Air Pollution
Chloe, Melissa, Jauza, Joe
To Wake You Up...
Pollution
“We rarely consider normal conditions a
problem, or imagine alternatives, until a crisis
makes us start to question the costs of
customary ways of doing business”
Natural Air Pollutants
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Volcanoes
Sea Spray and Decaying Vegetation
Trees and bushes
Storms in arid regions
Bacterial metabolism of decaying vegetation
in swamps
Criteria Pollutants
● What are criteria pollutants?
● Primary Pollutants vs Secondary Pollutants
Primary Pollutants: released directly from the source into the air in a harmful form
Secondary Pollutants: converted to a hazardous form after they enter the air or are
formed by chemical reactions as components of air mix and interact
● Fugitive Emission
those pollutants that do not go through a smoke stack.
Sulfur dioxide
Natural sources
● Evaporation of sea spray
● erosion of sulfate
containing dust from
arid soils
● fumes from volcanoes
and hot springs
● biogenic emission of
hydrogen sulfide and
organic sulfur containing
compounds
Anthropogenic sources
● Combustion of sulfur
containing fuel
● Purification of sour
natural gas or oil
● industrial processes smelting of sulfide ores
Effects of Sulfur dioxide?
● Further oxidised to sulfur-trioxide
reacts
with water vapour or dissolves in water
droplets forming sulfuric acid
Acid Rain
● Reduce visibility
● Smelly
● Corrosive
● Illness and death
Oxides of Nitrogen NOx
Natural sources
● Lightening
● Bacteria oxidize nitrogen
containing compounds
in soil and water
● Denitrifying bacteria
convert ammonia to
nitrous oxide
Anthropogenic Sources
● Fuel combustion in
transportation and
electric power
generation
● Fertilizers
Effects of Nitrogen oxides
● Reddish brown gas that gives photochemical
smog the colour
● Greenhouse gas - absorbs UV light
● Nitrogen oxides combine with water Acid
Rain
● Eutrophication
● Fertilise invasive plants and
weeds affecting terrestrial plants
Carbon monoxide (CO)
● Produced by incomplete combustion of fuel
● Natural source: Decomposition of organic
matter
● Anthropogenic Source:
* Burning fuel in furnaces, incinerators
and engines
* Land-clearing and cooking fires
Effects of CO?
● Blocks oxygen uptake in blood
● About 90% of CO in air converted to CO2 in
photochemical smog
this reaction
produces Ozone
What can be done to reduce
CO emission?
Catalytic convertors ensure
complete combustion.
Ozone and Photochemical Oxidants
● Ground level ozone is produced as a result of
photochemical reactions between other
pollutants.
● Photochemical oxidants
● Volatile Organic Compounds (VOC)
*Plants
* Natural wetlands and rice paddies
*Bacteria in guts of termites and ruminant animals
● Synthetic Organic Chemicals
Emitted mainly by unburned/ partially burned
hydrocarbons from transportation, power
plants, chemical plants, petroleum refineries.
● Ozone damages vegetation,
building materials,sensitive
tissues.
Lead
Sources:
● Smelting of metal ores
● Burning of coal and municipal waste
● Mining
● burning gasoline with lead
Effects:
Toxic to our nervous system
Particulate Matter
* Particulate Matter: solid particles or liquid
droplets suspended in a gaseous medium
* Aerosols: very fine solid or liquid particles
suspended in the atmosphere
Includes: dust, ash, soot, lint, smoke, pollen,
spores, algal cells
Produced by:
● Fires,
● Power plant or vehicle exhaust
● Construction
Effects:
● Reduce visibility
● Damage respiratory tissues
Mercury and Other Metals
● Released into atmosphere by burning coal and oil,
mining, smelting of metal ores, or manufacturing
● Lead, mercury, cadmium, nickel, and arsenic are
emitted as metal fumes or suspended particulates
● Lead and Mercury most abundant
● Small doses cause nerve damage and other impairments
● Young children and fetuses are most vulnerable
● Airborne mercury occurs naturally from volcanoes and
rock weathering
● 70 percent atmospheric mercury is from coal burning
power plants, metal processing, and industrial processes
Mercury cont.
● 75 percent of human exposure comes from fish
● Aquatic bacteria convert airborne mercury to methyl
mercury
● Methylmercury accumulates in animal tissue and is
passed on up trophic levels
● Predatory fish contain highest levels of mercury
● Tuna causes 40 percent of U.S. exposure
● Mercury also accumulates in freshwater fish
CO2 and other greenhouse gases
● Human activities have increased CO2 in the atmosphere to levels that are
changing our climate
● Regulating CO2 requires drastic changes in our technology and behaviors
● Greenhouse gas emissions often tied to economic productivity, which
makes it hard for policy-makers to impose severe regulations
● The Supreme Court ruled in 2007 that it was the EPA’s responsibility to
limit greenhouse gases
● The EPA regulates six greenhouse gases: CO2, methane, nitrous oxide,
hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride
Greenhouse gases cont.
