Download Atmospheric Science and Air Pollution

14
Atmospheric Science
and Air Pollution
PowerPoint® Slides prepared by Stephen Turnbull
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
14-1
Housekeeping Items
• Will hand back the mid-term assignments on
Thursday. If you don’t get one, then I never
received one.
• Did anyone go to any of the films last weekend?
• There’s another Climate Café tonight at 6 in
Building 355, Room 203. The film being shown is
“Revolution” by the same filmmaker as
“Sharkwater.” It is about efforts around the world
to promote sustainability.
• A reminder that the LCAs are due on Thursday. I
have quite a few new clippings in the folder, so
check them out.
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
Map of Linley Valley West and the designated new park areas
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
Upon successfully completing this chapter,
you will be able to
• Describe the composition, structure, and function of
Earth’s atmosphere
• Outline the scope of outdoor air pollution andassess
potential solutions
• Explain stratospheric ozone depletion and identify
steps taken to address it
• Define acidic deposition and illustrate its
consequences
• Characterize the scope of indoor air pollution and
assess potential solutions
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© 2010 Pearson Education Canada
14-4
Central Case: The Rain and the big Nickel
“Despite Canada’s success at reducing acid-causing
emissions, acid deposition is still affecting our environment.”
– Environment Canada
• Mining and refining in Sudbury, Ontario
generates high SO2 emissions, leading to acid
rain
• 1972: Built a 380m superstack to disperse
emissions
• 1980s: cleaned emissions prior to releasing them
• Acidification and remediation studied at the
Experimental Lakes Area in northwestern
Ontario
• Better ecological awareness today
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© 2010 Pearson Education Canada
14-5
Sudbury in 1888
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© 2010 Pearson Education Canada
The Atmosphere and Weather
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© 2010 Pearson Education Canada
14-7
The atmosphere and weather
• Atmosphere = the thin layer of gases that surrounds
Earth
- Absorbs radiation and moderates climate
- Transports and recycles water and nutrients
- 78% nitrogen gas, 21% oxygen gas (created originally
by stromatolites), 1% other gases
- Its four layers differ in temperature, density and
composition
• Minute concentrations of permanent (remain at stable
concentrations) and variable gases (varying
concentrations)
• Human activity is changing the amounts of some gases
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
14-8
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
14-9
The atmosphere is layered
• Troposphere = bottommost layer
- Air for breathing, weather
Don’t worry about
this slide through
#19…you will cover
it in GEOG 211
- Temperature declines with altitude
- Tropopause = limits mixing between troposphere
and the layer above it
• Stratosphere = 11-50 km (7-31 mi) above sea level
- Drier and less dense, with little vertical mixing
- Colder in its lower regions
- Contains UV radiation-blocking ozone, 17-30 km
(10-19 mi) above sea level
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© 2010 Pearson Education Canada
14-10
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© 2010 Pearson Education Canada
14-11
The atmosphere is layered (cont’d)
• Mesosphere = 50-80 km (31-56 mi) above sea level
- Extremely low air pressure
- Temperatures decrease with altitude
• Thermosphere = atmosphere’s top layer
- Extends upward to 500 m (300 mi)
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© 2010 Pearson Education Canada
14-12
Atmospheric properties include temperature,
pressure, and humidity
• Atmospheric pressure =
measures the force per unit
area produced by a column of
air
• Relative humidity = the ratio
of water vapor a given
volume of air contains to the
amount it could contain at a
given temperature
• Microclimate = different
weather pattern on side of hill
sheltered from wind or direct
sunlight
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© 2010 Pearson Education Canada
14-13
Solar energy heats the atmosphere, helps
create seasons, and causes air to circulate
• The spatial relationship between the Earth and sun
determines the amount of solar energy striking the
Earth
• Energy from the sun
- Heats air
- Moves air
- Creates seasons
- Influences weather and climate
• Solar radiation is highest near the equator
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© 2010 Pearson Education Canada
14-14
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© 2010 Pearson Education Canada
14-15
Solar energy heats the atmosphere, helps create
seasons, and causes air to circulate (cont’d)
• Earth is titled on its axis by about 23.5%
• Northern and Southern Hemispheres each tilt
toward the sun for half the year
- Results in change of seasons
- Regions near equator largely unaffected
- Near poles the effect is strong
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
14-16
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© 2010 Pearson Education Canada
14-17
Solar energy heats the atmosphere, helps create
seasons, and causes air to circulate (cont’d)
• Convective circulation = less dense, warmer air
rises and creates vertical currents
- Rising air expands and cools
- Cool air descends and becomes denser, replacing
warm air
- Influences both weather and climate
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© 2010 Pearson Education Canada
14-18
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© 2010 Pearson Education Canada
14-19
The atmosphere drives weather and climate
“Climate is what we expect; weather is what we get.”
