Chapter 22 (pgs 356-375) Air and Noise Pollution.
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Chapter 22 (pgs 356-375)
Air and Noise Pollution
Section 22.1 The Air Pollution Problem
Objectives:Describe air pollution.Explain the historical background of air pollution.Identify common air pollutants.
Think CriticallyIn 1976, 35 American Legion members died
mysteriously at a convention center in Philadelphia.
Doctors had no idea what was causing the people to die.
How do you think they were able to determine the cause?
Air Pollution ProblemAir is a mixture of gases – 78% nitrogen,
21% oxygen, and small amounts of argon, CO2, and water vapor
Air pollution – harmful materials that enter the environment and released into the atmosphere
Pollutants can be from natural sources (sandstorms, volcanic eruptions) or from human activity
Humans caused air pollutionAir pollution became a big problem during the
industrial revolution during the 1700’sHuge amounts of coal and wood were burned and
human health effects were devastating
Outdoor PollutantsAir Pollutants can be gases or
particulates (particles)Air particulates – tiny solids
suspended in the atmosphere (ash, dust, soot, liquid droplets, trace metals, pesticides, fertilizer dust, etc.)
Particulates are dangerous because they are so small and are easily inhaled and get trapped in people’s lungs
Gaseous Pollutants – most are oxides (compounds of oxygen and another element like carbon, sulfur, or nitrogen) released when fossil fuels are burned
Outdoor Pollutants
Photochemical Smog – a yellow-brown haze formed when sunlight reacts with pollutants produced by cars
Develops in cities with heavy automobile traffic (L.A., NYC, Newark)
Smog Contains:Ozone – (O3) very corrosive and breaks down rubber and
synthetic fibers. High concentrations are poisonous to plants and animals
Nitrogen Dioxide - (NO2) brown gas that gives smog its color
Outdoor Pollutants
Hydrocarbons – made of hydrogen and carbonMethane – most common –
produced by certain bacteria, livestock, and by rotting plant and animal matter
Chlorofluorocarbons – (CFC’s) compounds of carbon, chlorine, and fluorine once used in refrigerators, air conditioners, aerosol cans, and in the production of Styrofoam
Indoor PollutantsAir inside of buildings can often contain high levels
of pollutantsHome products such as plastics, insulation, and
cleaners can give off harmful fumesAir circulation in buildings is poor – especially in
winterMost people spend 16-18 hours/day insideIndoor air can contain:
Cigarette smoke – dangerous to smokers and nonsmokers
Microorganisms – bacteria and fungusRadon –colorless, odorless, radioactive gas from
natural breakdown of radium. Radon gas enters the soil and then your basement. Can cause lung cancer.
Section 22.2 Air Pollution and Living Things
Objectives:Identify the effects of air pollution on human
healthDescribe the effects of air pollution on plants
and animalsThink Critically
The number one cause of death in the U.S. is heart disease.
Heart disease is responsible for about 750,000 deaths annually.
Do you know what the leading cause of heart disease is?
Health EffectsCarbon Monoxide – dangerous
because it takes the place of oxygen on your red blood cells. High concentrations can stress the heart,cause headaches and dizziness, and even cause death
Ozone and Oxides of Sulfur and Nitrogen – irritate the eyes and respiratory tract, trigger asthma and allergy attacks, cause bronchitis and emphysemaEmphysema – disease in which tiny air sacs in the
lungs break downParticulates – can cause cancer – a disease in
which cells grow abnormally and without restraint.
Plants and AnimalsPlants :
Affected by ozone and sulfur oxides
Causes stems to be brittle and leaves to develop spots
Affected millions of Ponderosa Pines in L.A.Damages agricultural crops
Animals:Loss of plants – no food for animalsEye and lung irritation, bronchitis, and cancerIndustrial air pollutants (lead and zinc) can
contaminate rangelandand make grazing animals sick
Section 22.3 GlobalEffects of Air Pollution
Objectives:Identify the effects of acid precipitation and
ozone depletionExplain the greenhouse effect and global
warmingThink Critically
You have all heard the political talk about global warming.
What does global warming mean to us?Do you think it is something to worry about?
