Improving Indoor Air Quality

Checking and improving your indoor air quality

Do you need to improve your indoor air quality? What do you smell when you walk in your front door? Do you smell air fresheners, dryer sheets? Who knows what chemicals are in these products and how many are harmful to your health?

Who knows what they do when they accumulate in your body? Or what their synergistic effects might be? [“Synergistic” means that 2 + 2 = 5, that when two or more are added together, their total effects might be worse than the sum of either separately.]

The Environmental Protection Agency added synthetic fragrances to the list of chemicals that can promote asthma. For more information on synthetic fragrances, go to the website of the Environmental Working Group,

Incidentally, mold growth can quickly reduce air quality. Mold will be handled separately in the next topic.

Step 1. Get rid of synthetic fragrances

This is an easy first step to improve your indoor air quality. Though there are costly laboratory tests that can give you the total levels of volatile compounds in your air, you can improve air quality on your own, without laboratory testing. Simply, discard anything with fragrance, including the following:

  • Air fresheners, including plug-ins
    The alternative is to deal with whatever is being masked by the air fresheners, to bring in fresh air, ventilation, possibly some cinnamon sticks boiled on the stove. Essential oils may be ok but some people are sensitive to these oils and cannot be around them.

  • Laundry products, including dryer sheets
    The alternative is to buy fragrance-free products. Use less detergent than called for to make clothes softer. Use ½ cup of hydrogen peroxide instead of chlorinated bleach. Products with chlorine don’t belong in a healthy home. Vinegar is an air pollutant; use it in salad dressings, not for cleaning. One study assessed the air quality in dryer vent hoses and found unacceptable levels of pollutants. Try Branch Basics, a versatile laundry/cleaning product,
    One client had an ozone laundry treatment gadget installed and was very happy with it. No detergent needed. Search on Amazon.

  • Personal care products
    To improve your indoor air quality, remove all products with fragrance, including body washes, soaps, deodorants, aftershave lotions, perfumes, etc. Why walk around in a toxic cloud? Who knows what chemicals are being absorbed into your body from these products? Go to fragrance-free, hypoallergenic products. Buy a deodorant rock at a health food store.

  • Cleaning products
    Remove all products with fragrance, including pine scent. Few fragrances are "natural." Most are chemical concoctions. Seek out scent-free products, or make your own. You can find recipes online, or search on Amazon, "book natural cleaning products." Branch Basics was mentioned in the laundry section. SuperClean is an all-purpose cleaner available at
Step 2. Minimize your exposure to plastics, especially around food, water, and in your children’s bedrooms.
  • Don’t heat plastic in the microwave oven. Avoid microwave ovens in general for cooking or heating food.

  • Use glass containers for food storage. Remove plastic wrap on vegetables or better, shop in a local farmer's market.

  • Avoid plastic toys as much as possible.
Step 3. Minimize your exposure to combustion by-products.
  • Electric
    Study the offerings at If/when you can, convert to electric.

  • Natural gas
    If you have a gas stove, you will have combustion by-products in your kitchen. Gas stoves add to indoor air pollution. Some individuals cannot tolerate them. Use an exhaust fan to the exterior when cooking, or open a nearby window. The stove should have an automatic pilot. Preferably, update to an electric stove, not a model with the two big burners in the front. Cook on back burners first.

    If you have a gas fireplace, make sure the exhaust is directed outside, not released into the room. If the exhaust is released into the room, get rid of the gas fireplace – or use it only in power-outage emergencies and then have a nearby door or window open.

  • Oil
    If you have any small oil leaks, apply enzymes (available in the cleaning products aisle of a large health food store) on the oil. If you have an older buried oil tank, upgrade to a new tank, or convert to gas. Check with your health department for regulations about removal or shutting down of oil tanks. Homeowners’ insurance policies typically do not cover oil spills from tank failures. Tank failure can happen indoors, too. There are ways to pressure check for leaks. Check with your oil company or health department for advice.

  • Carbon monoxide
    Make sure you have working carbon monoxide detectors on each floor with a combustion gas appliance, plus where you would hear one at night. If you have an attached garage used for a car, it’s also a good idea to put one in the room next to the attached garage, should you ever dash inside to answer a phone and forget the car is running.

