Healthy indoor air

By The Old House Web


If you are like most Americans, youspend much of your time indoors.

Most of us are indoors-at home or at work-about90 percent of our time. Have you ever stopped to think about the quality of theair you breathe in your home? When you are at home, do you have frequentheadaches or feel tired or nauseous? Do you feel better when you are away fromhome? If so, your home's air may not be as healthy as it should be.

Air pollutionis a national health concern. Congress passed the Clean Air Act to help improvethe air we breath-outdoors. EPA recently released new standards for outdoor airquality that will benefit approximately 125 million Americans, including 35million children.

The new standards are expected to help prevent approximately15,000 premature deaths, 350,000 cases of aggravated asthma, and a million casesof significantly decreased lung function in children.

Researchers have found thatair quality inside American homes can be worse than the air outside. What couldbe causing this problem? For one thing, we are using more and more products andfurnishings in our homes that cause a variety of allergic reactions. In addition,new homes are being built and remodeled tighter to prevent the loss of heatingand cooling, so air flow into and out of new homes is very limited.

Because ourhomes are tighter, there is a greater chance for the air inside to becomepolluted. Pollutants will vary from home to home, but they may include one ormore of the following:

  • molds, mildew, fungi, and bacteria,
  • dust mites and animal dander
  • combustion products, including carbon mon- oxide
  • tobacco smoke
  • formaldehyde
  • radon
  • volatile organic compounds from household productsand home furnishings
  • asbestos
  • lead
  • particulate matter such as dust,smoke, and pollen

When indoor air is polluted, respiratory illness and other health-relatedproblems can affect families. To protect yourself and your family from airpollution inside your home, you need to know what the risks are and if they arepresent in your home. You need to be able to:

  1. identify the pollutant(s),
  2. control the source of the pollutant(s), and
  3. take action to manage orremove the problem.


The following categories describe a variety of pollution sources that affectindoor air quality. As you read over them, think about your home. Do yourecognize any of the situations? Are any of these factors influencing air qualityinside your home?

Biological Pollutants (Bioaerosols)

Molds, mildew, fungi, bacteria, dust mites,and animal dander are some of the biological pollutants inside a home. Some, suchas pollen, are generated outside and come inside with natural air flow and whendoors and windows are opened. Molds, mildew, fungi, and bacteria are often foundwhere there is high humidity, such as the bathroom, kitchen, and laundry room.Molds grow on organic materials such as paper, textiles, grease, dirt, and soapscum. Spores float throughout the house, forming new colonies where they land. Toprevent mold, mildew, and similar pollutants, keep your home clean and dry. Use adisinfectant to clean surfaces where there is evidence of pollutants. Dust mitesthrive on dead human skin cells and in textiles such as bedding, carpeting, andupholstery. They have been identified as the single most important trigger forasthma attacks. Dust mites and animal dander are best removed by vacuumingthoroughly and changing bed linens regularly. People who are sensitive to dustmites and animal dander may need to replace carpeting in the home with hardsurfaced flooring and use area rugs that can be removed and cleaned frequently.Allergic reactions are the most common health problems associated with biologicalpollutants. Runny nose, watery eyes, sneezing, congestion, itching, coughing,wheezing, and difficulty breathing are a few symptoms. Headache, dizziness, andfatigue also can occur.

Carbon Monoxide

Carbon monoxide is known as a silent killer.This colorless, odorless gas is fatal when breathed in sufficient quantities.There are many cases each year of individuals and families being overcome bycarbon monoxide--especially in the winter when a house is closed up tightly and afurnace, fireplace, or improperly vented heater may be in use. Sources of carbonmonoxide include poorly vented heaters and furnaces; blocked fireplace flues; andinadequate ventilation around operating ovens, ranges, grills, and fuel-burningspace heaters. Even a poorly vented gas water heater can produce enough carbonmonoxide to injure or kill. If the air pressure is not evenly balanced inside tooutside, car exhaust containing carbon monoxide from an attached garage can entera home, harming its inhabitants. Experts recommend having combustion heatingsystems inspected by a trained professional every year-usually when it is turnedon for the winter. Inspectors should look for blocked openings in flues andchimneys, cracked or disconnected flue pipes, signs of soot around openings inthe furnace, rust or cracks in the heat exchanger, soot or creosote build-up, andexhaust or gas odors. Carbon monoxide displaces oxygen in the blood. Survivors ofcarbon monoxide poisoning often have continuing physical and mental problemsafter exposure. Symptoms of carbon monoxide poisoning are similar to the flu:nausea, headache, etc. Consider installing a carbon monoxide detector in yourhome. They are inexpensive and fairly efficient. Check for detectors at yourlocal hardware or department store. They plug in to a wall outlet and sound analarm if the level of carbon monoxide in the home reaches dangerous levels.

