Note: This Instructional Module information comes from our Training Manual. The complete Training Manual can be ordered from our Program and comes with a video, transparency masters, module publications, and many other educational resources. 

Module Learning Objectives

• Identify and prevent indoor air quality problems from combustion pollutants in the home.
• Reduce the risk of carbon monoxide poisoning in the home.

Support Publications 

• What you Should Know About Combustion Appliances and Indoor Air Pollution, U.S. Consumer Product Safety Commission, U.S. EPA, American Lung Association, 1998. http://www.cpsc.gov
• See Home IAQ Overview Module for Indoor Air Hazards Every Homeowner Should Know About... Booklet

Videos (See "IAQ Video Sampler" included with the manual)

• Operation Safe Home - Backdrafting: Is Your Home Gasping for Air?, American Environmental Services, 1995, 7:00
• Carbon Monoxide - What You Need to Know About the Number One Cause of Poisoning Deaths in America, BRK Brands, Inc./First Alert, 1995, 4:45

Notes to the Program Leader:

Ideas for audiences for this program include: homeowners with gas or oil furnaces or woodstoves, new home buyers, and daycare providers. This program would be useful to respond to a "teachable moment" if there has been a carbon monoxide problem in your area. Also, because of the potential fatal consequences of combustion pollutants, this module can be used to gain attention for a broader program relating to indoor air quality issues.

The format provides a series of overhead transparency masters and a script to accompany each visual. The script is in recitation form. This is to encourage you to present information in a conversational style and to avoid reading an exact script during the program presentation.

The presentation begins with an introduction and a "Teaser Test" to get participants interested in the topic. The "Teaser Test" is used again (with answers) as the conclusion.

A shorter version of this presentation can be given by eliminating the "Teaser Test" and using only the following overheads: 1, 3, 5, 7, 9, 10, 13, 14, 15, 16, and 17. Also, teaching modules on "Carbon Monoxide in the Home" and "Secondhand Smoke" are available in this manual.

Script for Transparency #1

COMBUSTION POLLUTANTS IN YOUR HOME

Do you use gas, oil, wood, kerosene, or coal to heat your home, water, or to cook? If so, are you aware that these fuels and the equipment you use have the potential to pollute the air in your home? In this presentation, we will learn how to reduce the risk of indoor air pollution from these combustion fuels.

Script for Transparency #2

Note to the Program Leader: Use the "Teaser Test" to generate interest on the topic and focus the thinking of the participants. Ask participants to jot down their answers so that everyone can review the "Teaser Test" at the end of the program. You may wish to provide participants with a copy of the "Teaser Test" or use from an overhead. Also, you may want to incorporate the "Teaser Test" into your evaluation as a measure of learning. 

"TEASER TEST" 

1. Name two combustion pollutants that can affect your home's indoor air. 
2. Health effects from combustion pollutants often mimic other diseases. Name one clue that can be used to help determine if poor indoor air quality could be the cause of adverse health symptoms. 
3. TRUE or FALSE: Backdrafting of combustion pollutants from your furnace can occur when the indoor air pressure is higher than outdoors. 
4. How often should you have a professional inspection of a fuel-burning furnace? 

Script for Transparency #3

COMBUSTION POLLUTANTS

Combustion pollutants are gases or particles that come from the burning of fuels: 

• Natural or LP (liquified petroleum) gas 
• Wood 
• Oil 
• Kerosene 
• Coal 

Script for Transparency #4

COMBUSTION POLLUTANTS OF MOST CONCERN

Specific combustion pollutants that are of most concern in your home: 

• Carbon monoxide - an odorless gas that can kill 
• Nitrogen dioxide - gas that can damage the respiratory tract 
• Sulfur dioxide - gas that irritates the eyes, nose, and respiratory tract 
• Particulates - tiny particles that make up smoke and irritate the eyes, nose, and throat 
• Water vapor - excess moisture that can lead to mold and rot of the house structure 

Script for Transparency #5

SOURCES OF COMBUSTION POLLUTANTS

Combustion pollutants in the home come from a variety of sources: 

• Heating or cooking appliances that burn fossil fuels: 