    Some folk live in levels of CO too low to set off their alarm. A low-level CO detector is recommended, such as the Defender, LL6170, available at This company also offers better quality standard CO detectors..

  • Vehicle exhaust
    If you park your car in an attached garage, you will likely have exhaust gases in your home. Weatherproof the door between the garage and the house. Seal up holes as needed. Put an exhaust fan in the garage to run on a timer when a car comes or goes.

  • Vehicle exhaust from the street
    Hopefully you don’t live on a busy street. If you do, at least you could open windows during the night when the traffic is less. 
Step 4: Assess if you have sufficient fresh air in your home.
  • Fresh air
    Many homes are so tight that there is little fresh air coming in, especially in the bedroom at night. Levels of carbon dioxide go up, as levels of oxygen go down. Crack a window. The HVAC (heating, ventilation and air conditioning) fan could be put on "on" instead of on "automatic," to help dissipate the build-up of gases.

    Monitor levels of CO2 with a simple CO2 detector. Outside levels are typically under 500 ppm (parts per million). Inside levels are often at 1000 ppm or more, a level at which people experience mental sluggishness. Depending on the tightness of the house, the lack of ventilation, and the number of inhabitants, levels can rise to over 2000 ppm.

  • Ventilation
    Many indoor air quality specialists are recommending filtered, dehumidified, fresh air with a positive pressure for homes. Aprilaire is a leader in this area. A dehumidifier would bring in filtered fresh air, dehumidify it, and supply it to the return of your central air/heating system.

    There are two other components to be added to this. First, a 5 inch pleated media filter, MERV 11 or 13, would be placed in the return after the fresh air is brought in. Next, the HVAC contractor would seal off gaps where outside air is sucked in. You also could do that by removing the return filter and, in the dark, shining a light inside the furnace housing. The light will show where the gaps are that need to be sealed.

    Sadly, though ERVs and HRVs (energy/heat recovery ventilators) are energy efficient, they draw in air that is not dehumidified, and mold can grow in ductwork.

    Note: Your HVAC contractor may offer to sell you something else instead of a dehumidifier/ventilator, such as an air scrubber, UV light, stand-alone dehumidifier, electronic air cleaner, etc. No. No. And, no. You want just the above Aprilaire set up. If you have that, and start with a clean system, you don't need the rest. The Aprilaire website also lists Preferred Contractors, who have had advanced training. Please let me know if you have a good experience with one of them or if they try to sell you on a different approach. If your HVAC contractor is willing to work with you but is unfamiliar with the Aprilaire product line, Aprilaire Regional Sales Managers are available to answer questions and provide other guidance.

    An Aprilaire dehumidification unit can also be used to bring in fresh air even if your house has no ductwork. The fresh/filtered/dehumidified air can be released in the basement or upstairs.

    How to check if your system is clean

    Go to the website,, and order the Big 2 test, $85 version. If you have two central air units, order two tests. You will be sent a swab, a chain of custody form to fill out with your information, and instructions. Ignore the lab’s instructions on where to sample. You just want a clue about whether your central air/heat has mold growing deep inside it.

    Take the swab and sample at a supply vent cover (where the conditioned air comes into the room).

    First check your vent cover. If it is slippery, like being enamelized, it doesn’t hold dust. You may get a false negative result. Take off the slippery vent cover and sample as deep inside the ductwork as you can get. If the vent cover is rough, that’s good to check on the undersides of the fins. Most vent covers are OK to check.

    Hold the swab stick near the swab end. Press down on the underside of the fins of the vent cover. Rotate the stick to collect dust. Go up and down, up and down the undersides of fins. You could add another vent cover into the sample if you wish.

    The number you get will just be a clue as to what might be happening deeper in the system. See this writeup with three DIY model remediation stories to explain more what the numbers mean and what to do about them. The numbers will not represent spores. They are "spore equivalents." That means, if a spore dries out and disintegrates into 200 little parts, the report records "200." 30,000 spore equivalents in the report are elevated but the highest I have seen from a malfunctioning system was over three million.

