Transcript Air Pollution: Concepts that may be confusing

Air Pollution: Concepts that may
be confusing
The concepts we’ll deal with
today
• The difference between stratospheric and
tropospheric ozone
• Photochemical smog
– Inversion layers
• Acid rain
• Global change
– Especially predicted effects on Oklahoma
Where is ozone the “good guy”?
stratosphere
trophosphere
In the stratosphere….
• Ozone blocks incoming Ultra-violet
radiation --- That’s Good!
• Ultraviolet radiation
– Skin cancer
– Cataracts
– Plant Damage
But, what’s happening to ozone
in the Stratosphere?
1979-1985
1986-1992
Deeper purple color means
Less ozone above
Antartica
Why?
• Chlorofluorocarbons (CFC) are very stable
compounds that we produce at earth’s
surface
• They migrate to the stratosphere
• Their chlorine gets excited by ultraviolet
light
• After excitation, chlorine attacks ozone
layer, depleting it.
So, we’ve reduced use of CFC’s
• Their long life span means that they will be
in the stratosphere for a long time, still
destroying ozone.
• However, the rate of increase of ozone
depletion has slow, showing we are on the
right track
• By the way, ozone “holes” are opening up
in places other than Antarctica
Where is ozone the “bad guy”?
stratosphere
trophosphere
Photochemical Smog
VOCs break
Cycle, allowing
PAN to form from
NO +VOC
Chemical Equation for
Photochemical Smog
NOx + VOC
reactants
light
Ozone + Pan
products
Where reactants come from
• NOx primarily from transportation
• VOC from a variety of sources, including
refining, other industries, etc.
Inversion layers trap cold air, allowing
pollutants to build up in concentrations,
including the compounds needed for
photochemical smog
Cold air
Warm air
Ozone’s bad features
• Extremely reactive will burn leaves, lungs,
synthetic compounds (e.g. rubbers, plastics)
• Because of reactivity, is toxic in very long
concentrations (parts per billion)
We’re not the only ones concerned about
photochemical smog
Acid Rain: Where it comes from
Acid Rain:
Where it goes
Some Effects of Acid Rain
Human Health
Effects include
Emphysema
And Other
Respiratory
Diseases
Structures &
Buildings Also
Affected
A Mini-Quiz:
How will Acid Rain affect Soil
Cation Exchange?
What can we do about Air
Pollution?
This type of filter along with
Other forms known as scrubbers
Are one way to reduce
Smoke stack emissions. What
Else can be done?
Venturi Filter
Global Change
• Global Change includes all of the large
scale effects humans are having on the
global system
–
–
–
–
Greenhouse Gases: Global Warming
Reduced Ozone Layer
Habitat Changes
Loss of Biodiversity
• These changes are strongly interactive
What are predictions for effects
of Global Change on Oklahoma?
What are predictions for effects
of Global Change on Oklahoma?
What are predictions for effects
of Global Change on Oklahoma?
What are some other predicted
effects?
And some more predicted effects
• Human health effects
are also expected as
disease vectors find a
warmer world a more
hospitable place to be
– Includes diseases like
malaria and cholera
The latest report
• Out this fall– the United Nation’s Science
Council’s latest model on global warming
has found by looking at climate data over
the past decade that they underestimated the
amount of warming expected
• Now expect to see 10o F increase in air
temperature within the new century!