Indoor Air Quality and Environmental Health

It is estimated that people spend up to 90% of their time indoors. (1) As such, indoor air quality can have an immense impact on health and general quality of life. Both the Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) provide guidance based on research for indoor air quality but it is generally an unregulated field. (2) Indoor air quality crosses economic status, race and ethnicity. Poor indoor air quality can be present at work, home, school or vehicles. However, lower income areas tend to have greater indoor air quality concerns due to a predilection towards older infrastructure. (3)

There are many potential sources that lead to poor indoor air pollution with the most common being mold, radon, second hand tobacco smoke, smoke from burning wood, gas furnaces and various allergens. Volatile Organic Compounds (VOC), formaldehyde, pesticides, lead and asbestos are also common sources of air pollution. Some of these items are naturally occurring, some are man made and some depend on chemical reactions to occur under the right conditions.


Mold creates airborne allergens through spores and grows under damp conditions. It can be found just about anywhere on organic surfaces including wood, insulation, carpet and food. Humidifiers can also be a source of mold. (4) Molds feed on this organic matter and use the moisture to reproduce. (5) The spores can cause a wide range of symptoms from traditional allergies to more serious conditions. There is not an established level considered safe or hazardous.

Each person reacts to mold differently depending on their immune system and health condition but the most common is an allergic reaction. The elderly, young, those with a respiratory conditions and those with a compromised immune system tend to experience the greatest effects. The allergic reaction can be triggered instantaneously or over a period of prolonged exposure. Most of the time a reaction generally occurs when the mold is on a larger scale such as resulting from a flood, leaking water pipes or burst pipes. It should be noted that residue left after the mold has been killed can cause reactions in people unless it is removed. Typical symptoms of mold exposure can include difficulty breathing, shortness of breath, eye irritation, headaches, fatigue and coughing.

Since sources for mold growth can occur outside the line of sight such as within walls, some secondary indicators to look for are a musty odor, water stains and an unusually high water bill. There are some preventative measures you can take such as using paint that reduces the ability for mold to grow, cleaning often, keeping wet areas dry as possible (e.g. shower, tub, sink), minimize using carpet in wet areas since it can retain moisture and make sure the area has good ventilation. Preventing moisture is the best option and the second best is to fix any source of water leakage as soon as possible before it allows for the growth of mold.


Radon is a naturally occurring gas that is radioactive. It generally moves from the ground into the home but can also travel into drinking wells. Radon can be released into the air through showers or using water if the groundwater is contaminated. Lung cancer is the predominate illness associated with radon exposure. The EPA estimates that 21,000 cases of lung cancer deaths annually are connected to radon. The World Health Organization (WHO) estimates that 15% of lung cancer cases worldwide are attributed to radon exposure. Proper ventilation is the key to minimize exposure and reduce the possibility of the gas to accumulate in an enclosed area such as home or work.


Asbestos is a mineral that creates microscopic fibers that can be inhaled into the lungs and accumulates which causes damage. (7) Asbestos does not cause health concerns when it is intact or sealed. It can be found on pipes, roofing shingles, insulation and other construction materials. As the dangers of asbestos have become known, manufacturers have reduced the amount of asbestos within materials so most of the potential for exposure is within older structures.

Permanent scarring resulting from inhalation of asbestos is called asbestosis. Asbestos exposure has also been linked to lung cancer and mesothelioma. Most of these medical conditions are a result of repeated high-level exposure such as from a job site.


Similar to asbestos, formaldehyde is becoming less of a concern as manufacturers reduce the amount within adhesives or construction materials since the Department of Housing and Urban Development (HUD) implemented emission guidelines in 1985. Formaldehyde can be found predominately within manufactured housing because of the abundance of adhesives and bonding agents required. (7) Pressed wood products such as particleboard, cabinets and furniture can release formaldehyde.

The most common symptoms of formaldehyde exposure are eye irritation, throat irritation, nausea and has been known to trigger asthma attacks. (8) It is an odorless and colorless gas that becomes an issue in poorly ventilated buildings.


Lead is both an outdoor and indoor pollutant. Indoor lead exposure can be thorough older paint, dust or air. It must be either inhaled or ingested to accumulate. Low levels of lead poisoning cause damage to the kidneys, blood cells, brain and central nervous system. It has been known to cause learning disabilities within young children. High levels of lead poisoning have been known to cause convulsions and can induce comas.

Lead was used in paint and gasoline but has since been removed from both. Toys use to have lead but it is no longer used. As such, most of the exposure is in older homes with paint from the 1970's or earlier. It can also be problematic when lead is in soil that can be blown indoors or tracked into a home on shoes. Mopping can minimize the amount of airborne exposure. Lead based paint can be removed or abated but it must be done by an expert that can handle the material and dispose of it safely.


Pesticides come in various compositions including gas, vapor, dry granules and liquid. Considering that pesticides are poisons that are used specifically to eradicate unwanted pests, it can cause health issues in humans if too much is used or if they accumulate. It is estimated that 80% of exposure to pesticides occurs within the home. (9) People with respiratory illnesses and compromised immune systems can be more sensitive to exposure. Reducing the amount and frequency of pesticides can lessen symptom triggers.


Asthma is a debilitating respiratory illness where the lungs become inflamed and restrict the amount of oxygen from entering them. Approximately 25 million people in the United States struggle with asthma, including 7 million children. Numerous indoor pollutants can trigger asthma attacks such as smoke, mold, pesticides, cleaning products, airborne particulate matter (e.g. dust, asbestos, lead, formaldehyde). VOCs can also trigger asthma attacks. One of the most common indoor VOCs are interior paint. The Clean Air Act only regulates VOCs when they are outdoors and can react with sunlight and heat (e.g. photoreactive). As such, many items can be labeled as low VOC or no VOC without any established thresholds or consistent standards. This makes it difficult for consumers to know how much VOCs are actually being released and hinders the ability to compare products effectively.

Since indoor air quality is not regulated to a large degree, asthma sufferers cannot be assured they will work or live in an area without being exposed to triggers. More people are becoming aware of the correlation between health issues and pollutants, which means that many employers are working with their employees to identify and mitigate known triggers.


Susan Jaworski

Susan Jaworski, AICP, holds a Master's in Environmental Management from UMUC and a Bachelor's in Life Science from Otterbein University. She is a certified ecologist.Susan has over 15 years of experience within the environmental field and has recently transitioned to her newfound passion as a freelance writer and consultant.She has been a moderator at the National Association of Environmental Professionals annual conference and the USDOT's Environmental Symposium.Susan received the Partnering for Excellence Award by the Secretary of Transportation in 2013 and the Environmental Excellence Award by the Texas Council of Environmental Quality in 2009.