Virginia's Air Resources
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Indoor Air Pollution Solutions Background Discuss whith your students the concept of air pollution and its various forms. We have all seen air pollution - smoke that comes out of the exhaust pipe of buses, trucks, and cars. But what about the air inside your home or school? Is this air "safe" to breathe? Is it clean? Discuss the idea that while your indoor air may look and smell clean because you can't see any pollution, scientists have found that the air inside your house and school contains an invisible and often odorless form of gaseous chemicals emitted from many everyday furnishings and objects. In particular, poorly ventilated buildings trap these gases and are more prone to indoor air pollution, because the air cannot circulate and is not replenished with cleaner air. Discuss indoor air pollution, including tobacco smoke, dust, paint thinner, cleaners, pesticides, radon gas, wood burning fireplaces, chemicals from personal care products, and so on. Explain that gases can be odorless and invisible and that high concentrations can be harmful. The chemicals in the air are emitted from everyday objects that you would find and use around your home and in your school. Things that you would never expect to contribute to air pollution include: the furniture in your house or school, the paint on the walls, carpeting, the ink in printed materials such as books and newspapers, plastic and painted toys, and dry-cleaning solutions used to clean your clothes. Explain to students that the chemicals used in or resulting from the manufacturing process of these products are emitted into the air and can cause your eyes, nose, and throat to feel irritated. These chemicals may cause headaches, make you feel drowsy, or develop more severe symptoms. In these cases, where the air inside buildings has made people feel sick, scientists have come up with the name "sick building syndrome" to describe the problem. The strength of the pollutant in the air, the amount of air in the room, how much air is being used up (breathed in), as well as the sensitivity of each individual plays a role in this process. Often, scientific equipment is used to measure the presence and amounts of substances in the air. Share with students that there are some simple things that they can do to help clean the air. NASA researchers, led by Bill Wolverton, Ph.D., have found that common house plants can rid the air of a variety of pollutants. In particular, findings from his research are used to remove airborne pollutants from sealed environments like the space station. Discuss photosysthesis, the process by which plants clean the air. It works like this: plants absorb carbon dioxide, hich we exhale, and give off oxygen, which we breathe in. Plants absorb the pollutants/gases through their leaves and roots and convert them to harmless substances. Scientists have found that in laboratory studies plants removed as much as 87% of the indoor air pollution within 24 hours! |
Grade Levels: Objectives: Vocabulary Words: |
Table 1: List of common pollutants, side effects, sources, and pollution-fighting plants
Pollutant |
Possible Side Effect |
Source |
Pollution Fighter |
| Benzene | skin and eye irritant, headaches, loss of appetite, drowsiness, tiredness, and other | inks, oils, paints, plastics, rubber, dye, detergents, gasoline, tobacco smoke, synthetic fibers | Dracaena marginata, English ivy, Janet Craig (fern), Warneckel, Peace lily |
| Formaldehyde | irritated eyes, nose, throat, headaches, contact dermatitis, and others | foam insulation, plywood, particle board, pressed wood products, plastic grocery bags, wax paper, facial tissue, paper towels, water repellants, adhesive binders in floor coverings, cigarette smoke, natural gas and kerosene, new synthetic carpets, new furniture made from pressed wood | Boston fern, Chrysanthemum, Gerber daisy, Dwarf date palm, Bamboo palm |
| Thrichloro-ethylene | potential for liver damage | used in dry cleaning and in printing inks, paints, varnish, and adhesives | |
| Xylene | a solvent in paints and varnishes | Areca palm, Chrysalidocarpus, Lutescens, Dwarf date palm, Phoenix roebelenii, Bamboo palm, and others |
Dr. Bill Wolverton, who currently maintains his own laboratory facility, has worked both at NASA and as a consultant to The Plants for Clean Air Council. Through his research he developed a formula that you can use to create a plan for clean air in your classroom or home:
Two or three plants per 10 square meters* (or 22.6 cubic meters with a standard ceiling). If you have a newly constructed house or lots of new furniture, you should fill each room with plants.
*hundred square feet of space for a standard building
Activity #1 - 5th grade level
Read the following scenario to your students:
The school you attend is 10 years old. It is the fall and late last spring new carpeting was installed. In addition, during the past summer, all the halls in your school were repainted. Your classroom received a large workstation (3m x 2m) comprised primarily of pressed wood.
- Have students measure your classroom to determine its square footage.
- Determine the number of plants needed to keep the air clean.
- Determine the types of plants needed to clean the air based on materials contained in the room.
