The Top 10 Sources Of Indoor Air Pollution In The Home

Indoor air pollution can be a serious health risk. Studies by the Environment Protection Agency have shown that the air inside buildings is often two to five times more polluted than the air outside, and sometime much more. Combined with the fact that the average American spends something like 90% of his or her time indoors, this means that we absolutely cannot ignore the issue of inside air quality.

One thing we must keep in mind is how many different sources of pollution can contribute to lowering the air quality of our indoor spaces. The term “indoor air pollution” is an umbrella which covers a wide array of unhealthy material which can have different effects on the human body. This article will examine (in no particular order), the ten most common sources of air pollution in American homes, as identified by the U.S. Consumer Product Safety Commission (CPSC). For each item, we will focus on three things: what these pollutants are and where they come from, what health effects they have on humans, and how you can deal with them so that your home is as pollution-free as possible.

Curtailing these sources of indoor air pollution is one of three main strategies recommended by the CPSC for keeping the air in your home clean. The second is improving ventilation in your home, so that the following toxins do not stay trapped inside. The third is making use of quality air purification devices.

Most of the information below is based on material provided by the Environmental Protection Agency (EPA) or the CPSC.

1. Radon

Radon is a highly radioactive gas that can be introduced into the home through the ground beneath it, well water, and the building materials that constitute your house or apartment. Part of what makes radon so dangerous is the fact that it is colorless, tasteless, and odorless, and that it produces no immediate symptoms, which means that you will normally be completely unaware that you are inhaling it. According to the CPSC, one study of residential radon levels has indicated that radon is over three times as prevalent in homes as in the outdoors.

Inhalation of radon is linked to lung cancer, and the CPSC estimates that it causes between 7,000 and 30,000 lung cancer deaths every year. For smokers, radon exposure increases the risk of cancer even further, as radon can attach itself to the smoke and lodge itself in the lungs.

Fortunately, testing for radon is relatively inexpensive and easy to do using readily available radon testing kits. It is a good idea to test your home, and if radon levels are higher than 4 pci/L, take steps to reduce it. Contact a professional to help you.

  • Air Purifier Effectiveness for Radon Removal – None.  Radon must be vented to the outdoors.

2. Environmental Tobacco Smoke (Secondhand Smoke)

The chemicals that result from any form of tobacco smoking will stay in the air to be inhaled long after the cigar, cigarette, or pipe goes out.

The health risks of smoking are too well known to need any in-depth discussion here. Environmental tobacco smoke carries risks akin to those brought on by direct smoking, and include lung cancer and other lung ailments, heart disease, and general irritation of the eyes, throat, nose, and lungs. It can also exacerbate asthma and cause other health problem.

This is one source of pollution that is very easy to control: simply don’t smoke inside your home or let others do so. By choosing to keep your home smoke free, you can eliminate one major source of indoor air contamination entirely.

  • Air Purifier Effectiveness for Tobacco Smoke Removal – Medium.  Many air purifiers successfully remove a portion of tobacco smoke from the air.  Effectiveness varies by model.

3. Biological Sources

Remember that you are not the only life form that calls your house or apartment home. From pets, to insects, to mold and mildew, all the living things around you make their own contributions to the pollution in your air.

As this is a broad category, the health effects are also wide-ranging. Pollutants from biological sources can wreak havoc on your body, including irritation of the eyes, throat, nose, and lungs, breathing problems (including asthma), fevers, and many different diseases. There are plenty of reasons you don’t want bugs, mold, or mildew infesting your home; their contribution to air pollution should be one of them.

Unlike environmental tobacco smoke, there is no way to completely rid your home of this pollution source. But you can still take some simple steps to reduce it. Moisture encourages the growth of mold and mildew, for instance, so minimize moisture by making sure you have no leaks and using exhaust fans and ventilators if you have them. Be sure to dust and vacuum regularly as well. Wash your bedding in hot water to kill the mites that like to make their home there, and wash your rugs as well. Keep your home clean in order not to attract cockroaches and other pests. One caution to keep in mind: try to avoid using chemical pesticides when other means of pest control are available, as pesticides themselves are a source of indoor air pollution as well (see #9 below.)