    This sort of test is just a gauge, just a clue. Is there any mold? Is it a lot or a little? Is it one of the kinds of molds that need more water to grow and may point to a failed humidifier or a drainage issue in the air exchanger. The air exchanger would most commonly be the source of mold growth --- and a duct cleaner cannot access that. So what to do? The air exchanger may need to be replaced.

    Here’s something to remember: there can be a very high level of spore equivalents, but you won’t be able to see them, not even an accumulation, because they are little bits and pieces of spores, still identifiable through DNA testing, which is what the Big 2 test assesses.

    How to check if your room is clean

    Many folk use the ERMI or HERTSMI test on house dust. The Big 2 test does more and costs less. With ERMI, you get fewer than 20 species of Aspergillus/Penicillium scanned; with HERTSMI, 2 species. Because the Big 2 scans for the genus (instead of individual species), all 400 species are scanned, plus Stachybotrys, for about 1/3 the cost! There are 3 important add-ons with the $85 version, including Chaetomium, Trichoderma, and Cladosporium.

    So, you could use the Big 2 to check the dust in a room. Kim, a client who wanted to do the cross-contamination clean-up herself, rather than pay another $3,000 to the remediator who handled the source of the mold growth, did before-and-after testing on five rooms. Her results were phenomenal! Before cleaning, one room had 52,000 spore equivalents per swab for Aspergillus/Penicillium and 5,000 for Stachybotrys. After cleaning, levels were down to 180 for Aspergillus/Penicillium and to ND (non-detect) for Stachybotrys.

    I told Kim that she brought hope to many folk with her little experiment and these results.

    But two rooms were still high. They had received the same cleaning, but something went wrong. In our discussion, Kim immediately realized what had happened. She had forgotten to clean tops of window frames in those rooms, and the old dust skewed the numbers for the whole room. What are we told to sample with ERMI/HERTSMI? Old dust! Joe Spurgeon, PhD, at, tells us "Presence does not equate to exposure." Sample where you would be exposed.

Step 5: Minimize exposure to pesticides.
  • Pesticides
    Remove all pesticide sprays. Call your town to learn about proper disposal of toxic wastes. If you need a pest control operator, seek out an organic pest control operator. An Integrated Pest Management company would be second choice. IPM means different things to different companies. If you use an IPM company, question them carefully about what products they will be using.

  • Gardening
    Seek out an organic lawn care company, or provide your own organic products to your current company. Practice organic gardening, for everyone’s health at your home. Chemicals can be tracked inside. Children and pets may be exposed. If food is grown, you don’t need to be eating chemicals along with it.
Step 6: Reduce levels of dust and other particulates in your air.
  • Cleaning
    Use only a HEPA vacuum cleaner with a sealed chassis. "HEPA" stands for "High Efficiency Particulate Arrestor." That is, it captures tiny particulates as small as mold spores. Other vacuum cleaners tend to recycle these particulates back to room air. Check out the Miele C3, among other HEPA models. The C3 has rubber gaskets to seal against room air. Shark is a lower end vacuum, with most models being HEPA and some labeled "sealed container," so dirty air doesn’t leak out before it gets to the filter. Some stick vacuums are HEPA and some are not.

  • Carpeting
    Carpeting is one of the worst investments in a home, from a health standpoint. It traps allergens (dust and dirt, pollen, mold spores, cat and dog dander, dust mites), and is impossible to get completely clean. If you have used a conventional vacuum cleaner, there are likely to be years of accumulated tiny particulates in the carpeting.

    In addition to being a storehouse for particulates, carpet typically off-gases toxic chemicals, especially when new. You can reduce, but not eliminate, the risk of off-gassing by looking for a green label carpet or a natural fiber carpet/padding. Don’t put carpeting, particularly natural fiber carpeting, in a basement.

    If you have high pile carpeting, you will likely need a power nozzle for vacuuming. Even though you might have the best HEPA vacuum cleaner, the vent at the power nozzle does not also have a HEPA filter and typically discharges high levels of particulates back into room air. Avoid high pile and shag rugs. For low pile, you could use a turbo nozzle, which is not electrified, to greater or lesser success.

    Filter at HVAC system
    An 11 or 13 MERV boxed, 5 inch pleated filter, such as an Aprilaire, Lennox, Carrier, or other quality filter is recommended, in the return before the furnace. Avoid fiberglass filters, because dust passes through them. Avoid electrostatic and electronic cleaners, because they work fine until they get coated with dust. Electronic cleaners also add electrostress throughout the house.

