How Cleaning Chemicals Fuel Microbial Resistance in Household Dust

New research finds toxic dust carries virulent, drug-resistant bacteria and chemicals.

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Household dust isn’t a menace just because it’s dirty. Lurking within it are allergens like animal dander and chemicals wrapped in hair, soil, and dead skin cells.

Dust can also harbor virulent and antibiotic-resistant microbes—a result of the destructive nature of household cleaners, medications, and environmental pollution that makes its way to surfaces and floors.

In many cases, dust accumulates for months or even years to create a stew of microbes.

“Eventually, those microbes will come in contact with us and consequently influence our health. It becomes a mixture of chemistry and also microbiology,” said Patrick K. H. Lee, a professor at City University of Hong Kong and former associate dean at the University of California, Berkeley, specializing in environmental microbiology and biochemical engineering.

The Nature of Dust

Dust exposure is a known trigger for respiratory symptoms in people with allergies and compromised breathing, including chronic obstructive pulmonary disease. People react to dust mites, pet dander, and mold found in dust. These allergens irritate airways and trigger inflammation and airway constriction, resulting in symptoms such as wheezing, shortness of breath, and coughing.

Dust can also contain microbes that are detrimental to health.

Like the human microbiome, dust can either harbor mostly favorable microbes or be heavily concentrated with disease-causing microbes, including those with antibiotic-resistant and virulent properties.

A study published in Scientific Reports examined 56 homes in Ireland and found 176 antimicrobial-resistant genes associated with dust. The authors described dust as an antimicrobial reservoir that hasn’t been widely recognized, stating that their findings warrant monitoring, particularly since most people spend 90 percent of their time indoors.

In another study published in Microbiome, Lee and a team of researchers studied dust collected from homes. He told The Epoch Times that while chemicals and microbes were expected to be found in dust, researchers weren’t sure whether the antimicrobial-resistant genes found in samples would be significant enough to warrant concern.

The chemicals—including endocrine-disrupting phthalates, non-antibiotic pharmaceuticals, and antibiotics—had antimicrobial properties, causing resistance among the dust microbiome and leading to a growth in antibiotic-resistant bacteria.

“These resistant, virulent bacteria may be opportunistic pathogens, posing an infection risk for immunocompromised individuals,” the authors wrote.

Dust can be problematic for people with compromised, weak, or developing immune systems, including those with diabetes, babies, the elderly, those taking antibiotics or other medications, and those with cancer, infections, or autoimmune diseases.

The authors noted that “house dust is both a reservoir and a vehicle for the dissemination of these resistant, virulent bacteria.”

Dust harbors four harmful classes of chemicals—phthalates, phenols in disinfectant products, flame retardants, and fluorinated chemicals like those used to make non-stick cookware—that can cause serious health issues such as lower IQ in children, interference with hormones and development, and cancer.

“The number and levels of toxic and untested chemicals that are likely in every one of our living rooms were shocking to me,” co-author Veena Singla, a staff scientist at the Natural Resources Defense Council, said in a news release.

“Harmful chemicals used in everyday products and building materials result in widespread contamination of our homes—these dangerous chemicals should be replaced with safer alternatives,” Singla added.

Watch for Chemicals

Any chemicals we use in our home will likely end up in our surroundings, Lee said.

In his study, researchers ask subjects to clean their homes as they normally would before filters were used to trap dust samples. The aim was to illustrate that dust accumulation happens regardless of cleanliness and to see whether samples mirrored the chemicals used in the homes, Lee added.

The study represented 32 households with an average of two residents each who lived in their homes an average of 23 years and spent 20 or more hours a day there. The residents were 72 and older, and nearly all were taking pharmaceutical drugs, which were detected in the dust samples.

“These were not dirty homes. These were homes considered in very good shape, good hygiene,” Lee said.

Chemicals can contaminate an environment through excretion of human skin while sweating, improperly thrown out drugs, outdoor air pollution in open windows, cleaning products, cosmetics, foods, and personal care products. Lee said home furnishings can also leach out chemicals like flame retardants.

