What Causes Indoor Air Pollution?

Just like pollution outside, there’s no single source of air pollution inside our homes. It’s a mixture of things inside that release gasses and airborne particles combining to create what ends up being unhealthy air.

The EPA says the following list is the main sources of poor indoor air quality:

Indoor air pollution arises from these variety of sources, each contributing to the overall air quality in distinct ways. For instance, household products and building materials are a significant source of volatile organic compounds (VOCs) which are released from paints, varnishes, wax, cleaning, disinfecting, and cosmetic products, as well as furnishings and building materials like adhesives and carpeting. These compounds tend to release pollutants into the air over time and can continue for an extended period.

Moreover, combustion sources such as appliances that burn fuels like gas stoves, heaters, fireplaces, and tobacco products release a variety of pollutants including carbon monoxide, nitrogen dioxide, and particulate matter into the indoor environment which often lacks adequate ventilation to disperse them. Biological contaminants like mold, bacteria, viruses, pollen, animal dander, and dust mites are another concern as these pollutants are often a result of inadequate moisture control and can be exacerbated by factors such as dampness and humidity. Lastly, the use of pesticides indoors and presence of radon are more major sources that lead to poor indoor air quality.

Building materials, cleaning solutions and hazardous chemicals are also a big cause of bad indoor air. If you live in a home built before 1978, your paint may contain lead. Some older building materials like drywall, insulation or tile products may contain asbestos. Disturbing these through remodels can send dangerous chemicals into the air. Newer building materials like plywood or pressed wood are made with chemicals that give off gasses and odors as they age.

We store adhesives, carpets, chemicals, cleaning products, paints, polishes, and solvents in our homes and attached garages. As they age they can emit toxic chemicals like benzene and formaldehyde which are bad for the air and for breathing. It’s best to store things like these outside in a shed or detached garage.

Why Indoor Air Quality is Worse Compared to the Outdoors

It is easy to think of common sources of outdoor air pollution such as vehicle exhaust and industrial emissions. However, we are now aware of the various pollutants that exist and are released in our homes. Hence, the reasons for poorer air quality indoors are multifaceted and largely stem from concentrated exposure to these pollutants, inadequate ventilation, and the nature of modern lifestyles and building designs.

Concentration of Pollutants

• Indoor spaces accumulate higher densities of pollutants due to limited air circulation.
• Common household products release Volatile Organic Compounds (VOCs) and other chemicals.
• Daily activities like cooking and heating contribute to increased particulate matter and gases indoors.

Modern Building Design

• Energy-efficient, airtight buildings trap pollutants inside.
• Reduced air exchange rates lead to pollutant accumulation.

Extended Indoor Exposure

• People spend up to 90% of their time indoors, increasing exposure to pollutants.
• Continuous exposure even to lower concentrations can have significant health impacts over time.

Indoor-Specific Pollutants

• Radon: A naturally occurring radioactive gas that can seep into buildings.
• Asbestos: Found in older buildings, poses serious health risks.
• Biological contaminants: Mold, dust mites, and other allergens thrive indoors.

Comparison of Indoor vs. Outdoor Pollution Levels

Aspect	Indoor	Outdoor
Pollutant Levels	Often 2-5 times higher, sometimes 100 times higher	Generally lower due to dispersion
Air Circulation	Limited	Constant movement and dilution
Pollution Sources	Concentrated from household products and activities	Dispersed from vehicles and industry
Exposure Time	Up to 90% of time spent indoors	Limited exposure time

To improve indoor air quality:

• Ensure proper ventilation
• Use low-VOC products
• Maintain regular cleaning schedules
• Consider air purifiers with HEPA filters

By understanding these factors, we can take steps to create healthier indoor environments and mitigate the risks associated with poor indoor air quality.

Simple Ways You Improve the Air Quality in Your Home

There are some simple yet crucial methods you can employ, and changes you can make in order to help improve the air quality in your home.

Open the Windows and Increase Ventilation

Open your windows from time to time to let fresh air inside to circulate and dilute indoor pollutants. It’s a good idea, even during the winter months. Make sure to check the air quality outside before you do it as you don’t want to choose a day when outdoor air quality is bad – forcing more unhealthy air inside. Moreover, use exhaust fans in bathrooms and kitchens to remove contaminants directly at their source and prevent them from spreading throughout the house.

