Transcript Ch 19 Lecture (T) 10-11 printable

Chapter 19
AIR POLLUTION
YOUR RESPONSIBILITY…
Pages 438 - 441,
447 - 452
452 - 457,
READING QUIZ!!!
483 - 484
Atmosphere as a Resource
• Composition:
–
–
–
–
Nitrogen (78.08%)
Oxygen (20.95%)
Argon (0.93%)
Carbon Dioxide (0.04%)
• 2 most important to living organisms:
– CO2 and O2 (photosynthesis & respiration)
• N2 also important (N2 cycle)
• Ecosystem Services
– UV filter, moderating climate, redistributing water
Types and Sources of Air Pollution
Air Pollution = gases, liquids, or solids
present in the atmosphere in high enough
levels to harm humans, other organisms, or
materials.
• Natural pollution (lightning causes forest
fires, volcanic eruptions)
• Human-induced pollution (ANTHROPOGENIC)
– Harmful for 2 reasons:
• They precipitate & settle on Earth
• They alter the chemistry of the atmosphere
– Much of the air pollution released by humans is
concentrated in densely populated urban areas
Primary Air Pollutants
• Harmful chemicals that
enter directly into the
atmosphere
• EX: carbon oxides, nitrogen
oxides, sulfur dioxide,
particulate matter, and
hydrocarbons
Secondary Air Pollutants
• harmful chemicals that form
from other substances that
have been released into the
atmosphere.
• EX: ozone & sulfur trioxide
Primary Air Pollutants
and Sources
Effects of Air Pollution
Class Discussion
Air Pollution & Human Health
• Exposure to Low Levels causes…
– Eye irritation
– Inflammation of the respiratory tract
– Immune system suppression
– Development of emphysema & chronic bronchitis
Health Effects of
Specific Air Pollutants
QUESTION: Why are people who live & work in
the country’s most polluted cities 15-17% more
likely to die prematurely than those living in US
cities with the cleanest air?
ANSWER:
Exposure to Sulfur Dioxides (SOx),
Nitrogen Oxides (NOx, N2O),
Carbon Dioxide (CO2), Ozone (O3),
Particulate & VOC’s
SO2 & Particulate Matter
•Produced as part of the coal combustion process & industry
•Travels long distances from source.
•SO2 reacts with H2O vapor and forms sulfuric acid  ACID RAIN!
•Sulfate particles + nitrogen oxide  create small particles or
particulates which have detrimental health effects including:
1. Respiratory tract irritation
2. Decrease in lung’s ability to exchange gases
3. Airway constriction
4. Increased sensitivity to pollen and dust mites
5. Leach nutrients from soil
Vulnerable Ecosystems: Lakes, Streams, Forests, High Elevations
Nitrogen Oxides (NOx)
• Nitrogen oxides are formed from
atmospheric nitrogen when coal and other
fuels are burned.
• Ways to reduce the amount of NOx produced include catalytic
converters on cars and low-NOx burners on power plants.
• Interact with sunlight and other molecules to produce
ground level ozone.
• Health effects include:
1. Asthma among children
2. Airway constriction
3. Increased sensitivity to
pollen and dust mites
4. Acid rain & atmospheric haze (photochemical smog)
Vulnerable Ecosystems: Lakes, Steams, Forests, High Elevations
CARBON DIOXIDE
• Formed when fuels are burned- Coal has highest content.
• Big greenhouse gas responsible for global warming.
• CO binds irreversibly with iron in the blood’s hemoglobin,
eliminating its ability to transport O2 (asphyxiation)
• Health Effects include:
1.Linked to the spread of infectious disease, higher ozone levels,
increased heat & cold related illnesses
2.Medium Concentrations: causes headaches & fatigue
Higher Concentrations: slower reflexes & drowsiness
Very High Concentrations: death
3.Greatest risk: pregnant women, infants, those with
heart or respiratory diseases.
Ecosystem effects: Rising sea levels, increased disease, larger
storms, extinction of sensitive species.
Ozone & VOC’s
Produced when nitrogen oxides
react with volatitle organic
compounds (VOC) in the
presence of sunlight.
• Health problems include:
1. Irritants: burning eyes, coughing,
chest discomfort
2. Asthma attacks, immune system
suppression
3. Pregnant women exposed to high
levels of O3 and CO are 3X more
likely to give birth to infants with
serious heart defects.
