Dust busters: what’s really in household dust and how to get rid of it

The first thing I noticed when I moved in with my boyfriend was that his apartment was dusty. Dust bunnies huddled behind the couch and TV, and thick, purplish deposits of what I called “greasy dust” cloaked the windowsills, bookshelves and even old bottles on the bar cart.

This dust became my nemesis, reappearing quickly after I cleaned. I began to feel like it was our third roommate, an entity akin to Tim Curry’s goopy character from the movie FernGully – tenacious, insalubrious and sinister.

Related: Thread carefully: your gym clothes could be leaching toxic chemicals

We’ve all heard that dust is full of dead skin, hair and other seemingly benign detritus, but the sheer robustness of my greasy dust made me wonder: what else is really in the stuff, and could it be making our homes less healthy?

What is dust made of and is it harmful?

Dust has a lot of components. It contains things that are possibly irritating to our skin and airways, but don’t pose major health risks, such as dead skin cells, hair, pet dander, bacteria and microscopic mites. According to a 2009 study of household dust in the US midwest, about 40% of the dust in our homes comes from outside, via air or the bottoms of our shoes. This can comprise soil and other outdoor debris tracked inside from our shoes, and allergens like pollen.

But dust also contains chemical contaminants with more concerning health implications. “Dust is basically a repository for indoor chemicals that have shed from various products,” says Tasha Stoiber, senior scientist researching indoor contaminants at the Environmental Working Group. Depending on where we live and what products we keep in our homes, these can include harmful PFAS, chemicals often used to treat stain- and waterproof fabrics which have been linked to certain types of cancer and lower birth weights.

Dust can also harbor flame retardants, which typically shed from older foam furniture, and phthalates, which are found in air fresheners and plastics; both are linked to hormonal disruption and neurodevelopmental issues in children, among other health concerns. In homes where lead, asbestos and mold are present, these highly hazardous materials are also typically present in dust.

Additionally, dust can contain microplastics, themselves tiny parcels of chemicals.

Does household dust get into our bodies?

We are potentially exposed to harmful components in dust via ingestion, inhalation and skin contact, with researchers now understanding that humans can absorb chemicals from ambient household dust through our skin.

The authors of a 2023 study from the University of North Carolina found that dust that has settled on our food containers, packaging and serving plates could actually be a more significant source of microplastic intake than our food. While there is no current threshold for the amount of plastics we can safety ingest, the cumulative effects of long-term exposure to microplastics and the chemicals they contain are detrimental.

Stoiber says children, who may be crawling on the floor and putting their hand in their mouths, are at the greatest risk of exposure to the pollutants in dust; studies have found children eat on average 60 milligrams of dust a day, with adults consuming half that amount, in addition to being exposed through inhalation and dermal absorption. That’s sort of like taking a small dust pill daily.

Related: Plastics, pesticides and pills: how chemical exposures affect sperm health

What about dust that results from wildfires?

With the northern hemisphere seeing record-breaking wildfires last year, and the average American breathing in more harmful wildfire smoke in 2023 than any other year since 2006, an increasing amount of dust from wildfire smoke is reaching us, especially if we live on the west coast or are within the range of an extreme wildfire event. This smoke contains a chemical component (polycyclic aromatic hydrocarbons, or PAHs), that “can be in the air, but can also deposit as particulate matter on surfaces”, explains researcher Aurélie Laguerre.

Laguerre says PAHs can enter our homes after wildfire events via our buildings’ air filtration system. Landing as a thin “black layer” of dust on your furniture, bedding and walls, PAHs remain hazardous for 40 days, exposing you to toxins even after the smoke in your area has cleared.

While the health effects of PAHs vary depending on factors like the duration, volume and pathway of exposure, these substances are “very well-known for their human toxicity”, says Laguerre.

Occupational exposure to PAHs are linked to higher incidences of lung, skin and bladder cancers. They exacerbate respiratory conditions, and researchers believe they may contribute to cataracts, kidney and liver damage, and jaundice. Some PAHs are known to be mutagens and teratogens, agents that can create genetic mutations and affect fetal development.

PAHs aren’t only produced by wildfires. They can be created when we cook and partially burn food, and are also a component of car exhaust and pollution released by the industrial processing of petroleum.

Learning about PAHs made me reassess my greasy dust. Not only am I located on the west coast of Canada, where summer wildfires are frequent, but our building was next to a superhighway and an industrial area. All those times I idly swiped up a fingerful of windowsill gunk, I was probably scooping up landed particulate PAHs – gross.

What’s the best way to get rid of PAHs dust?

Fortunately, there are many easy, affordable ways to mitigate all types of dust in our homes. In one of Laguerre’s studies, she and her team found commercially available cleaning products, like spray or foam glass cleaner, were able to remove 62% of PAHs from glass, and a regular cold laundry cycle and stint in the dryer reduced PAHs from bedding by 48%.

Related: Are you doing laundry all wrong? An expert guide to caring for your clothes

Running your kitchen exhaust fan while cooking, using a Hepa air purifier and keeping windows closed during wildfires or if you live near a busy road can all cut down on harmful particulate matter in your home.

What’s the best, most comprehensive dusting technique?

According to Sharon Garcia, who runs the Los Angeles-based Next Level Cleaning Services company, the most effective way to dust a room is from top to bottom, using an extendable microfiber or lambswool duster to trap buildup that accumulates on walls and atop light fixtures, fans and high furniture. Then, she recommends vacuuming thoroughly with a Hepa-filter vacuum, as these are able to catch smaller particles than a regular filter (Garcia wears a mask while dusting for extra protection). For blinds, baseboards and windowsills, she’s a particular fan of Scrub Daddy Damp Dusters, as wet materials capture dust effectively.

In her own home, Garcia launders her fabric curtains and vacuums her upholstered furniture and mattress every three months. She also uses a mattress protector to limit dust accumulation. “If you’ve never cleaned your mattress, I’d recommend starting now, or hiring a professional to do it, and then getting a protector so you don’t have to worry about it,” she advises.

If you want to go the extra mile, replacing carpet – which both accrues dust and can contribute to synthetic microfiber pollution – with wood flooring is a great step. But there are plenty of simple habits that go a long way to limiting dust getting into your home, and body, too: remove outdoor shoes before coming inside, wash your hands before eating and clean or replace your HVAC filter annually.