hemisphere,
recorded by NASA’s total-
ozone mapping
spectrometer (TOMS),Blue
and purple areas are areas
of ozone depletion; red and
green areas are areas of
higher-than-normal ozone
levels.
17.4 Air pollution may result in global warming
Fig 17.18 glass acts as
a one-way valve,letting
visible light in and
preventing infrared
energy from exiting.
Fig 17.19 the greenhouse effect in
the earth’s atmosphere,Visible light
from the sun is absorbed by the
ground,which then emits infrared
radiation,Carbon dioxide,water
vapor,and other greenhouse gases
in the atmosphere absorb and re-
emit heat that would otherwise be
radiated from the earth into space
Long-wavelength
infrared radiation is
not transmitted out
through the glass
and is trapped inside
Short-wavelength visible light
from the sun is transmitted
through the glass
Atmospheric carbon dioxide is a greenhouse gas
Increased emission from carbon dioxide is mainly from
burning of fossil fuel and deforestation.
The potential effects of global warming are uncertain
levels of atmospheric carbon dioxide and global
temperatures appear to be closely related to each other
