In April 2022, the World Health Organization (WHO) reached a startling conclusion that should cause sheer panic in every breathing person.
The WHO stated that 99% of all people on Earth breathe air that fails their air quality guidelines (AQG) for at least one pollutant.
That high percentage implies it’s not just citizens of poor countries who are at risk.
In fact, the United States is a rich country where over 40% of the population breathes unhealthy air (ozone and particle pollution) daily.
In light of these staggering statistics, you may be considering indoor air quality (IAQ) testing in your own personal quest for clean air.
Certainly, some dirty air enters your home from the outside. But there are several sources of indoor air pollution in your own home.
If you’re like many who suffer from airborne allergies, asthma, or other respiratory illnesses, good IAQ is essential for health.
Before you break out your wallet and drop big money on indoor air quality testing, there are several things to consider.
In this article, you’ll find out everything you need to know about the pros and cons of indoor air quality testing for the major air pollutants.
You’ll also discover ways to save money through alternatives to indoor air quality testing and still get cleaner air that you can feel good about breathing.
What are the major indoor air pollutants?
The World Health Organization (WHO) updated its air quality guidelines (AQG) in September 2021.
Unlike the United States Environmental Protection Agency (EPA) which states that its own guidelines do not apply to indoor air, WHO standards apply globally to both outdoor and indoor air (occupational settings excluded).
Sadly, neither set of AQ standards are legally binding on governments.
In this article on indoor air quality (IAQ) testing, we’ll use the WHO’s AQGs for reference.
Here are the six air pollutants and their acceptable levels according to the WHO:
| Air Pollutant | Acceptable Level |
| PM2.5 | 15 μg/m3 |
| PM10 | 45 μg/m3 |
| Ozone O3 | 100 μg/m3 |
| Nitrogen dioxide NO2 | 25 μg/m3 |
| Sulfur dioxide SO2 | 40 μg/m3 |
| Carbon monoxide CO | 4 mg/m3 |
Note: WHO guidelines do not take into account air pollutant mixtures or the combined, cumulative effects on health due to pollutant exposures. Yet, in daily life, people are exposed to mixtures of air pollutants both outside and indoors.
Unfortunately, there is little research on the health effects of indoor air pollutant mixtures. Studies on the health impacts of indoor air pollution have established numerous negative health outcomes for each of the major air contaminants including:
- Heart attacks
- Irregular heartbeat
- Reduced lung function
- Cancer
- Liver and kidney damage
- Premature death
How can I know what indoor air pollutant to test for?
Although people spend approximately 90% of their time indoors where air pollution may be 2-5 times worse than outdoor air pollution for some contaminants, there is not a large body of research on indoor air quality.
Using the WHO air quality guidelines (AQG) discussed above, particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide are a good place to start.
But these are not the only indoor air contaminants you may have.
There may be ultrafine particles (PM0.1) and volatile organic compounds (VOCs), including formaldehyde, lead, mercury, and microplastics.
To get a better idea of which indoor air pollutants you’re dealing with in your home, conduct a home pollutant source inventory.
Since indoor air quality testing is contaminant-specific as well as expensive, you need to have a good idea of what you’re dealing with.
If not, you may literally be throwing money away — because of a problem you don’t have.
Home pollutant source inventory checklist for better indoor air quality
Here’s a home pollutant source checklist to use as a guide as you go from room to room and then outside around your home.
Note: All potential sources are listed once. They may be present in other rooms. See the next section for more information on particular air contaminants associated with each source.
The more checks you have, the more contaminated your indoor air will be unless you’re using certain products and appliances that do not contain the pollutants commonly associated with them.
Off-gassing of building materials (including paint and carpet) over the years may dramatically — even completely — reduce VOCs typically associated with them.
