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How to Improve Indoor Air Quality

by | Nov 29, 2022 | 0 comments

In this article, we will walk through the different dangers present in your indoor air and how to minimize them. Indoor air pollutants fall into three different categories and the solutions to each of them are different. No matter how well you clean the air in your home there will always be volatile organic compounds (VOCs), fungi or mold, and particulates. What is important is removing the most harmful pollutants entirely and keeping the others at minimal concentrations. In this report, we will tell you how to improve your air quality and reduce all harmful pollutants to safe levels.

How can poor air quality harm your health?

Poor indoor air quality (IAQ) can be deadly even with limited exposure. It is very important to take your indoor air pollution seriously. The risks that pollutants can pose to your health are scary because of their outcomes but also because they often don’t induce any symptoms until it is too late. Radon, asbestos, lead dust, and carbon monoxide all cause either cancer or nearly immediate death, and all of them are imperceptible during exposure. On top of that, all of these are VOCs, which air filter or purifiers can’t remove from the air. See below for mitigating VOC exposure.

Other perceptible pollutants like mold and particulates are often hard to pinpoint and have harmful effects over any exposure period. Mold, fungi, and particulates can cause eye and throat irritation, shortness of breath, dizziness, lethargy, fever, digestive problems, and asthma. If you are having any of these issues, it is worth can your air quality checked. We recommend continuous air quality monitoring or at a minimum getting your air quality checked on an annual basis.

Why is indoor air worse than outdoor air?

First of all, yes, indoor air quality is almost always worse than outdoor air quality. This is true even in large, industrialized cities like Boston. If you are like most Americans, then you probably spend at least 95% of your day indoors or even 100% during the winter. On top of that, the people that are spending the most time indoors and are exposed to the most pollutants are the ones that are most susceptible to air quality problems. Those groups include the young, the elderly, and the chronically ill, especially those suffering from respiratory or cardiovascular disease.

So now to answer the question… indoor air is worse than outdoor air because 1) everything in your home is slowly decomposing and releasing harmful gases into the air. 2) The humidity in your home is generally higher and the temperature is more stable than the outside air which promotes the growth of fungi and mold. 3) You live in your home and cook in your home which introduces particulates like dirt and exhaust fumes. In the outdoor air, all of these pollutants are diluted to below harmful levels. Newer homes often have even worse indoor air quality than older homes because they are better sealed and they have newly fabricated materials inside that are just beginning to outgas into the home.

Common indoor air pollutants and how to solve them

Volatile Organic Compounds

What are VOCs?

Many VOCs are human-made chemicals that are used and produced in the manufacture of paints, pharmaceuticals, and refrigerants. Volatile organic compounds (VOCs) are contaminants emitted as gases from certain solids or liquids. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. They come from a wide variety of products including paint, carpets, glue, lumber, cleaning supplies, printers, gas burners, candles, and furniture.

Some of the most common VOCs and where they come from:

  • Radon – from the earth and found in the basement
  • Formaldehyde – floor lacquers and certain molded plastics
  • Benzene – paint, glue, and carpeting
  • Butanal – burning candles, stoves, and cigarettes
  • Dichlorobenzene – mothballs and deodorizers
  • Ethanol – glass cleaners, and detergents
  • Terpenes – fragrant products such as soap or laundry detergents
  • Toluene – paint
  • Xylene – car exhaust

How do you remove VOCs from the air?

You generally can’t use filters; even high-quality MERV 16 filters will not remove harmful VOCs from the air. The best way to remove the pollutants from your home is by ventilation and maintaining a slight positive pressure inside your home. In other words, the solution to pollution is dilution. A nine-month-long study in Finland found that positive pressure i.e., higher pressure inside your home and ventilation will reduce the presence of VOC by up to 55% and reduce indoor humidity levels.

Mold and fungi spores

How does mold enter your home?

Mold spores are everywhere. There is a tiny amount of mold in your home already. The spores enter your home on your clothes or through an open window, but they won’t start to grow mold unless the right temperature and humidity is present. The key is never letting the environment be suitable for growing mold inside your home.

Is mold harmful to your health?

Yes, with extensive contamination and with extended exposure, mold can cause allergic reactions, respiratory symptoms, and sick building syndrome. If you find mold in your home, you should hire a professional to remove it and inspect your home for mold that you haven’t found and remove all of it.

How can you prevent mold in your home?

Mold and other fungi want to grow in areas with high humidity and when humidity is low the mold growth will dry out and die. Luckily a comfortable humidity level for humans is inhospitable to mold. A target humidity level to maintain inside of your home is below 60 percent. This level will be more comfortable and will also enable your HVAC system to run more efficiently and last longer. Boston and most of New England can have high humidity levels in the summertime. It is important to run your air conditioner and run a dehumidifier. We recommend dehumidifiers with built-in hygrometers that will measure the ambient air’s relative humidity. This will ensure that the humidity level in your home will be maintained at a safe level.


What are particulates in the air?

Particulates are tiny pieces of material as small as 2.5 microns. The human eye can only see matter down to 25 microns, so most particulates are not visible to the naked human. Particulates include materials like pollen, sanding and spray paint dust, cement dust, pet dander, dust and dust mites, mold spores, textile and carpet fibers, fabric protectants, hairspray, and nebulizer droplets.

Are particulates in the air harmful to your health?

Yes, particles in the air can cause eye, nose, and throat irritation, respiratory infections, bronchitis, and in some cases lung cancer.

How do you clean the air of these pollutants?

For particulate matter, the best solution is a good old-fashioned air filter or air purifier. The best filters are MERV 16 filters which are generally used for hospitals. We recommend MERV 11 filters for homeowners. MERV 11 filters will remove particles as fine as 3 microns and will not reduce the efficiency of your HVAC system like a MERV 13 or 16 filter will. We only recommend a MERV 13 filter for families with severe allergies, asthma, or other lung conditions. We also recommend that you replace your MERV filter at least 3 times per year. If you replace it less frequently your air conditioning system work run less efficiently, and your air will not be as clean as it should be.

Call a professional for MERV filter installation. High-quality MERV rated filters are significantly thicker than standard filters and will likely need to be retrofitted on your HVAC system. It is a relatively simple installation, but doing it incorrectly could result in an imperfect seal that will render your filter useless.

Indoor air cleaners to avoid


You shouldn’t necessarily avoid having plants, but you shouldn’t count on them to clean your air either. Potted plants can also be a source of mold and bacteria growth, so be mindful of the risks when adding them to your home. In 1989, NASA did a study that found that plants can improve air quality in a sealed environment. Unfortunately, your home is not a spaceship, and it would take over 1,000 plants in your home to make any measurable improvement in air quality. Follow-up air quality studies have proven that plants won’t improve your air quality.

Ozone Generating Air Cleaners

Ozone cleaners are popular because they make the air smell fresher than other types of filters. The problem is that ozone can be harmful to your health and ozone cleaners don’t regulate ozone concentrations in the indoor air. High ozone concentrations can be harmful to your health and long-term exposure can result in asthma, bronchitis, and emphysema. The EPA has studied ozone generating air cleaners extensively and they don’t recommend them, so we don’t either.


If you have not had your air checked by a professional, call us today. The first step to improving your indoor air quality and living conditions is to assess your current air quality state. After determining the current air quality in your home, we will provide a free plan to solve air quality problems for good. Poor indoor air quality is extremely dangerous, and an effective mitigation strategy involves a plan for reducing VOCs, preventing mold growth, and removing particulates, all of which demand different filtration and ventilation strategies. Let us help you develop that plan.


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