    From a health standpoint, the purpose of a filter is to keep the AC coils clean. Since the AC coils are a site of condensation, if they are dirty, you have food and water for mold to grow.
    Duct cleaning was addressed above.

  • Room air purifier
    If you like windows open, don’t run a room air purifier, or you will be purifying the great outdoors. If you have a HEPA vacuum cleaner and a controlled indoor environment (windows closed, fresh air source, superior pleated media filter in your HVAC system, good housekeeping, lack of clutter), you probably don’t need a room air purifier to remove more particulates from room air.

    If you need a room air purifier for health reasons, plug it in on the opposite side of the room from a bed. If you can, turn it off at night to reduce electrostress from the motor.

    Again, look for a room air purifier marked "HEPA," which removes 99.97% of all particulates 0.3 microns or larger (the size of mold spores). Check out the Aprilaire room air purifier, the IQ Air, maybe the Air Doctor or similar. If you order the Air Doctor, call in the order. They may be having a special not listed on their website.

    If a sensitive person needs a "safe room," the IQ Air can be modified to accommodate. Please email me for details.

    Know what you are trying to remove from the air. Use a HEPA room air purifier if you are removing particulates. HEPA will do nothing for gases, though. If you want to reduce levels of gases, you will need a room air purifier with carbon, such as the Austin Air. Don’t place an Austin Air in a musty-smelling basement, though, because mold and bacteria can grow in carbon.

    Remember, dust collects on horizontal surfaces. If you feel stuffy in bed, your bedspread or blankets may need to be washed. What about a bedspread that needs to be dry-cleaned? Try shaking it outside. In the olden days, the blankets and quilts were hung on a clothes line and beaten with something like a tennis racket for dust removal.
Step 7: Reduce exposure to biological contaminants.
  • Dust mites
    Dust mites like elevated relative humidity. A target level for relative humidity at home is 30-50%, which is high enough to moisten mucous membranes and low enough to discourage the growth of dust mites and mold. In the basement, the target level is 50% or lower. Dust mites like to live in mattresses (so buy a mattress cover against the mites or, better, against bedbugs), carpeting (good to avoid), and upholstered furniture. Check out the or other source for related products.

  • Cockroaches and other insect pests, such as bedbugs
    Seek out an organic pest control company or deal with the plague yourself by sprinkling Borax in the path of the cockroaches. Also sprinkle diatomaceous earth around. DE works well against bedbugs.

  • Rodents
    If you have areas that have a history of mice infestation, be careful about cleaning them. Rodent droppings can contain harmful viruses. Check with your health department for recommendations, or search on-line. Wear a P100 or N95 mask and gloves and goggles. Use a bona fide HEPA vacuum cleaner. Apply Benefect, a least-toxic sanitizer, Or, hire an organic pest company to deal with the issue.

  • Pets
    Many individuals who have beloved cats and dogs are allergic to them. If in doubt, check with an allergist. Exposure to allergens is an added burden on the body. At least use a HEPA vacuum cleaner frequently and keep pets off your bed. Wash the pet’s bed frequently. Get checked periodically for parasites.
Step 8: Reduce your exposure to formaldehyde

Formaldehyde is a sensitizing agent, that is, it can make you more sensitive to other chemicals that didn’t bother you. New building materials, such as OSB and other pressed wood, kitchen cabinets made with pressed wood, and new furniture, drapes, etc., can contain formaldehyde. New carpeting is no longer supposed to contain it.

Renovating and redecorating a house can put a person over the edge with formaldehyde reactions. That happened to me 25 years ago. I was working and living in newly renovated surroundings, and one day I got a migraine, and then more followed for a few years. I was fortunate enough to finally find an environmental physician who diagnosed the underlying issue as mercury toxicity (from silver amalgam fillings, which I then had removed). He worked with homeopathic detoxification, put me on an anti-candida diet, and within two years, the migraines ceased.

