How to make your air healthier to breathe.~ Lesson #3

It is much easier to prevent mold from growing in your house than to remove biotoxins once they become established in the indoor environment.  This article covers determining particle sizes of concern in your air to eliminate, filtration options,  decreasing humidity in your home and brief tips on if you have a sudden water damage event.


Water damage causes bio amplification in the form of bacteria and mold within 48 hours.  TO BE CLEAR ABSOLUTELY NO FILTER IS ADEQUATE TO HELP YOU WHEN THERE REMAINS A WATER SOURCE FOR GROWTH OF MOLD.  The machines can’t keep up! The source contamination must be removed, negated and or diluted in order to restore a normal fungal ecology that you can then maintain a healthy home and body.

Another common mistake is believing when the water appears to have evaporated that the risk has disappeared, but these little bio-farms then become airborne and your HVAC could spread it through your entire home. 

Determining Particle Sizes of Concern in Your Air to Eliminate

Allergens have significantly different sizes.

  • Fungal Spores (Mold) (1 -10 microns)­­
  • Bacteria (.5 – 10 microns)
  • Microbial Fragments (Myctotoxins/Endotoxins) (.05 – 3 microns)
  • VOCs

Most particulates below 0.3 microns are the ones that can make you sick or kill you.  Those particulates are smaller than our red and white blood cells.  Whereas the larger particulates are often considered irritants because our body is better able to filter them.

Airborne particles can enter the nose and mouth during normal breathing.

  • 10 microns diameter and less will pass through the nose and throat, reaching the lungs.
  • 5 microns or less can penetrate into the gas exchange region of the lungs and take a long time to settle from the atmosphere.
  • Anything less than 2.5 microns is highly likely to end up on the blood stream and fatty tissues.  According to the American Lung Association these particulates can remain in the body for a long time.

True HEPA filters are certified to trap 99.97% of particles that are .3 microns or larger.  Anything smaller than this is difficult to impossible to filter from air (Click to view larger image.)

Filtration Options

There are essential two categories of machines; air filters and air purifiers.  Air purifies capture ultra-fine particulates but have significant safety concerns. (ionizers, electrostatic, or air sanitizers which use UV or heat)

Your primary focus is to use a HEPA air filter and keep your air conditioning units well maintained by using a high rated filter and changing it every six months.  Be sure to also keep the air conditioner’s drip pans and drain lines clean and dry so that mold do not grow in them.

Additional options to consider:

  • If you live around stagnant bodies of water, you could get mold spores coming into your home. If this concerns you, you can place HEPA A/C filters on your windows to reduce the outside spores coming into your house.
  • Otherwise open windows as much as possible for fresh air exchange.
  • If possible, avoid forced air central heating due to risk of cross contamination. This is especially a risk with air conditioners.
  • Using diffusers with essential oils can help if you don’t have a humidity concern in your home.

Shopping of air filtration devices is difficult because there is no standardized testing for comparison and differing language can be used to describe the same methodology for managing ultra-fine particulates.

Air Filtration

Typically you won’t find both filtration and purification in one machine without compromising performance.  A filter is designed to pass large quantities over the filter quickly, where as air purification requires air to linger in order for it to be treated.

True HEPA filters are certified to trap 99.97% of particles that are .3 microns or larger. To give you a point of reference, most mold spores range from 3-100 microns, and even the smallest spore only gets down to 1 micron.

When choosing a unit, you will need to be mindful of sizing the unit correctly to meet or exceed the square footage it is designed for.  Also noise can matter a lot so check the specifications for sleeping areas, for the greatest comfort.

Carbon filters can be used in conjunction with your HEPA filters to trap small, gaseous compounds, volatile organic compounds (VOC) and odors.   It will not trap mycotoxins and bacteria.

HEPA filters need to be replaced annually and carbon filters every six months, or less depending on the environment.

I have looked at about a dozen filtration units.  Here’s a list of  some reputable manufacturers, so you can do the research yourself.   If price isn’t a concern, IQAir seems to be the most favored and I think is the unit chosen by several Chinese hospitals after COVID started.

I am price sensitive so I  chose the AirDoctor because it had a high level of performance and the best prices on replacement filters.  I have no marketing relationship with them.   I called their customer service question and found them very helpful.  You will also be very pleased to know I found a link for a $280 discount on the unit from a Buyer’s Review Guide website.

Besides efficacy and price point, I really like their particulate sensor that automatically increases fan speed when there are more pollutants in the air.  For example, I cooked bacon and the fan kicked into high for 20 minutes or so.  During normal operation it is reasonably quiet, which is an important factor to consider.

If you need to do remediation of a contaminated space, you might want to consider a serious air mover like the AlorAir PureAiro HEPA Pro 870 Air Scrubber 3-Stage Filtration Negative Machine Air Scrubber which can move up to 550 CFM

Air Purification

Air purifiers will not treat the air from the things that make you sneeze, but rather treat the things that make you sick. This is a difficult topic and I haven’t landed yet on my choice for a unit because there is no easy answer.  Each technology seems to pose some risk.

I listen to podcasts by Michael Schwartz called IEP Radio (LINK).  Each podcast features luminaries in the field of health and indoor air quality.  The sessions are well structured and worth the time to listen to. Podcasts #17 and #18 discuss air purification technology and provide a couple good options to consider on this topic.