● Three of the six greenhouse gases regulated by the EPA are halogens,
which are highly reactive and toxic in elemental form
● These have been used as fumigants and disinfectants, and in hundreds of
industrial and commercial products
● Chlorofluorocarbons (CFCs) had long been used as spray propellants and
in refrigerator compressors until being banned
● These diffuse into elemental chlorine and fluorine in the stratosphere and
destroy ozone molecules
● Halogens are also strong greenhouse gases that trap far more heat than
CO2
● Strategies for containing greenhouse gases include subsidies for alternative
energy, less subsidies and tax breaks for fossil fuels, taxes on coal and oil,
and cap and trade systems
Hazardous Air Pollutants (HAPs)
● Particularly dangerous toxins monitored by the EPA
● Include carcinogens, neurotoxins, mutagens, teratogens, endocrine system
disruptors, etc.
● Persist in ecosystems for long periods of time and accumulate in animal
tissues
● Common HAPs include gasoline vapors, solvents, and components of
plastics
● EPA’s Toxic Release Inventory (TRI) provides information from 23,000
factories, refineries, mines, power plants, and manufacturers about 667
different toxic chemicals
● 100 million Americans live in areas where cancer rates from HAPs exceed
10 in 1 million (10 times accepted standards)
Atmospheric Processes
● Temperature inversions: a stable layer of warm air
overlying cooler air, trapping pollutants near ground level
○ This greatly concentrates air pollutants because these
conditions prevent convection currents from dispersing
pollutants
○ These conditions often occur when cold air settles in a
valley that is surrounded by hills or mountains
○ Inversions might last from a few hours to a few days
Examples:
● The London Smog of 1952
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Where drivers were blinded by the smoke and fog
Hundreds of cattle died because their lungs were blackened by soot and suffered
suffocation while standing in their pens
People ran to their homes but soot penetrated inside buildings and homes
At least 4,700 deaths were attributable to air pollution and recent epidemiological studies
have found that perhaps another 8,000 people had died in the months that followed
making a total death toll of over 12,000
● Los Angeles
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The city is surrounded by mountains on 3 sides and the climate is dry with abundant
sunshine for photochemical oxidation and ozone production
Millions of automobiles and trucks create high pollution levels
Wind Currents and Pollutants
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Areas downwind from industrial complexes often suffer serious contamination, even if they have no
pollution sources of their own
 Examples of wind carrying pollutants are:
 Pollution from the industrial belt between the Great Lakes and the Ohio River Valley
which regularly contaminates the Canadian Maritime Provinces and sometimes can be
traced as far as Ireland
 Long range transportation of Asian mercury to North America
 A 3-km-thick toxic cloud of ash, acids, aerosols, dust and photochemical reactants
regularly covers the entire Indian subcontinent and can last for much of the year
o Places usually considered among the cleanest in the world have heavy metals, pesticides, and
radioactive elements in their air
 Places like:
 Samoa, Greenland, Antarctica, and the North Pole
o Grasshopper transport or atmospheric distillation: helps deliver contaminants to the poles
o Contaminants accumulating in cold places bioaccumulate in food chains
 Top carnivores in polar regions have been shown to have dangerously high levels of pesticides,
metals, and other HAPs in their bodies
Some Estimates:
● Nobel laureate Paul Crutzen estimates that up to 2 million people in India
alone die each year from atmospheric pollution
● The Asian smog layer cuts by up to 15% the amount of solar energy
reaching the earth's surface
● Meteorologists suggest that the cloud -80% of which is human-madecould disrupt the monsoon weather patterns and may be disturbing
rainfall and reducing rice harvests over much of South Asia
● UN Environment Programme executive director Klaus Töpfer said, "There
are global implications because a pollution parcel like this, which stretches
3 km high, can travel halfway round the globe in a week"
Layers of the
Atmosphere
● In 1985 the British Antarctic
Atmospheric Survey announced a
startling and disturbing discovery:
the Stratospheric ozone
concentrations over the South Pole
were dropping abruptly during
September and October every year
as the sun reappeared at the end of
the long polar winter
● What was this discovery called?