  • Air Purifier Effectiveness for Biological Source Removal – Minimal.  Some airborne mold particles may be captured but mold must be removed at the source where it grows.

4. Carbon Monoxide

Like radon, carbon monoxide (CO for short) is colorless, tasteless, and odorless, and therefore particularly insidious. Environmental tobacco smoke is one source of CO, but there are many others, including gas stoves and heaters, wood stoves, chimneys, and furnaces. Automobiles also produce CO, so attached garages increase the risk as well.

CO attacks, among other things, your bloodstream and central nervous system. Exposure to low-level doses of carbon monoxide will leave you feeling sluggish, which means an inexplicable lethargy is a good early warning sign. Heavier levels of ingestion can cause nausea, dizziness, headaches, and a lack of coordination. Carbon monoxide is fatal when you come into contact with too much of it.

Keeping the CO sources listed above in proper working order and well ventilated will reduce the risk of CO poisoning. Also, you should install CO detectors in your house or apartment; they are cheap and easy to find and should be a standard accessory in every home.

  • Air Purifier Effectiveness for CO2 Removal – None.  Sources of CO2 pollution must be eradicated.

5. Nitrogen Dioxide

Nitrogen dioxide (NO2) comes from many of the same sources as carbon monoxide and carries with it similar health risks. In addition, it can also help produce another very dangerous chemical, ozone. Unlike CO, however, NO2 possesses a sharp and easily detectable smell and a reddish-brown color.

Reducing NO2 can be done using the same methods recommended to reduce CO. Since it is more easily detectable than radon or carbon monoxide, even without the aid of any equipment, it poses less of a threat, but you should never take anything for granted when it comes to a deadly chemical like this one.

  • Air Purifier Effectiveness for Nitrogen Dioxide Removal – None.  Sources must be eliminated or reduced to safe levels.

6. Organic Gases

“Organic gases,” or “volatile organic compounds” (VOCs), is something of a catch-all term for gases that are emitted from many different sources. Among the common sources for VOCs identified by the EPA are paint, cleaning supplies, pesticides, glue, printers and photocopiers, permanent markers, and certain building materials. As you can see, your home probably has many VOC sources, so being aware of them is important.

The effects of organic gases are likewise various, and range from irritation of the eyes, nose, and throat to dizziness and nausea to even more serious problems, including cancer and damage to the central nervous system. Different gases have different levels of toxicity.

One way to limit the concentration of VOCs in your home is to store VOC-producing material outside when possible. Do not buy unnecessarily large quantities of things like cleaning supplies, so that they are not sitting unused in your home giving off gases. Also, use them in ventilated areas when you can and always follow manufacturer’s instructions—often they are there to help limit you exposure to the gases.

  • Air Purifier Effectiveness for VOC Removal – Varies By Product.  Some air purifiers can trap VOC particles but they must had the filtration system to accommodate, most don’t.

7. Respirable Particles

Respirable particles are simply small bits of matter that can easily be inhaled (“respire” is another word for “breathe”). Environmental tobacco smoke contributes to their presence, as do fireplaces, kerosene heaters, and wood stoves.

Respirable particles, like many other indoor air pollutants, can irritate the eyes, nose, and throat, and they can also cause ailments such as bronchitis. They are a cause of cancer as well.

Reducing their presence can be accomplished by proper maintenance of the devices that cause them, by ensuring good ventilation, and by not smoking indoors. Homes without the sources listed above rarely have significant levels of repairable particles, so long as they are well ventilated.

  • Air Purifier Effectiveness for Respirable Particles – Medium-High.  Depending on the model, some air purifiers are quite effective at removing particles from the air.

