What Is Dust?

No matter where you live, dust is a nuisance that invades your home, work, and car every day. While dust surrounds us 24/7, most of us know very little about it. 

This article will delve into the science of dust, answering the questions “what is dust,” “where does dust come from,” and “can an air purifier get rid of dust?”.

So What Is Dust?

Dust is a fine, dry material that is made up of tiny particles of organic and inorganic material. This includes fragmented soil, plant matter, volcanic matter, and pollution.

Roughly 50% of all household dust is dead skin cells. Dust particles are extremely light, which is why they drift through the air and settle on surfaces in your home.


Where does dust come from?

Dust comes from inside and outside your home. While internal dust (like skin cells) originates in your home, external dust travels into your home on your shoes, bags, clothes, and items you bring into your home.

If you have a pet, they are likely your primary dust culprit – as they bring external dust into your home on their paws and fur.

Once inside, this external dust combines with internal dust to form the dust layer you are used to sweeping up. 

As dust comes from various sources, dust particles don’t look the same under a microscope.

If you were to examine the dust in your home, you would notice that your fust consists of pollen, hairs, furs, skin, fibers, minerals, soil, soot, cigarette matter, and plastic waste.

dirty dust

How small are dust particles?

Household dust particles are generally less than 100 microns in diameter. A micron is a millionth of a meter (or 1/25,400 of an inch). As dust is so small, it can have serious health effects when it enters the human body. 

Generally, there are three types of dust particles in the human body. That includes inhalable, thoracic, and respirable dust particles.

Inhalable dust particles enter your nose when you’re breathing normally and travel through your digestive tract. These are 100 microns in diameter or less.

On the other hand, Thoracic dust particles enter through your mouth and nose and are small enough to reach your lungs at 10 microns in diameter or less. These particles are often referred to as PM10.

Finally, respirable dust particles are small enough to penetrate the alveoli, the part of the lungs where gas exchange happens. They are less than 2.5 microns in size. Respirable dust is the most dangerous type and is often referred to as PM2.5.

What Are The Body’s Defense Mechanisms Against Dust?

When you breathe in, your nose filters out most of the dust particles. Dust is also removed through sneezing and exhaling.

When dust particles reach the trachea (the tube leading to the lungs), the cell lining of your lungs will secrete mucus that traps particles. The cilia or fine hairs covering the airways then move the mucus upward for disposal.

If dust precedes past the trachea, they are attacked by macrophages. These special cells eat the particles and push them back to the cilia. The cilia then move the macrophages upward (just like they do to mucus).

These layers of defense mechanisms mean most people shouldn’t be too worried about inhaling a low level of household dust.

What Are The Health Effects Of Inhaling Dust?

Inhalable dust particles that manage to get through the many defense mechanisms in the airways may trigger asthma attacks, coughing, sneezing, and hayfever.

In more severe cases, the particles may cause injuries to your lung tissue. The seriousness of the injuries depends on the type of dust particles and the length of exposure. Severe inhalation may cause fibrosis, scarring, and fibrous tissue formation.

One dangerous type of dust that can cause fibrosis is silica dust. Fibrosis by crystalline silica is a condition called silicosis. It impairs lung function and can be lethal.

If you inhale asbestos dust, not only will you get fibrosis, you can also get cancer. Studies have shown that asbestos can cause lung, larynx, and ovarian cancer.

Asbestos can also cause mesothelioma, a rare form of cancer that commonly attacks the membranes enveloping the lungs (pleura) and abdomen organs (peritoneum).

Is A Facemask Effective In Preventing Dust From Getting Into Your Lungs?

It depends on what kind of mask you’re talking about. If the mask is only a piece of handkerchief tied around your nose and mouth, then it can stop 28% of dust particles from entering your airways.

If you want to prevent dust exposure, you need a mask with a HEPA filter. If you can’t get your hands on one of those, use a surgical mask instead.

They can block up to 80% of dust. For best results, find out what name-brand masks the doctors and nurses in your local hospital use. If it’s good enough for them, it’s good enough for you.

If you want something even better, go and buy cheap 3M masks. Despite their low price, they can block over 90% of dust particles.

What Are Dust Bunnies?

Dust bunnies are just balls of dust, lint, and hair that you can find under the bed, under the furniture, and in corners that are rarely cleaned. They are called dust bunnies because the lump sometimes resembles a cute little bunny.

dust bunnies

Dust bunnies are not dangerous on their own. Only when dust mites settle in them that they become a threat to your family’s health.

To get rid of dust bunnies, use the crevice attachment on your vacuum cleaner to clean under the bed, furniture, corners, and other hard-to-reach places. An air purifier will also help prevent dust bunnies from gathering.

What Is A Dust Mite?

Dust mites are microscopic bugs that dwell in household dust. Dust mites are 250 to 300 microns in length. That’s about double the thickness of the average human hair. Almost every home has dust mites hidden somewhere.