PollutionPollution can
threaten ecosystems and even the entire planet
Three major air pollution problems threatening the global environment:Acid precipitationOzone depletionGlobal warming
Acid RainRain or snow that is more acidic than normal
precipitationNormal precipitation (rain or snow) has a pH of 5.6
Carbon dioxide mixes with water in the air and forms carbonic acid
Burning fossil fuels releases:sulfur into the air which mixes with water to form
sulfuric acidnitrogen into the air which mixes with water to form
nitric acidAcid rain:
falls in forests and hurts the treesfalls into lakes and hurts the fishFalls on buildings/statues and deteriorate them
Ozone Layer
At earth’s surface, ozone is a poisonous gas
At 20-50 km above earth, it forms a protective layer around earth
The ozone layer absorbs almost all of the ultraviolet (UV) radiation given off by the sun
This prevents the UV rays from reaching earth and harming living things.
Hole in the Ozone Layer1980’s – scientists discovered a hole in the
ozone layer over both the South Pole and the North Pole
Damage to the ozone layer could greatly increase the amount of UV radiation that reaches earth
In humans this can cause:SunburnBlindnessSkin cancer
Can also cause severe crop damage
Causes of Ozone Depletion
CFC’s – main cause of ozone depletion – used in refrigerators, air conditioners, and aerosol sprays
CFC’s are OK in the lower atmosphere, but when they reach the stratosphere they are exposed to UV radiation
UV radiation causes CFC’s to break down and release chlorine and fluorine atoms
Chlorine and fluorine atoms destroy ozone
Global Warming
Greenhouse Effect – the trapping of radiated heat by gases in the atmosphereLight energy from the sun enters the
atmosphere and is absorbed by earth’s surfaceOnce absorbed, light energy is changed to heatEarth radiates this heat back into space in the
form of infrared radiationSome of the infrared radiation gets trapped
and warms the air in the lower atmosphereWithout the greenhouse effect, life on earth
would not be possible!
Greenhouse Gases
Atmospheric gases that trap heat:Carbon dioxide (CO2)MethaneSulfur and nitrogen oxidesCFC’sWater vapor
Amounts of greenhouse gases are increasing because of pollution caused by human activities
Burning fossil fuels releases CO2 into the airIce cores are used to determine the levels from
many years ago
Global Warming
An increase in earth’s average surface temperature caused by an increase in greenhouse gases
Another large increase in atmospheric carbon dioxide occurred at the end ofthe last ice age (14,000 years ago)
Scientists think there is the same link between increased carbon dioxide and temperature now
As the temperature rises, water in the oceans will expand, polar ice caps will begin to melt and flooding will occur
Section 22.4 Controlling Air PollutionObjectives:
Describe natural processes that help control air pollution.
Explain human efforts to control air pollution.
Identify federal legislation for curbing air pollution.
Think CriticallyWe know of ways to decrease air pollution.Most of these ways cost money.Would you be willing to pay more for
products to have cleaner air?
Natural Air Pollution Control
Precipitation is the most effective natural method of removing particulates and aerosols from the airBut, removing pollutants from the air
means putting them somewhere else – land, waterCarbon dioxide is removed from the air 2 ways:
Biological activity – plants remove CO2 to make sugars (photosynthesis) – it plants get buried, we get fossil fuels
Ocean water – depends on temperature. If temperatures rise due to global warming, the ocean will begin to release CO2
Human Air Pollution Control
Automobiles – major source of air pollutionStates have set strict emission control
standardsCars equipped with catalytic convertersCars designed for better gas mileageLook for other means of fueling cars
(electricity)Power Plants – major source of
pollutionDesign ways of cleaning the emissions
– scrubbersCan be very expensive
Section 22.5 Noise PollutionObjectives:
Describe the problem of noise pollution.
Explain measures and legislation for controlling noise pollution.
Think CriticallyConcerts can be as loud as 120 dB.This can cause physical pain and serious
hearing damage.Would this make you not attend a
concert?
Noise PollutionCan cause annoyance, stress, and hearing damage
Sources are airplanes, machines, and concerts
Sound intensity is measured in decibels (dB)Softest sounds are around 0 dBAnnoying sounds are around 70-80 dBDamaging sounds are around 120-130 dB
1972 – Congress passed the Noise Control Act – set standards for maximum noise levels
Industries have also tried to reduce sources and levels of noise pollution in the workplace
Don’t listen to very loud music and wear earplugs if you will be in a noisy area!!
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