  1. Ionizers: Ionic air purifiers: These are appealing for their lack of filters and low maintenance, however, it has been noted that these air purifiers create ozone, another pollutant that can cause irritation in the lungs, especially for people with asthma or other sensitivities. While air purifiers are tested to meet ozone requirements, the cost-benefit analysis doesn’t make sense for most people.
  2. Electrostatic Purifiers: They have a very similar approach to the ionizer air purifiers, however, they trap the “charged particles” inside the machine. The plate where these pollutants are stored needs to be cleaned to work properly. Again, we don’t recommend this type of purifier, especially knowing that any amount of ozone could be transmitted into the air. However, ionizers have been known to knock out tough tobacco odors from the air, being a beneficial force in airing out a home with heavy smokers.
  3. Air Sanitizers (heat /UVC): These sterilize the air by using heat or UV light to eliminate viruses, bacteria, and spores. This is another strategy that you can add on to your air purifier, making your air purification system that much stronger when it comes to the different types of particulates that you have floating around in your room.

Understanding and Controlling Humidity

Controlling humidity is often overlooked in the war against indoor air pollution, yet it is often the most effective area to improve air quality, especially in very air tight buildings.

To control the humidity in your home, it is important to understand that the ability of the air to hold moisture increases as the temperature rises.  Here are two important terms:

  1. Dew point: This is the point at which the water is 100% saturated.  Warmer air can hold more water than cold.  (See this video for an explanation.)
  2. Relative humidity: Since our monitoring devices don’t easily provide dew point calculations, a generally accepted standard for assessment is the monitoring of relative humidity in a home which should be below 55%.

Tools to Control Humidity

Here are a couple tools I recommend considering to reduce humidity:

  1. Automatic ventilation fans.  The best type turn on and off automatically based on relative humidity.  (Very important for your bath and kitchen. Panasonic has one of the quietest motors according to several professionals.  Here’s the Home Depot links: With light 50-110 CFM $289 or without light $199 50-110 CFM
  2. Humidity monitors Get a temperature and humidity monitor with an alarm.  Evaluate risky or unknown areas of your home so you can handle accordingly. I have one inside and one outside, so I have a basis for comparison.  Here’s the data logger I use.  I also find it interesting to monitor what the weather service provides on their 10 day forecast for comparison, which varies based on time of day.
  3. Dehumidifier.  A basic and important tool that is required for basements or in humid climates.   A dehumidifier is like running an air conditioner, so expect it to cause a jump in your utility bill.  You could run at night which is when the environment is most humid.The type you get depends on your square footage and proximity to a drain. CAUTION: Air conditioners and dehumidifiers can be a breeding ground for mold, especially in a water damaged building.  So if you do not have a normal fungal ecology in your home and a commitment to cleaning and maintaining these devices, then DO NOT USE THEM!!!

Reducing Sources Of Humidity

  • Make sure any spills or leaks you come across are dried within 24 to 48 hours.
  • Keep your basement, kitchen, bathroom and closets near these spaces as dry as possible. These areas have the highest humidity.
  • In the kitchen, mold is particularly likely to grow in refrigerator drip pans, door seals, and garbage pans. Regularly check under sinks for leaky pipes, as these will create wet environments amenable to mold growth.
  • Use dehumidifiers to keep indoor moisture levels low in problem areas to prevent growth. Set dehumidifiers to 50% humidity or lower.
  • Get rid of excess moisture following everyday activities like bathing or dishwashing, as even small amounts of water can enable mold growth.
  • Dry bathroom floors and walls after taking a shower.
  • Use exhaust fans to remove excess moisture in the kitchen and bathroom to the outside of the home. Clean exhaust fans once every 6 months.
  • Opening a window when cooking or showering will also help.
  • Make especially sure appliances that produce moisture, such as clothes dryers and stoves, are ventilated, and that they do not vent into your attic.
  • Don’t leave wet clothes in the washing machine after they’ve been cleaned, and don’t leave wet items lying around the house.
  • Leave wet shoes and clothes outside to dry. If you’re entering your home after walking in the rain or through wet grass, don’t place wet shoes or clothes in the closet. Leave them outside until they are dry or in an area with good air circulation.
  • Pay special attention to your windows if you live in a humid area. Poorly insulated windows can pick up a great deal of condensation, which makes them very hospitable for mold.

If You Have a Sudden Water Damage Event

If you ever have a sudden water damage event, get on it within 24-48 hours or you will have mold and bacteria colonize which will make remediation exponentially difficult.  You must remove drywall 2 feet beyond the water mark or as determined by a moisture meter. You must also lift all floor covering, hard or soft. — People think putting fans on a damaged spot is enough.  DO NOT MAKE THAT MISTAKE PLEASE!!!!!  You can’t effectively dry quickly enough to avoid biological colonization with just a fan.

If you don’t do this immediately, when you do take dry wall down, WITHOUT containment, you will spread a ridiculous amount of mold spores and other contaminates throughout your home.

Also on a related note, no insurance, either owner’s or renter’s, will cover your losses on a slow leak.  You will only be covered on sudden water damage events, so don’t waste your time with insurance or your expectations in that case.

Please take excess water seriously, act quickly and prevent moisture inside your building from ANY source.

~ Wishing you well, Kim Carr