Transcript What Are the Major Outdoor Air Pollutants?

Air Pollution
Chapter 18
18.1 What is the nature of the atmosphere?
(11 miles above sea level at (11-30 miles above surface)
equator; 5 miles at poles)
• Similar to
❹
❸
❷
❶
92,960,000 • N2 (78%)
• O2 (21%)
miles
• H 2O
o (.01% at poles)
o (4% at equator)
• Ar, CO2
• Trace amounts of
dust, soot, CH4,
O3 (ozone), N2O
• Involved in:
chemical
cycling, weather,
climate, air
currents rising
and falling
• Ozone in
troposphere
BAD!!!
troposphere, but
less water, more O3
• Ozone layer 11-19
miles above surface
• Filters UV
• 3O2 + UV ↔ 2O3
• Ozone in
stratosphere
GOOD!!!
❹ THERMOSPHERE (51 – 75 miles)
❷ STRATOSPHERE
❸ MESOSPHERE (31 – 50 miles)
❶TROPOSPHERE
Air Pollution Comes from Natural and
Human Sources
 Air Pollution – the presence of chemicals in the
atmosphere in concentrations high enough to
cause harm to:
1. organisms
2. ecosystems
3. man-made materials
Air Pollution Comes from Natural and
Human Sources
 Natural sources:
• Wind (dust)
• Wildfires
• Plants
• Animals
• Volcanic eruptions
 Anthropogenic (human) sources: burning of fossil
fuels
• Stationary sources – power plants; industrial plants;
landfills
• Mobile sources – motor vehicles
Air Pollution Comes from Natural and
Human Sources
 Major PRIMARY Pollutants: (emitted directly into the air)
1. * CO – carbon monoxide
2. * CO2 – carbon dioxide
3. * NO – nitric oxide
NOx
4. * NO2 – nitrogen dioxide
5. * SO2 – sulfur dioxide
6. N2O – nitrous oxide
7. PM – particulate matter (suspended)
8. VOCs – volatile organic compounds
Chemical Reactions That Form Major
Outdoor Air Pollutants
*
Many of the primary pollutants are formed from
the combustion reaction of carbon-, nitrogen-, or
sulfur-containing materials.
*
Air Pollution Comes from Natural and
Human Sources
 Major SECONDARY Pollutants:
(primary pollutants reacting with each other or with air components)
1.
2.
3.
4.
5.
6.
7.
8.
HNO3 – nitric acid
H2SO4 – sulfuric acid
H2O2 – hydrogen peroxide
O3 – ozone (ground-level or tropospheric)
PANs – peroxyacyl nitrates
SO3 – sulfur trioxide
NO3- – nitrate salts
SO42- – sulfate salts
Sources and Types of Air Pollutants
Secondary Pollutants:
Industrial Smog
Photochemical Smog
Acid Precipitation
(and Greenhouse Gases)
CO2 ,SO2,
H2S, H2O,
CO2 ,NOX,
PM
SO2, VOC,
PM, Hg
VOCs
CH4
CO, CO2,
NOX, SO2,
VOCs, PM
CO2, CH4
History of SMOG
 “Smog”
• First used in early 1900’s in London
• Described the dense mixture of coal smoke and
fog
• Had been causing respiratory illnesses and death to
thousands each year since the beginning of the
Industrial Revolution in the late 1700’s.
 In the U.S., similar illnesses and deaths were
occurring throughout the 19th and 20th centuries as a
result of the use of coal in industry.
Industrial
Smog:
Formed from
Burning Coal
and Oil
Oxygen (O2)
Water vapor
Ammonia
Gray color
Secondary
Pollutants
SO3 , H2SO4,
(NH4)2SO4
CO and CO2
Primary
Pollutants
Sulfur dioxide (SO2)
O2 →
← O2
London
Burning coal
and oil
Sulfur (S) in
coal
Carbon (C) in
coal and oil
Fig. 18-8, p. 476
Photochemical
Photochemical Smog: Formed from Nox Pollutants
Smog:
and VOCs
Formed
under the influence of UV radiation from
from Pollutants
the sun.
