The chemistry behind household dust


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The chemistry behind household dust

Houses collect dust as sure as the sun rises. It collects on our trinkets and covers the carpets. House dust is a complex mixture of sloughed-off skin cells, hair, clothing fibers, bacteria, dust mites, bits of dead bugs, soil particles, pollen, and microscopic plastic specks. It’s our garbage, and it turns out it has a lot to tell us about our way of life.


Initially, dust is not inert. Those discarded hairs and skin cells can absorb a wide range of contaminants that originate from the products we bring into our homes, such as household cleaners. It is possible to bring other pollutants into the house with us on the soles of our footwear. Persistent organic pollutants, metals, endocrine disruptors, and more can be found in dust, in addition to fluffy hair and garden dirt.

Household residents are continually exposed to pollutants because dust has a long memory of contaminants introduced to the home. When dust is disturbed, it is re-suspended and recirculates through the house, picking up substances before returning to the floor. According to University of Toronto environmental chemist Miriam L. Diamond, dust builds up in homes year after year. Despite the fact that homes are tightly sealed environments, the dust accumulates even after regular cleaning. Despite the fact that DDT was banned in the 1950s, the dust from an old house may still contain the chemical.

The chemistry behind household dust
House dust mites; Source

Scientists study dust. Using dust as a proxy to better understand what chemicals are in our environment and how they move, as well as a way to characterize exactly what we are exposed to via dust, scientists study dust. Human health and the effects of dust are unknown. Infants and toddlers, who spend 90% of their time indoors, put everything in their mouths, and are more sensitive than adults to many of the compounds found in dust, are particularly vulnerable to the effects of dust pollution. However, neither the extent nor the compounds and sources of greatest concern for health risks from dust exposure have been nailed down. 

And there are many compounds that have yet to be discovered. According to environmental chemist P. Lee Ferguson of Duke University, the thousands to over a million chemicals in commerce do not even come close to accounting for the few to a hundred compounds that we know are in dust. Using high-powered analytical tools, researchers are able to uncover the full range of chemicals in the dust. It’s no longer acceptable to ignore dust.

In operating rooms, researchers began observing human pathogens adhered to the dust in the 1940s and realized that dust could tell them a lot about environmental health. Researchers began testing household dust in the 1970s for lead contamination from paint and gasoline, with the goal of determining potential exposure levels for children. Toxins such as now-banned polychlorinated biphenyls (PCBs), which were used in electrical cables and wood floor finishes, and endocrine disruptors like phthalates, which are softening agents in vinyl flooring and other plastics, have been discovered in more recent studies.

The chemistry behind household dust
Microscopic House Dust; Source

Our understanding of how volatile and semi-volatile compounds interact with our environment is still being developed by researchers. There is a strong driving force for compounds to be shed from consumer goods like vinyl flooring and personal care products into materials with lower concentrations of the substances, such as carpet pads, paints, and cleaning products.

The plastic parts of a TV set, for example, could release a flame retardant into the air, which would then stick to airborne particles and settle as dust on floors and carpets. According to Diamond, there will be constant movement of the compounds. As a result, a compound will condense in a cooler area of a room, where dust often accumulates, as the product heats up, allowing it to enter the home more quickly.

For example, flame retardant decabromodiphenyl ether is a high-molecular-weight compound that does not volatilize but becomes dust when people physically knock fibers or microplastics off couches or computer cases. University of Birmingham environmental chemist Stuart Harrad says that he and his colleagues discovered another mechanism: direct transfer or diffusion into dust. To put it another way, if dust falls on a television or Wi-Fi router, the flame retardants are likely to migrate into the airborne dust. 

Things get more complicated when there are other people in the room. An environmental chemist at Duke University tells NPR that “like Pig-Pen from the Peanuts comic strip, people walk around with their noses in the air all day.” Deodorant or fragrance compounds from personal care products are volatilized by people’s warm bodies, adding to the organic load in the dust. According to Diamond, when skin and clothing fibers are shed to dust, they can pick up additional toxins from the air before being reabsorbed into the environment. When people put dusty hands to their mouths, the compounds can be ingested, inhaled, or absorbed through the skin, making it difficult for scientists to determine which exposure route is most important.

The chemistry behind household dust
Airborne dust; Source

The majority of research has concentrated on identifying specific classes of dust contaminants, such as polybrominated diphenyl ether (PBDE) flame retardants found in furniture foam, carpet pads, and electronics; phthalates found in vinyl flooring; and pesticides tracked in on shoes or evaporated off pet collars. Researchers are now attempting to gain a more complete picture of the mixtures to which people are exposed by examining the overall chemical load in household dust. Researchers may be able to determine which chemicals or combinations of chemicals are the most toxic by combining toxicity tests with evolving ways to determine the complete profile of compounds in dust, Stapleton says.

According to Robin E. Dodson, an exposure scientist at the Silent Spring Institute, one new approach was to comb through two dozen dust studies of 45 compounds to get a snapshot of national exposures. Veena Singla, a Natural Resources Defense Council scientist, and she ranked the substances based on the amount of dust they were found in and the potential harm they pose to human health. Polyethylene terephthalate (DEHP), also known as phthalate plasticizer di (2-ethylhexyl) Vinyl flooring, food containers, and cosmetics all contain phthalate plasticizers. In animal and human studies, DEHP has been linked to decreased sperm motility in men. Perfluorinated stain repellents, phenol preservatives, flame retardants, the fragrance compound Galaxolide, and flame retardants are also on the list.

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