Transcript Chp. 8: “Air and Air Pollution”

Chapter 10
The Atmospheric Environment
Air Pollution: Long Distance
Traveler
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Winds distribute pollutants
Developing countries lack regulations
Global distillation effect
Canadian Arctic accumulates
high levels of toxins
Inuit people
 High levels of PCBs
 Why?
The Atmosphere
 Gaseous envelope surrounding Earth
 Mostly oxygen & nitrogen (99%)
 Four layers
 Troposphere
 Stratosphere
 Mesosphere
 Thermosphere
The Atmosphere
The Atmosphere
What’s In Our Atmosphere
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Nitrogen
Oxygen
Argon
Carbon dioxide
Other Gases
78%
21%
0.93%
0.04%
0.03%
The Atmosphere
 Ecosystem services
 Protects Earth from UV radiation
 Allows visible light and some infrared
to penetrate
 We depend on
the atmosphere
 Oxygen balance
 The sun makes life on Earth possible:
 Primary determinant of climate: amount
of sunlight received
 Solar radiation powers
 Earth’s cycles
Solar Radiation and
Atmospheric Circulation
 Electromagnetic spectrum
 Entire range of electromagnetic radiation
 Includes gamma, x-ray, ultraviolet, visible, infrared,
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microwave, and radio
43% of incoming solar radiation peaks in visible light
wavelengths
Gamma, x-rays and most UV rays are absorbed by the
stratosphere
Plants use portions of visible light for photosynthesis
 Sun does not
reach all places
uniformly:
why?
 Temperature
varies locally
 Inclination on its axis determines Earth’s
seasons
 N. and S. hemispheres are opposite
The Atmosphere
 Temperature differences drive circulation
 Continuous circulation moderates surface
temperature on the Earth
Atmospheric Circulation
 Winds
 Small-scale, horizontal movements
 Result of atmospheric pressure and Earth’s
rotation
 Prevailing winds
 Major surface winds; blow continuously
 Polar easterlies, westerlies, trade winds
Atmospheric Circulation
 Coriolis effect
 Earth’s rotation
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from west to east
Moving air or
water is
deflected
N. hemisphere:
deflected right
S. hemisphere:
deflected left
Influences wind
direction
Oceanic Conveyor Belt
 Transfer of warm water from Pacific ocean to the
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Atlantic as a surface current
Cold dense water sinks and slowly flows from
Atlantic to the Pacific Ocean as a deep water
current
 Weather
 Atmospheric conditions at a specific place
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and time
 Rapid changes
Climate
 Average weather conditions
 Changes over hundreds/thousands of
years
 Important factors: temperature and
precipitation
Air Quality &
Air Pollution
 Various chemicals present in the
atmosphere in levels high enough to cause
harm
 Natural & human sources
 Seven important types
 Two categories
 Primary: enter directly into atmosphere
 Secondary: form in the atmosphere
Primary and Secondary Air Pollution
Carbon Oxides
 Gases
 Carbon monoxide
 Colorless, odorless, tasteless
 Reduces blood’s ability to transport
oxygen
 Carbon dioxide
 Produced in very large quantities
 Major greenhouse gas
Sulfer Oxides
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Gases
Acid deposition
Corrode metals, damage stone
Damage plants, respiratory irritant
Nitrogen Oxides
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Gases
Inhibit plant growth
Aggravate health problems
Photochemical smog
Nitrous oxide: greenhouse gas, depletes
ozone
 Nitrogen oxides: corrode metals &
textiles
Particulate Matter
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Different solid and liquid particles
Suspended in the atmosphere
Soil particles, soot, lead, etc…
Corrodes metal, erodes buildings, soils
clothing
 Can be microscopic!
 Inhaling can be hazardous
Hydrocarbons
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Contain only carbon and hydrogen
Methane, benzene, paraffin
Many different kinds!
Varying effects
 Some have no effect
 Some cause respiratory damage
 Some cause cancer
Sources of Sulphur and
Nitrogen Oxide Emissions
Volatile Organic Compounds
 VOC’s: unburned hydrocarbons and
vapors that evaporate easily in the
atmosphere
 VOC concentration may be 10 times
higher indoors, why?
