Asthma and Indoor Air Quality

How to Identify, Prevent and Cleanup Indoor Air Problems That Cause Asthma

When we experience ill health, we often turn to our doctors for solutions, who in turn prescribe medications and the like to remedy the problem. But what if you could prevent or minimize a health problem like asthma by taking care of your home’s indoor air quality? Many homeowners and renters don’t realize that their indoor air is actually a major contributing factor to asthmatic symptoms. Common allergens can turn into menacing threats to those with asthma, including the following:

Asthma and dust mites

These tiny insects (invisible to your eye) feed on your dead skin and are especially prevalent in linens, upholstered furniture, clothing, soft toys, and fabrics. The dust mite trigger for asthmatics are their feces and dead body parts.

  • Causes: A build of dust mite feces and body parts will cause a reaction for asthmatics.
  • Prevention: Keeping your home’s humidity between 30% and 50% is a start (using a dehumidifier in moist environments). You’ll also want to use allergen-impermeable zippered covers on mattresses and pillows to avoid dust build-up, and wash linens and stuffed toys on a regular basis in hot water once a week and dry completely.
  • Clean-up: While the asthmatic is out of the house, make it a habit to dust your home often with a damp cloth (not a dry cloth) and vacuum (with a high-efficiency filter) carpeting and upholstered furniture on a regular basis.


Asthma and Mold

This is a common irritant for people with asthma and can lead to wheezing, shortness of breath, coughing, and throat irritation, though there’s no direct evidence that it actually causes asthma.[1] Nevertheless, it’s important to remove any signs of mold to reduce the discomfort experienced by asthmatics.

  • Causes: Mold grows in damp areas such as bathrooms (tubs, shower curtains, leaky toilets, ceilings), basements, and kitchens.
  • Prevention: Inspect a new home or rental property to ensure there is no mold before you move in. If you notice leaky plumbing or dampness in the basements or bathrooms, work on structural issues to prevent moisture build-ups. Also be sure that you dry wet or damp items within 1 to 2 days to avoid mold growth on an ongoing basis. This guide to mold, moisture, and your home will give you some other prevention ideas.
  • Clean-up: Be sure to clean up mold when you first discover it with soap and water and then thoroughly dry the area by opening a window or running a fan. Find out more with this guide to getting rid of mold.


Asthma and Nitrogen dioxide

Another major irritant for those with asthma is nitrogen dioxide (NO2). This reddish-brown gas will increase the impact of allergens on asthmatics as well as decrease lung function, making it a double-whammy. Long-term exposure will increase coughing and wheezing symptoms.

  • Causes: Nitrogen dioxide can come from outdoors through vehicle exhaust (through windows and ventilation systems) as well as from indoors through things like gas stoves, oil furnaces, fireplaces, wood stoves, kerosene appliances, generators, gas heaters, and the like.
  • Prevention: Ensure that your home is properly ventilated, especially when using some of the appliances mentioned above (which should have exhaust fans vented outdoors installed nearby). Additionally, follow safe fire keeping methods (follow directions for starting, stoking, and put them out and be sure the flue is open), maintain your ventilation system diligently, and avoid idling vehicles in the garage or near the home.
  • Clean-up: A quick remedy is to open a window or turn on a fan if you see smoke build-up or notice your asthmatic experiencing symptoms. You’ll also want to have your entire heating system inspected to ensure that your ventilation and air circulation systems is working properly.


Asthma and Ozone

Another problematic gas for asthmatics, ozone (O3) is best known for its ability to insulate our planet from harmful UV rays.

  • Causes: When ozone comes to ground level it becomes known as ground-level ozone. In high quantities, it can enter your home and lead to coughing, chest discomfort, shortness of breath, reduced lung function, and eye irritation.
  • Prevention: A simple solution to preventing high ozone levels in your home is to close your windows when outdoor ozone levels are high (your local weather network should be able to give you current atmospheric ozone levels). Additionally, Health Canada recommends against using an ozone generator type air cleaner as these can add ozone at problematic levels.
  • Clean-up: You can use an air cleaner to take ozone out of your indoor air - check out this guide to indoor air cleaners.


Asthma and secondhand smoke

Having a smoker in the house can add to the health burdens of your family in many ways (ear infections, bronchitis, pneumonia, sudden infant death syndrome (SIDS) to name a few), asthma being one of the big health concerns. Secondhand smoke irritates chronically inflamed bronchial passages seen in asthmatics, exacerbating the problem for these people.

  • Causes: As cigarettes, pipes, and cigars are burned and smokers exhale the smoke within your home or your vehicle, they add more than 4,000 substances to your indoor air including benzene, carbon monoxide, cyanide, lead, nickel, and formaldehyde, some of which are known carcinogens.[2] Secondhand smoke affects between 200,000 and 1 million children with asthma annually.[3]
  • Prevention: Ask that no one smokes in your home or vehicle and keep secondhand smoke away from the asthmatics in your home, indoors and out. Additionally, stay away from smoking facilities like restaurants and bars.
  • Clean-up: If there is smokiness in your home, open the windows and use fans or air conditioners to get the air out of your home. Air purifiers can also help with this problem.


Asthma and Formaldehyde

This is a chemical prevalent in a whole manner of products and over the long term (even at low levels) can cause respiratory symptoms and allergic reactions. In high concentrations, it can irritate eyes, nose, and throat and cause cancer of the nasal cavity.

  • Causes: This comes into your home when you use products that contain formaldehyde, including things like paints, adhesives, floor finishes, pressed wood products, hardwood, varnishes, wallpaper, vehicle exhaust, fireplaces, tobacco smoke, and more.
  • Prevention: There are many things you can do, including having proper ventilation for fireplaces, stoves, and wood burning appliances. Don’t allow anyone to smoke in your home, don’t idle your vehicle in the garage or near doors and windows, and do your best to avoid high-VOC products as noted above.
  • Clean-up: Be sure to keep windows open during times when you’re applying paints, varnishes, stains, adhesives, and so on.


Asthma and Scented products

Things like air fresheners and cleaning supplies as well as adhesives, paints, and personal care products can all contain scents that are irritating to people with asthma.

  • Causes: Chemical scents made from synthetic ingredients are considered pollutants and can cause problems for people with asthma when used indoors.
  • Prevention: Choose products made scent-free and/or with plant-based scents only. Additionally, when choosing building supplies for renovations or new home construction, look for low-VOC options only.
  • Clean-up: If you have used products with chemical irritants, use fans and open windows to vent the pollutants out of your home as quickly as possible. An air purifier can also help to assist with cleaning your air after using scented products.

If you would like to learn more about keeping your indoor air quality pollution free check out these ecolife articles: Top 20 Air Purifying Plants, Common Indoor Pollutants, and our Homemade Air Freshener Recipes



1 Effects of Mould on Health. (n.d.). Retrieved 05 16, 2010, from Health Canada:

2 Secondhand Smoke. (n.d.). Retrieved May 16, 2010, from US Environmental Protection Agency:

3 Secondhand Smoke Can Make Children Suffer Serious Health Risks. (n.d.). Retrieved May 16, 2010, from US Environmental Protection Agency:


Stay Connected.
You've been added to our mailing list.
Thank you for signing up!
Like ecolife on Facebook & Google, and join us in the Green movement!