Kitchen
- Gas stove, oven
- Woodstove
- Appliances
- Lighting
Bathroom
- Personal care products
Laundry
- Cleaning products
- Gas appliances
Living room
- Furniture
- Fireplace
- Carpet
- Paint
- Varnish
- Walls
Bedroom
- Bedding
- Dry-cleaned clothes
Basement
- Oil or gas heating/cooling system
- Gas water heater
Garage
- Gas-powered car
- Gas-powered lawn equipment
Lawn
- Pesticides
Neighborhood
- Traffic
- Factories
Fossil fuel burning lowers indoor air quality
All of WHO’s major air contaminants listed above are generated from the incomplete combustion of fossil fuels in or around your house.
The older the gas-powered appliance or gas/oil HVAC system, the more likely they are present.
In addition, there are thousands of other pollutants and their decomposition products created in small quantities by the burning of oil and gas.
But don’t assume that small quantities are necessarily less deadly.
Benzene, a known carcinogen, may be one of those air contaminants produced in small quantities by the combustion of fossil fuels.
Charring or burning food may release benzo[a]pyrene, another known carcinogen.
Some personal care and cleaning products lower indoor air quality
The major indoor air pollutants from personal care and cleaning products in your home include:
- Formaldehyde (carcinogen)
- Phthalates (associated with birth defects, cancer)
Sadly, these may not be labeled as ingredients.
For safer products, see the next section on low-cost tips to reduce indoor air pollution.
Some appliances and furniture lower indoor air quality
Dust on appliances and furniture is always a major source of indoor air pollution.
What you may not know is there are fire retardant chemicals that may have been applied to the surface or make up the interior of these items.
Known as polybrominated diphenyl ethers (PBDEs), this is a large family of chemicals. Many have been banned in some countries because they are so toxic.
PBDEs latch easily onto dust that you may inhale.
Lead & mercury lower indoor air quality
If you live in an older house, (pre-1978 in the U.S.), old paint may be a source of indoor air pollution. Chipped and peeling paint are obvious sources of lead contamination.
Lead may also be carried by dust, especially if you’re sanding painted wood or cleaning painted surfaces with abrasive cleaners.
Some paints may contain mercury compounds as antimicrobials. Disturbance to the painted surfaces — by cleaning or hammering — could dislodge this heavy metal and make it go airborne.
Similarly, certain light bulbs contain mercury. If broken, mercury particles could be released into your living space.
Microplastics lower indoor air quality
The most recent addition to this long list of indoor air pollutants is microplastics.
Formed by the breakdown of plastic objects and also released by washing synthetic fabrics, microplastics possess the same toxicity as plastic, a solid fossil fuel.
Many could be ultrafine particles (UFP) of less than 0.1 micron in diameter. They may even be much smaller, of nanometer dimensions.
Recent studies report that microplastics can be airborne. They are both inhaled and ingested.
Functioning much like dust particles, microplastics serve as airborne carriers for other toxic chemicals, too.
Top 10 solutions to improve indoor air before air quality testing
Fortunately, there are several solutions to improve your indoor air quality (IAQ) before paying a lot of money for air quality testing that may not even provide you with reliable results.
By adopting these solutions, you will greatly reduce the quantity of the major indoor air pollutants in your home. You could even eliminate certain pollutants entirely.
Some of these ways may be expensive. Viewed as an investment in your and your family’s health, that will pay you back every day, these are guaranteed ways to improve your IAQ.
- Convert all major appliances to electric.
- Switch your HVAC to electric.
- Do not use a wood stove or fireplace.
- Do not smoke or vape in your home.
- Do not burn incense in your house.
- Choose personal care and cleaning products from less-toxic sources. The Toxic Free Future or Made Safe are sites to begin your search.
- Verify from manufacturers that there are no fire retardants on the appliances, furniture, carpet, or clothes before purchasing.
- Choose paint and light bulbs without mercury.
- Select paint and varnish with no VOCs – or do without entirely.
- Do not park a gas-powered car in an attached garage.
