Transcript Air Pollution Ch 19 2014

Chapter 19
Air Pollution
When Is a Lichen Like a Canary?
• Some lichen species are
sensitive to specific air-polluting
chemicals. Ex. Sulfur dioxide
• Good biological indicators –
continually absorb air as a
source of nourishment.
• Orange crusty – moderate
pollution
• Gray-green crusty – high
pollution
• Leafy lichens – fairly clean air
Figure 19-1
BIOLOGY REVIEW
• A LICHEN IS MADE UP OF A
______________ AND AN ALGA.
• NAME 2 OTHER SYMBIOTIC
RELATIONSHIPS BESIDES MUTUALISM.
• IN MUTUALISM, WHICH SPECIES
BENEFITS?
• WHY COMPARE A LICHEN TO A CANARY?
CASE STUDY ASSIGNMENT
• RESEARCH AND LIST LICHENS (SCIENTIFIC
NAME AND COMMON NAME) NATIVE TO THE
UNITED STATES (10 MINIMUM)
• EXPLAIN THE CONTROLLED EXPERIMENT YOU
WOULD SET UP AND CONDUCT TO DETERMINE
THE TYPES AND AMOUNT(S) OF POLLUTION IN
VARIOUS AREAS AROUND THE U.S.
• DUE TUESDAY OCTOBER 14 , DO NOT TYPE –
WRITE LEGIBLY
STRUCTURE AND SCIENCE OF
THE ATMOSPHERE
• Troposphere –
• life giver & weather breeder
• 11 miles above sea level at
equator
• 5 miles above sea level at
poles
• Dynamic system: chemical
cycling of many vital
nutrients;
• Rising/falling air currents &
winds largely responsible for
weather & climate; Figure 19-2
STRUCTURE AND SCIENCE OF
THE ATMOSPHERE
• Troposphere – Air
composition:
– 78% N2
– 21% O2
– Water vapor, Argon, CO2,
CH4, O3, N2O, Dust &
soot particles
Figure 19-2
STRUCTURE AND SCIENCE OF
THE ATMOSPHERE
• Troposphere
• Temperatures decrease with
altitude until the Tropopause
(upper boundary) is reached;
• Cold temperatures produce a
thermal barrier that prevents mixing
of air between the Troposphere &
Stratosphere;
• Then temperatures increase with
altitude in the Stratosphere
Figure 19-2
STRUCTURE AND SCIENCE OF
THE ATMOSPHERE
• Stratosphere – 11 – 30
miles above sea level
• 78%N2, 21%O2, O3% much
higher than in Troposphere
• Contains the ozone layer that
shields 95% of UV from earth
• Ozone layer 11 – 19 miles
above sea level
• Also prevents much of O2 in
Troposphere from being
converted to photochemical
ozone
Figure 19-2
FACTS YOU NEED TO
KNOW
• OZONE IS PRODUCED WHEN O2
INTERACTS WITH UV RADIATION;
• 3O2 + UV YIELDS 2O3
• GOOD OZONE IS O3
• BAD OZONE IS PHOTOCHEMICAL
• PREFIX PHOTO MEANS LIGHT
• Mesosphere – temperature decreases with
increasing altitude (maximum altitude for
aircraft) – area for meteors to burn up
• Thermosphere – outer layer – orbiting areas
for satellites – UV rays cause ionization
(radio waves bounce off here & are returned)
– responsible for aurora borealis/australis
AIR POLLUTION
• Primary vs. secondary pollutants
• Stationary vs. mobile sources
• Natural sources (volcanoes, dust, fires, pollen, salt, VOCs)
Figure 19-3
National Ambient Air Quality
Standards (NAAQS)
• Regulates the following
pollutants:
• 1) SO2
• 2) SPM (Suspended
• Particulate Matter)
• 3) Pb
• 4) O3
• 5) NO2
• 6) CO
Major Air Pollutants
• Carbon oxides:
– Carbon monoxide (CO) highly toxic gas - forms
during the incomplete
combustion of carboncontaining substances, ex.