Combustion Pollutants

Combustion pollutants are the result ofburning fuels-natural gas, propane, wood, oil, kerosene, or coal. Other itemsburned in the home also can cause pollution. Harmful gases include carbonmonoxide, nitrogen dioxide, and sulfur dioxide. Particulate matter such as ashesand excess moisture in the air also can result from combustion. Combustion gasescan kill. They also irritate the eyes, nose, and throat and can cause lungcancer. Excess moisture can contribute to the growth of molds and mildew.Particulates can irritate eyes and lungs as well as become a nuisance-more dustto clean. Cigarette smoke is a major pollutant in many homes. More and morehomeowners are asking people not to smoke in their home. Some communities havepassed regulations that limit where cigarettes can be smoked-some restaurants nolonger have a smoking section. There are federal regulations about smoking in thework place, elevators, and public buildings. Yearly inspections of combustionequipment are recommended. Always operate combustion equipment only for itsintended purpose, and be sure it is installed correctly.


Formaldehyde is a chemical released into theair as a pungent gas. Remember how your eyes used to burn when you went into afabric store? Formaldehyde was the culprit. It does have some good properties andis an excellent adhesive. Formaldehyde is used in many building materials andhome furnishings. It is still used in some textiles and is an importantingredient in fabric finishes that prevent wrinkling. Evidence of formaldehydeirritation include watery eyes and a burning sensation in the eyes, nose, andthroat. Some people may experience wheezing and coughing. Skin rashes, headaches,loss of coordination, and nausea also can occur. To reduce formaldehyde in thehome, consumers can use special sealants or varnishes to coat any exposedsurfaces or edges such as the undersides of countertops, cabinet interiors, anddrawers.


Lead is a metallic element widely dispersed inthe environment. It has been an important ingredient in paint, gasoline, solder,and fixtures and pipes. In the early 1950s, paint was as much as 50 percent lead.Lead-based paint was banned after 1978, but it still can be found in olderresidences and buildings. As long as it is not disturbed and is in goodcondition, lead paint is not a problem. It becomes a problem when paint chips orpaint dust occur-such as when windows are raised up and down frequently or when ahome is remodeled your home. Water is also a potential source of lead. Thisoccurs when there is lead in solder, fixtures, and pipes in your home. If lead isfound in your water, it may be necessary to change fixtures and replace pipewhere possible. Although lead is no longer used in gasoline, the effects ofleaded gas are still being felt in some areas. Children who play in the dirt nearbusy streets or highways, or who live near highly industrial areas may be exposedto lead that has accumulated over time. Lead accumulates in the body, and itseffects are irreversible. Exposure to lead is especially risky for youngchildren. It can cause delayed development, reading and learning problems, lowerIQ, hyperactivity, and discipline problems. Large doses can cause high bloodpressure, anemia, and kidney and reproductive disorders in children and adults.The simplest way to avoid lead exposure is to keep the area clean. Frequent dampmopping or wiping surfaces down with a wet cloth will remove loose dust. Avoidvacuuming-it can disperse lead dust back into the air. Wash your child's handsand toys frequently to reduce exposure from dirt in the playground or yard.Do-it-yourself lead detection kits are available-but their sensitivity islimited. If you believe there may be a problem with lead in your home, contact aprofessional who has been trained in removing lead.