Low-cost actions to improve indoor air quality before air quality testing
Besides the top ten steps you can take to reduce or eliminate indoor air pollutants, here are some low-cost tips to minimize air contaminants and improve indoor air quality before paying for air quality testing.
- Open the windows when the outdoor air quality is good. This information is available through your local weather station.
- Do not wear shoes in the house. You track in pollutants — especially pesticides (like glyphosate) without knowing it.
- When cooking, cover all pots and pans.
- Run the exhaust fans in the kitchen and bathroom.
- Set dry cleaning and new carpets outside for days or weeks so VOCs will off gas outside.
- Seal cracks around windows and doors if outdoor air pollution is bad.
- Vacuum. Vacuum. Vacuum.
Indoor air quality testing for select air pollutants
For people who have (1) completed a home inventory of air pollutant sources; and (2) have followed the recommendations given in the preceding section to reduce or eliminate air pollutants but remain concerned about the potential health consequences for sensitive family members, you may wish to seek professional indoor air quality testing.
Using the World Health Organization’s air quality guidelines (AQG), particulate matter that is 10 microns or smaller (PM2.5 and PM10) is a major air pollutant.
Mold, dust, and pollen are examples of common PM pollution.
Indoor air quality testing for mold, dust, and pollen
There are several at-home test kits intended to identify dust, mold, and pollen levels in your home. Most require that you send away samples to be evaluated.
All test kits for these air contaminants share similar problems including:
- Qualitative results (high, moderate, or low levels) are not informative since there’s no regulatory standard to weigh them against
- Sampling devices (for example, pumps) are not accurately calibrated. They must be recalibrated frequently to get accurate readings. Kits don’t provide the recalibration device needed to do this properly. So, the volume of air you’re collecting is not accurately known. Without knowing the volume of air, you cannot measure the concentration (in micrograms/cubic centimeter for example) of the pollutant.
If you’re concerned about mold, seek a professional mold specialist certified by the American Industrial Hygiene Association (AIHA) or the American Conference of Government Industrial Hygienists (ACGIH) to help you eliminate the problem.
Optical particle counters (OPCs) are commercially available to count the number of particle pollutants in the air.
As noted above, problems with calibration are common with OPCs and DIY digital sensors.
Dust and pollen are best controlled by the low-cost ways to improve IAQ listed above.
Indoor air quality testing for ozone
Because ozone is a highly volatile gas that quickly breaks down, it is unlikely that any testing for it will be worthwhile.
If you’re using an ozone generator in your home for mold remediation, you may have temporary high levels of ozone inside.
Stay away from the area during remediation, then ventilate by opening windows and using exhaust fans to clear the area before re-entering a few hours after ozone generation ends.
Indoor air quality testing for nitrogen dioxide, sulfur dioxide, or carbon monoxide
Some of the byproducts of fossil fuel combustion are nitrogen dioxide, sulfur dioxide, and ozone. They are not present in significant quantities inside your home unless you live next to a major highway or industrial zone and keep your windows open all the time.
Nevertheless, you may find diffusion tubes on the market intended for residential use. These passively collect air.
Rather than using a pump to collect air samples, a substance coating a metal platform inside the tube reacts with NO2 or SO2. The extent of the reaction can be quantified, allowing these pollutants to be measured.
A research study showed that for sulfur dioxide and the VOC benzene, this test result is accurate against standard reactions of known low quantities of contaminants (like those in a home setting). For nitrogen dioxide, this test is not reliable.
You can also buy air quality meters for these air pollutants. They may cost several hundred dollars for each contaminant.
If you’re interested in purchasing one of these meters, request the results from any studies conducted by independent researchers.
If they’re not available, you may rethink whether the purchase would be worthwhile.
The same goes for air quality monitors.
Indoor air quality testing for smoke pollutants from tobacco and vaping
An accurate way to test for secondhand smoke contaminants in your indoor air is through a blood test for cotinine, a biomarker.