-   Gas, oil, coal, or wood furnaces or boilers 
-   Gas or oil water heaters 
-   Gas or kerosene space heaters 
-   Fireplaces 
-   Wood or coal stoves 
-   Gas ranges and ovens 
-   Gas clothes dryers 
• Tobacco smoking 
• Exhaust from automobile engines operating in attached garages 
• Other equipment with internal combustion engines, such as lawn mowers or generators 
• Other combustion/burning activities, such as welding or soldering 
• Gas or charcoal grills and hibachis 

Script for Transparency #6

COMBUSTION POLLUTANTS MAY CREATE AIR QUALITY PROBLEMS

Combustion pollutants are more likely to create air quality problems when: 

• Pollutants from combustion equipment are not exhausted to the outside of the home 
• Combustion equipment is not maintained in good working order 
• Combustion equipment is not regularly inspected for safe operation 
• Air pressure indoors is lower than outdoors, preventing safe exhaustion of combustion pollutants 
• Tobacco smoking is permitted in the home 

Throughout the rest of this program, we will learn more about how to recognize and reduce your risk of exposure to combustion pollutants. 

Script for Transparency #7

HEALTH EFFECTS

Health effects from exposure to combustion pollutants vary from very mild to lethal. Typical health effects are: 

• Headaches 
• Dizziness 
• Sleepiness 
• Nausea 
• Irritated eyes 
• Breathing difficulties 
• Respiratory problems (i.e., coughing) 

Script for Transparency #8

COMBUSTION POLLUTANTS

Combustion pollutants in indoor air may be the source of health problems if: 

• Symptoms occur only in the home 
• Symptoms improve when you leave the home 
• More than one person in the home has similar symptoms 
• Your home has one or more of the five air quality problems mentioned in Transparency #6

Script for Transparency #9

WHAT IS CARBON MONOXIDE? 

The combustion pollutant carbon monoxide (CO) is of greatest concern because it can be fatal. Hundreds of people are killed each year by CO in their homes.

Carbon monoxide can build up in an enclosed space and it is odorless and colorless, so you may not be able to sense what is making you sick. Carbon monoxide reduces the ability of hemoglobin in the blood to carry oxygen. Health effects or symptoms of CO poisoning can be similar to other illnesses, such as the flu or allergies.

Lower doses of CO:
Nausea, dizziness, weakness, muscle ache

Higher doses of CO:
Impaired judgment, paralysis, coma, death

Script for Transparency #10

CARBON MONOXIDE BUILDUP

Carbon monoxide buildup typically occurs in one of several ways: 

• Flues or chimneys from combustion equipment become blocked (such as by a bird's nest), disconnected, rusted, or broken. Therefore, combustion pollutants, high in CO, cannot be exhausted to the outside. 
• A fuel-burning appliance, such as a furnace, has a cracked heat exchanger, allowing combustion gases into living spaces instead of being exhausted up a chimney or flue 
• Unvented fuel-burning (such as kerosene or gas) heaters are operated in the home without adequate ventilation 
• Charcoal cookers, grills, or hibachis (which produce high levels of CO) are operated in the home 
• Gas ovens are improperly used for space heating 
• Carbon monoxide from an idling car, lawnmower, or other engine in an attached garage enters the home 
• Combustion equipment is poorly maintained and incomplete combustion occurs, which produces a high level of CO. Yellow flames are sometimes an indication that CO is being produced; blue flames means more complete combustion and fewer pollutants. 
• Low indoor air pressure compared to the outside prevents adequate venting of natural draft combustion equipment, causing combustion pollutants to "spill" into the home in a condition known as backdrafting 

Script for Transparency #11

BACKDRAFTING

Backdrafting occurs when there is negative pressure in the area where the combustion device is located. This means the air pressure inside the area is lower than the air pressure outside. 

Negative pressure indoors can occur when there are duct leaks in the heating system, or when exhaust ventilation, such as from a clothes dryer or kitchen or bathroom exhaust fan, is greater than air replacement through infiltration or other means. This scenario is most likely to occur in "tight", well constructed, energy efficient homes that do not have controlled ventilation. 

When there is negative pressure indoors, combustion by-products from conventional (natural draft) furnaces, water heaters, fireplaces, or similar equipment tend to spill into the room, or BACKDRAFT, rather than exhaust to the outside.