 Toxic effect on humans
Ozone
 Essential component of stratosphere
 Filters out harmful UV radiation
 Pollutant in the troposphere
 Most harmful component of photochemical smog
 Reduces visibility,
causes health problems
 Reduces plant vigor
Sources of Air Pollutants
 Natural:
 Erupting volcanoes
 Forest fires (lightening)
 Ocean spray and salt particulates
 Volatile organic compounds from coniferous
forests
 Natural process from other vegetation
Air Pollution
Human Activities:
Fossil fuels (coal, natural gas)
Transportation (mobile)
Industrial (stationary)
Human Health Effects
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Eye and respiratory tract problems
Suppresses immune system
Chronic respiratory disease
Cancer
Birth defects
Neurological damage
Effects of Air Pollution
 Injures organisms
 Reduces visibility
 Corrodes metals, plastics,
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textiles
Harms respiratory tracts
Reduces plant production
Ozone depletion, climate
change
Managing Air Pollution
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Difficult due to long-range transport
Nations have to work together
Emissions trading – “cap and trade”
EU ETS – one of the largest programs
Kyoto Protocol uses emissions trading system
for six major greenhouse gases
Carbon credit trading – two types
 COC’s
 CRC’s
Canada’s Response
 Clean Air Act
 Includes air pollutants and greenhouse gases
 Controversial
 Federal and provincial governments need to
work together
 Incentive-based regulation
 Kyoto Protocol
 Signed in 1997
 Conservative government dropped it in 2006
 Second Clean Air Act introduced
Urban Air Pollution
 Smog
 Industrial smog
 Sulphur oxides, particulate matter
 Worst in winter…why?
 More problematic in developing
countries…why?
Urban Air Pollution
 Photochemical smog
 Brownish-orange haze
 Chemical reactions
 Worst in
summer…why?
 Sources?
Urban Air Pollution
Weather and Topography
 Temperature change  air circulates 
pollutants dispersed
 Temperature inversion
 Cold air layer trapped near the ground
by warm layer
 Traps pollutants close to ground
 Cities in valleys: more temperature
inversions
Temperature Inversion
Commitments to
Reduce Smog
 Smog has serious impacts on Canadian
economy
 1990, Canadian Council of Ministers of
the Environment developed
regulations, guidelines and education
initiatives
 Targeted automobile emissions and
commercial emission restrictions
Los Angeles
 Very bad
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smog…why?
1969: California is
first state to enforce
vehicle emission
standards
Every pollutant
regulated today
Should meet federal
standards by 2010
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Sulphur and nitric acids in precipitation
Dry acid particles in air
Around since Industrial Revolution
Causes much damage
 Kills fish, damages structures
 Affects forest ecosystems
 Sulphur dioxide and nitrogen oxides
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released
Where do these pollutants come from?
Wind carries these pollutants
React with water in atmosphere
Form dilute acids
 Sulphuric
 Nitric, nitrous
How Acid Deposition Develops
 Ph Scale runs from zero (most acidic) to
fourteen (most alkaline)
 A one unit change on the Ph scale
represents a 10 fold unit change in
acidity
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Corrodes metals and building materials
Decline in some fish species
Birds lay eggs with thinner shells
Damaging to forests
 Research at ELA on lake 223
 Reduction in Ph
 Reduction in biodiversity
 Ph lower than 4.0 may mean no fish at all
 Damage to forests
 Overall tree weakening
 Increase in UV radiation
 Insect infestation
 Changes in soil chemistry
 Difficult to control
 Who should pay for the pollution?
 Acids are released in one place
 Returned to Earth’s surface hundreds
of miles from source
 Over past 15 years, Canada has committed to
reducing sulphur dioxide
 1985, Eastern Canadian Acid Rain Program
 1991, Canada-United States Air Quality
Agreement
 Canada Wide Acid Rain Strategy for Post-2000
 Reduction achieved by:
 Scrubbers installed in smoke stacks
 Low sulphur coal (but other problems arise)
 Acid Neutralizing Capacity
Ability of water or soil to neutralize
acids
 Critical Loads
Maximum amount of pollution an
ecosystem can tolerate before it
becomes damaged
Indoor Air Pollution
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May be more pollution inside than out!