fossil fuels
CARBON MONOXIDE
• SOURCES INCLUDE: MOTOR VEHICLE EXHAUST,
BURNING OF FORESTS/GRASSLANDS,
TOBACCO SMOKE, COOKING WITH OPEN FIRES,
INEFFICIENT STOVES
• CHRONIC EXPOSURE CAUSES HEART ATTACKS,
ASTHAMA, BRONCHITIS, EMPHYSEMA
• HIGH EXPOSURE CAUSES HEADACHE,NAUSEA,
DROWSINESS,MENTAL IMPAIRMENT,
COLLAPSE, COMA, DEATH
CARBON DIOXIDE
•
•
•
•
• IS NOT REGULATED UNDER THE U.S. CLEAN AIR ACT;
93% RESULTS FROM NATURAL CARBON CYCLE
7% FROM HUMAN ACTIVITIES (BURNING)
S/B REGULATED BECAUSE CO2 IS BEING ADDED TO THE
ATMOSPHERE FASTER THAN C CYCLE CAN REMOVE IT
CONTRIBUTES TO GLOBAL CLIMATE CHANGE
–
–
–
–
–
HEAT EXHAUSTION
DECREASE FOOD SUPPLIES
WATER SHORTAGE
DROUGHT
EXCESSIVE FLOODING
Major Air Pollutants
• Nitrogen oxides and nitric acid:
– Nitrogen oxide (NO) - forms when nitrogen and
oxygen gas in air react at high-combustion
temperatures in automobile engines and coalburning plants. NO can also form from lightning and
certain soil bacteria – cause lung irritation &
infections
• NO reacts with air to form NO2 (reddish-brown gas in
smog)
• NO is a greenhouse gas (GHG)
• NO2 reacts with water vapor in the air to form nitric
acid (HNO3) and nitrate salts (NO3-) which are
components of acid deposition.
• Both play a role in the formation of photochemical
smog-mixture of chemicals formed from interaction of
sunlight in cities with heavy traffic
Major Air Pollutants
• Sulfur dioxide (SO2) and sulfuric
acid:
– Two-thirds come from human sources, mostly
combustion (S+ O2  SO2) of sulfur-containing coal
and from oil refining and smelting of sulfide ores.
– SO2 in the atmosphere can be converted to sulfuric
acid (H2SO4) and sulfate salts (SO42-) that return to
earth as a component of acid deposition.
– Causes breathing problems & bronchitis.
– Irritating odor
– All are major components of South Asian Brown
Clouds
Major Air Pollutants
• Suspended particulate matter
(SPM):
– Consists of a variety of solid particles and liquid droplets small
and light enough to remain suspended in the air (62% from
smoke, dust, pollen, soot)
– 38% from coal burning plants (power & industrial), motor
vehicles & road construction;
– SPM Toxic Particulates include Pb, Cd, PCBs)
– The most harmful forms of SPM are fine particles (PM-10, with
an average diameter < 10 micrometers) and ultrafine particles
(PM-2.5) – these are small enough to get to alveoli.
– Causes bronchitis, acid rain, mutations, reproductive problems
Major Air Pollutants
• Ozone (O3):
– Is a highly reactive, irritating
gas - major component of
photochemical smog – reacts
with VOCs & NOx’s.
– It can
• Cause and aggravate respiratory
illness.
• Decrease resistance to
colds/pneumonia
• Can aggravate heart disease.
• Damage plants, rubber in tires,
fabrics, and paints.
Major Air Pollutants
• Volatile organic
compounds (VOCs):
– Most are hydrocarbons emitted by the
leaves of many plants and methane (CH4)
– About two thirds of global methane
emissions comes from human sources (rice
paddies, landfills, oil/natural gas wells)
– Other VOCs include industrial solvents such
as trichlorethylene (TCE), isoprenes (C3H8),
terpenes (C10H15), benzene (C6H6),
gasoline (C8H18), and vinyl chloride
(C2H3Cl)
– LT Exposure – leukemia, blood disorders,
immune system damage
Major Air Pollutants
• Radon (Rn):
– naturally occurring
radioactive gas found in
some types of soil and
rock (primarily granite
bedrock).
– It can seep into homes
and buildings sitting
above such deposits
through cracks in
foundations & through
well water.
URBAN OUTDOOR AIR
POLLUTION
• Industrial smog (gray-air smog) - mixture of SO2, H2SO4, and a
variety of SPM’s emitted mostly by burning coal.