- Mark Twain
• Weather = specifies atmospheric conditions over short
time periods and within a small geographic areas
• Climate = describes patterns of atmospheric conditions
across large geographic regions over long periods of
time
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© 2010 Pearson Education Canada
14-20
Air masses interact to produce weather
• Front = the boundary between air masses that differ in
temperature, moisture, and density
• Warm Front = the
boundary where
warm moist air
replaces colder, drier
air
• Cold Front = the
boundary where
colder, drier air
displaces warmer,
moister air
Disregard this slide
through #26
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
14-21
Air masses interact to produce weather
(cont’d)
• High-pressure system = air that moves away from a
center of high pressure as it descends
- Brings fair weather
• Low-pressure system = air moves toward the low
atmospheric pressure at the center of the system and
spirals upward
- Clouds and precipitation
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© 2010 Pearson Education Canada
14-22
Air masses interact to produce weather (cont’d)
• Normally there is vertical mixing
• Thermal inversion = a layer of cool air occurs beneath a
layer of warmer air
- Inversion layer = the band of air in which temperature
rises with altitude
- Denser, cooler air at the bottom of the layer resists
mixing
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© 2010 Pearson Education Canada
14-23
Large-scale circulation systems produce
global climate patterns
• Hadley cells = a pair of convective air currents near the
equator where surface air warms, rises, and expands
• Ferrel cells and polar cells = convective cells that lift
air and create precipitation at 60 degrees latitude north
and south
• These interact with Earth’s rotation to produce global
wind patterns
• Coriolis effect = the north-south air currents of the
convective cells appear to be deflected from a straight
path
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© 2010 Pearson Education Canada
14-24
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© 2010 Pearson Education Canada
14-25
Large-scale circulation systems produce
global climate patterns (cont’d)
• Doldrums = near the equator
- Few winds
• Trade winds = between the equator and 30 degrees
latitude
- Blow from east to west
• Westerlies = from 30 to 60 degrees latitude
- Originate from the west and blow east
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© 2010 Pearson Education Canada
14-26
Outdoor Air Pollution
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© 2010 Pearson Education Canada
14-27
Outdoor air pollution
• Air pollutants = gases and particulate material added to
the atmosphere
- Can affect climate or harm people and other species
• Air pollution = the release of pollutants
• Outdoor (ambient) air pollution = pollution outside
- Has recently decreased due to government policy and
improved technologies in developed countries
- Developing countries and urban areas still have
significant and often increasing problems
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14-28
Natural sources can pollute
• Dust storms = Hundreds
of millions of tons of dust
are blown westward across
the Atlantic Ocean by trade
winds every year
- From Africa to the
Americas
- Unsustainable farming
and grazing can
exacerbate erosion and
desertification
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© 2010 Pearson Education Canada
14-29
Natural sources can pollute (cont’d)
• Volcanic eruptions =
release large quantities of
particulate matter, sulfur
dioxide & other gases
• Can remain for months or
years
• Aerosols = reflect sunlight
back into space and cool
the atmosphere and surface
- Sulphur dioxide
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© 2010 Pearson Education Canada
14-30
Natural sources can pollute (cont’d)
• Burning vegetation =
pollutes atmosphere with
soot and gases
• Over 60 million hectares of
forests and grasslands burn
per year (that’s almost 2/rds
of the province of BC)
• Fires are made more severe
by human action
- Decades of fire
suppression
- Fires from “slash-andburn” clearing of forests
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© 2010 Pearson Education Canada
14-31
We create various types of outdoor air
pollution
• Point Sources = specific spots where large quantities of
pollutants are discharged (power plants and factories)
• Nonpoint Sources = more diffuse, consisting of many
small sources (automobiles)
• Primary Pollutants = directly harmful and can react to
form harmful substances (soot and carbon dioxide)
• Secondary Pollutants = form when primary pollutants
interact or react with constituents or components of the
atmosphere (tropospheric ozone and sulfuric acid)
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© 2010 Pearson Education Canada
14-32
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
CEPA identifies harmful airborne
substances
• 1999: Canadian Environmental Protection Act
• Environment Canada groups pollutants of greatest
concern into four categories:
- Criteria air contaminants
- Persistent organic pollutants
- Heavy metals
- Toxic air pollutants
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© 2010 Pearson Education Canada
14-34
CEPA identifies harmful airborne substances
(cont’d)
• Criteria air contaminants = pollutants judged to pose
especially great threats to human health, produced by a
number of processes (burning of fossil fuels)
•
•
•
•
•
•
•
Sulphur dioxide (SO2)
Acid precipitates
Nitrogen dioxide (NO2)
Particulate matter (PM)
Volatile organic compound (VOC or VOX)
Carbon monoxide (CO)
Ammonia (NH3)
Tropospheric ozone (O3)
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© 2010 Pearson Education Canada
14-35
weighing
the issues
Bad Air Days
Are you sensitive to smog?