We spend a lot of time indoors
Radon, cigarette smoke, cleaners, etc…
Viruses, bacteria, fungi, dust mites
Sick building syndrome
 Eye irritations, nausea, headaches, fatigue
 Caused by indoor air pollution
 Lost work time
Indoor Air Pollution
Radon
 Most serious indoor air pollutant
 Radioactive gas produced by decay of radium
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in Earth’s crust
Seeps into homes
Dangerous when inhaled
Can cause cancer
Energy efficient homes,
 radon can’t disperse
Test your home!
 Temperature is increasing
 Spring arriving earlier; autumn later
 more heat waves
 Radiative forcing – the imbalance in
the Earth’s energy budget that results
when the amount of energy radiated to
outer space is changed through either
natural or human influences
 Positive forcing results in warming
 Negative forcing leads to cooling
 Greenhouse gases
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absorb infrared
radiation 
warms
atmosphere
We are increasing
concentrations of
these gases
 Two important factors: amount of gas
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emitted and properties of the gas
Average residence time: length of time gas
resides in the atmosphere
Global warming potential: how much given
mass of greenhouse gas contributes to global
warming over a period of time compared to
the same mass of carbon dioxide
 CO2, CH4, N2O, CFCs,
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O3 accumulate
Where do these gases
come from?
Concentrations of
these gases are
increasing
Carbon Footprint
 What is a Carbon
footprint?
 Calculate your
carbon footprint
 Think about what
steps you can take
to reduce your
carbon footprint
 Some pollutants cool the atmosphere
 Atmospheric aerosols
 Natural human sources
 Reflect sunlight into space
 Cools atmosphere
 Sulphur haze, volcanic
 eruptions
 Most nations
 trying to reduce
 Precipitation patterns will change
 More droughts, floods
 Impact on freshwater supplies
 Agricultural changes
 Some areas will flood
 Pests could increase their ranges
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Polar amplification
More extinctions
Melting sea ice
Rise in sea level, devastating impacts on
coastal communities
 Increasing coastal erosion rates
 Changing salt levels in ocean
 Rise in sea level with flood some agricultural
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lands
Agricultural pests and disease causing
organisms will reduce crop yields
Increased frequency of drought (occurrence
and duration) – more drought resistant crops
Changing length of growing season
New areas suitable for agricultural production
 Every species on earth affects
 Some will expand and thrive – example
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Mountain Pine Beetle
Inter-related ecosystem changes
At greatest risks are
 polar seas
 coral reefs
 mountain ecosystems
 coastal wetlands
 tundra
 More extinctions
 Antarctica: less silverfish  less Adélie
penguins; more egg failures
 Bleaching of coral reefs ; increase 10-20 C
 Tree species may shift ranges
 More heat-related illness
 More malaria, dengue & yellow fever: why?
 More schistosomiasis, cholera
 CO2 must be the focus
 Two ways to manage
 Mitigation
 Moderate/postpone global climate change
 Buy us time
 Adaptation
 Response to changes
 Implies that climate change is unavoidable
Mitigation of Global
Climate Change
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Developing fuel alternatives
Increasing energy efficiency
Plant and maintain trees:
Carbon management
 Separate and capture CO2
 Sequester from atmosphere
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Coastal populations must move inland
Build massive sea walls
Plant different crops: why?
Develop heat and drought-resistant trees
Change coastal sewage systems to reduce
flooding
 Pollutant in troposphere
 Essential in stratosphere: why?
 CFC’s, halons,
industrial solvents
 First used in 1960’s
 These chemical were
 cheap and easy to
produce
 Were eventually
banned
 More UV radiation reaches Earth
 Damage to ecosystems
 Human health problems
 More cataracts
 More skin cancer
 Weakened immunity
 1987 Montreal Protocol – 50% reduction
 By 2007, 191 countries participating
 Industry substitutes such as
hydroflurocarbons do not attack ozone
but are potent greenhouse gases
 Most countries have phased out HCFC’s
 Long residence time
Eco Canada Career Focus
 Consider a career as
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a Climatologist
Use long range data
to study trends and
make predictions
about climate
change
Case Study: IDHP
 Management of the atmospheric
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environment on a global scale
Promotes scientific and social research
Initiated in 1990
Decision making, policy creation, raising
awareness happens across many
governmental levels
Assists with linkages and multi-level
decision making