Air Quality
by Bao Quach
Lesson I - Major Air Pollutants
(7th grade L.E.P. students. Duration: 40 min.)
Objective: The students will be able to determine what are the potentialsources of major air pollutants.
Materials:
a piece of candle
matches
a plastic box with cover
Activities:
-Show pictures of some heavily air-polluted cities where motorcyclists hadto cover their noses and mouths with handkerchiefs knotted behind theirheads, or news clippings about carbon monoxide poisoning.
-Students light the candle fixed inside the box. Cover the box. Measurethe time elapsed until candle light went off.
-Have students explain the phenomenon and relate to life science.
-What is there in common between candle wax and gasoline?
-What is fossil fuel? Is it renewable or not?
-What substances are there in a car exhaust? Name the major pollutants.
-Divide class into groups of 3. Designate each group to find informationin available reference books concerning a couple of pollutants then reportto class.
-Reports should include sources of contaminant, actions and effects, remedialsolutions individually and collectively.
-Major air pollutants:
carbon monoxide, what is incomplete combustion?
nitrogen oxides
sulfur dioxide
ozone
lead
asbestos
particulates
-Define level of tolerance.
Evaluation:
What do you think is the key word for air pollution control? What wouldyou do as an individual to reduce air pollution?
Extension:
Besides the above-cited pollutants, what other physical factors do you thinkare potential air pollutants susceptible to harm your body and mind as well?
Lesson II - Acid Rain
(6th grade L.E.P. students. Duration: 40 min.)
Objective: The students will understand air pollution is at the origin ofacid rain.
Materials:
a sample of new rainwater
a sample of distilled water
pH paper
Activities:
-Students take turn to measure both samples' pH.
-Take the medians and compare.
-Was there a difference in acidity levels between the two samples?
-What could have caused the difference?
-What acids do you predict present in the rainwater? Why?
-Where do most air pollutants come from?
-Sulfur oxides and nitrogen oxides combine with water through a series ofcomplex chemical reactions to form tiny bubbles of sulfuric and nitric acidswhich fall to the earth in rain.
-Does acid rain fall just where the original source of air pollutants is?
-How does acid rain affect living (fish, forests) and non-living things?
-How can people control acid rain?
-Can we achieve by reducing the sulfur content in the fuel?
-Or, can we use an alternative fuel which is cleaner than fossil fuel?
Evaluation:
Explain how acid rain is generated. How does acid rain affect the environment?
Extension:
Using acid rain as an example, explain why most environmental problems gobeyond a country's border and involve the whole world.
Lesson III - Global Warming or The Greenhouse Effect
(6th grade L.E.P. students. Duration: 40 min.)
Objective: The students will understand why a global warming may resultfrom an excessive use of fossil fuel by man.
Materials:
a plastic box covered by a stretched clear plastic sheet
a 100 watt electric lamp
2 thermometers
Activities:
-Place one thermometer inside and the other outside and close to the box.
-Switch on the lamp and direct it toward the box.
-Record the temperature every minute until it becomes stationary.
-Graph the results.
-Graph the temperature outside the box on the same coordinate plane.
-Draw conclusions from the graphs.
-Switch off the lamp and follow up the variations of temperature insidethe box.
-Graph the variations.
-Can the heated box be compared to a greenhouse?
-Make generalizations to the earth under a blanket of carbon dioxide.
-Can the heat from the sun escape from that blanket?
-What would happen to the ocean temperature? Effects on ocean life?
-What would happen to the polar ice caps? to semi-arid lands? to the crops?and finally to humans?
-Where does carbon dioxide come from? (burning fossil fuel and deforestation)
-Normally, where is CO2 absorbed in nature? (photosynthesis and oceans)
-Excess of CO2 forms with CFC and CH4 a blanket which traps energy.
-What would be the remedial solution? by improving the efficiency of coaluse? by using new clean coal technology? by using less energy (conservation)?
Evaluation:
Explain why a global warming may result from an excessive use of fossilfuel. As an individual, what would you do to reduce and encourage othersto reduce fossil fuel use?
Extension: Do you think pushing up prices for gas, electricity and wateris a good way to reduce fossil fuel use?
Lesson IV - Ground Level Ozone
(6th grade L.E.P. students. Duration: 40 min.)
Objectives: The students will:
-understand where, when, and how ozone is generated
-distinguish the nocent effects of ground level O3 from the protective effectof atmospheric ozone.
Materials:
a battery run toy car
battery
Activities:
-Put the car on and hold it in your hand. Wait for 5 minutes.
-What did you smell? Was the odor due to heated paint or oil?
-Try again. Was it the same odor?
-Explain: Atmospheric oxygen combined to ionized oxygen under electricaldischarge to form a new gas called ozone.
-Explain: ozone is not directly emitted into the air like other major airpollutants but is formed through reactions between NOx and volatile organiccompounds in the presence of sunlight.
-Can you explain why we may smell ozone during heavy thunderstorms?
-What are the major sources of ozone?
motor vehicles
petroleum refineries
oil storage tanks
household products, petroleum marketing, chemical manufacturing, surfacecoating and printing industries.
-What are rush hours in cities? Can you predict what time ozone reachespeak levels in a day? Why?
-Ozone affects the lungs: asthma, lung functions reduced, chest pain coughing,wheezing and congestion
-Ozone affects vegetation: plant yield reduced (tomato, bean, soybean, snapbean, peanut and corn crops, premature leaf-drop in forests).
-Ozone causes cracking of rubber products, weakening of textiles, changesin dyes and premature cracking of paint.
-Projection of pictures of Los Angeles smog (if available).
-What can be done? Individual: reduce emissions, use solvent-free householdproducts. Industries: regulations to reduce emissions.
-Distinguish with beneficial atmospheric ozone: U.V. protector.
Evaluation:
-What are the major sources of ground level ozone?
-What process keeps G.L.O. from joining atmospheric ozone? (t inversion)
-What can an individual do to reduce harmful G.L.O.?
Lesson V - Atmospheric Ozone Depletion
(7th grade L.E.P. students. Duration: 40 min.)
Objectives: The students will understand:
-the protective role of atmospheric ozone to earth
-the cause of atmospheric ozone layer thinning
Vocabulary: upper stratosphere, CFCs, ozone-destroying and ozone-friendlychemicals, phase-out, allowances
Materials:
satellite photo of ozone depletion over Antarctica and North America andthe North Pole
projector
Activities:
-What is ozone? Its place in the periodic table of the elements.
-Where is the ozone layer located in the atmosphere?
-What is the role of atmospheric ozone?
-What is ultraviolet B radiation in the visible spectrum? What is cosmicray?
-How do these radiations affect human health, plants and animals?
-What are chlorofluorocarbons? Where are they used? How can they reach thestratosphere? How does ozone react with CFCs?
-How large are the holes over Antarctica and the North Pole?
-What are the ozone-destroying chemicals used in industries? CFCs, Halons(fire extinguishers), carbon tetrachloride (solvents), methyl chloroform(very widely used solvent), hydro CFCs (CFC substitutes)
-How to repair the ozone layer?
individually,
countrywide and globally,
the 1990 Clean Air Act: phasing out the production of ozone-destroying chemicals,encouraging the development of ozone-friendly chemicals, EPA issuing allowancesto control manufacture of chemicals being phased out.
Evaluation:
-Explain the reason why atmospheric ozone is being depleted.
-How does atmospheric ozone react with Cl, Br, NOx?
-Compare and contrast atmospheric ozone and ground level ozone.
Extension:
Suppose CFCs banning were achieved globally and ozone replenishment complete,do you think the harmful effects of ozone depletion will immediately stopravaging on earth?