Transcript Air pollution - Duluth High School

Air pollution
Part B
A Model of How Pollutants That Make Up Photochemicals Are Formed
SMOG…
• Is worse on hotter days
• Increases as traffic increases
• Is more common in cities with sunny, warm
and dry climates with lots of cars like LA,
Denver, Sydney (Australia), Mexico City, Jakarta
(Indonesia) and Santiago (Chile)
Several Factors Can Decrease Air
Pollution
• Outdoor air pollution may be decreased by
– Settling of particles due to gravity
– Rain and snow
– Salty sea spray from the ocean
– Winds
– Chemical reactions
• ex. SO2 reacts with O2 in atmosphere to form SO3
which reacts with water vapor to form H2SO4-falls out
as acid rain
Several Factors Can Increase Outdoor
Air Pollution
• Outdoor air pollution may be increased by
– Urban buildings
– Hills and mountains
– High temperatures
– Emissions of VOCs from certain trees and plants –
oaks, sweet gums, kudzu
– Grasshopper effect-volatile pollutants transported by
evaporation and wind from tropical and temp. areas
– Temperature inversions
– Precipitation, wind
Look at the temperature
inversion diagram in your text
18.3 Acid Deposition Is a Serious Regional Air
Pollution Problem
 Acid deposition, acid rain
 Formation
1) sulfur dioxide (SO2) - forms H2SO4 (sulfuric acid)
2) nitrogen oxides (NOx) - forms HNO3 (nitric acid)
In the U.S., ~ 2/3 of all SO2 and ~ 1/4 of all NOx comes from
electric power generation that relies on burning fossil fuel
 Local versus regional problems-tall smokestacks
 Effects of prevailing winds: prevailing winds can blow acidic
compounds over hundreds of miles
a) wet deposition: acidic rain, fog, and snow
b) dry deposition: acidic gases and particles
 Soils with limestone/calcium carbonate neutralize acid
deposition
 Where is the worst acid deposition? Asia!! China is biggest
emitter of SO2
Natural Capital Degradation: Acid
Deposition, Acid Rain
Acid Deposition Has a Number of Harmful Effects
 Human respiratory disorders
 Aquatic ecosystems affected: Leach metals such as Pb and Hg into
water and can accumulate in tissues of fish.
EX: Mercury (Hg)
in fish
 Most fish cannot survive in water with pH < 4.5
 Al+3 and Hg become more soluble
 Acid Shock - A sudden acidification of runoff waters from the spring
melting of accumulated snow in the middle latitudes because of the
winter deposition of acidic precipitation.
 Many lakes in Norway and Sweden have no fish
Acid Deposition Has a Number of
Harmful Effects
Harms crops by making soil too acidic (< 5.1)
Damage waxy coat on leaves
Impair germination
Leaches nutrients
Reduces plant productivity and the ability of
soils to buffer acidic inputs
Synergistic effects
Acid Deposition Has a Number of Harmful Effects
 Affects forests by leaching plant nutrients such as Ca, Mg
and releasing ions of Al, Pb, Cd and Hg which are toxic to
trees)
 promotes acid-loving mosses that kill trees.
 Tree foliage damaged, making trees more susceptible to
cold temps, diseases, insects, drought, fungi
 Hubbard Brook Studies- found that trees do not suffer
directly from acid rain, but from insufficient nutrients. In
order for trees to recover, nutrients need to be
replenished- this can take decades if left to nature.
Damages exterior paint on cars and houses,
deteriorates roofing, marble statues, historic
buildings, stain glass windows- costs $5
billion/yr in US
Is a regional problem that affects areas that
are downwind from large car-dominated
cities and from polluting coal-burning
facilities (acidic components remain in air for
a few days)
Acid Deposition Has a Number of Harmful
Effects
Damage to buildings, statues, and monuments
 effects of acid rain
Natural Capital
Degradation: Air
Pollution Damage to
Trees
Emissions
SO2 NOx
Acid
HO
deposition 2 2 O3
PANs Others
Direct damage to
leaves and bark
Reduced
photosynthesis
and growth
Tree death
Soil acidification
Leaching
of soil
nutrients
Acids
Release
of toxic
metal ions
Increased
susceptibility to
drought, extreme
cold, insects,
mosses, and
disease organisms
Root
damage
Reduced nutrient
and water uptake
Lake
Groundwater
Fig. 18-14a, p. 481
We Know How to Reduce Acid Deposition
• Prevention approaches that reduce or
eliminate emissions from SO2, nitrous oxide,
and particulates. Remove S from coal before it
is burned, use low-S coal, remove NOx from
car exhaust. Tax emissions, improve energy
efficiency.
• Reduce coal use? Expensive and cost passed
on to consumers. Alternative energy sources?
Areas affected are often far from sources.
• Clean up
– Add lime to neutralize acidified lakes and soil
We Know How to Reduce Acid Deposition
• Prevention approaches that reduce or
eliminate emissions from SO2, nitrous oxide,
and particulates. Remove S from coal before it
is burned, use low-S coal, remove NOx from
car exhaust. Tax emissions, improve energy
efficiency.
• Reduce coal use? Expensive and cost passed
on to consumers. Alternative energy sources?
Areas affected are often far from sources.
• Clean up
– Add lime to neutralize acidified lakes and soil
18-4 Indoor Air Pollution Is a Serious Problem
• Developing countries
– Indoor burning of wood, charcoal, dung, crop residues
and coal
– Poor suffer the greatest risk
– Few, if any, regulations
– Is the most serious air pollution problem
• Developed countries
– Indoor air pollution poses a greater threat than
outdoor air pollution.
Indoor Air Pollution Is a Serious Problem
• Why? We spend up to 70-98% of our
time indoors or inside our cars!