Secondary
Pollutants
HNO3, O3, PAN’s,
aldehydes
Hydrocarbons
Brown color
Los Angeles, CA
H2O
O2
VOC’s
UV radiation
NO2
PANs
O2
Primary
Pollutants
NO
O2
Burning fossil fuels
Nitrogen (N) in fossil fuel
Fig. 18-9, p. 477
Natural Capital Degradation: Acid
Deposition, Acid Rain
2
Up to 600 miles
HNO3,
H2SO4
4-14 days
NO
Wet acid
deposition
1
2-3 days
NO, SO2
1
Dry acid deposition
(particles of SO42- and
NO3- salts
(droplets of
H2SO4 and HNO3)
Current and Possible Future Acid Rain
Problem Areas
Air Pollution Damage
to Trees
Emissions
Acid deposition and other
secondary pollutants
Direct damage to
leaves or needles
and bark
Reduced
photosynthesis
and growth
Increased
susceptibility to
drought, extreme
cold, insects
Tree death
Indirect-Soil acidification
Leaching
of soil
nutrients
Lake
Acids
Release
of toxic
metal ions
Root
damage
Reduced nutrient
and water uptake
Hg2+ , Pb2+
Groundwater
& others Al3+
Fig. 18-14a, p. 481
Laws and Regulations
1. Clean Air Acts (1970, 1977, and 1990):
• Air pollution regulations that focus on key pollutants
2. EPA
• National Ambient Air Quality Standards (NAAQS) for:
maximum allowable levels for:
• SIX CRITERIA POLLUTANTS - CO, NOx, SO2, PM, O3,
Pb
• National emission standards for:
• 188 Hazardous Air Pollutants (HAPs)
Several Factors Can Decrease or
Increase Outdoor Air Pollution
 Outdoor air pollution may be decreased by:
1. Settling of particles due to gravity
2. Rain and snow
3. Salty sea spray from the ocean
4. Winds
5. Chemical reactions
Several Factors Can Decrease or
Increase Outdoor Air Pollution
 Outdoor air pollution may be increased by:
1. Urban buildings
2. Hills and mountains
3. High temperatures
4. Increased numbers of trees, plants, animals
5. Temperature inversions
A Temperature Inversion
• Normal conditions
•
•
•
Sun warms surface air
Warm air/pollutants rise
Descending warm air mass
Warmer air
Pollutants mix, disperse with cooler air above
Inversion layer
Inversion layer
A Temperature Inversion
Warmer air
Inversion layer
Descending warm air mass
Inversion layer
• Under certain atmospheric conditions:
•
•
•
Layer of warm air lies atop layer of cool air near ground
Air at surface does not rise
Pollutants are trapped and build up in stagnant layer of
cool air near ground
Fig. 18-11, p. 478
A Temperature Inversion
Warmer air
Inversion layer
Descending warm air mass
Inversion layer
Areas susceptible to prolonged temperature inversions:
1.
2.
Town located in a valley; surrounded by mountains; cloudy
part of year
Mexico City
City with mountains on three sides; ocean on fourth side;
millions of motor vehicles; sunny climate; light winds
L.A.
Fig. 18-11, p. 478
CONTROLLING HARMFUL EMISSIONS
 Catalytic converters in automobiles
• Required by the Clean Air Act
• Clean exhaust gases of pollutants before pollutants
are able to exit the tailpipe.
• Helped reduce CO2 emissions by 40% since 1970’s
• Helped reduce other pollutants by 95% since 1970’s
CONTROLLING HARMFUL EMISSIONS
 Scrubbers in industry
• Required by the Clean
Air Act
• A machine that moves
gases through a spray of
water that dissolves
many pollutants.
CONTROLLING HARMFUL EMISSIONS
 Electrostatic precipitators
in industry
• Required by the Clean
Air Act
• Used in cement factories
and coal-burning power
plants to remove dust
particles from smoke
stacks by blowing them
through an electricallycharged chamber.
