The Toxicity of House Dust
As modern life focuses more of our time indoors, indoor air quality becomes more of a concern. One measure of indoor air quality and chemical exposure involves measuring contaminants found in house dust. You often hear house dust described as containing dead human skin cells and hair, although research has been turning up a host of other components. In reality, house dust is a complex mix of organic and chemical compounds, including (Araki 2018):
- Skin cells and hair
- Plant and pollen particulates
- Bacterial, viral and fungal organisms
- Insect parts and dust mites
- Natural and synthetic fibers
- Soil and/or dirt
In addition, mixed in with all these components, you find numerous chemicals derived from:
- Combustion (soot from smoking, cooking, natural gas, candles, etc.)
- Furniture (flame retardants, stain blocking chemicals)
- Building materials (including lead from paint if your home was built before 1978)
- Electronics (plasticizers, flame retardants, metals)
- Cleaning agents
- Personal care products
While concerns for house dust may on first blush seem overblown, research has shown that dust gets consumed. Estimates suggest that young children between 6 months and two years of age consume about 90 mg of dust per day. Children between the ages of two and nine years old consume about 60 mg of dust (Lindern 2016). Children have higher exposure since they are closer to the floor and often put things in their mouth. In addition, they are more vulnerable since their nervous system is still developing. Adults likely consume about half as much dust as children. This still may have significant health effects long-term depending on what’s in the dust.
It’s been shown that lead levels in house dust correlate well with blood lead levels found in children. In some cases, lead levels are high enough to be of significant concern (Lanphear 1996). Correlations between lead found in dust and children clearly demonstrates risks of significant exposure through house dust. I discussed some of the issues around lead exposure in a previous blog article if you want to read more about the history and concerns around lead.
Mold is a common problem in homes. When humidity is consistently above 60%, you have increased risk for mold growth. In damp homes with high humidity, mold can create significant problems and mold spores readily build up in house dust. Exposure can cause allergic reactions and increase risks of respiratory infections (Mendell 2011). Estimates suggest that somewhere between 18% and 50% of all buildings have problems with high humidity (Gunnbjornsdottir 2006, Mudarri 2007).
Combustion products are carcinogenic and toxic. While smoking is a well recognized risk for lung cancer, cooking smoke from oil and meat are a likely cause as well (Jia 2018). Candles are also a potential source of soot and indoor air pollution (Derudi 2014). For candles, the wax quality has a significant impact on pollutants emitted.
Gas cooking has often been preferred by chefs for quicker heating times and better performance. Unfortunately, gas cooking stoves (along with other fuel burned inside the home) release significant toxicants including particulates that can wind up in dust. Evidence suggests exposure to these compounds raises the risk for asthma (Belanger 2008).
Flame Retardants, Plasticizers and Other Chemicals
A meta-analysis from 2016 looking at the research on chemicals in dust found numerous chemicals of concern (Mitro 2016):
- Phthalates (plastics)
- Phenolics (including BPA plastic and parabens used as preservatives in cosmetic products)
- Flame retardants (furniture and electronics)
- Fragrances (cosmetic, cleaning and air freshener products)
- Perfluoroalkyl substances (found in non-stick cookware and water or stain repellent fabrics)
Exposure to these chemicals have been correlated with adverse health outcomes, including reproductive harm, hormone disruption, cognitive and behavioral problems in children, cancer, asthma, immune problems and other chronic diseases (Mitro 2016). Unfortunately, house dust is exposing us to a plethora of dangerous chemicals that could have a negative impact on our long-term health.
Methods to Reduce Indoor Air Pollution
While it is concerning that so many chemicals are turning up in house dust, there are things we can do. Dust and clean on a regular basis. When replacing vacuum cleaner bags wear an N95 dust mask and gloves. Dust sensor vacuums can also help clean the deep dust out of carpet more effectively than standard vacuums.
Don’t burn things in your home. There are electric candles that simulate candle light. If you’re choosing kitchen appliances, choose electric over gas. When buying furniture ask about the presence of stain resistant chemicals and flame retardants. Avoid furniture and clothing that uses these chemical treatments. Try to use less plastic.
When cleaning, use vinegar, hydrogen peroxide and liquid soap. Try to avoid harsh chemicals. Don’t use air fresheners, scented laundry products or harsh cleaning agents as these often release numerous toxic compounds, some of which I’ve covered previously.
Indoor air quality is important to maintain for overall health, and house dust is a major contributing factor to indoor air pollution and indoor toxic exposures. By knowing the sources of pollutants found in dust, it’s possible to take action to reduce exposures and clean up your indoor air quality.