Common health hazards lurking in your home

By Alistair Gardiner
Published December 9, 2020

Key Takeaways

Thanks to the coronavirus, we’re spending the vast majority of our time in one place: our homes. According to a 2020 review of literature on indoor air pollution, most people tend to spend about 90% of their time inside—and that figure is likely higher since the pandemic took hold. Even if you still are seeing patients in the clinic or hospital, you are likely spending more time self-isolating within your own four walls.

Your home, however, may not be as safe as you think. There are a whole host of activities and substances in our houses that can cause indoor air pollution—including cooking, smoking, using electronic machines or consumer products, and just breathing emissions given off by various building materials. The air in your home may well be polluted with things like carbon monoxide, volatile organic compounds, particulate matter, radon, and others. Research indicates that these harmful pollutants may negatively affect health and can cause a range of diseases.

According to the WHO, indoor air pollution is responsible for the deaths of 3.8 million people annually, and the review authors referred to the phenomenon as a “serious threat to human health.” But there are ways to mitigate these risks, and the first step is awareness.

Here’s a look at five pollutants that may be present in your home.


Radon is an odorless, radioactive gas that is generated through the natural decay of uranium and radium, which is found in nearly all rocks and soils. As such, it can be found in rooms that are in contact with the ground, like basements. It can also accumulate in groundwater, which is a primary source of drinking water for some. 

According to the EPA, roughly 1 in 15 homes in the United States has radon that is above dangerous levels, and elevated levels of this gas have been found in every state across the country. Prolonged exposure to radon is known to cause lung cancer—in fact, it’s the second leading cause of the disease in the United States. Moreover, for nonsmokers, it’s the leading cause of lung cancer, and causes roughly 21,000 deaths per year. According to the 2020 review on indoor air pollution, studies have indicated that indoor radon can increase your risk of lung cancer by 3-14%, depending on the level of exposure.

As such, the EPA advises testing your home using one of the many low-cost radon test kits available. If levels are high—4 pCi/L or higher—they can be mitigated. A qualified contractor can help you identify the right radon reduction mitigation to limit your exposure.   

Airborne particles 

Known as particulate matter (PM), these airborne carbonaceous particles are a mixture of solid particles and liquid droplets found in the air. They’re mostly made up of sulfates, nitrates, endotoxin, polycyclic aromatic hydrocarbons, and heavy metals like iron, zinc, copper, nickel, and vanadium. Indoors sources of PM include cooking, smoking, fossil fuel combustion sources (like fireplaces, stoves, or even candles), machine operation, and residential hobbies. According to the 2020 review on indoor air pollution, indoor levels of PM often exceed outdoor levels.

Because PM contains particles that are small enough to be inhaled, they can cause serious health issues, according to the EPA. Particles have the potential to find their way deep into your lungs and possibly even your bloodstream. As such, long-term exposure to PM can have a negative impact on your lungs and heart. The EPA notes that numerous studies have linked particle pollution exposure to health issues such as aggravated asthma, premature death in people with lung or heart disease, nonfatal heart attacks, irregular heartbeat, decreased lung function, and increased respiratory problems, among others.

Those who live with heart or lung disease, as well as the very young and the very old, are most likely to be affected by PM exposure. Good first steps to reduce PM levels include ensuring that your house has a good ventilation system, and making sure any wood stove in your home is certified to meet EPA emission standards.

Volatile organic compounds

Volatile organic compounds (VOCs) are gases with high vapor pressure and low water solubility, which are emitted by a wide variety of products. Most are human-made chemicals typically used in the production of things like paints, pharmaceuticals, and refrigerants, and are often components of petroleum fuels, hydraulic fluids, paint thinners, and dry cleaning agents.  

According to the 2020 review on indoor air pollution, the most widespread VOC is formaldehyde, a gas released from building materials, such as particleboard, plywood, and certain glues. But VOCs are also generated by human activities like using cleaning and personal care products, smoking, and cooking. In fact, up to 50 VOCs can be detected during a 90-minute cooking session. VOCs are also emitted by paint strippers, pesticides, furnishings, copiers and printers, and craft materials like adhesives and permanent markers. Typically, levels of VOCs are up to 10 times higher indoors compared to outdoor levels.

According to the EPA, exposure to VOCs may cause a range of both short- and long-term impacts on health. While these include relatively benign effects like irritation to eyes, nose or throat, health impacts may also involve damage to liver, kidney and central nervous system. Researchers believe that VOCs can cause cancer, according to the review authors.

Here’s the EPA’s advice: Ensure you are using proper ventilation when using VOC-emitting products, never mix household care products unless directed to by the label, and dispose of unused or underused containers properly. And, of course, always follow any precautions noted on the label.

Carbon monoxide 

Indoors, carbon monoxide (CO) is primarily generated through activities that involve combustion, like cooking or heating. Common sources of CO in the home include unvented kerosene or gas space heaters, leaking chimneys and furnaces, wood stoves and fireplaces, gas stoves, and various other gasoline-powered equipment. 

Because the toxic fumes of CO are odorless and colorless, you can be exposed to the gas without even realizing it. According to the EPA, the impacts of exposure depend on a variety of factors like age and overall health, as well as concentration and length of exposure. These include relatively minor impacts like fatigue to much more serious health issues. Moderate CO exposure can cause angina and reduced brain function. Exposure to high concentrations of CO can result in flu-like symptoms, headaches, dizziness, and impaired vision/coordination. At very high concentrations, CO exposure can cause fatalities. This is due to the formation of carboxyhemoglobin in the blood, which inhibits the absorption of oxygen.

As such, it’s important to use proper fuel in kerosene space heaters; vented (rather than unvented) space heaters; wood stoves that adhere to EPA standards; and an exhaust fan over gas stoves. And certainly, don’t leave a vehicle idling in your garage. 


While possibly the least deleterious on this list of indoor pollutants, molds are common and still have the potential to cause health problems. Molds grow by breaking down dead organic matter and reproduce by emitting spores. In the home, molds develop where there’s ample moisture.

When it comes to human health, molds can be problematic because they produce allergens, irritants, and, in some cases, mycotoxins. As such, inhaling or touching spores can cause reactions similar to hay fever in some individuals. Mold exposure can also cause irritation to the eyes, skin, nose, throat, and lungs, even in those who aren’t allergic. 

Research on the health effects of mold is ongoing. However, a 2018 review of studies found there was enough evidence to indicate a causal relationship between exposure to indoor molds and the developing and/or exacerbation of asthma in children. The review, however, found that more research was needed to confirm whether this is true in adults. Additionally the authors noted that ill health from mold exposure is often likely part of a larger exposure involving various other biological elements like bacteria.

That said, it’s best to follow the EPA’s advice and do what you can to get rid of the mold in your home, and also fix any issue that’s resulting in moisture accumulation. 

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