4. Plant damage at low
concentrations
Vulnerable Populations: Children,
elderly those with respiratory
disease, those who exercise outside.
Pollutants from
Motor Vehicles,
businesses &
Industry
Long-term exposure is linked to
cancer (although the risk is rather
low compared to others like
smoking)
Some Health Effects of Air
Pollution Nationwide
Mortality: 23,600
Hospital Admissions: 21,850
DON’T
WRITE
Emergency
Room
Visits THESE….
for Asthma: 26,000
Heart Attacks: 38,200
Just
some
statistics16,200
for ya
Chronic
Bronchitis:
Asthma Attacks: 554,000
PHOTOCHEMCIAL SMOG
Nox + VOC  O3
PARTICULATE
MATTER
smoke
detector
filters
sticky
materials
N&S&C
OXIDES
devices /
equipment
CO detector
chemical tests
ACID DEPOSITION
pH tests
indirect evidence
HYDROCA
RBONS
devices /
equipment
OZONE
Schoenbien
papers
chemical
tests
indirect
evidence
(plant
growth, etc)
ozone action
days
AIR TOXICS
mold tests &
filters
radon detectors
Children and Air Pollution
• Air pollution is a greater health threat to children
than adults.
• Restricts lung development
• Causes early stages of lung disease
• Children have higher metabolic rates than adults
• they breathe ~2X as much air per pound of body weight
• Studies show that children who move to areas
with…
• less particulate matter have increased lung development.
• more particulate matter have decreased lung development
GOOD NEWS:
• Fewer people in highly developed nations smoke.
• Cigarette production in the US is down
• Smoking decline in Japan & most European countries
BAD NEWS:
• More smokers in China, Brazil,
Pakistan, and other developing nations.
• Some nations: smoking habit = 20% of a worker’s annual income
• Sales in developing countries has increased 80% since 1990.
• US tobacco companies promote smoking abroad, and we export
much of our tobacco.
• 3M people die each year of smoking-related causes worldwide.
• US: some minority groups & those with the least education have
high numbers of tobacco addicts
• More than 1M US children & teens take up smoking every year.
Smog…
Air pollution that is localized in urban areas
where it reduces visibility
1. Industrial Smog:
aka: smoke pollution
principal pollutants are sulfur oxides and particulate
matter. Worse in the winter months because of
heating needs.
Composition of
Photochemical Smog
REVIEW…. What causes smog?
More people means more fuel!
Fossil fuel combustion creates NOx and VOCs (reactants)
Sunlight is the energy catalyst for the reaction.
Precipitation cleans the air, and winds disperse the smog.
Topography and Air Pollution
Under normal conditions, air circulation patterns
prevent toxic pollutants from increasing to
dangerous levels near the ground.
That is not the
case in this
picture of LA….
What do you
think is causing
this to happen?
Temperature Inversions
AKA: Thermal Inversions
Air near the ground
is cooler than the
air at higher
levels and the
polluting
gases/particulate
matter remain
trapped in high
concentrations
near the ground.
Los Angeles
• Located between coast and mountains
• Sunny climate produces a layer of warm dry air at higher elevations
• Upwelling in the ocean produces cool ocean air
• As cool air blows inland, the mountains block movement further and
layer of warm dry air overlies cool air at the surface…
 Temp inversion!!
Think back to the
Global Winds...
how does this
relate??
HINT:
Where is LA
Longitudinally?
Urban Heat Islands & Dust Domes
Urban Heat Island: air in urban areas is warmer
than the air in the surrounding suburban and
rural areas.
Affects local air currents and weather conditions.
Q: Why do they increase the number of thunderstorms???
Dust Domes: buildup of pollutants,
especially particulate matter over cities.
Convection of air lifts pollutants into the
air where they remain because of somewhat
stable air masses produced by urban heat
island
CONTROLLING AIR POLLUTANTS
Read pages 446- 447 in Raven & Berg and write a paragraph about
how scrubbers and electrostatic precipitators remove
pollutants from factory exhaust.
HOMEWORK/CLASSWORK…..
Read and understand page 447-452
Key points to KNOW:
LINK TO
DIISCUSSION
- Clean Air Act 1970
SLIDES
- Changes to the Clean Air Act (1997)
- Ways to improve air quality
- CASE IN POINT: Los Angeles
- Meeting the challenge: clean cars, clean fuels
- Pollution in developing Countries
- CASE IN POINT: Mexico City
…homework will be checked in one way or another….
