Indoor Air Quality
by Alice Smith Jones
Introduction:
All of us face a variety of risks to our health as we go about our day-to-daylives. Driving in cars, flying in planes, engaging in recreational activities,and being exposed to environmental pollutants all pose varying degrees ofrisk.
Indoor air pollution is one risk that you can do something about. For manypeople, the risks to health may be greater due to exposure to air pollutionindoors than outdoors. People, who may be exposed to indoor air pollutantsfor the longest periods of time are often those most susceptible to theeffects of indoor air pollution. Such groups include the young, the elderlyand the chronically ill, especially those suffering from respiratory orcardiovascular disease.
Background:
Most homes have more than one source that contributes to indoor air pollution.There can be a serious risk from the cumulative effects of these sources.Many Americans spend a lot of time in offices with mechanical heating, coolingand ventilation systems with poor air quality. Fortunately, there are stepsthat most people can take both to reduce the risk from existing sourcesand to prevent new problems from occurring.
Lesson I
Objectives: Students will be able to:
-identify primary causes of indoor air pollution
-identify pollutant sources
-identify proper ventilation in their homes, apartments and schools
-measure pollutant levels
-improve air quality indoors
Tap Prior Knowledge Using (KWL)
-what you know
-what you want to know
-what you have learned
How Does Outdoor Air Enter a House?
Outdoor air enters and leaves a house by: infiltration, natural ventilationand mechanical ventilation. In a process known as infiltration, outdoorair flows into the house through openings, joints and cracks in walls, floors,ceilings and around windows and doors. In natural ventilation, air movesthrough opened windows and doors. Air movement associated with infiltrationand natural ventilation is caused by air temperature differences betweenindoors and outdoors and by wind. Finally, there are a number of mechanicalventilation devices, from outdoor-vented fans that intermittently removeair from a single room, such as a bathroom or kitchen, to air handling systemsthat use fans and duct work to continuously remove indoor air and distributefiltered and conditioned outdoor air to strategic points throughout thehouse. The rate at which outdoor air replaces indoor air is described asthe air exchange rate. When there is little infiltration, natural ventilationor mechanical ventilation, the air exchange rate is low and pollutant levelscan increase.
What if You Live in an Apartment?
Apartments can have the same indoor air problems as single-family homesbecause many of the pollution sources, such as interior building materials,furnishings, and household products, are similar. Indoor air problems similarto those in offices are caused by such sources as contaminated ventilationsystems, improperly placed outdoor air intakes or maintenance activities.
Solutions to air quality problems in apartments, as in homes and offices,involve such actions as:: eliminating or controlling the sources of pollution,increasing ventilation, and installing air cleaning devices. Often a residentcan take the appropriate action to improve the indoor air quality by removinga source, altering an activity, unblocking an air supply vent, or openinga window to temporarily increase the ventilation. In other cases, however,only the building owner or manager is in a position to remedy the problem.
Time Allotment: 45 minute class period
Activity:
Show children pictures from a booklet titled "Reference Guide to MajorIndoor Air Pollutants in the Home". You may also wish to show a video.You can get this video from the public library entitled "IdentifyingAir Quality Problems".
With a partner, the children will make a list of some indoor air pollutantsand look for signs of ventilation problems they notice in their home, apartmentor classroom.
Discussion:
Identifying Air Quality Problems
Some health effects can be useful indicators of an indoor air quality problem,especially if they appear after a person moves to a new residence, remodelsor refurnishes a home or treats a home with pesticides. If you think thatyou have symptoms that may be related to your home environment, discussthem with your doctor or your local health department to see if they couldbe caused by indoor pollution. You may also want to consult a board certifiedallergist or an occupational medicine specialist for answers to your questions.
Another way to judge whether your home has or could develop indoor air problemsis to identify potential sources of indoor air pollution. Although the presenceof such sources does not necessarily mean that you have an indoor air qualityproblem, being aware of the type and number of potential sources is an importantstep toward assessing the air quality in your home.
A third way to decide whether your home may have poor indoor air qualityis to look at your lifestyle and activities. Human activities can be significantsources of indoor air pollution. Finally, look for signs of problems withthe ventilation in your home. Signs that can indicate your home may nothave enough ventilation include moisture condensation on windows or walls,smelly or stuffy air, dirty central heating and air cooling equipment andareas where books, shoes or other items become moldy. To detect odors inyour home, step outside for a few minutes and then upon reentering yourhome, note whether odors are noticeable.
Lesson II
Time: 45-60 minute class period
Discuss with the children ways that pollutant levels can be measured.
Measuring Pollutant Levels:
The federal government recommends that you measure the level of radon inyour home. Without measurements there is no way to tell whether radon ispresent because it is a colorless, odorless, radioactive gas. Inexpensivedevices are available for measuring radon. EPA provides guidance as to risksassociated with different levels of exposure and when the public shouldconsider corrective action. There are specific mitigation techniques thathave proven effective in reducing levels of radon in the home.
For pollutants other than radon, measurements are most appropriate whenthere are either health symptoms or signs of poor ventilation and specificsources or pollutants have been identified as possible causes of indoorair quality problems. Testing for may pollutants can be expensive. Beforemonitoring your home for pollutants besides radon, consult your state orlocal health department of professionals who have experience in solvingindoor air quality problems in non-industrial buildings.
Activity:
With a partner, children will make a graph of weatherizing their home orapartment.
