Everything You Need to Know About Testing Your Home’s Indoor Air Quality—Including the Best Way to Do It

Paying attention to the cleanliness of the air you breathe is a critical part of protecting your well-being. But while outdoor air pollution levels are set, screened, and managed by experts for the population’s overall health, it’s up to you to decide when—and how—to assess the air quality within your home.

Mold, mildew, and radon are some of the most well-known hazards, but overall air quality is affected by much more, including how air circulates inside your home, how clean (or dirty) the space is, the building materials used, and each area’s function. Even the smell of a fresh coat of a paint or the new-plastic scent of a just-opened shower curtain impact your indoor air quality—and so can pollutants you may not even be aware of.

“The tricky thing about air pollution is that it is often invisible,” says David Hill, senior design manager at Dyson. “When we think of air pollution, we often think about the smog over major cities or dust suspended in the air made visible by light streaming in through a window. But actually, much of the pollution in the air is invisible to the naked eye—things like microscopic particles, NO2, formaldehyde, benzene, and viruses.”

The Causes of Poor Indoor Air Quality

Healthy, comfortable indoor air quality is all about balance, says Lisa Rogers, president of the Indoor Air Quality Association (IAQA). Chemical and biological elements, pressurization and ventilation, and temperature and humidity all need to be considered together to determine the quality of your indoor air. “Poor indoor air quality results when there is a failure in the balance,” says Rogers.

Chemicals and Pollutants

“Chemicals like carbon monoxide, formaldehyde, and ozone can originate from furniture, paints, carpeting, cleaning products, and even from the ground beneath the structure we occupy,” says Rogers. “Biological pollutants, such as allergens, fungi, and bacteria can result from unmitigated moisture—like plumbing leaks and relative humidity, animals, and indoor plants. Inorganic sources, like dust, combustion, asbestos, and lead, are associated with poor housekeeping, heating sources, and construction materials.”

Temperature, Circulation, and Humidity

Those pollutants may seem like obvious hazards, but they aren’t the only ones that can make your space uncomfortable. If it’s too hot or too cold; if the air doesn’t circulate, affecting the building’s pressurization; or if the humidity is off kilter, you’re also likely to feel it. “Not all IAQ concerns are the result of a chemical or biological pollutant in the dwelling,” says Rogers.

Ventilation

“Poor ventilation can concentrate otherwise low-level pollutants, and fluctuations in temperature and humidity, lighting, and even sound can be sources of perceived IAQ problems,” says Rogers. The indoor environment can be affected by a multitude of sources that pollute the air we breathe and affect the comfort in our homes and places of work.”

When to Assess Your Home’s Air Quality

Rogers offers a simple technique for deciding whether you need to have your indoor air quality assessed: “Senses and observations!” she says.

Physical Signs of Poor Air Quality

Pay attention to both conditions you can see and smell: You might see visible water damage or discolorations on your walls, floors, and ceilings or smell strange, persistent odors, which could be associated with gas leaks, chemical emissions from new building materials, or hidden moisture sources, Rogers explains.

It’s possible to feel poor air quality’s effects, too. If you observe persistent health symptoms (like a cough, headache, or congestion) inside your house (and nowhere else!); know that your building is old enough to contain asbestos insulation or lead paint; or learn that radon is prevalent in your area, you could have an invisible air quality issue.

Air Quality Monitors

Air quality monitors, which are often built into air purifiers, can identify sudden dips in indoor air quality that might indicate the need for further assessment—even before you register the change. “Sometimes odors can be an indication that you need to test your indoor air quality, but not all pollutants have a smell,” says Hill, noting that these monitors make “invisible pollution more visible.” The reality, he says, “is that everyone is going to have air pollution in their home at some point.”

How to Perform an Indoor Air Quality Test

A professional indoor air quality assessment includes observations, data collection, sampling, and testing, says Rogers. Self-testing kits do exist and allow homeowners to complete parts of this process on their own, but don’t always provide enough information to understand the full picture of your indoor air quality: “Just testing or sampling cannot tell you what the source of your problem is or how to fix it,” says Rogers.

Assessing indoor air quality without the help of a professional offers another challenge, too: It’s difficult to decipher the results. “Air quality is an incredibly complex world,” says Hill. Agencies like the EPA, the American Industrial Hygiene Association, and OSHA offer guidelines for indoor air quality, chemical exposure, and other space concerns, but there’s not a consistent, single standard for “poor” or “healthy.”

“There are very few specific numbers associated with good or bad indoor air quality,” says Rogers. “Often, there are no guidelines or permissible exposure limits available to interpret the data.” This is common with mold, she says: You can obtain equipment and sampling media to perform your own mold sampling, but there are no governmental or industry-related standards or guidance to help you decide if you have a problem. “There are no specific exposure limits for biological contaminants,” says Rogers.

Why It’s Best to Hire a Professional

When you hire a professional to assess your indoor air quality, expect them to take samples and use testing equipment, while also identifying potential problem areas within your home. “Investigating indoor air quality concerns is not just the collection of samples or the use of testing equipment. Rather, it’s a thorough assessment performed by a competent professional,” says Rogers.

Something as simple as storing bleach and ammonia next to each other, for example, can create an unpleasant odor that homeowners may not be able to identify; a professional would spot this mistake immediately. “That is the value of the professional—they provide the whole picture, including the source, interpretation from experience, and the steps to take to fix it,” says Rogers.

How to Improve Your Home’s Indoor Air Quality

When you’re on a mission to keep your home as healthy as possible, fresh, clean air is essential. Air purifiers, increased circulation, and some simple changes to your habits can keep your home’s air quality at its best.

Purchase an Air Purifier

“Adding a whole room purifier can be a great first step in improving air quality,” says Hill. “You need to have an efficient filter system that can capture those pollutants. Dyson’s filter system includes HEPA media and activated carbon and is fully sealed.”

Improve Circulation

“Circulation is key—with no circulation, dirty or bad air can stay in a room,” says Hill. “At the very least, turning on a fan or opening a window may promote better air circulation.”

Keep Air Clean

“Consider activities that may be contributing to poor air quality and take steps to reduce or minimize them,” says Hill. “For example, you may find that cooking on a gas stove may cause a spike in air pollution. Keeping that in mind, you may want to grill outside or add a vent over the stove.”