Transcript ch17_lecture new - La Habra High School

Air and Air Pollution
Key Concepts
 Structure and composition of the atmosphere
 Types and sources of outdoor air pollution
 Types, formation, and effects of smog
 Sources and effects of acid deposition
 Effects of air pollution
 Prevention and control of air pollution
Fig. 17-2 p. 419/ see
also fig. 17-3 p. 420
The Atmosphere
 Troposphere: 75-80%
of mass of the atmosphere
 78% N, 21% O, 1-4%
H2O(v), 1% Ar and
.037%CO2
 Stratosphere: much less
H2O(v), and much more O3.
 Ozone layer: Beneficial
in the stratosphere damaging
in the troposphere (smog).
 Greenhouse effect:
necessary for life
8-17 km
Outdoor Air Pollution
 Primary pollutants:
from both natural and
human (anthropogenic)
sources
See Table 17-1 p. 420
See Table 17-2 p. 422
 Secondary pollutants:
from chemical reactions that
occur in the atmosphere with
the primary pollutants
Indoor Pollutants:
Come from infiltration from
outside polluted air and
various chemicals used or
produced inside buildings
Fig. 17-4 p. 421
Photochemical Smog
 Brown-air smog
due to NO2
Factors that influence:
topography, population density,
industry, fuels used, urbanization,
high temperatures
 Photochemical
reactions (see pg. 423-424)
 Photochemical
oxidants (PAN’s,
NO2, and O3 )
Oxidize compounds
in air or lungs 
Irritate lungs,
damage plants
Fig. 17-6 p. 424
Photochemical Smog
• At the high temperatures of the car's combustion chamber (cylinder), nitrogen and
oxygen from the air react to form nitric oxide (NO):
Step 1: N2 + O2 -----> 2NO
• Some of the nitric oxide (NO) reacts with oxygen to form nitrogen dioxide NO2):
Step 2: 2NO + O2 -----> 2NO2
• When the nitrogen dioxide (NO2) concentration is well above clean air levels and
there is plenty of sunlight, then an oxygen atom splits off from the nitrogen dioxide
molecule:
Step 3: NO2 ---------->NO + O (sunlight)
• This oxygen atom (O) can react with oxygen molecules (O2) in the air to form
ozone (O3):
Step 4: O + O2 -----> O3 (ozone)
Industrial Smog
See pg. 423
Gray-air smog:
Suspended particles and
soot
Industrial smog:
largely due to burning of
coal and release of sulfur
impurities
Sulfuric acid
Sulfur dioxide
Particulates: < 10
microns dangerous to health
Fig. 17-8 p. 426
Temperature Inversions
 Subsidence inversion:
Fig. 17-9 p. 427
Warm air mass moves over a
cold air mass and decreases
vertical mixing
 Radiation inversion:
Inversion layer
Increasing altitude
occurs at night, air near
ground cools faster than air
above. Sun rise heats up the
air and usually diminishes
by noon
Descending warm air mass
Sea breeze
Mountain
range
Decreasing temperature
Figure 17-9 (2)
Page 427
Slide 12
Regional Outdoor Air Pollution from Acid
Deposition
Acid deposition: due to tall smokestacks pollution is
decreased locally and increased regionally and transformed in
the atmosphere as it is spread downwind and deposited as acid
deposition
acid
acidic particles
rain snow fog and cloud vapor
Wet deposition:
Fig. 17-10 p. 428
Dry deposition:
Acid Deposition in the US
Fig. 17-11 p. 429
Acid Deposition and Humans
 Respiratory diseases
 Toxic metal leaching
 Decreased visibility
 Damage to structures, especially
containing limestone
 Decreased productivity and
profitability of fisheries, forests,
and farms
Acid Deposition and Aquatic Systems
 Fish declines
 Undesirable
species
 Aluminum
toxicity
Fig. 17-14 p. 431
Acid Deposition, Plants, and Soil
 Nutrient
leaching
 Heavy metal
release
 Weakens trees
Fig. 17-15 p. 432
Prevention
Reduce air pollution
by improving energy
efficiency
Reduce coal use
Cleanup
Add lime to neutralize
acidified lakes
Add phosphate
fertilizer to neutralize
acidified lakes
Increase natural gas
use
Increase use of
renewable resources
Burn low-sulfur coal
Remove SO2
particulates, and NOx
from smokestack gases
Remove Nox from
motor vehicular exhaust
Tax emissions of SO2
Figure 17-16
Page 433
Indoor Air Pollution/Sick Building
Syndrome
Fig. 17-17
p. 434
Radon
 Radon-222
 4 picocurie level
 Occurs in certain
areas based on
geology
 Associated with
uranium and organic
material in rock
Fig. 17-18
p. 436
Effects of Air Pollution on Living
Organisms and Materials
Damage to mucous membranes
Respiratory diseases (see Fig. 17-19 p. 438)
Damage to plant leaves and roots
Reduction in primary productivity
Deterioration of materials
(See Table 17-3 p. 440)
Solutions: Preventing and Reducing
Air Pollution
Clean Air Act: passed 1970, 1977, and 1990
National Ambient Air Quality
Standards (NAAQS)
Primary and secondary
standards: primary set to protect human health;
secondary set to prevent environmental and property
damage
Emission Reduction
Fig. 17-22 p. 441
Fig. 17-23a p. 442