Check and Change Your Filters

Your HVAC system can be a contributor to poor indoor air quality if you don’t have the ducts professionally cleaned. The filters used for your HVAC system will primarily only filter out larger particles and will do so only when the system is running. Since your HVAC system circulates air in your home, leaving a dirty filter can force dirty air inside when the system is on. It’s a good idea to buy lower-rated filters. The high-grade HVAC filters can choke off your system and shorten the life of your unit.

It’s easy to forget when to change the filters for your HVAC system – so you can write the date you change them on the filter with a pen, put a reminder in your phone or mark it down on the calendar to help you remember. In between filter changes, check it once a month. There’s a chance it may be dirtier than you expect and might need to be changed sooner.

Don’t Smoke Indoors

If you or a loved one is a smoker, then go outside to do it. And don’t let anyone else smoke inside your home. Smoke from tobacco products is unhealthy to breathe and can cause serious health problems in the short and long term.

Reduce Use of VOC-emitting Products

Limit the use of products that emit volatile organic compounds (VOCs). These include certain paints, varnishes, air fresheners, and cleaning products. Opt for low-VOC or VOC-free options and use such products according to manufacturer instructions, ensuring proper ventilation during and after use.

Test Your Home for Radon

Radon is a dangerous, invisible gas that’s produced naturally from the breakdown of uranium in soil and rocks. Sometimes, it can seep into homes that are built on dirt with natural uranium deposits. It’s believed to be a key cause of lung cancer since it exposes someone to small amounts of radiation when it’s breathed in. It’s important to have your home tested for radon since you can’t see or smell it. You can call a professional or buy a do-it-yourself kit at a hardware store to test your home for it.

Keep the Humidity Level Low

Doing your best to keep the humidity level in your home low – below 50 percent is best. Humidity creates moisture and moisture creates the perfect environment for mold to grow. Mold spores can cause significant breathing issues. Standing water also promotes mold growth, so be sure and fix any leaks or drips you may have in pipes and faucets inside and under your house as soon as you discover them.

Don’t Burn Wood

A wood-burning fireplace is really cozy on a cold night, but burning wood inside causes pollution by sending smoke and unhealthy soot into the air.

Put Things Away

It’s easy to leave food or trash out and think, ‘I’ll get to that later.’ But it’s best to put food away and throw away and cover up your trash. Food and trash create pests like mice and cockroaches. And you may not realize it, but these types of pests leave dander and urine behind that contribute to the pollution in your home.

Keep Things in Working Order

Make sure your stove, furnace, space heater or any other gas-powered piece of equipment is in good working order. Have your HVAC system serviced every spring and fall. The central heat and air system can develop leaks and build up carbon monoxide in your home if it isn’t well-maintained.

Keep Your House Clean

Regular dusting and vacuuming will help keep the air in your home clean. The dust, dirt and pet dander inside your home circulate in the air – making it easier for you to breathe them in. Weekly cleaning and vacuuming won’t get rid of it all, but it will help cut down on the amount that’s inside. And don’t forget to dust off the blades on your ceiling fans. Using them to help circulate air doesn’t do any good if they’re covered in dust.

Invest in an Air Purifier

Air purifiers are made to purify the air. Most of them come equipped with a HEPA filter – which is a highly effective tool at capturing the smallest of pollutants in the air. HEPA filters can capture up to 99.97 percent of the irritants floating around, sending clean air back out. Air purifiers can greatly reduce the amount of particle pollution inside your home and are one of the best ways to ensure you and your family are breathing in healthy air. Here are a couple of our top recommendations:

Alen BreatheSmart 75i True HEPA Air Purifier

The BreatheSmart 75i cleans up to 1300 square feet every 30 minutes. It works with a HEPA filter and has a particle sensor that can let you know the air quality in real-time and adjust accordingly. The unit has five fan speeds and is whisper-quiet. It’s also Wi-Fi-enabled and can be run through the app. It sells for between $700 and $800 and has a lifetime warranty.

Blueair Classic 605

This unit covers up to 775 square feet and can purify the air in the room up to five times an hour. It’s Wi-Fi-enabled, has a HEPA and activated carbon filter, and is equipped with a child safety lock. The Blueair Classic 605 has three fan speeds and wheels to move it around. It costs between $300 and $400 and has a one-year warranty.

Summary

We spend a lot of time at home – because as the saying tells us – there’s no place like it. It can be a source of comfort and peace, but you don’t want it to be a source of polluted air. Taking some simple steps such as improving your homes ventilation, reducing sources of pollution, and regularly monitoring your appliances can ensure a healthier indoor environment.