The most harmful indoor pollutants are invisible and rarely can be smelled, but your lungs, eyes, and nose will still feel them. We spend a lot of our lives indoors, and if you’re experiencing headaches, breathing problems, difficulty sleeping, or allergies, your indoor air quality (IAQ) might be the culprit. This article explains how to measure IAQ and interpret your results, a practical first step toward identifying hidden pollutants and improving the health of your indoor living space.
Why Testing Indoor Air Quality Matters
Since most of us spend the majority of our time indoors, whether at home or at work, we should be concerned with indoor air quality, which can influence our sleep and health.
The problem is in many homes, pollutant concentrations can exceed levels outdoors. Outdoor pollutants make their way inside, but we also get indoor pollutants from our HVAC systems, cooking, cleaning, pets, and more. These become concentrated in enclosed spaces where they can negatively impact your health and even affect your skin.
Unlike outdoor air, residential indoor air quality lacks standardized federal performance limits for most pollutants, making testing it yourself even more important.
What Indoor Air Quality (IAQ) Actually Means
We often use the air quality index (AQI) to tell us how good our outdoor air is, yet far too few people think about their indoor air quality (IAQ).
IAQ is a measure of how clean the air inside your home is. Good IAQ means you have low levels of dust, allergens, chemicals, and biological pollutants, and your humidity is balanced to prevent the growth of mold.
Poor IAQ happens when pollutants become concentrated indoors. This can trigger headaches, fatigue, sneezing, coughing, and itchy eyes. Over time, it may worsen allergies, asthma, and other respiratory conditions.
What Pollutants Should You Test Indoor Air For?
Here are some of the main pollutants that IAQ tests look for.
PM2.5 and PM10
Particulate matter (PM) are small airborne particles. PM2.5 are small particles ≤2.5 microns in size, while PM10 are those that are ≤10 microns in size. Both of these classes are easily inhaled, where they can penetrate our lung tissue and may enter our bloodstream, contributing to asthma, cardiovascular disease, and even premature death.
Particulate matter inside our living spaces comes primarily from combustion (smoking, cooking, incense, and heating), carpets, clothing, and blankets. It can also come from renovations, terpene-based air fresheners, and outdoor pollutants that come indoors.
VOCs
VOCs are volatile (gaseous) organic (carbon-containing) compounds emitted from paints, household cleaners, disinfectants, stored and burned fuels, building materials, furniture, office equipment, dry-cleaned clothing, art supplies, and more.
VOCs vary widely in their chemical makeup, and so do their health effects, depending on their chemical composition and exposure, resulting in a wide range of symptoms.
Carbon Monoxide
Carbon monoxide is an odorless and colorless gas that causes carbon monoxide poisoning, killing 400 people every year in the United States. Indoors, it primarily comes from the combustion of fossil fuels used in cooking or heating.
Allergens
Anyone who is allergic to pollen, dust mites, or pet dander knows how important it is to minimize those pollutants inside our homes. Exposure to airborne allergens can result in itchy, watery eyes, sneezing, and coughing and may trigger asthma.
Biological Pollutants
Biological pollutants include things like molds, mildew, bacteria, and viruses, some of which routinely inhabit poorly maintained HVAC systems. Exposure to biological pollutants can make us sick or cause allergic reactions, watery eyes, shortness of breath, dizziness, and asthma.
Radon
Specialized tests are required for radon, a naturally occurring radioactive gas found in soils and bedrock. High levels can damage lung tissue and may cause cancer. If you find high levels, consult a professional, as you may need a pump installed under your foundation to remove the gas before it enters your home.
How Can I Test My Indoor Air Quality at Home?
Use a Smart Indoor Air Quality Monitor
The easiest and most effective way to test IAQ is using a smart indoor air quality monitor that uses sensors to sample the air in your home. They provide real-time readings for things like particulate matter, VOCs, carbon monoxide, humidity, and more. They should have a display or app that allows for easy monitoring, alerts, and trend tracking.
Choosing a high-quality air purifier that already comes equipped with built-in sensors makes this process even more convenient.
At-Home Indoor Air Quality Test Kits
An at-home IAQ test kit can provide a quick assessment, but they’re rather imprecise. If you notice anything concerning, you may want to confirm it using a second testing method.