Each group of partners will share their graph with their class. The classwill make one large graph depicting all the group results.
Keep data of weathering in home, apartment and school. Afterwards, childrenwill discuss and compare results.
Weatherizing Your Home:
While weatherization is underway, however, steps should also be taken tominimize pollution from sources inside the home. Residents should be alertto the emergence of signs of inadequate ventilation, such as stuffy air,moisture condensation on cold surfaces or mold and mildew growth. Additionalweatherization measures should not be undertaken until these problems havebeen corrected.
Weatherization generally does not cause indoor air problems by adding newpollutants to the air. (There are a few exceptions, such as caulking, thatcan sometimes emit pollutants.) However, measure such as installing stormwindows, weather stripping, caulking, and blown-in wall insulation can reducethe amount of outdoor air infiltrating into a home. After weatherization,concentrations of indoor air pollutants from sources inside the home canincrease.
Lesson III
Discuss with the children 3 basic strategies that will improve the air qualityin their home, apartment or school.
Activity:
Children will make a list of these strategies. List their responses on theboard and discuss.
Time Allotment: 45-60 minute class period
3 Basic Strategies (Improving the Air Quality in Your Home):
1. Source Control
2. Ventilation Improvements
3. Air Cleaners
Source Control:
Usually the most effective way to improve indoor air quality is to eliminateindividual sources of pollution or to reduce their emissions. Some sources,like those that contain asbestos, can be sealed or enclosed. Other, likegas stoves, can be adjusted to decrease the amount of emissions. In manycases, source control is also a more cost efficient approach to protectingindoor air quality than increasing ventilation because increasing ventilationcan increase energy costs. Specific sources of indoor air pollution in yourhome are listed later in this section.
Ventilation Improvements:
Another approach to lowering the concentrations of indoor air pollutantsin your home is to increase the amount of outdoor air coming indoors. Mosthome heating and cooling systems, including forced air heating systems,do not mechanically bring fresh air into the house. Opening windows anddoors, operating window or attic fans, when the weather permits, or runninga window air conditioner with the vent control open increases the outdoorventilation rate. Local bathrooms or kitchen fans that exhaust outdoorsremove contaminants directly from the room where the fan is located andalso increases the outdoor air ventilation rate.
Air Cleaners:
Some air cleaners are highly effective at particle removal, while others,including most table top modes, are much less so. Air cleaners are generallynot designed to remove gaseous pollutants.
Over the past few years, there has been some publicity suggesting that houseplantshave been shown to reduce levels of some chemicals in laboratory experiments.There is currently no evidence, however, that a reasonable number of houseplantsremove significant quantities of pollutants in homes and offices. Indoorhouseplants should not be over watered because overly damp soil may promotethe growth of microorganisms which can affect allergic individuals.
Lesson IV
Time Allotment: 45-60 minute class period
How Does Radon Get Into Your Home?
Radon is a radioactive gas. It comes from the natural decay of uranium thatis found n nearly all soils. It typically moves up through the ground tothe air above and into your home through cracks and other holes in the foundation.Your home traps radon inside, where it can build up. Any home may have aradon problem. This means new and old homes, well sealed and drafty homesand homes with or without basements. Radon can be a problem in schools andworkplaces, too. Radon from soil gas is the main cause of radon problems.Sometimes radon enters the home through well water. In a small number ofhomes, the building materials can give off radon, too. However, buildingmaterials rarely cause radon problems by themselves.
Children will discuss the effect of radon in the home, apartment and school.
Activity:
Children will describe parts of the home where radon can enter, such as:
1. cracks in solid floors
2. construction joints
3. cracks in walls
4. gaps in suspended floors
5. gaps around service pipes
6. cavities inside walls
7. water supply
Lesson V
Children will discuss and list health effects of radon and what we can doto reduce exposure to radon in our homes, apartments and schools.
Health Effects of Radon:
The predominant health effect associated with exposure to elevated levelsof radon is lung cancer. Research suggests that swallowing water with highradon levels may pose risks too, although these are believed to be muchlower than those from breathing air containing radon.
Reducing Exposure to Radon in Homes:
-Measuring levels of radon in your home
You can't see radon, but it is not hard to find out if you have a radonproblem in your home. Testing is easy and should only take a little of yourtime. There are many kinds of inexpensive, do-it-yourself radon test kitsyou can get through the mail and in hardware stores and other retail outlets.
-If smoking indoors cannot be avoided, increase ventilation in the areawhere smoking takes place.
Open windows or use exhaust fans. Ventilation, a common method of reducingexposure to indoor air pollutants also will reduce but not eliminate exposureto environmental tobacco smoke. Because smoking produces such large amountsof pollutants, natural or mechanical ventilation techniques do not removethem from the air in your home as quickly as they build up.
-Do not smoke if children are present, particularly infants and toddlers
Children are particularly susceptible to the effects of passive smoking.Do not allow baby-sitters or others who work in your home to smoke indoors.Discourage others from smoking around children. Find out about the smokingpolicies of the day care center providers, schools and other care giversfor your children. The policy should protect children from exposure to ETS.
Lessons Assessment:
Upon completion of this unit, the children should:
-identify the sources of indoor air pollution
-list and name proper ventilation in the home, apartment and school.
-have an understanding of measuring pollutant levels
-have an understanding of what we all can do to improve air quality indoors