Indoor air can be more seriously polluted than outdoor air even in the industrialized cities most known for air pollution.
What’s more, many of us spend up to 90% of our time indoors. For that reason, even if indoor air were not the more polluted, we would have greater exposure to air pollutants there.
People can experience the health effects of indoor air pollution both immediately and over the long term.
Immediate effects include irritation of the eyes, nose, or throat; headaches; dizziness; and fatigue. Indoor air pollutants can also aggravate diseases such as asthma.
These effects resemble those of the common cold or other respiratory illnesses. That makes it difficult to be sure of the cause. So pay attention to when and where symptoms occur. If they fade or go away when you go to another room, suspect indoor air pollution.
If it’s possible to identify what causes these symptoms, simply eliminating exposure is adequate treatment.
Long-term or repeated exposure to indoor air pollution can cause respiratory diseases, heart disease, or cancer. These diseases can be severely debilitating or even fatal. Everyone’s reactions to exposure are different. The medical profession has not determined what concentration or periods of exposure to specific pollutants produce specific health conditions.
Therefore, keeping indoor air quality as good as possible is important to health even when nothing smells bad or no one is showing symptoms.
Common sources of indoor air pollutants
- Gas furnace, hot water heater, stove, or oven
- Wood-burning furnace, hot water heater, stove, or oven
- Burning food while cooking
- Smoking tobacco or marijuana, both of which contain a mixture of thousands of different compounds
- Burning candles
Many common household products release volatile organic compounds (VOCs). The products include cleaning products, paint and, ironically, air fresheners. When you buy new furniture or carpeting, they can release VOCs.
The compounds include benzene, xylene, naphthalene, toluene, and especially formaldehyde. These are only a few of hundreds of VOCs capable of causing multiple health problems. Although bleach and ammonia are not technically VOCs, they are major indoor air pollutants.
Biological air pollutants
Biological indoor air pollutants include pollen, mold, mildew, germs, pet dander, and dust mites. If you have infestations of rodents or roaches, their feces and dried urine can become airborne.
Dust likewise pollutes indoor air. It might look like something that accumulates on surfaces, but air currents can lift it and return it to the air.
Any solid matter can become dust if it’s broken into small enough pieces. Dust from outside that gets tracked inside includes sand, pollen, dirt, and the portion of air pollution from particulate matter. Indoor sources include dead skin, hair, the dead bodies and waste material of dust mites, and fragments of clothing and everything else that breaks down.
In old buildings, asbestos and lead may also become part of the dust that impairs indoor air quality.
Use a moist cloth to remove dust. Dry cloth or paper towels merely move it around. Air filters attached to the furnace, vacuum cleaner, etc. remove dust from the air.
And, of course, if the air outside is polluted, your ventilation system and opening doors and windows will bring them inside. Outdoor air pollutants include automobile exhaust, pesticides, radon, and ozone.
Keeping a mat by all doors and immediately removing shoes minimizes tracking in dust from outside.
How to improve indoor air quality
- Source control. Find anything that causes indoor air pollution and remove it. Some sources, such as asbestos and radon, require hiring professionals. You can deal with others as simply as choosing not to use products that produce pollutants.
- Ventilation improvement. If you have to do something, such as paint a room, that adds air pollutants, keep windows and doors open or use an exhaust fan to send them outside. If the weather and activity permit, work outside instead of inside. Also, vent your clothes dryer outside. It has a high level of particulate matter.
- Air cleaners. Your heating and air conditioning system has at least one air filter. Your vacuum cleaner probably does, too. Clean and/or replace them regularly. If maintaining those filters does not adequately treat the air in your home because of a chronic health condition, you can operate air cleaners.
How does dust get in a house when the doors and windows are always closed? / Christopher S. Baird, West Texas A&M University. April 29, 2019
The inside story: a guide to indoor air quality / US Consumer Products Safety Commission
Introduction to indoor air quality / US Environmental Protection Agency