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Indoor Air Quality Part 1: Causes and Effects

Air is the most basic component of our health. The best of us can’t survive more than a few minutes without it (please don’t try). Have you ever walked into a friend’s home, or your own, or a restaurant or store, and noticed that something in the air was just…”off”? Maybe it’s a subtle odor or a feeling you get in your throat or nose. For some, this sensation passes quickly and is forgotten. Other people, though, get a headache or upset stomach, or worse, their asthma is triggered or an allergic reaction starts. The worst thing about the smell or reaction is that the cause is invisible. There’s no trail to follow or visible pile to sweep up.

The quality of outdoor air and its pollution gets lots of attention in the media. However, according to the EPA, indoor air is typically two to five times more polluted than outdoor and can be worse than that in many cases. We know how frustrating it can be to live with respiratory problems, allergies, or headaches, and we hope these articles can help you find and treat them. Whether its mold, chemicals, pollen, or just a dusty air filter, we want you find solutions and to breathe easy.

In Part I of this two part series, we examine the leading causes and effects of indoor air quality problems.

8 Frequent Air Pollutants:

There can be many sources of indoor air pollution in any home. The relative importance of any single source depends on how much of a given pollutant it emits and how hazardous those emissions are. Some sources, such as building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants intermittently.

Below is a list of SOME (but not ALL) of the most common home indoor air quality pollutants:

Biological Pollutants

Includes molds, bacteria, viruses, pollen, animal dander, and particles from insects. These may cause infections, provoke allergic symptoms, or trigger asthma attacks. Means of control include washing bedding, keeping animals out of areas affected persons frequently visit, and practicing careful cleaning. It is also critical to control moisture since it can promote mold growth.

Combustion Pollutants

Combustion pollutants come from sources such as fuel burning stoves, furnaces, fireplaces, heaters, and water heaters. The most dangerous are both colorless and odorless gases: carbon monoxide (CO) and nitrogen dioxide (NO2). CO interferes with the delivery of oxygen to the body. It can produce fatigue, headache, confusion, nausea, and dizziness. Very high levels can cause death. NO2 irritates the mucous membranes in the eyes, nose, and throat and can cause shortness of breath and promote infections.


Radon, a naturally occurring radioactive gas, can enter the home through cracks in the foundation floor and walls, drains, and other openings. Indoor radon exposure is estimated to be the second leading cause of lung cancer in the U.S., responsible for at least 21,000 lung cancer deaths each year. Steps to control radon include testing your home and following recommendations for further testing and repairs. Most counties in Texas have a low potential for radon, but a few have moderate potential. See the Department of Health and Safety’s map here.


A non-flammable mineral that can produce microscopic fibers that when inhaled into the lungs can cause scarring of the lung tissue, lung cancer, and mesothelioma. Global concern about the use of asbestos began in the early 1900’s when an increased death rate among asbestos miners caught the attention of healthcare professionals. It wasn’t until 1973, however, that the United States began banning asbestos in the manufacturing of certain household products. Common potential asbestos-containing products in older homes include roofing and flooring materials, insulation for ceilings, walls, pipes, and heating equipment, and “popcorn” ceiling texture installed prior to 1978. Services are available to test and remove any materials you think could contain asbestos.


According to a recent survey, 75 percent of U.S. households used at least one pesticide product indoors during the past year, and 80 percent of most people’s exposure to pesticides occurs indoors. Measurable levels of up to a dozen pesticides have been found in the air inside homes. It is important to note that the “-cide” in pesticides means “to kill.”


A common chemical found primarily in cheap adhesives for many materials including flooring, cabinetry, upholstery, particle board, and plywood paneling. The release of formaldehyde into the air may cause health problems such as coughing; eye, nose, and throat irritation; skin rashes, headaches, and dizziness.

Volatile Organic Compounds (VOCs)

The EPA explains it well: VOCs are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. Higher concentrations of VOCs are commonly up to 10 times higher indoors than outdoors. VOCs are emitted by a wide array of products numbering in the thousands. Examples include: paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials, and home furnishings.

Hazardous Air Pollutants

Sort of a catch all phrase, HAP’s are other chemicals that contribute to poor air quality but do not contain carbon, so are not classified as “organic.” Probably the most common HAPs found around the home are ammonia and ethyl glycol. Other irritating chemicals are forms of alcohol, solvents, sulfates, and synthetic dyes and fragrances. Their toxicity depends largely on method of entry and amount of exposure, though they can all cause some irritation.

Short Term Effects

Most of the problems, pollutants, and chemicals listed above are not the kinds of things that will ruin your life or kill you after one or two short exposures. We are, after all, living longer than ever. Short term or immediate effects are likely to include things like eye, nose, and/or throat irritation, headache, dizziness, or fatigue. Ever feel tired and sluggish despite having good rest and a good diet? The culprit might be air quality.

Some people can react quite strongly to allergens, toxins, or chemicals, and others not at all. The likelihood of a reaction depends on a complex variety of factors such as genetics, age, fitness, preexisting medical conditions, concentration and length of exposure, and previous exposure. Some people can become sensitized to pollutants after repeated exposures.

Some short term effects are similar to those from colds or other common diseases, so it can be difficult to determine if the symptoms are a result of indoor air pollution or just seasonal allergies. For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from home, for example, an effort should be made to identify indoor air sources that may be possible causes.

Long Term Effects

Long term exposure to harmful chemicals and pollutants are the real problem. Most of us don’t live around chemical concentrations that will cause us to keel over tomorrow. A growing body of scientific evidence is showing, however, that breathing and being exposed to those chemicals for years and decades can cause serious issues. These effects, which include respiratory diseases, neurological disorders, hormonal imbalance, heart disease, and cancer, can be severely debilitating or fatal. For that reason, indoor air quality issues are not to be taken lightly.

For instance, according to the American Lung Association the prevalence rate of pediatric asthma has increased from 40.1 to 69.1 — a 72.3 percent increase. Asthma is the sixth ranking chronic condition in our nation and the leading serious chronic illness of children in the U.S. Now what happened here? It isn’t likely that the human gene suddenly crapped out overnight, or that plants started producing 72% more pollen, or that super-mold started growing 72% faster. The most likely explanation is that we are beginning to see the effects of low levels of chemicals introduced into all areas of our life.