Air PollutionHVAC

The Dangers of Indoor Air Over Outdoor Air: How to Prevent Them

By January 25, 2018 No Comments
9 minutes to read

Most people think of air pollution as the pollutants in the air found outdoors, like vehicle exhaust or fumes from industry smokestacks. However recent studies have investigated the dangers of indoor air over the outdoor air and found that frequently indoor air is more polluted and more harmful than outdoor air. Hazardous chemicals like those found in cleaners, as well as mold and smoke, can build up inside. How do these indoor air pollutants impact us? Furthermore, what can be done to protect ourselves from these air pollutants?

Sources of Indoor Air Pollutants

Indoor air pollutants include things like dust, mold, pet dander, particulate matter, nitrogen dioxide, radon, carbon monoxide, ozone, and bioaerosols. Sources of indoor air pollution include building materials, cleaning chemicals, furniture, environmental or a cigarette smoke, cooking equipment, people, and animals. Indoor air is often more polluted than outdoor air because unlike outdoor air it stays in one place, slowly accumulating more pollutants.

Biological air contaminants such as mold can come from moisture that builds up in the house, while pets will leave pet dander around a home. Dust tends to come from dirt tracked in from outside as well as dead human skin.

“Radon is an invisible and radioactive gas that occurs naturally in certain rock formations. Radon can leak into houses through the foundation,” says Camfil’s Charlie Seyffer, Manager of Marketing & Technical Materials and 37-year ASHRAE member and active committee participant

. “Volatile organic compounds can be found in chemicals like paints, brushes, cleaning materials and building materials. Particulate matter and smoke frequently come from secondhand cigarette smoke but it can also come from sources like fireplaces and stoves.” (1)

Ozone is caused when sunlight reacts with certain air pollutants, but it can also come from indoor ionizers which are often used to purify the air. Carbon monoxide is a colorless and odorless gas that is released primarily by the burning of fossil fuels, so gas stoves, heaters and other sources of combustion can release it

Harms of Indoor Air Pollution

The harms of indoor air pollution range from short-term effects such as coughing, eye irritation, and difficulty breathing to longer-term effects such as the development of respiratory diseases and cancer. Depending on how dangerous the pollutant is and its concentrations, more severe effects can occur. Exposure to some pollutants, like carbon monoxide, can even cause death rather quickly.

Common symptoms of exposure to indoor air pollution include fatigue, headaches, sneezing, coughing, and congestion. More severe symptoms include rashes, chills, and fever, irregular heartbeat or shortness of breath, nausea, and vomiting.

“Exposure to biological contaminants like animal dander and mold usually results in allergic reactions but can potentially cause the flu or other infectious diseases,” says Seyffer. “Ozone exposure can lead to damage to the respiratory tract and difficulty breathing if exposure is continuous lung damage can even be permanent.” (2)

Particulate matter exposure from stoves and heating systems can cause the exacerbation of asthma symptoms, irritation of the eyes nose and throat, as well as respiratory and cardiovascular diseases. It can also cause lung cancer and is a frequent contributor to premature death.

Nitrogen dioxide can cause irritation of the eyes, nose, and throat, as well as respiratory infections and permanent damage to the lungs. Pollutants like asbestos, lead, and radon can all be extremely damaging but difficult to detect, so it is important that proper procedures be followed to safeguard yourself from these pollutants. Asbestos can cause lung cancer, and so can radon. Lead can lead to brain and nerve damage, kidney damage, cardiovascular damage, and anemia.

Preventing the Dangers of Indoor Air Over Outdoor Air

“The World Health Organization (WHO) has estimated that when compared with deaths from outdoor air pollution, indoor air pollution may actually kill more people. Household cooking with coal or other biomass burning stoves killed around 4.2 million people in 2012, while outdoor air pollution killed around 3.7 million,” says Seyffer. “Preventing the danger of indoor air over the outdoor air is a matter of monitoring and controlling indoor air pollutants, and though it can be complicated it is absolutely necessary for people’s health.” (3)

One of the most effective ways to fight indoor air pollution is to improve ventilation. Ventilation can be done through natural means such as opening doors and windows, and with mechanical systems like HVAC systems which regulate outdoor air intake and conditioning. You’ll want to use air filters and have your HVAC systems regularly checked for any maintenance issues.

“Don’t let people smoke in your house, as cigarette smoke is both one of the most common and one of the most dangerous indoor air pollutants,” explains Seyffer. “Be sure to use household cleaners properly, in well-ventilated areas. Also be sure to store these chemicals properly, and use natural cleaning supplies if possible.” (4)

Be sure to clean your house regularly, and remove things like pet dander, bacteria, dust, and mold wherever it is found. Vacuum often, and try to use a low emissions vacuum if you can. Finally, if you are going to use an air purifier make sure that it is the right kind. Some air purifiers can actually make home air worse by releasing pollutants like ozone.

If you need help purchasing the right air filters or air purifiers to fight the dangers of indoor air over the outdoor air or want to learn more about how indoor air pollutants can harm you along with measures you can take to protect yourself, contact Camfil as soon as possible.

Lynne Laake

Camfil USA Air Filters

T: 888.599.6620,


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