What is Indoor Air Pollution and What Causes It?

It seems like everyone is talking about indoor air pollution these days.

And the threat it poses to your health.

Within the last decade, there’s also been a surge in the air purifier market to help combat this problem.

But what is indoor air pollution exactly?

And what causes indoor air pollution?

Those are the two topics we’re going to cover in this post.

By the end, you’ll know enough about indoor air pollution to talk about it with your family and friends as well as how to protect yourself against the threat of it.

What is Indoor Air Pollution?

Indoor air pollution refers to the contaminants floating within any structure, such as a house or commercial building.

These pollutants might be chemically or biologically based, depending on your region and daily habits.

Most people don’t think too much about the indoor air’s potential for contaminants. The home or office might smell good or have no odor at all, but there will always be particles floating around that cannot be seen.

Whether you’re indoors or outdoors, all air contains a mixture of substances that can make you sick. If you could trap a square foot of air into a virtual box, you can create a PPM or parts per million count of particles versus air molecules.

For many households, the contaminant levels can be alarming. In fact, the U.S. Environmental Protection Agency estimates that indoor pollutant levels are 2 to 5 times higher than the outdoors.

That’s because there are so many things that contribute to indoor air pollution, which we’ll cover next.

What Causes Indoor Air Pollution?

Now that you understand what is indoor air pollution, what are the root causes behind it?

Some of the things listed below may seem obvious, while others not so much.

Is indoor manageable? In most cases, the answer is yes.

Often, you just need to make smarter choices about what you use or bring into your home to cut down on the level of indoor pollutants. However, the best thing you can do is use an air purifier in your home.

An air purifier can eliminate most airborne contaminants from the air you breathe. This leads to cleaner air and a healthier living environment.

To see what’s most affordable, check out our best inexpensive air purifier page. Or, to browse through the best models, regardless of price, view our list of best home air purifiers.


One of the major contributors to air pollution is moisture. Homes are prone to numerous leaks, including plumbing pipes and fixtures. Some of these leaks may not be visible to the owners at first.

The result is mold and mildew growth within the moisture. These microbes give off particles that can float in the air. If a leak is chronic, the microbes will continue to replicate and move within the indoor space. After some time, the indoor air will be saturated with particles that can harm the residents.

Building Materials

Carpet, paint, drywall, and furniture can all give off specific fumes. These fumes might have harmful chemicals mixed into them. Older homes are more vulnerable to this type of indoor air pollution. The building materials manufactured at the time weren’t based on today’s health concerns.

Asbestos and lead are two materials that greatly contribute to the home’s pollution levels. There are professionals who can identify affected homes. They must remediate the home so that harmful contaminants don’t continue to impact the family. The only way to reduce pollution from old building materials is to have them removed from the property altogether.

Household Cleaners

Household cleaners with harsh chemicals leave lasting air pollution within the rooms. Look for products that have organic ingredients. There are many products that are leaning towards this type of ingredient makeup. Bleaches and similar products produce fumes and leave residues that can be harmful to people over time.

Be aware that sprays contribute to indoor air pollution more readily than liquids. They become airborne at the outset when sprayed onto a surface. Isolate the cleaner to your target area whenever possible.

Outdoor Sources

Radon and pesticides are outdoor contaminants that frequently enter the home. As elements break down in the soil, radon can be the byproduct of this process. Its fumes move up through the ground, into household cracks and spread into the indoor spaces. Radon is odorless, and it can cause severe health problems.

Sprayed pesticides around the home pose an issue as well. Ideally, avoid pesticide sprays and try alternative methods. The nearby outdoor areas will be free of these chemicals, which makes it easier for you to control the indoor air mass.

Fuel-Burning Appliances

Natural gas that fuels your furnace, stove or oven is certainly safe for daily use, but there are contaminants that do enter the indoor area. Levels of carbon monoxide and nitrogen dioxide are known to rise in households with gas-burning appliances. Contaminant levels are worse when the home is completely closed up, such as during the winter months.

Other fuels include charcoal or wood. Although these items are inexpensive and traditional as sources of warmth, they give off an astounding amount of toxins. Use these fuels on an infrequent basis if possible.

Smoking Habits

Tobacco and vaping are two sources of indoor air pollution that can be immediately controlled. The fumes permeate fabrics and even drywall. Smoke and vapor will remain in the living space for a long time after the smoker has finished with his or her session. Anyone within the home will inhale the secondhand smoke, which is full of harmful contaminants.

Control these contaminants by asking any smoker to go outside. Ask the smoker to stay away from the front door too. It’s always a good idea to control indoor air pollution whenever possible.

Pet Contributions

The family dog or cat is a loving member of the household, but these animals create their own form of indoor air pollution. Dander from fur, skin, and nails mixes with other contaminants at the carpet level. Babies and toddlers are particularly vulnerable to pet dander because of their proximity to the floor.

Cats using the litter box and dogs that move in and out of the home through a pet door will also add more contaminants to the indoor air. Vacuuming the home and bathing the pets on a regular basis can control the dander to a certain point.

Air Purifiers Can Help

So, what can you do to lower the level of indoor air pollution inside your own home?

We mentioned this briefly at the start of the last section, but one thing you can do to keep contaminants out of the air you breathe is to use an air purifier.

Air purifiers clean the air of harmful particles so it becomes fresh and pollutant-free.

You can check out the most inexpensive air purifiers available on our best inexpensive air purifier page. Or take a look at the very best models on our top 10 list of best air purifiers.

Regardless of the model you choose, having any type of air purifier in your home is better than none.