• Sulfur in coal reacts with O2 yielding SO2 yielding H2SO4 + NH3
yielding (NH4)2SO4 (ammonium sulfate)
• (Coal from Eastern U S – bituminous - high in sulfur)
• Frequency & severity depends on:
• 1) Local climate & topography (bad with hills/mtns)
• 2) Population density
• 3) Amount of industry
• 4) Types of fuels used
South Asia’s Massive Brown Clouds
• Caused by coal-burning in China and
India
• Covers India, Bangladesh, China’s
industrial heart, parts of Western Pacific
Ocean
• 3 KM thick (approx. 2 miles);
• Size of continental U S
• Contains small particles of dust, smoke,
ash, soot, acidic compounds, toxic
metals (Hg, Pb)
South Asia’s Massive Brown Clouds
• Problems:
– Reduces photosynthesis
– Changes weather patterns
– Changes food production due to decreased rainfall in
North and flooding in South
– Moves across continents
– Moves to West Coast of U S
– EPA has determined for LA that 25% of SPM, 77% of soot
and 33% of Hg comes from China
– Satellites show that long-lived air pollution can circle the
world in about two weeks;
– Air Pollution Connects Us All.
Sunlight plus Cars Equals
Photochemical Smog
• Photochemical smog - mixture of air
pollutants formed by the reaction of nitrogen
oxides and volatile organic hydrocarbons
under the influence of sunlight (Atlanta’s
summer smog).
Sunlight plus Cars Equals
Photochemical Smog
• Mexico City, L.A.,
Sydney, Bangkok,
Santiago, Sao Paulo
& Atlanta all suffer
from photochemical
smog due to dry,
sunny climates with
lots of motor vehicles
Figure 19-4
Factors Influencing Levels of
Outdoor Air Pollution
• Outdoor air pollution can be reduced by:
– settling out, precipitation, sea spray, winds, and
chemical reactions.
– Ex. SO2+O2 = SO3 + H2O = H2SO4 which falls
out as acid precipitation becoming acid deposition;
• Outdoor air pollution can be increased by:
– urban buildings (slow wind dispersal of pollutants),
mountains (promote temperature inversions), and
high temperatures (promote photochemical
reactions), VOC emissions, Grasshopper Effect,
Temperature Inversions;
Temperature Inversions Can Occur in 2
Types of Areas
• Cold, cloudy weather in a valley surrounded by mountains
can trap air pollutants (left). (October 1948, Donora, PA
Yellow fog)
• Areas with sunny climate, light winds, mountains on three
sides and an ocean on the other are susceptible to
inversions (SoCal)
Figure 19-5
Temperature Inversions
• Subsidence inversion –
large mass of warm air floats
in at high altitude – floats
over the cooler air – no
vertical mixing
• Radiation inversion – at
night, air near the ground
cools faster – usually clears
up next day when sun comes
out (see this more in valleys
in cloudy/cold areas)
ACID DEPOSITION
• Sulfur dioxides, nitrogen
oxides, and particulates
react in the atmosphere to
produce acidic chemicals
– Tall smokestacks reduce local air
pollution but increases regional air
pollution.
– Prevailing winds can transport
primary pollutants, SO2 & NO2 up
to 1000 km
ACID DEPOSITION
• Acid deposition consists of rain, snow, dust,
or gas with a pH lower than 5.6.
Figure 19-6
FORMS OF ACID
DEPOSITION
• Wet deposition = acidic rain, snow, fog,
cloud vapor
• Takes place within 4-14 days of
emission
• Dry deposition = solid particles that are
acidic
• Takes place within 2-3 days of emission
ACID DEPOSITION
• pH measurements in relation to major coalburning and industrial plants.
Figure 19-7
ACID DEPOSITION
• RESULTS FROM HUMAN ACTIVITIES
THAT DISRUPT THE NATURAL
NITROGEN AND SULFUR CYCLES
• BY ADDING EXCESSIVE AMOUNTS
OF NITROGEN OXIDES AND SULFUR
DIOXIDE TO THE ATMOSPHERE;
ACID DEPOSITION
Figure 19-8
EFFECTS OF ACID
DEPOSITION ON SOILS
• SOILS WITH BASIC COMPOUNDS
SUCH AS CALCIUM CARBONATE OR
LIMESTONE CAN BUFFER SOME
ACID
• AREAS MOST SENSITIVE HAVE
THIN, ACIDIC SOIL WITH NO
NATURAL BUFFERING OR ALREADY
DEPLETED
EASTERN U.S.
• TYPICAL PRECIP IS 10X MORE ACIDIC THAN NATURAL
PRECIP
• WHY?