How do you avoid formaldehyde if you are furnishing a home? Don’t count on off-gassing, since even old pressed wood cabinets still off-gas years later, according to one study. A presenter at the 2021 Indoor Air Quality Annual Convention said that in a kitchen with an average of eight cabinets, figure there are 11 pounds of formaldehyde.

Check out formaldehyde-free furniture. Avoid pressed wood, or encapsulate it with a formaldehyde sealing product. Inquire at a “green” home supply store, of which there are more and more. (Not all green products are least-toxic products.) Buy unfinished wood furniture and apply a least-toxic finish.

For floor covering, Marilee Nelson (specialist in least-toxic building materials for chemically sensitive individuals and co-owner of Branch Basics) recommends Kahrs Engineered floor covering, with underlayment, check with Joel Hershberg, Also check out Lumber Liquidators. They had a class action suit against them some years back for formaldehyde and now get many products from the European Union.

Step 9: Reduce your exposure to lead paint.

Lead paint was outlawed in 1978 but painters were allowed to use up their supplies, so conceivably houses painted in 1979 or 1980 might have lead paint. If lead paint is buried under other layers of paint, it likely is not a health issue. The problem comes when lead paint is in bad condition, and the flaking dust adds lead to the air. Another issue is when the inside runners of window frames were painted with lead paint. Every time the window goes up or down, lead dust could be released.

Lead paint was more durable and more expensive than regular paint, so it was used in high use areas, such as on doors and base molding, also on old radiators and exterior paint. Do you have any wine glasses with gold rims? Or embossed mugs without a glaze coating? Stained glass? Imported toys? Lead crystal (though it is not known if LeadCheck would pick up on that), old China?

To test for lead paint, search on Amazon for a lead paint detector kit. 3M Lead Check swabs are tried and true. Follow the instructions. With Lead Check swabs, if the yellow solution turns red upon contact, it’s lead. (You can double the number of surfaces tested by squeezing a few drops on a Q-Tip.)

Children under 6 should be regularly tested for lead levels. Besides paint, sources could include toys and sandboxes near roads with a lot of traffic. Go to and search on Lead for a copy of the EPA’s brochure on lead exposure.

For testing, a small bulk sample can be forwarded to a lab such as EMSL, Microbac Lab, or check with your health department. Lead cleanup is similar to mold cleanup. Your HEPA vacuum cleaner should pick up lead particulates.

We’ll come back to lead in the section on water.

Step 10: Reduce your exposure to asbestos.

Old houses likely have asbestos somewhere, but the most obvious place would be pipe insulation, but also old shingles, furnace covering, floor tiles, insulation, etc. For testing, a small bulk sample can be forwarded to a lab such as EMSL (, Microbac Laboratories (, or call your local health department for a referral. Read the EPA brochures on asbestos, and search on Asbestos.

Asbestos cleanup is similar to mold cleanup. Your HEPA vacuum cleaner should pick up asbestos fibers.

Last words on Indoor Air Quality

Some years back, I was asked to conduct air quality testing in a vacant cottage on the grounds of an estate. The homeowners' daughter and son-in-law, with their new baby, were coming for a visit, and my clients wanted to make sure the air quality was good.

I ran a VOC scan for volatile organic compounds, a standard air quality test. An indoor sample was done, as well as an outdoor sample for comparison. Results showed indoor test levels just about the same as outdoor levels. Both were good. The lab fees for the tests were in the area of $800.

I thought to myself: "Just wait until the new family arrives, with their cleaning and polishing products and their personal care products and their air fresheners and their car exhaust in the attached garage. No longer will the indoor air quality in the cottage be so pristine." If the cottage were being redecorated, with new furniture and new carpet and new paint, the levels of VOCs would be even higher.

The most common source of indoor air pollution is what we ourselves bring into our homes. For just about every product, there is a healthier choice. We need to gear our thinking that way and then to go looking for the healthier choices.

Sometimes, however, there is a reason to do the more sophisticated test for volatile organic compounds. Check out Fike Analytical Lab for such a test, as well as the MVOC scan, for mold gases. Randy Fike is a wealth of knowledge and experience at A lesser test, not very sensitive for mold gases, is the Home Air Check at

Now let’s proceed to the Mold topic.

Page Last Updated: March 20, 2022

Improve your indoor air and water quality and reduce exposure to mold and electromagnetic fields