While COVID-19 made people more aware of the need to regularly disinfect their homes, it also led to overuse of harsh chemicals that may contribute to more infections than they prevent. This may have contributed to findings, Lee noted, and may be part of a wider worldwide trend.

“Obviously, we cannot make our homes sterile, but our study also highlights the message that we do need to keep our homes clean to avoid accumulation of dust particles, because this will create a reservoir for antimicrobial resistance, and we don’t want to do that,” he said.

Clean Up Chemicals

Substituting natural products for as many chemicals in the home as possible can reduce the chemical burden on the dust microbiome, Lee said.

It’s one of the easiest health threats to fix, Dr. Aly Cohen, a rheumatologist and environmental toxin expert, said on the Model Health Show podcast on May 6. She described taking her drawer of air fresheners, candles, and incense—things that brought her joy—and throwing them out along with her cleaning products when she learned they contained phthalates.

Phthalates are used in plastics and found in high concentrations in dust. They interfere with hormones and are associated with many serious health hazards, particularly for children. Associated problems include miscarriage, abnormal fetal and child development, and reproductive damage.

“There are so many ways to be aware and choose better, and I think that’s the easiest—don’t bring [phthalates] in the home where they reside and end up in your body,” Cohen said. “It makes a lot of sense to cut off that line of exposure.”

These toxins all end up in the dust, she added, which she described as a well-studied aggregator of household chemicals that are harmful to humans. Worse, she said, is that vulnerable babies and pets are on the floor where much of the dust is.

Identifying and finding substitutes for chemical products you use is a process you can become better at. Cohen compared it to gamifying—identifying and eliminating threats one at a time.

“We’ve got to clean our homes of these toxins and keep from breathing them in,” Nonia Larsen, founder of Clearwater Cultures, told The Epoch Times.

Larsen prefers cleaning with chlorine dioxide, which she makes herself and uses to wash her food from the market and her garden. Chlorine dioxide—often used in the medical industry for sterilizing equipment—can be used as a hand sanitizer, wound cleaner, and household cleaner for mirrors, windows, and all surfaces, she said.

When used appropriately, chlorine dioxide is effective against bacteria, viruses, and fungi without the toxic effects of bleach and other chemical-based cleansers. A systematic review in the Journal of Medicine and Life found that even at low concentrations of 20 to 30 mg/L, chlorine dioxide can eliminate harmful microorganisms from food, drinking water, and on and in people and animals.

Fight Microbes With Microbes

Larsen also uses probiotic cultures in her cleaning products, usually made from homemade vinegars, either from fruit or a kombucha SCOBY—short for symbiotic culture of bacteria and yeast. SCOBYs are beneficial microbes that consume sugar and can kill harmful microbes.

“Living cultures will go after pathogens and poisons and help destroy them,” Larsen said. “These vinegars can be enhanced by infusing them with medicinal herbs like rosemary, oregano, and thyme. They will be more potent if people grow their own herbs.”

Italian researchers measured the effects of using probiotic strains of Bacillus in sanitation procedures in a hospital to counteract the growth of pathogens on surfaces. It worked to decrease microbes harboring drug-resistant genes. Additionally, no new drug-resistant infections were reported in the study.

Homemade cleaning products cost only pennies to make, Larsen said. Other tips she offered for lowering exposure to indoor air pollution are:

• Always clean vacuum filters because they can recirculate dust.
• Regularly clean air purifiers.
• Open the windows if you live in a rural area to circulate outdoor air inside.
• Spend more time outdoors in nature to counter the effects of breathing in dust and indoor pollution.

In light of emerging research, Lee said most people should rethink chemical cleaning supplies and techniques that favor disinfecting over washing.

“Even our daily practices that we have been doing for decades are changing the microbes surrounding us,” he said. “It’s time to pause and think about whether—as scientific evidence emerges—these practices should continue in the future.”