Do you suffer from itchy eyes, burning lungs, or other
symptoms on “bad air days”?
Do you think there is a smog problem in our area?
• If you visit the website of the National Air Pollution
Surveillance Network (NAPS), maintained by
Environment Canada, you can watch animations of severe
smog events in which ground-level ozone exceeded the
accepted air quality standard levels over very large areas
of both Canada and the United States
(http://www.ec.gc.ca/rnspanaps/Default.asp?lang=En&n=5C0D33CF-1).
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
14-36
CEPA identifies harmful airborne substances
(cont’d)
• Persistent organic pollutants = can last in the environment
for long periods of time, they are volatile (evaporate readily)
•
•
•
•
•
They can enter food supply
Bioaccumulate in body tissues
Significant impact on human health and environment
Come primary from human activity
Examples include industrial chemicals
- PCBs
- DDT
- Contaminants from incomplete combustion processes
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© 2010 Pearson Education Canada
14-37
A Current Controversy Involves Incinerators
• In Europe, Energy From
Waste incinerators are
operated with virtually
zero pollution, but in
North America they
inspire mortal fear. Metro
Vancouver wants to build
one at Duke Point. Earlier
it wanted to build one that
would send emissions
down the Fraser Valley,
and this was vigourously
opposed.
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada
CEPA identifies harmful airborne substances
(cont’d)
• Heavy metals = can be transported by air, water,
and food supply, and can reside in the sediment for
long periods of time
•
•
•
•
Mercury and lead
Poisonous even in low concentrations
Accumulate in body tissues
Carried long distances from source
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© 2010 Pearson Education Canada
14-39
CEPA identifies harmful airborne substances
(cont’d)
• Toxic air pollutants = broad category of “other”
pollutants as being harmful or toxic
• Cause cancer
• Cause developmental or neurological problems in
various body systems.
• Overlaps with other types of air pollutants (lead, ozone)
• Most are produced by human activities (smelting,
sewage treatment, industrial processes)
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© 2010 Pearson Education Canada
14-40
weighing
the issues
Investigating Your Region’s
Air Quality
How polluted is the air near where you live? Go to the
National Pollutant Release Inventory (NPRI) website at
www.ec.gc.ca/pdb/npri/npri_home_e.cfm. Use the
Google Earth mapping tool to check on the amounts of
pollutants released in your own province or local area.
• Are there any specific facilities in your area that are
major emitters of atmospheric pollutants?
• http://ec.gc.ca/inrp-npri/donneesdata/index.cfm?do=facility_substance_summary&lang=
en&opt_npri_id=0000001383&opt_report_year=2012.
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© 2010 Pearson Education Canada
14-41
In Addition to Climate Change – to be Addressed
Next Time – Another Crucial Issue is That of the
‘Ozone Hole’
• While the issue is far from solved, it is one instance
where nations have collaborated relatively quickly in the
face of a global threat – in contrast to climate change
since Kyoto. Here’s a short video on the subject:
http://digital.films.com.ezproxy.viu.ca/PortalViewVideo.aspx?xt
id=47776
• Any thoughts – now that we’re more than halfway
through – about the course or about things you would like
to see us cover.
• Was the mid-term assignment an enjoyable one?
Copyright © 2013 Pearson Canada Inc.
© 2010 Pearson Education Canada