Install a Carbon Monoxide Detector
Carbon monoxide detectors can literally be a lifesaver. Similar to a smoke alarm, it will emit a warning if it detects high levels of this deadly gas. However, it will only detect carbon monoxide, no other pollutants.
Professional Air Quality Testing Services
Finally, if you want highly precise results, you may want to consider professional air quality testers. They will come to your home and test your air for you.
Where and When to Test Indoor Air Quality in Your Home
The best place to test your IAQ is in high-traffic areas like living rooms and bedrooms. However, if you have a damp basement or bathroom and suspect mold, you may want to test it or place an air purifier there.
If your purifier has built-in sensors, you can monitor your IAQ continuously from your phone. Otherwise, if you choose the DIY or professional testing methods, testing every 12–18 months is a good idea. However, if you experience headaches, sneezing, fatigue, or irritability that improve when you leave your home, test your IAQ immediately.
How to Interpret Indoor Air Quality Test Results
Different tests will display pollutant levels in different units, like parts per million (ppm) for gases, % for humidity, and micrograms per cubic meter (µg/m³) for particulate matter.
Knowing what thresholds to be concerned about is important. While this varies with the pollutant, here are a few things to look for:
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The EPA recommends PM2.5 levels below 9.0 µg/m³ (outdoors) to protect human health; indoor targets should remain below this level.
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The EPA suggests a carbon monoxide limit of 35 ppm for 1 hour (outdoors). Levels indoors next to poorly adjusted gas stoves may be around 30 ppm.
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Humidity levels between 30 and 50% are ideal to reduce the growth of mold.
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Track your results and look for changes, like VOC spikes during cooking or cleaning. If you see this, improve your ventilation or try different cleaners.
What to Do After Testing Your Indoor Air Quality
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If elevated pollutants are detected, a high-efficiency air purifier should be used to remove the majority of airborne pollutants.
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Inspect and maintain your HVAC system and any gas appliances.
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Ensure proper ventilation by using fans and opening windows or doors to reduce the buildup of pollutants.
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Use smart monitoring systems for real-time monitoring and ongoing control.
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Use a dehumidifier if your humidity is high.
Frequently Asked Questions
How to Tell if Your Indoor Air Quality Is Bad?
An air quality test is the best way to tell if your air quality is bad. However, if you experience sneezing, coughing, watery eyes, nausea, or worsening allergies or asthma that improves when you leave your home, your quality is likely poor.
How Often Should You Test Indoor Air Quality?
If you rely on DIY or professional testing, every 12–18 months is often recommended, while some sources say every 1–3 years. Alternatively, an air purifier that has built-in air quality sensors will allow you to continuously monitor your IAQ.
Indoor Air Quality Testing Enables Healthier Home Environments
We all want clean air, and IAQ testing should not be guesswork if you want to control what you breathe. By understanding what indoor air quality is, identifying common pollutants such as particulate matter, VOCs, and allergens, and choosing the right testing method, you can obtain real data. Once you know what’s in your indoor air, you can take steps to improve your air quality. You can improve your ventilation, maintain your HVAC system, and use an advanced system like the Dreame’s high-efficiency air purifiers with multi-stage filtration, intelligent sensors, and continuous monitoring to provide measurable IAQ improvements without guesswork.
References:
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Elsevier (2019) Are we safe inside? Indoor air quality in relation to outdoor concentration of PM10 and PM2.5 and to characteristics of homes. Available at: https://www.sciencedirect.com/science/article/abs/pii/S2210670718307339
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PubMed Central (2024) The impact of indoor air pollution on children’s health and well-being: the experts’ consensus. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11017701/
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U.S. Environmental Protection Agency (n.d.) Carbon Monoxide's Impact on Indoor Air Quality. Available at: https://www.epa.gov/indoor-air-quality-iaq/carbon-monoxides-impact-indoor-air-quality
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U.S. Environmental Protection Agency (n.d.) What is the average level of carbon monoxide in homes? Available at: https://www.epa.gov/indoor-air-quality-iaq/what-average-level-carbon-monoxide-homes
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