Ozone Depletion
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Ozone depletion has been occurring at least since the 1960s but wasn't recognized because early
researchers ignored the ozone changes since they thought that they were "erroneous"
Chlorine- based aerosols, especially chlorofluorocarbons (CFCs) and other halon gases, are the
principal agents of ozone depletion
o CFCs were extremely useful as industrial gases and in refrigerators, A/Cs ,Styrofoam
inflation, and aerosol spray cans for many years
An ozone "hole" is really a vast area of reduced concentrations of ozone in the stratosphere.
o Although ozone is a pollutant in the ambient air, ozone in the stratosphere is important
because it absorbs much of the harmful ultraviolet (UV) radiation that enters the outer
atmosphere.
 A 1% loss of ozone could result in about a million extra human skin cancers/year
worldwide
 Excessive UV exposure could reduce agricultural production and disrupt ecosystems
 Antarctica's exceptionally cold winter temperatures help break down ozone.
Summary Video
The video mentions
the Montreal
Protocol, does
anyone know what it
is?
The Montreal Protocol
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In 1987 an international meeting in Montreal, Canada, produced the Montreal Protocol, the first of several major
international agreements on phasing out most use of CFCs by 2000
 Upon evidence of how fast and widespread the losses of the stratospheric ozone were, the deadline moved to
1996 and a $500 million fund was established to assist poorer countries in switching to non- CFC technologies
 The first substitutes were hydro-chlorofluorocarbons (HCFCs), which release much less chlorine per
molecule
 Montreal Protocol is cited as the most effective international environmental agreement ever established
 Global CFC production has been cut by more than 95% since 1988
 Based on the progress, it's expected for stratospheric ozone levels to be back to normal by 2049.
 There are varying views in this trend, however. The 2006 ozone hole was the largest ever. Ironically,
climate warming (heat retention) in the lower atmosphere has contributed to cooling of the stratosphere.
This cooling increases ice crystal formation over the Antarctic and results in more ozone depletion.
o Reductions in emissions of these gases under the Montreal Protocol amount to 1 quarter of all greenhouse gas
emissions worldwide
o Under the Montreal Protocol, China, India, Korea, and Argentina were allowed to continue to produce 72,000 tons
(combined) of CFCs per year until 2010
Effects of Air Pollution
Damages to lungs
● 5-6 million people die yearly due to illnesses
related to air pollution.
● In industrialised nations, soot and
particulate matter is the biggest health
threats
● Linked with heart attacks, asthma,
bronchitis, lung cancer, immune suppression
and abnormal fetal development
Make us sick
● damage delicate tissue like the eyes and
lungs.
● penetrate deep into the lungs and carry
metals and other HAPs on the surface.
● Inflammation impair lung function and
trigger cardiovascular problems
Bronchitis
- severe bronchitis
leads to
emphysema
- 300,000 people
suffer from pollution
related bronchitis in
US.
Plant Damage
● Fumes from refineries, smelters, furnaces, and
chemical plants can destroy nearby vegetation
● Since 1886, a copper and nickel smelter in Sudbury,
Ontario released sulfur dioxide into nearby
ecosystems, killing all vegetation and leaving the land
barren after rain washed away the soil
● 400 m tall smokestacks and sulfur scrubbers were
added and ecosystems began to recover
● Pollution damages plants in two ways:
o Can be directly toxic, resulting in damage of cell
membranes, mottling (discoloration), and necrotic
(dead) spots
o Synergistic effects are caused by exposure to
multiple pollutants that individually would have
no effect
Acid deposition
● Release of wet acidic solutions
or dry particles from the air
● Carried long distances by wind
currents
● Can occur naturally from sea
spray, volcanoes, and
decomposition
● Anthropogenic acids are far
more abundant than those that
occur naturally
● Causes damage to forests and
other ecosystems, and buildings
and monuments
Controlling Air Pollution
● Sulfur Removal
o “Clean Coal”
● Nitrogen Oxides
o Control of air and fuel
● Hydrocarbon
o Complete combustion
o Closed systems
● Particulate Removal
o electrostatic precipitator
Alternatives + Progress
Clean Energy = Less Air Pollution
● Low-sulfur coal
● Switching fuel
● Clean Air Act
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“new source review”
Generally successful
Personal Change - What Can
You Do?
● Carpool
● Plant a tree!
● Be involved in clean air
legislation
● Avoid aerosol products
(spray paints)
International
Population and industrialization growth is outpacing
pollution safety measures, but there is progress
● China
● India
Minnesota, Olaf
● Van Go!
● Sustainable Energy move
● Toxic Taters Movement
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Pesticide Drift
Northfield
http://weather.weatherbug.com/MN/Northfield-weather/air-quality.html
CAFO’s
● Waste Storage/Disposal
● Housing of Animals
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Methane, Ammonia, Hydrogen Sulfide