• MIDWEST COAL BURNING POWER PLANTS EMISSIONS (W
TO E WINDS)
• + AUTO EMISSIONS & OTHER INDUSTRY
• SOME MTN TOP FORESTS RECEIVE ACID PRECIP 1000X
THAT OF NORMAL PRECIP
OTHER COUNTRIES
• ACIDIC EMISSIONS FROM UK & GERMANY BLOW
S & E INTO SWITZERLAND & AUSTRIA
• AND BLOW N & S INTO NORWAY
• ASIA HAS THE WORST ACID PRECIP ESP. CHINA
• 70% TOTAL ENERGY FROM BURNING COAL
• CHINA IS THE WORLD’S TOP EMITTER OF SO2
• DAMAGES CROPS IN CHINA, JAPAN AND N/S
KOREA
THE HARMFUL EFFECTS OF ACID
DEPOSITION – AQUATIC ECOSYSTEMS
• Leaches toxic metals, lead and mercury, into lakes used
as drinking water source;
• Toxic metals can accumulate in tissues of fish consumed
by humans & other animals;
• Hg is transformed to methylmercury & biomagnifies
• Few fish can survive in water with ph less than 4.5;
• Releases Al+ causes mucus formation on fish, clogging
gills and suffocation
• Aerosols in Asian Brown Clouds are pulled into
thunderstorms that dump acid rain into Indian & Pacific
Oceans
THE HARMFUL EFFECTS OF ACID DEPOSITION –
TERRESTRIAL ECOSYSTEMS
•
•
•
•
Soil ph less than 5.1 can harm crops by
Reducing plant productivity & the
Ability of soils to buffer acidic inputs
In forests, Ca and Mg leached from soils (both necessary
nutrients)
• In forests, Al+, Pb+, Cd+, Hg+ released into soil, damaging
roots.
• Trees are weakened and vulnerable to severe cold, disease,
insects and drought.
ACID DEPOSITION & MOUNTAIN
TOP AREAS
• Hardest hit terrestrial areas by acid
deposition due to
• Thin soils with little buffering capacity &
• Bathed almost continuously in highly
acidic fog and clouds
ACID DEPOSITION
• Nutrient leaching
• Heavy metal
release
• Weakens trees
(evident on
mountaintops
where pH can be
2.3 on balds)
Figure 19-9
WHAT ACID DEPOSITION HAS DONE TO
THE WORLD’S FORESTS & LAKES
• Has not reduced overall tree growth in US and
Canada due to significant reductions in SO2 & NO2
• It has accelerated the leaching of plant nutrients from
soils, hindering tree growth
• An additional 80% reduction in SO2 emissions
needed in Mid Western US before NE lakes, stream
& forests can recover
SOLUTIONS TO ACID
DEPOSITION
• Prevention
• Homework – Discuss the many ways to
decrease the problem of acid
deposition, pages 451 -452.
SOLUTIONS TO ACID DEPOSITION
• FIG. 19-10 PAGE 452
• BEST:
– PREVENTION APPROACHES THAT REDUCE OR ELIMINATE
EMISSIONS OF SULFUR DIOXIDE, NITROGEN DIOXIDES AND
PARTICULATES INCLUDING:
•
•
•
•
•
IMPROVE ENERGY EFFICIENCY
REDUCE COAL USE
INCREASE NATURAL GAS USE
BURN LOW SULFUR COAL
TAX EMISSIONS OF SULFUR DIOXIDES
INDOOR AIR POLLUTION
• IAP = greater threat to human health than
outdoor air pollution ( 2-5x higher than
outside) - #1 source of cancer risk.
• 17% of US buildings are “sick”
• According to the EPA, the four most
dangerous indoor air pollutants in developed
countries are:
– 1) Tobacco smoke.
– 2) Formaldehyde.
– 3) Radioactive radon-222 gas.
– 4) Very small fine and ultrafine particles.
Chloroform
Para-dichlorobenzene
Tetrachloroethylene
Formaldehyde
1, 1, 1Trichloroethane
Styrene
Nitrogen
Oxides
Benzo-a-pyrene
Particulates
Tobacco
Smoke
Asbestos
Carbon Monoxide
Radon-222
Methylene Chloride
Fig. 19-11, p. 453
Asbestos
• Fibrous silicate minerals – was
used in brake linings, shingles,
water pipes, flooring
• Must be completely sealed or
it’s a fibrous dust
• Causes asbestosis, lung
cancer, & mesothelioma
(cancer of lung’s lining)
Radioactive Radon
• Radon-222 radioactive gas –
produced by
decay of uranium
238 – 4 picocurie
level = EPA’s
recommended
max – no safe
threshold level
Figure 19-13
HEALTH EFFECTS OF AIR
POLLUTION
• Cancer, asthma, chronic bronchitis,
emphysema
Figure 19-14
HEALTH EFFECTS OF AIR
POLLUTION
Normal human lungs (left) and the lungs of a
person who died of emphysema (right).
