What is household dust, and where does it come from?

One of the most unpleasant aspects of life — for homeowners and apartment dwellers alike — is dusting. It often seems like it’s a never-ending war. And sadly, dusting done poorly (and even dusting done well) is a self-perpetuating cycle. The very act of dusting stirs up dust and sends it airborne again.

For you to clean up… again.

In this article, I will cover everything you ever wanted to know about household dust, including what it is and where it comes from.

The three kinds of dust: Organic, inorganic and biological

Several of the thousands — if not millions — of unique constituents in dust derive from three general categories. They all reside quite comfortably in the dusty particles under your sofa or on your bed sheets, among many other places, all part of your home biome. 

1. Organic dust

Organic, in this sense, refers to chemicals containing carbon. Here are some examples:

• Synthetic pesticides
• Polycyclic aromatic hydrocarbons (PAHs) from fossil fuel burning
• Black carbon (soot) 
• Semi-volatile organic compounds (SVOCs) from household products

The major chemicals to worry about are synthetic pesticides and polycyclic aromatic hydrocarbons (PAHs). Certain examples from both of these categories are known as carcinogens (cancer-causing) or neurotoxins that may lead to autism spectrum disorders or neurological conditions such as Alzheimer’s. PAHs, along with black carbon (soot), are byproducts of fossil fuel and biomass burning.

Glyphosate (sold as RoundUp) and declared “probably carcinogenic to humans” by the International Agency for Research on Cancer (IARC), is brought inside by tracking or as an aerosol in sprayed areas. So, too, are soot components released from power plants and factories.

Indoor fireplaces, smoking, vaping, and grilling food in your home, creates PAHs, such as the highly carcinogenic benzo[a]pyrene. PAHs are present in leftover charred particles, and these toxic chemicals can also be released into your home airspace. 

Once PAHs settle out of the air, they — and their decomposition products — join up with the closest dust bunny and hunker down indefinitely. The same is true for many other semi-volatile organic chemicals (SVOCs). They are frequently released from furniture, pillows, and carpets through normal wear and tear. Common household items, including certain clothes, shoes, cookware, and personal care products also contribute to the toxic load of SVOCs in dust. 

SVOCs in dust, on carpets, or rubbed off from many objects are easily picked up by your playful toddler or puppy and go directly into their mouths. We identified the best air purifiers for dust in our recent buying guide, which is worth looking at if you have an issue with this type of dust.

2. Inorganic dust

Fossil fuel burning from power plants and factories results in the release of many heavy metal air contaminants such as:

• Mercury 
• Lead 
• Chromium
• Arsenic

A study in the United States Midwest found that 60% of arsenic in household dust came from outside air. The remainder was tracked in on shoes.

Similarly, that study revealed that lead (Pb) primarily entered homes through air transmission from gasoline exhaust. But since lead was banned from fuel in the 1970s in the United States, most of it is now tracked into residences from shoes in contact with Pb fallout from power plants and factories.

Unfortunately, there are many indoor sources of these inorganic air pollutants, too. They are generated from gas stoves, oil-driven furnaces, certain types of light bulbs, or maybe the antimicrobial paint on your walls.

Lastly, inorganic sources of dust include radioactive materials and even stardust from space.

3. Biological dust

Many little critters and their waste products lurking in your indoor dust. Here’s a short list:

• Dust mites and other insects
• Insect waste products and corpses
• Pet dander
• Urine and droppings from household pests (mice)
• Microbes (bacteria and fungi)
• Viruses (technically considered non-living but virulent outside of a living host for several hours)
• Tree and flower pollen
• Human hair and sloughed-off skin cells

Why is it important to know the sources of household dust?

Scientists are keen on understanding the sources of household dust because of the negative health impacts arising from dust exposure. 

The health issues from dust include:

• Respiratory problems
• Asthma
• Allergies
• Lead poisoning

From a public health perspective, once the sources of indoor dust are known, they can be monitored and controlled to prevent community health crises as well as your own personal health issues.

Since most humans living in Western societies spend 90%+ of their time indoors, researchers have coined the term “home biome” for the indoor place where you spend the majority of your time.

Similar to ecological biomes, such as forests or grasslands, your home biome is made up of a community of living organisms  — including you and your family members as well as the living components of dust. For all of you, the physical space of your home is part of the communal home biome, too. 

Another common characteristic among a biome’s members is the complex interactions between them. In the case of dust as a part of your home biome, there are potentially health-harming effects when you interact with the components of dust via breathing or touching it. (Think allergies, asthma, or contact dermatitis here.)

Basically, dusty air reduces your indoor air quality and potentially diminishes your overall health and well-being.

Is all household dust bad for you?

Evidence suggests regular contact with diverse soil microbes when you’re young could boost your immune system by training it to recognize what to attack vs. what to tolerate.

The absence of contact with a wide variety of soil microbes in an overly clean home, some researchers — but not all — hypothesize is analogous to the effect of inappropriate antibiotic use, especially in childhood. You’re more likely to develop asthma or allergies by killing off both good and bad microbes.

There’s also evidence that shows an association between cesarean sections (C-sections) and increased risk of allergy and asthma. Explanations given for this include (again) lack of early exposure to a wide spectrum of maternal microbes that prompt and regulate the immune system to function normally. 

Lastly, owning a pet or growing up on a farm is protective against developing asthma or allergies. In other words, exposure to animal dander is a good thing when you’re young.

However revealing this evidence is, it does not support the notion that living in a dusty environment is a good thing. Although it may be a good idea to have a dog if you have a young child at home, this doesn’t imply leaving all their dander and hair everywhere in large piles of dust that attract VOCs, SVOCs, and microbes.

Maintaining a healthy gut microbiome when young as a way to ward off asthma and allergies is better for you than breathing in dust to accomplish this. In fact, the multiple harmful health effects of dust — especially those caused by extremely small (nano) particles — are well-documented.

Final thoughts

There will always be some dust in your home, including fine particles you cannot see. Because of the multiple negative health effects of dust, it’s a good idea to control the amount of dust in your household air through regular cleaning and vacuuming. A HEPA filter-equipped air purifier will eliminate airborne dust 0.3 microns or larger from your home, making it a great investment for improved indoor air quality.