Script for Transparency #12

PREVENTION OF BACKDRAFTING 

To prevent backdrafting of carbon monoxide and other combustion pollutants in your home: 

• Keep all combustion equipment, flues, and chimneys in top working order 
• Do not use an exhaust fan in the same area where a naturally-vented combustion appliance is operating 
• Select closed combustion or draft-induced combustion equipment, or provide an outside air source for combustion appliances, especially in tightly constructed homes 
• Do not implement air-tightening measures, such as caulking, weather stripping, insulation, or new/improved windows, without investigating potential impacts on the operation of combustion equipment 

Script for Transparency #13

CARBON MONOXIDE ALARMS 

Consider the installation of a carbon monoxide alarm with an audible warning. A CO alarm will alert you to dangerous, high levels of carbon monoxide, and give you time to vacate or ventilate the home. Depending on the type of CO alarm, it may not detect low levels of CO that can still make you ill. 

A CO alarm does not replace regular maintenance, inspection, and safe operation of combustion equipment!

Note to the Program Leader: For more information on CO alarms, see the "Carbon Monoxide in the Home" module.

Script for Transparency #14

REDUCING COMBUSTION POLLUTION RISKS IN YOUR HOME

Reducing the risk of carbon monoxide pollution in your home involves many of the same steps as reducing your risk of all combustion pollution. Our last four overheads review how to reduce combustion pollution in your home. 

First...Keep all combustion equipment well-maintained and inspected for safety:

• Experts recommend combustion heating systems, such as furnaces and boilers, be inspected by a trained professional every year prior to the heating season for: 

-   Blocked or clogged openings to flues and chimneys 
-   Excessive production of carbon monoxide 
-   Cracked, separated, or disconnected flue pipes 
-   Dirty filters (clean or replace monthly) 
-   Rust or cracks in the heat exchanger 
-   Soot, corrosion, or creosote buildup 
-   Burner/flame adjustment 
-   Exhaust or gas odors 
• Always operate combustion equipment safely, according to directions, and for its intended purpose. For example, never use an oven or clothes dryer as a space heater, or never use a charcoal grill inside the house. 
• Have combustion equipment installed correctly by a trained installer and according to local safety codes 

Script for Transparency #15

Second...Exhaust all combustion pollutants to the outside of the home:

• Avoid the use of unvented combustion appliances, such as kerosene or gas space heaters 
• Do not disconnect vents on combustion appliances, even if it seems like a way to get extra heat in the winter 
• Use an exhaust fan ducted to the outside to provide spot ventilation if a combustion appliance is not vented directly outside; always use an exhaust fan when operating a gas range or oven 
• When purchasing new combustion appliances, look for sealed combustion units that use outside air for combustion and then exhaust it back outside; therefore, combustion pollutants are never mixed with room air

Script for Transparency #16

Third...Maintain an adequate pressure balance between the home and the outside: 

• Provide an outside air source for combustion equipment 
• Consider opening a window slightly when operating an exhaust fan 

Script for Transparency #17

Fourth...Do not allow tobacco smoking in your home

Note to the Program Leader: For more information on tobacco smoke, see the "Secondhand Smoke" module. 

Note to the Program Leader: Use the "Teaser Test" (overhead #2) to conclude the program. Ask participants to give answers to each question. Encourage them to identify which facts or concepts were new to them. You may also wish to emphasize other points made during the presentation, but not included on the "Teaser Test." Ask questions about how they will use the information learned at the presentation. 

Answers to Teaser Test: 
1. See transparency #4 
2. See transparency #8 
3. See transparency #11 (Answer is False) 
4. See transparency #14 
 
 

Prepared by: 
Kathleen Parrott, Ph.D. 
Associate Professor/Housing Extension Specialist 
Virginia Tech 
October 1996, Revised October 1999

“www.healthyindoorair.org” is a partnership program of the Montana State University Extension Service - Housing Program, U.S. Department of Agriculture - Cooperative State Research, Education, and Extension Service, the Healthy Homes Partnership - Alabama Cooperative Extension System @ Auburn University, U.S. Dept. of Housing & Urban Development, , and the U.S. Environmental Protection Agency - Indoor Environments Division.