Noise Pollution
 Any unwanted, disturbing, or harmful sound that:
1. Impairs/interferes with hearing
2. Causes stress
3. Hampers concentration or efficiency
4. Causes accidents
Formaldehyde *
Chloroform
Source: Chlorine-treated water in hot
showers
Source: Furniture stuffing, paneling,
particleboard, foam insulation
Possible threat: Cancer
Threat: Irritation of eyes, throat, skin, and
lungs; nausea; dizziness
Nitrogen oxides
Source: Unvented gas stoves and
kerosene heaters, woodstoves
Tobacco Smoke *
Source: Cigarettes
Threat: Irritated lungs, children's colds,
headaches
Threat: Lung cancer, respiratory
ailments, heart disease
Particulates *
Asbestos
Source: Pollen, pet dander, dust
mites, cooking smoke particles
Source: Pipe insulation, vinyl ceiling and
floor tiles
Threat: Irritated lungs, asthma
attacks, itchy eyes, runny nose, lung
disease
Carbon Monoxide
Threat: Lung disease, lung cancer
Radon-222 *
Source: Faulty furnaces, unvented gas stoves and
kerosene heaters, woodstoves
Source: Radioactive soil and
rock surrounding foundation,
water supply
Threat: Headaches, drowsiness, irregular
heartbeat, death
Threat: Lung cancer
Important
Indoor
Pollutants
Fig. 18-16, p. 484
Indoor Air Pollution Is a Serious Problem
 Four most dangerous indoor air pollutants
1. Tobacco smoke
2. Formaldehyde
3. Radon-222 gas
4. Particulates
Indoor Air Pollution Is a Serious
Problem
 Why?
• Major pollutants - higher levels inside than
outside
• People spend 70-98% of time indoors
• Greater levels inside vehicles than outside
Indoor Air Pollution
Science: Sources and Paths of Entry for
Indoor Radon-222 Gas
Science: Magnified View of a Household
Dust Mite in a Dust Ball
What Are the Major Outdoor Air Pollutants?

Carbon compounds
1. CO (Primary pollutants)
• Sources:
a) Motor vehicles, coal-burning plants
b) Forest and grass fires; open fires
c) Tobacco smoke
•
Human effects: Low oxygen levels in blood
What Are the Major Outdoor Air Pollutants?

Carbon compounds
1. CO2 (Primary pollutant)
• Sources:
a) Motor vehicles, coal-burning plants
b) Forest and grass fires; open fires
c) Tobacco smoke
d) C-cycle
•
Environmental effects: global warming
What Are the Major Outdoor Air
Pollutants?
 Nitrogen compounds (NOx)
1. NO and NO2 - Primary pollutants
• Sources:
a) Motor vehicles; coal-burning plants
b) Lightning
c) N-cycle (soil bacteria)
• Environmental effects: reduced plant growth,
photochemical smog
• Human effects: respiratory ailments
What Are the Major Outdoor Air
Pollutants?
 Nitrogen compounds
2. Nitric acid (HNO3) - secondary pollutant
• Source: Acid deposition
• Environmental effects:
•
•
•
•
reduced plant growth/damage
photochemical smog
harm aquatic ecosystems
leaching of Pb, Hg from soil/rock
• Human effect: respiratory ailments
What Are the Major Outdoor Air
Pollutants?
 Sulfur compounds
1. SO2 - primary pollutants
• Sources:
a) Coal-burning plants
b) Natural part of S-cycle
• Environmental effects: damage crops; industrial
smog
• Human effects: respiratory ailments
What Are the Major Outdoor Air
Pollutants?
 Sulfur compounds
2. Sulfuric acid (H2SO4) - secondary pollutant
• Sources: Acid deposition
• Environmental effect: damage crops, industrial
smog
• Human effect: respiratory ailments
What Are the Major Outdoor Air
Pollutants?
 Particulates - Suspended particulate matter (SPM)
• Sources:
• Motor vehicles; coal-burning plants
• Tobacco smoke
• Road construction
• Human health effect: respiratory ailments
What Are the Major Outdoor Air
Pollutants?
 Toxic particulate
• Lead:
• Sources – paints, gasoline, water pipes
• Human effect – neurological damage
Lipsticks with highest lead content:?
Lowest levels of lead found in the following brands:
Wet n' Wild, Bobbi Brown, and Shiseido
No lead found in the following brands:
Bare Minerals, Avon UltraColor, The Body Shop
What Are the Major Outdoor Air
Pollutants?
 Toxic particulate
• PCB’s: (polychlorinated biphenyl’s)
• Sources - fire-retardant fabrics, adhesives, pesticides
• Human effect – cancer, learning disabilities
What Are the Major Outdoor Air
Pollutants?
 Ozone (O3)
• Sources – formed when NOx from vehicle emissions
react with UV
• Environmental effect: photochemical smog; damages
plants
• Human effect: Respiratory ailments
What Are the Major Outdoor Air
Pollutants?
 Volatile organic compounds (VOCs) (includes
methane)
• Sources:
• Natural - emitted by plants and animals
• Human – industrial solvents, plastics, gasoline
• Environmental effects: global warming, photochemical
smog
• Human effects: blood disorders, immune system
damage