Activity #2 - 5th and 6th grades
Dr. Wolverton's research has found that different plants remove chemicals from the air at varying rates. In other words, the volume of "air exchange" that one plant can treat varies by the type of plant and chemical being treated for. In addition, the U.S. Environmental Protection Agency (EPA) has conducted research to determine the mean indoor air concentration of chemicals found in various buildings.
Table 2: Removal Rate Per Hour by Plant Type
| Plant Type | Formaldehyde | Xylene |
Boston Fern |
1863 µg/hour 1361 µg/hour 617 µg/hour |
208 µg/hour 154 µg/hour 168 µg/hour |
µg=microgram (one-thousandth of a gram)
Table 3: Mean Indoor Air Concentration of Chemicals Found in Nursing Homes
| Chemical | Mean Concentration |
Formaldehyde |
0.081 µg/liter 0.005 µg/liter |
Use the following as a case study to determine which and how many plants are needed to clean the air continuously:
- You have been brought in to consult with the managers of a local nursing home facility. Residents have complained recently of headaches and tired, scratchy, irritated eyes. The facility is 25 years old and has undergone recent renovation including new paint throughout and new carpeting in each resident's room. Each resident has also received new furnishings made of pressed wood board, including a bed and bedside table for their individual room. The room measurements are 3.05 meters long by 3.05 meters wide, with a 2.4-meter ceiling.
- The managers of this facility are asking for your help to reduce the number of complaints they are receiving from the residents and make them more comfortable in their surroundings.
- Determine the origins of the chemicals that may be causing the residents' symptoms.
- Determine which types of plants would be best used to clean the air of the specific chemicals involved.
- Use the steps below to determine how many plants are needed to clean the air in each nursing home room:
- Calculate the air volume in the room by entering the dimensions of the room into the formula below: length_______ x width_______ x height ________ = cubic meters
Answer: 22.64 cubic meters - Calculate the average concentration (amount) of each pollutant in the room by using the data in Table #3.
22.64 cubic meters x 1000 liters x _______mean (concentration) µg = _______ µg
Answer:
22,640 liters x .081 micrograms per liter (formaldehyde)=1834 µg
22,640 x .005 micrograms per liter (xylene) = 113 µg - Refer to Table #2 for the removal rates of plants to determine the number of each type of plant needed to clean the air.
______µg pollutant divided by the removal rate/hour = number of plants needed to clean the air
Answer: 1834 divided by 1863 (Boston fern) = 1 Boston fern plant.
You can use the same formula for other plants types as well.
Use the table below to collect your responses:
Chemical |
Amount of Chemical Number of Plants Chemical (found in each room) |
Plant Type |
Number of Plants Required |
Answers:
Chemical |
Amount of Chemical Number of Plants Chemical (found in each room) |
Plant Type |
Number of Plants Required |
| Formaldehyde | 1834 µg | Boston Fern | 1 |
| Janet Craig | 2 | ||
| Rhododendron | 3 | ||
| Xylene | 113 µg | Boston Fern | 1 |
| Janet Craig | 1 | ||
| Rhododendron | 1 |
Extension: Complete the above activity(ies) using the dimensions of your own classroom and any applicable environmental conditions.
Major Man-made Air Pollutants |
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Pollutant |
Description |
Sources |
Effects |
Carbon monoxide (CO) |
colorless, odorless gas |
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Lead (Pb) |
metallic element |
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Nitrogen oxides (NOx) |
several gaseous compounds made up of nitrogen and oxygen |
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Ozone (O3) |
gaseous pollutant |
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Particulate matter |
very small particles of soot, dust, or other matter, including tiny droplets of liquids |
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Sulfur dioxide (SO2) |
gaseous compound made up of sulfur and oxygen |
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OZONE "BUSTERS"
Virginians can help reduce ozone on summer days in a number of ways: C Avoid unnecessary car trips. Use the telephone or fax machine whenever possible. If you must drive, combine errands. C Carpool, vanpool, or use public transportation (buses, subways, trains) when possible. C Drive the most fuel-efficient vehicle available. C Keep your car engine properly tuned and tires properly inflated. C Avoid excessive engine idling while driving. Idling for more than 30-40 seconds uses more gasoline than restarting the engine. C Refuel vehicles after dusk or early in the morning. C Limit lawn mowing and the use of other gasoline-powered equipment, including outboard motors. C Limit or halt open burning. C Turn off unnecessary lights and electric appliances. If possible, raise the thermostat setting by 2-4 degrees to use less air conditioning. The less energy used, the less must be generated by power plants.