Results for serum cotinine as an indicator for vaping use are also reliable.
The higher the serum value, the concentration of smoke contaminants in your air will be correspondingly higher.
This test may be most instructive if done both before and after an air purifier is used while the indoor smoking continues.
If the blood level drops significantly after you start using an air purifier, you’ll be assured that the device is doing its job.
Indoor air quality testing for lead
If you’re concerned about airborne lead particles in your indoor air, you don’t want to risk making a collection mistake with an at-home test kit, especially if you have a baby or young children in your house. Lead is a neurotoxin that causes lasting mental and physical damage.
Airborne lead is believed to be a problem in industrial nations like the U.S. with 250,000 children with elevated blood lead levels in recent years, decades after lead was banned in paint and gasoline.
So to conduct IAQ testing for airborne lead, seek a professional. Consult with your state’s department of the environment for certified testers in your area.
Indoor air quality testing for microplastics
Microplastics are the newest type of airborne contaminant. They are believed to be very common in indoor air, typically found with other pollutants attached to them.
There are various experimental sampling techniques used to collect microplastics. Eventually, one or more of them will become available for home use. However, much more research needs to be conducted before this happens.
To date, there is no at-home test kit specifically designed to detect microplastics. So, for the near future, don’t expect reliable results from any purchase of IAQ testing for microplastics.
Pros and cons of indoor air quality testing
For those still considering indoor air quality testing, here are some pros and cons to consider. We had to think hard to come up with advantages (and still aren’t convinced that they really are pros rather than cons)!
| Pros | Cons |
| Some good-quality tests require a professional to collect air samples from your home | High-quality tests can be costly |
| In cases where you’re sure of the results, it will allow you to select the best air purifier for that particular contaminant(s) | May be a wait time of several weeks before you get results |
| Inexpensive test kits lack accuracy and/or precision | |
| Test results based on one or a few samples taken on the same day (provides a snapshot not overall picture of your air) | |
| Can’t monitor changes in IAQ over long periods of time | |
| There are thousands of contaminants with no reliable testing method for detection or quantification; EPA regulates only 187 of them as “hazardous” |
Air purifiers instead of indoor air quality testing
As an alternative to indoor air quality (IAQ) testing, good air purifiers are an immediate solution to unhealthy indoor air.
As described earlier, your home inventory for pollutant sources enables you to narrow down the most likely air contaminants you have in your living space.
If your problem is dust or pollen, an air purifier with a high-efficiency particulate air (HEPA) filter is required to deal with them.
For smoke, odors, or volatile organic chemicals (VOCs), an air filter with activated carbon, zeolite, metal oxides, or some hybrid of these materials is your best bet.
Because IAQ is dynamic — sometimes changing frequently depending on outdoor pollution and new contaminant sources in your home — it’s wise to purchase an air purifier with both types of specialized filters.
If you’re very concerned about IAQ and absolutely must know exactly what you’re dealing with for health reasons, an air purifier equipped with sensitive sensors for particular airborne contaminants is a good idea.
Key takeaways on indoor air quality testing
Indoor air quality (IAQ) testing may seem like the obvious answer to your indoor air problems. Unfortunately, in most cases, it’s not.
IAQ testing is costly and unreliable.
Another disadvantage is that, by itself, it won’t result in instantly cleaner air.
If you’re experiencing a health problem like difficulty breathing in your home, it’s more critical to get the air clean immediately rather than spend time and money trying to figure out which pollutant is the issue.
Or, if you’re a family with a baby, child, older person, or someone who’s immunocompromised, clean indoor air is important for safeguarding health.
So, opt for a high-quality air purifier instead of indoor air quality testing to eliminate most major indoor air contaminants from your home as soon as possible.
This way, your hard-earned dollars are working for you as an investment in your health and well-being soon after you turn it on. Your money won’t be wasted on IAQ testing that comes up short in many ways.