Figure 19-15
Air Pollution is a Big Killer
• Each year, air pollution prematurely kills
about 3 million people, mostly from indoor
air pollution in developing countries.
– In the U.S., the EPA estimates that annual
deaths related to indoor and outdoor air
pollution range from 150,000 to 350,000.
– According to the EPA, each year more than
125,000 Americans get cancer from breathing
diesel fumes.
Air Pollution is a Big Killer
• Spatial distribution of premature deaths from
air pollution in the United States.
Figure 19-16
CLEAN AIR ACTS 1970, 1977, 1990
• 1) Regulates SPLONC’s – through NAAQS
• 2) Command & Ctrl Approach – federal gov establishes the regulations,
states & cities enforce it
• 3) Primary standards – protect human health
• 4) Secondary standards – prevent environmental & property damage
• 5) States must develop SIPs – how they will meet CAA reguirements. –
must list all pollutants & estimate quantities
Deficiencies in the Clean Air Act:
– The U.S. continues to rely on cleanup rather than
prevention.
– The U.S. Congress has failed to increase fuelefficiency standards for automobiles (recently
changed).
– Regulation of emissions from motorcycles and
two-cycle engines remains inadequate.
– There is little or no regulation of air pollution from
oceangoing ships in American ports.
Deficiencies in the Clean Air Act:
– Airports are exempt from many air pollution
regulations.
– The Act does not regulate the greenhouse gas
CO2 (in debate right now)
– The Act has failed to deal seriously with indoor air
pollution.
– There is a need for better enforcement of the
Clean Air Act.
ATTEMPTS TO IMPROVE AIR
QUALITY
• 1) MTBE added to fuels (increases O2 content – makes it
burn more completely) (methyl tert-butyl ether)
• 2) RFG – reformulated gas
• 3) CAFÉ standards (27.5 for cars, 23.5 for light trucks, SUVs
– 35 mpg in 2020) set by DOT (corporate average fuel
economy)
• 4) New diesel engines – decrease emissions by 1/3
• 5) Catalytic converters – burn any unburned hydrocarbons in
fuel
Using the Marketplace to Reduce
Outdoor Air Pollution
• To help reduce SO2 emissions,
the Clean Air Act authorized and
emission trading (cap-and-trade)
program.
– Enables the 110 most polluting
power plants to buy and sell SO2
pollution rights.
– In 2002, the EPA reported the capand-trade system produced less
emission reductions than were
projected.
Ways to Prevent and Control Air
Pollution from Coal-burning
Facilities
–1) Electrostatic precipitators: are
used to attract negatively charged
particles in a smokestack into a
collector.
–2) Wet scrubber: fine mists of water
vapor trap particulates and convert
them to a sludge that is collected and
disposed of usually in a landfill.
Electrostatic Precipitator
• Can remove 99% of
particulate matter
• Does not remove
hazardous ultrafine
particles.
• Produces toxic dust
that must be safely
disposed of.
• Uses large amounts
of electricity
Figure 19-18
Wet Scrubber
• Can remove 98% of
SO2 and particulate
matter.
• Not very effective in
removing hazardous
fine and ultrafine
particles.
Figure 19-18
What Can You Do?
Indoor Air Pollution
• Test for radon and formaldehyde inside your home and take
corrective measures as needed.
• Do not buy furniture and other products containing formaldehyde.
• Remove your shoes before entering your house to reduce inputs
of dust, lead, and pesticides.
• Test your house or workplace for asbestos fiber levels and for
any crumbling asbestos materials if it was built before 1980.
• Don't live in a pre-1980 house without having its indoor air
tested for asbestos and lead.
• Do not store gasoline, solvents, or other volatile hazardous
chemicals inside a home or attached garage.
• If you smoke, do it outside or in a closed room vented to the outside.
• Make sure that wood-burning stoves, fireplaces, and keroseneand gas-burning heaters are properly installed, vented, and
maintained.
• Install carbon monoxide detectors in all sleeping areas.
Fig. 19-21, p. 461
INDOOR AIR POLLUTION
• USING DIAGRAM 19-11, PAGE 453,
MAKE A CHART LISTING THE INDOOR
AIR POLLUTANT, THE SOURCE AND
THE POSSIBLE THREAT TO HUMAN
HEALTH;