– 11 of the common air pollutants are at
higher levels inside than outside
– Greater inside vehicles than outside
– Health risks magnified because pollutants
are magnified indoors.
Indoor Air Pollution Is a Serious Problem
• Who is at greatest risk from indoor air pollution?
–
–
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–
–
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Children under 5 and the elderly
Sick
Pregnant women
People with respiratory disorders or heart problems
Smokers
Factory workers
Indoor Air Pollution Is a Serious Problem
• Four most dangerous indoor air pollutants
– Tobacco smoke
– Formaldehyde(CH2O) – found in plywood, particle board,
paneling, drapes, furniture, carpet and wallpaper adhesives
Estimated that 1/5,000 people who live in manufactured homes
for more than 10 an lead to Lou Gehrig’s disease (kills nerve
cells)
– Radioactive radon-222 gas- colorless, odorless,
radioactive gas that is produced by the natural
radioactive decay of U-238.
– Very small particles
 Sources of these
pollutants-brought in
on shoes, pesticides,
paints, sprays, living
organisms (bugs), mold
 Human health risks-sore
throat, headache,
chronic breathing
problems, rash (flu-like
systems)
Indoor Air Pollution Is a Serious Problem
Other possible indoor air pollutants
Pesticide residue
Pb particles
Living organisms and their excrements
E.g., Dust mites and cockroach droppings
Airborne spores of molds and mildews
Sick-building syndrome
What exactly is a sick building?
• Term that refers to a building in which a number
of people report adverse health effects that they
believe are related to the time they spend in the
building
• A building in which occupants suffer persistent
symptoms that disappear when they go outside
• A building which contains unhealthy levels of
indoor air pollutants
How do you know if a building
is really “sick”?
• When people report relief of symptoms when
they go outside
• When 20% or more of the occupants report some
adverse health effect when inside the building
• When occupants report any of the following
symptoms: chronic respiratory problems, sinus
infection, sore throat, asthma, shortness of
breath, depression, forgetfulness, headaches, eye
irritation
What type of building can be sick?
• Old
– Asbestos and lead
• New
– Formaldehyde or VOC’s
• Houses with wood-burning stoves
– Carbon monoxide
Some Important Indoor Air Pollutants
Radioactive Radon Gas
• Colorless, odorless, radioactive gas
• Sources: natural radioactive decay of Uranium-238
(rocks and soil)
• Human health risks-damage to lung tissue-cancer
• Testing for radon - detectors
• Correcting a radon problem:
– Sealing cracks in walls and foundation,
increase ventilation
Sources and Paths of Entry for Indoor
Radon-222 Gas
It’s a fantastic house with the
exception of the radon gas.
Your Body’s Natural Defenses against Air
Pollution Can Be Overwhelmed
• Respiratory system protection from air
pollutants
– Role of cilia, mucus, sneezing, and coughing
• Effect of smoking and prolonged air pollution
exposure
– Chronic bronchitis
– Emphysema
– 6% of people in US suffer from asthma
Major Components of the
Human Respiratory System
Lung Attack
Air Pollution Is a Big Killer
• 3 Million deaths per year world-wide
– Mostly in Asia
– Main causes-indoor air pollution
– In US, more than 150,000 die each year from air pollution
• EPA: proposed stricter emission standards for
diesel-powered vehicles
– Reduce emission by 90%
– Car makers hope they can delay
• Link between international trade and air
pollution
– Cargo ships and pollution
Premature Deaths from Air
Pollution in the U.S.
Laws and Regulations Can Reduce
Outdoor Air Pollution
• United States
– Clean Air Acts: 1970, 1977, and 1990
• EPA
– National ambient air quality standards (NAAQs) for 6
outdoor criteria pollutants
• Carbon monoxide, nitric oxides (NOx), sulfur dioxide,
ozone, lead, and suspended particulate matter (SPM)
• Primary Standard-Human health
• Secondary Standard-environmental and property
damage
– National emission standards for 188
hazardous air pollutants (HAPs)
• Mainly toxic metals, VOCs, and
chlorinated hydrocarbons
• Toxic Release Inventory (TRI)-for power
plants, refineries which requires by law
for release of info about chemical
releases and waste management
Laws and Regulations Can
Reduce Outdoor Air Pollution
• Good news in U.S.
– Decrease in emissions 49% from 1980-2006
– Use of low-sulfur diesel fuel
• Cuts pollution
• Developing countries
– More air pollution
We Can Use the Marketplace to
Reduce Outdoor Air Pollution
• Emission trading or cap-and-trade program
• “Pollution Credits”
– Mixed reactions to program
– SO2 emissions down significantly
– NO2 will be tried in the future
– Mercury from coal plants-does not break downmust set limits
There Are Many Ways to Reduce
Outdoor Air Pollution
• 1980 –2006
– SO2 emissions from U.S. electric power plants
decreased by 66%
– NOx emissions by 41%
– Particulate emissions by 28%
• Older plants not governed by the same
regulations
• New cars have better emissions
Reducing Indoor Air Pollution
Should Be a Priority
• Greater threat to human
health than outdoor pollution
• What can be done?
– Prevention
– Cleanup
We Need to Put More Emphasis
on Pollution Prevention
• Output approaches
• New shift to preventing
outdoor and indoor
pollution
– Pressure from citizens
Air Pollution…
• Global climate change, ozone depletion, acid
rain, photochemical smog, and indoor air
pollution are some of the most significant
environmental problems faced by humanity.
All of these problems/issues emphasize how
important a healthy atmosphere is.
ON THE AP EXAM…
• Don’t just state something “causes pollution”.
At least state that the activity causes “air
pollution” or “water pollution”. Most likely,
though, graders will want more specific
information such as “this activity releases
sulfur dioxide into the atmosphere”.