8. Formaldehyde

Formaldehyde, or CH2O, is an organic compound that exists as a gas at room temperature. Formaldehyde is invisible, but has a distinctive pungent smell. Common sources of formaldehyde in the home include glues, environmental tobacco smoke, and textiles such as durable press drapes. But the top source of formaldehyde in most people’s homes is the presence of pressed wood containing urea-formaldehyde resins in building materials and furniture: this category includes particle board, hardwood plywood paneling, and, above all, medium-density fiberboard. Homes built in the 1970s were sometimes insulated with urea-formaldehyde foam insulation (UFFI), which is a major source of indoor formaldehyde pollution.

In high enough concentrations, formaldehyde can cause irritation of the eyes, nose, and throat, coughing, rashes, and fatigue. It may also be a cause of cancer and other serious health problems.

If you do not have UFFI as insulation in your home, you probably do not have excessive levels of formaldehyde. To keep formaldehyde at a minimum, reduce the humidity and moderate the temperature in your home. In the future, use exterior-grade pressed wood products, which release less formaldehyde because they have different resins.

  • Air Purifier Effectiveness for Formaldehyde Removal – Minimal-None.  Some air purifiers can remove a small amount gases but sources of formaldehyde pollution must be removed.

9. Pesticides

Pesticides’ very purpose is to kill, so clearly, you do not want to be continuously inhaling them at home. Pesticides release a variety of chemicals into the air. Pesticide containers in the home are the primary source of this pollutant, but pesticide can also be unwittingly tracked in from the yard by those who use them outside.

Pesticides can irritate the eyes, nose, and throat, and they are detrimental to the central nervous system and the kidneys. They are also associated with an increased risk of cancer.

To reduce the pesticides in your indoor environment, avoid using chemical pesticides when possible. If you do need to use them, follow instructions on the label, do not use excessive amounts, and make sure you keep the area well ventilated after use. Do not purchase more than you need, so that you don’t have extra pesticides resting unused in your home giving off fumes. It is best to store pesticides outside rather than inside. If you need the services of a pest-control company, check its credentials before you allow it to spray harmful chemicals in your house.

  • Air Purifier Effectiveness for Pesticide Removal – Minimal-None.  Pesticide sources should be stored outside the home.

10. Asbestos

Finally, asbestos is a type of magnesium silicate fiber that was once commonly used in home construction for its ability to insulate the home and resist fire. Asbestos fibers are so small that they can easily be inhaled by someone without the person knowing it. Today, many forms of asbestos are banned by the federal government, and even those that are not are rarely used. Therefore, asbestos is a major risk in older homes rather than newer ones.

Asbestos produces no immediate symptoms, so there are no early-warning signs. In the long term, it can contribute to abdominal cancer, lung cancer, and mesothelioma. There is even a condition known as asbestosis, which occurs when the fibers cause scarring in the lungs.

If your home has asbestos, this does not necessarily mean that you are in danger. If the asbestos is of good quality and left undisturbed, it will not release fibers into the air to be inhaled. If some operation needs to be performed on your home that might lead to the asbestos being disturbed, it is best to use professionals. If you are worried about asbestos levels in you home, the wise action may be to seal the asbestos off rather than try to remove it, which may just lead to more asbestos being released into the air.

  • Air Purifier Effectiveness for Asbestos Removal – Varies.  Many air purifiers can filter asbestos particles suspended in the air column down to .3 microns.  However, asbestos sources should be removed by experts and surfaces cleaned if asbestos contamination is suspected.  Should never rely on an air purifier alone to deal with asbestos pollution.


As you can see, although there are numerous sources of indoor air pollution, many of them can be fought using relatively simple steps. Also, some actions will help to reduce multiple sources: keeping humidity in your house or apartment low, for example, and not storing excess chemical products inside. By being aware of the dangers and following the advice above, you may significantly improve the quality of the air you breathe at home. Remember also to ensure good ventilation, so that the sources you can’t completely eliminate will not stay trapped inside.

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