Radon is a naturally occurringgas that results from the breakdown of uranium. It is typically concentrated inareas with lots of granite, shale, phosphate, and pitchblende. It can be found inbuilding material made from concrete or stone. Because it is a gas, radon canleak into the home through the basement, crawl space, or foundation from exposedsoil and rock. It can be found in well water in some areas. It can even becarried into your home through natural gas. Exposure to radon can increase yourchances of getting lung cancer. If they are present in the air, radon particlesgets into your lungs when you breath. These particles accumulate in the lungs andrelease bursts of energy that can damage lung tissue and lead to lung cancer.Smoking combined with radon exposure is an especially dangerous health risk Radondetectors are available to test your home. There are two types-a long test of atleast a month, or a test that requires about seven days. Longer tests areconsidered more reliable. If radon is detected in your home, contact your localhealth department or a professional for assistance in dealing with the problem.It is possible to vent the gas out of an existing home, and there are simpletechniques to protect against radon when building a new home.

Household Products

Household products also impact air qualityinside your home. They contain volatile organic compounds, or VOCs, whichevaporate into the air. Some are flammable. These products include such things assolvents, paints, paint stripper, wood preservatives, aerosol sprays, mothrepellents, air fresheners, stored fuel, automotive products, hobby supplies,pesticides, and some cleaners and disinfectants. Short-term effects of exposureto VOCs in household products may include eye, nose, and throat irritation; andheadaches. Long-term exposure can cause loss of coordination; nausea; and damageto liver, kidneys, and the central nervous system. Always use care when workingwith household products. Read labels and be aware of any warnings. Use productsas intended and follow instructions carefully. Most should be used in awell-ventilated area. When considering the purchase of a household product, askyourself the following questions: Is there something you can use in its place?How much do you really need? How is it to be used? How is it stored? How is itdisposed of?

Home Remodeling

Preserving the quality of indoor air canbecome a problem when a home is being remodeled. Asbestos, formaldehyde, leadpaint dust, and other organic and biological pollutants can be released into theair when you begin removing walls, windows, and carpeting and disturbing existingstructures. Asbestos was once used in some building products. It is often foundin older homes in the floor tile, roofing, siding, textured paints, millboard,and artificial ashes used in decorator fireplaces. Asbestos was often used as aninsulation for pipes and around water heaters and boilers. It is not a problem ifit is in good condition. Covering the material is recommended over it. If it isdisturbed, particles of asbestos can be inhaled. These particles lodge in thelungs, irritate them, and can increase the risk of cancer. If you find asbestosin your home, contact the health department or local building codes office forinformation about removing it. Some of the materials used to remodel are alsopollutants-paints, wood strippers, finishes, adhesives, waxes, and cleaners. Theycontain such chemicals as petroleum distillates, mineral spirits, chlorinatedsolvents, carbon tetrachloride, methylene chloride, trichloroethane, toluene, andformaldehyde. All of these should be very used carefully to avoid problems. Readthe label to learn about clean-up and disposal. Thorough clean-up is importantwhen remodeling. Dust and fibers, mold and mildew spores, and other pollutantsneed to be carefully and completely removed to prevent future contamination.


Indoor air quality is an important consideration in today's world, which is fullof products that are intended to make our lives better. Many of those productscan cause problems if they are not managed correctly. A major hazard whenconsidering problems related to indoor air quality is misinformation. Consumersneed to know what causes indoor air quality problems and how to recognize them.Knowing what can be done to prevent or eliminate pollutants from indoor air willbe very important in maintaining a healthy home. Take time to become informedabout indoor quality and how you as a consumer can make sure the air in your homeis as healthy as possible.


  • Unusual and noticeable odors, stale or stuffy air
  • Noticeable lack of air movement
  • Dirty or faulty central heating or air conditioning equipment
  • Damaged flue pipes or chimneys
  • Unvented combustion air sources for fossil fuel appliances
  • Excessive humidity
  • Tightly constructed or remodeled home
  • Molds and mildew
  • Health reaction after remodeling, weatherizing, using new furniture or carpeting, using household or hobby products, or moving into a new house
  • Feeling noticeably healthier outside the home

Susan Wright,
Extension Consumer Education Specialist

College of Agriculture and Home Economics
New Mexico StateUniversity

Search Improvement Project