Where Does House Dust Come From?

It’s an all-too-familiar feeling: you just cleaned a few days ago, yet when you swipe a finger across your desk or bookshelf, it comes up covered in dust. It’s enough to make you want to throw all your belongings out the window.

Unfortunately, dust is just a fact of life. Anywhere you live, it will live there with you. A certain amount is tolerable, but too much can cause serious health problems. So, where does it all come from? And what can be done about it?

What Is Dust Exactly?

It may be comforting to think that dust is just dirt, but it’s so much more than that. It’s a combination of particles from indoors and outdoors that float in the air and settle in every crack and crevice in your home.

Although its exact components will change based on the type of house, the outdoor environment, and other lifestyle factors, house dust is generally a mixture of:

• dead skin cells
• human and animal hair
• dust mites
• dead insect particles
• soil
• pollen
• fabric fibers
• microplastics

If this partial list isn’t gross enough, consider this: the dust hanging around in our houses can absorb toxic pollutants from cleaning products and other contaminants carried inside on the soles of our shoes. These can include metals, organic pollutants, and a slew of other nasty things that we don’t want in our houses or in our lungs.

Dust is also home to a wide variety of bacteria and fungi, much of which is fortunately harmless to our health.

So, what is all of this stuff, and how does it get in our homes? Let’s explore some of the sources of dust further.

Common Sources of Dust

There is a myriad of potential sources of dust in your house. Some of them are obvious, but others may surprise you.

Dead Skin

Many of us have likely heard someone say that household dust is mostly dead skin cells. However, this isn’t actually correct. Although dust often contains dead skin cells, it’s not the majority of what’s in there.

Dust Mites

Perhaps the most apparent source of dust, dust mites are near-microscopic arachnids that live in basically every indoor space. They thrive in moist environments and can be found in high concentrations in bedding, carpets, and other household fabrics.

Live dust mites – as well as their feces and corpses – contribute to the amount of dust in your house. They like to eat dead human and animal skin particles (gross, we know), so greater dust concentrations in your home will attract higher numbers of dust mites. In other words, dust attracts more dust. Pretty nightmarish, right?

Pets

We love them, but we can’t deny it: pets are a huge source of dust. More specifically, pet dander (tiny pieces of dead skin) attracts dust mites and contributes to dust buildup in many homes. It is also a common allergen. Interestingly, a study conducted in the U.K found that it could predict what kind of pet lived in a particular house based only on analyzing dust samples. Certain types of microbes were found to be more related to cats than to dogs, and vice versa.

Soil and Pollen

The majority of the dust in your house comes from outside. Pollen and soil can both be carried inside on your shoes and clothing. Once inside, they settle in furniture, carpets, and linens. In addition to increasing the amount of dust in your home, pollen is a common allergen and can trigger allergic rhinitis and even asthma.

Construction

Another external source of dust, construction sites produce an incredible amount of airborne particles that can be carried on the wind into your home. Construction dust mainly contains silica (which is released from working with concrete and sandstone), wood particles, and even microscopic pieces of metal. All of these can easily become airborne and end up in your house and in your lungs.

Food Crumbs

Crumbs and smaller food particles are likely to gather around your kitchen table, in cupboards, in your couch – basically in any place where food is eaten or stored. Unless you sweep or vacuum after every meal, crumbs are likely to contribute to the dust in your house.

Lint

It doesn’t just hang out in your washing machine and dryer. Lint and other tiny fibers from your clothing are huge contributors to the dust in your house, and using liquid fabric softener, in particular when you wash your clothes, makes even more dust. This is because fabric softener works by coating the fibers in your clothes and making them feel soft. This coating breaks down, however, and when it flakes off, it contributes to – you guessed it – dust.

Insects

It might gross you out to know that a common component of house dust is insects: specifically, their body parts and fecal matter. This is even more likely if you live in a home prone to infestations of cockroaches or other common pests. Insects can enter your home through the drain in your sink or shower or through open doors and windows.

Contrary to popular belief, insects such as cockroaches aren’t only attracted to dirty homes. Unfortunately, that means no matter how clean you keep your space, you’re still likely to find bugs every now and then.

Toxic Substances

While many people experience allergies and other health problems resulting from dust, most of the components of household dust are not inherently harmful. However, toxic substances such as lead, arsenic, and even DDT (a pesticide that has been banned since 1972 in the U.S) can be found in trace amounts. Trace amounts of lead generally come from wall paint and auto exhaust, and arsenic is the byproduct of processes including mining and burning fossil fuels.

Of course, if you dust off surfaces regularly, then it’s unlikely toxic chemicals are hanging out on your countertops or bookshelves. But carpets, rugs, and hard-to-reach places such as the top of your fridge are another story. In older houses, it’s worth considering deep cleaning your carpets or even replacing them altogether – especially if you have children who play on the floor and are likely to put their hands in their mouths.

Why Is There So Much Dust in My House?

Now that we know some of the most common sources of dust, it’s easier to pinpoint where it might be coming from in your house. The amount of dust in your home can depend on a lot of different factors, including:

• seasonal and weather conditions
• the area you live in
• how many pets you have
• the number of people living in your house
• the habits of the people you live with (particularly with regard to smoking)
• how often you clean

In fact, while it can be tempting to focus on the sources of dust within your home, about two-thirds of all dust comes from outside. It gets tracked inside on our shoes and clothing or enters our houses through windows, doors, and vents as tiny particles flying in the air. Controlling these outdoor sources is definitely more of a challenge, but all hope is not lost.

What Can I Do About It?

It may be impossible to ever fully win the war against dust, but you can put up a good fight. Here are a few things you can do to decrease the amount of dust in your house.  

• Since the majority of dust comes from outside, not wearing shoes in the house and putting screens on your windows can make a big difference.
• Common sense measures such as vacuuming and dusting regularly also help a lot. When you dust flat surfaces, make sure to use a damp towel or microfiber cloth rather than a dry one. This will trap the dust and make sure that you aren’t releasing it back into the air to settle somewhere else.

• Brushing and grooming pets frequently is another important step towards minimizing dust in your home.
•  If you have carpets, make sure to get them deep-cleaned at least once a year. The same goes for washing your curtains, couches, and any other fabric upholstery in your home.
• In your bedroom – one of the dustiest places in most homes – make sure to wash your sheets regularly. If you suffer from allergies, it’s best to wash your sheets once a week in 160°F (70°C) water.

Finally, products such as air purifiers and HEPA filters also make a huge difference and will leave you taking a deep, clean breath of relief.