HINT…HINT...HINT…HINT…HINT…HINT...HINT…HINT
Developing Countries & Energy
~Richard Spencer, The Daily Telegraph, from Beijing:
“…Here comes the man with the coal bricks we residents all use to fire the
boilers of our homes... Not cold enough for the central heating yet? You're
right, but there's a discount - the earlier you buy, the cheaper it is.”
Global Distillation Effectvolatile chemicals evaporate from land as far away as the
tropics and are transported by winds to higher latitudes where
they condense and fall to the ground
Certain hazardous air
pollutants are distributed
globally by atmospheric
transport
PCB’s & DDT are both persistent
chemicals that do not readily
break down and accumulate in
the environment.
They are still used in developing
countries and move through the
atmosphere to developed nations
where they are deposited on land
and surface water.
Global Distillation Effect cont…
• Dangerous level of persistent toxic
compounds have been measured in the Yukon
• Chemicals enter food webs and become
concentrated in the body fat of animals
Inuit eat the animals
And the concentration
of chemicals increases
in their system causing
problems for their
Health.
Why does this happen to
Canada?
What can we do to stop
this problem?
What can the US do to
stop Canadian smog
Convention ofproblem?
Persistent
Stockholm
Organic Pollutants (2001)
Goal: phase out the use of 12Should
persistent
wetoxic
helpchemicals
alleviate
the smog
problem?
Countries: Canada, US, Russia, Finland, Norway,
Sweden, Denmark, Iceland
Are we?
Il, IN, MI, OH, PA, TN & WV
produce 50-75% of the acid
deposition that contaminates
New England and Canada
Why is science involved
in foreign relations?
Indoor Air Pollution
How Radon Infiltrates a House
End of
Ch 20
ACID DEPOSITION
• Acid deposition (rain, sleet, snow and fog) is a
type of air pollution
• Sulfuric acid & Nitric acids
 Estimated cost to the US is $10 Billion/yr
• Wet Deposition:
– Sulfuric and nitric acids in
precipitation
• Dry Deposition:
– Sulfuric acid and nitric acid
containing particles that
settle out of the air.
The pH scale
measures the
amount of H+ ions
present in the
solution.
A pH of 6 is 10x
more acidic than a
pH of 7.
Normal rain has a pH
of ~ 5-6 because CO2
in the air dissolve in
rainwater forming
dilute acids. Acid rain
= 3-4
Acid deposition occurs when sulfur dioxide and
nitrogen oxides are released into the
atmosphere.
Sources: Cars, Coal burning power plants, smelters,
industrial boilers
Effects: SO2 and NO react with water to produce dilute
solutions of H2SO4, HNO3, HNO2
• Effects of Acid Deposition
– Corrodes metals and building materials
Affects Animal populations (Adirondacks)
• 1,469 lakes examined,
325 found with pH <5
• Birds with thin fragile
shells (lack of Ca due to acidic soils)
–Forest Decline
Characterized by gradual
deterioration and eventual
death of trees.
- Black forest of Germany
50% of trees dead
-MOUNT MITCHELL, NC
Results from a
combination of multiple
stressors
(acid deposition, tropospheric O3, UV
radiation, insect attack, drought, etc.)
Soil Chemistry
Ca & K wash readily
out of acidic soil
where others (N)
become available in
large amounts
Heavy metals
dissolve in acidic soil
becoming available
for absorption in toxic
amounts.
Links between GW, Ozone
Depletion & Acid Deposition
• Global warming, ozone depletion and acid
deposition interact
• Combined effects of acid deposition and
climate warming make North American
lakes more susceptible to damage from
UV radiation caused by the thinning of the
ozone layer.
READ PAGES 483-484….
The book says it best!!!
Is the Clean Air Act working?
What does this
cartoon tell you
about the United
States air
quality in 2002?
Is this a fair
representation?
Is there bias? If
so, WHAT???
What can we do
to avoid this
type of
situation?
Discussion points of the HOMEWORK…
Sources of smog in Los Angeles
What would happen to
California’s smog if 20 of
every 100 cars was a hybrid?
Do you think that it is alright
for the government to restrict
car companies from
producing polluting cars?
Should tax incentives be
given to those who purchase
fuel economic vehicles?
Would it be fair to impose a
tax on vehicles that do not
burn fuel efficiently?