Dust mites feed on dead skin cells, but they don’t bite humans. However, dust mites are still dangerous to human health because their feces and body fragments can trigger an allergic reaction.

To prevent dust mites from breeding freely in your home, use a dehumidifier to keep the humidity level less than 50%. You should also wash bedding bi-weekly and use an anti-allergy mattress cover.

dust mite

How Do I Save Time When Dusting?

First, you need to dust from top to bottom (to let gravity help you clean up). Secondly, dust before you vacuum the room. If you dust after vacuuming the room, you’ll need to vacuum the dust that falls onto the carpet and floor.

Finally, stop using a feather duster. It will push the dust around instead of catching it. Instead, go with a damp microfiber towel as it picks up and removes dust completely. 

Microfiber is a synthetic material made by blending polyester and nylon. Microfiber towels are superior to cotton towels when it comes to cleaning surfaces. Microfiber towels leave no lint – so you won’t end up leaving extra microparticles to clean later.

Here’s a close-up view of what microfiber cloth looks like.


Microfiber cloths also work great on windows, as they trap the dust between its fibers and prevent smearing.

I Clean Daily, But My House Is Always Dusty. What’s Going On?

First, check that your house is well insulated. A lack of insulation is a common theme among homeowners with similar complaints. 

Sealing any air leaks will also reduce the chance of outdoor dust getting into your home. A properly sealed home is also easier (and cheaper) to cool and heat. Consider that as a bonus.If you want to find areas with air leakage,m look for spider webs.

Spiders rely on a breeze to carry their thread across a vast distance. That’s why you find spider webs span across trees. If you see a spider web on a corner in your home, then there is a leakage nearby with a breeze.

Do Air Purifiers Get Rid Of Dust?

While your home will never be fully dust-free, running an air purifier can reduce the amount of dust significantly. With an air purifier, you’ll see less dust, as the purifier will collect it before it can stick to any surfaces.

Air purifiers also reduce dust mites and dust bunnies.

In addition to an air purifier, you should vacuum regularly (especially if you have plenty of carpeting in the house). Be sure to vacuum upholstery, bedding, and every surface, nook, and cranny you can find.

Groom your pets regularly too. Do it outside so their fur, hair, and dander won’t spread all over your home. Or just take them to a professional grooming service.

What About Drywall Dust?

Ah, yes. Drywall dust – the devil of home improvement. If there’s ever a contest for the most annoying type of dust, drywall dust is the winner. Unlike normal dust that gets blown away easily, drywall dust lingers long term. Whenever you’re remodeling a room in the house, you will find yourself still cleaning up drywall dust for months after.

The best way to get rid of drywall dust is to run your air purifier on full blast while you’re working on the drywall. Be sure to cover all furniture (and we mean everything) while you’re at it. Drywall dust has a knack for going places you don’t think is possible.

Once you’re done doing the dusty work, vacuum immediately while keeping the air purifier running. Vacuuming will blow some of the dust particles back into the air.

The air purifier will capture those particles before they find a place to settle

Tip: Running your air purifier during a major home improvement project means you must replace the filter once the project is completed. Don’t wait until the normal replacement schedule. That filter will be too clogged.

How Do I Stop Road Dust From Getting Into My Home?

Living on a street with heavy traffic will give your house road dust, plus exhaust dust, as a fun bonus. An excellent way to reduce the amount of dust getting to your home is to plant shrubs and trees.

These act as buffers and shields while improving your privacy. Plants are also excellent for blocking out road noises. 

If your street is particularly dusty, make it a habit to spray the leaves every month. This will help the trees grow healthily so they can keep blocking those dirty dust particles from entering your home.

Tip: Please note that some of the dust particles will still get through as long as your home is not airtight. It will be prudent to keep an air purifier running so your home won’t end up dusty all the time.

Does Dust Have Any Use At All?

Of course. Dust plays an important role in the climate. Airborne dust particles act as condensation nuclei, which allows clouds to form. There’s a piece of dust particle hidden within each raindrop and snowflake.

So far, scientists have not found any special properties of dust particles that help form ice crystals and raindrops. Any random piece of dust that passes by you may end up inside a raindrop one day.

The usefulness of dust particles can even manifest thousands of miles from where the dust is formed.

Each year, about 27 million tons of dust from the Sahara fertilizes the Amazon rainforest and the Atlantic Ocean. Saharan dust is rich in Phosphorus, an important nutrient for trees. The migration of dust from the Sahara is so massive that it is seen from space.

Watch this video from NASA that visualizes just how much dust is involved in this process.


So there you have it. Dust, dust mites, and dust particles are a natural part of the world around us. While dust may be natural, however, it is both annoying and potentially dangerous when inhaled.

To keep yourself and your family safe, always vacuum regularly, monitor dust levels in your home, and use an air purifier to keep your home dust-free.


Karie is a science-obsessed writer with a sensitive nose. She has been using air purifiers for many years, and uses them obsessively to keep her home dust-free. She is passionate about helping people find the right air purifier for them.