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Indoor Mold Summary White Paper

What is indoor Mold and how does it affect us? 

Overgrowth of mold in the home can produce high levels of mycotoxins and microbial volatile organic compounds (mVOCs), causing illness.  

While there is much more for the scientific community to explore, thankfully there is a growing focus on mold in our environment with a significant amount of new research being conducted on these topics.  

What are mold, mycotoxins and mVOCs?

Mold includes various types of fungus that grow on damp or decaying organic matter.  Mold can grow outdoors or indoors; it only needs moisture and a carbon source. 1  Outdoors, moisture from the ground and decaying leaves or wood provide the perfect habitat for mold.  Indoors, moisture from the air (excess humidity) or from a leaking pipe or roof will saturate a substrate such as wood, cardboard or even dust, and provide the moisture and carbon food for mold to grow. It produces particulate pollution (physical spores that replicate and spread) as well as various chemical byproducts. 

Mycotoxins are secondary metabolites, which are organic compounds that are produced by various organisms that are not directly involved in the growth, development, or reproduction of the organism but are essential in the ecological and other activities (contrasted with primary metabolites, which are directly involved with these activities).2  These are chemicals that are specifically toxic to humans, which scientists believe the mold produces to cause plant disease, defend the mold from other microbes, or simply when the mold is stressed. 

Mold can cause two broad types of disease, mycoses and mycotoxicoses.

(1) Human mycoses3:

• Are caused by growth of the fungi on or in our bodies, which can be treated with antifungals.  (Mycotoxins produced while the mold is in the body cause a secondary reaction).

• are mainly caused by opportunistic fungi, which produce illness by taking advantage of debilitated or immunocompromised hosts 

• are frequently acquired via inhalation of mold spores from an environmental reservoir or by unusual growth of a commensal species that is normally resident on human skin or the gastrointestinal tract

• portal of entry can be through the pulmonary tract or direct contact with the skin

• are largely diseases of the developed world, usually occurring in patients whose immune systems have been compromised by advanced medical treatment.

(2) In contrast, mycotoxicoses: 

• Are caused by dietary, respiratory, dermal, and other exposures to the mycotoxins, causing “poisoning by natural means” similar to the pathologies caused by exposure to pesticides or heavy metal residues.3

• Can be successfully treated by regimens of mycotoxin antigens, sauna, oxygen therapy, and nutrient..4

• Are common in underdeveloped nations due lack of resources to harvest and store foods properly.3 However, it is hypothesized that mycotoxicoses in the Western World are mainly due to inhalation of mycotoxins from mold growing in indoor environments (our inference from mold experts). 

As a company focused mainly on air quality, HypoAir has focused on mycotoxins that cause illness due to inhalation (which are mainly mycotoxicoses), as a result of mold growing indoors and releasing conidia (entire spores or fragments of mold or its spores) that contain mycotoxins.  In samples collected from water-damaged indoor environments in Sweden in 20075, here are the main mycotoxins found:

• Trichodermol and Verrucarol are trichothecenes. Trichothecenes are a very large family of chemically related mycotoxins produced by various species of Fusarium, Myrothecium, Trichoderma, Trichothecium, Cephalosporium, Verticimonosporium, and Stachybotrys molds. Trichothecenes inhibit protein synthesis in human and animal cells. 6,7

• Sterigmatocystin is also generated by Aspergillus molds.  It is structurally and biologically related to aflatoxins and is regarded as a precursor of aflatoxin B1 (see below). Therefore, the acute toxicity and carcinogenic properties of this mycotoxin are similar to those presented by aflatoxins, although less potent, and Sterigmatocystin has been recognized as a group 2B carcinogen.8

• Satratoxins G and H are produced by the black mold Stachybotrys chartarum.  Neurotoxicity and inflammation within the nose and brain are potential adverse health effects of exposure to satratoxins and Stachybotrys in the indoor air of water-damaged buildings.9

• Gliotoxin is produced by the common indoor mold genus Aspergillus and is immunosuppressive (it can dampen the body's ability to ward off disease and infection). To do this it impairs the activation of T-cells and induces cell death in monocytes, a type of white blood cell.10

• Aflatoxin B1 (AFB1) is one of the most potent carcinogens in foods, and it was postulated to account for the prevalence of hepatocellular carcinoma (HCC) in high exposure areas. 11

Volatile Organic Compounds (VOCs)

VOCs are gasses and can be anthropogenic (produced by human activity) or biogenic (produced by living organisms, but more specifically plants and animals).   A subclass of biogenic VOCs is microbial VOCs (mVOCs), which are gasses produced by bacteria or fungi.  Indoors, mVOCs diffuse through and sometimes accumulate in the air.  Some mVOCs are responsible for that “musty” odor that is the telltale sign of mold growth (such as geosmin and 1-octen-3-ol), but others can be odorless. Compounds with eight carbon atoms, such as 1-octen-3-ol, 3-octanol and 3-octanone are among the most common fungal VOCs, and among fifteen of the most prevalent mVOCs in water-damaged buildings (thse are 2-methyl-1-propanol, 3-methyl-1-butanol, 3-methyl-2-butanol, 2-pentanol, 3-octanol, 1-octen-3-ol, 2-octen-3-ol , 3-methylfuran, 2-hexanone, 2-heptanone, 3-octanone, 2-methylisoborneol, 2-isopropyl-3-methoxy-pyrazine, geosmin, and dimethyl disulphide).12  Although these mVOCs have not been tested for carcinogenicity, DNA damage was detected for all fifteen of the common mVOCs. 13  Low concentrations of the vapor form of several C-8 compounds including 1-octen-3-ol are toxic to larvae and adult fruit flies.  Moreover, 1-octen-3-ol (octenol for short and also called mushroom alcohol) selectively affects dopaminergic neurons in adult Drosophila (fruit fly) brain and induces Parkinson’s-like behavioral alterations in a fly model for this disease.14,15  Volatile phase 1-octen-3-ol was 80 times more toxic than the volatile phase of toluene in stem cells studies.16  Unfortunately, due to studies mostly conducted on the liquid phase of octenol, the FDA has approved it for use in foods and perfumes, and the EPA has approved it for use in insect lures. The problem with the vapor phase octenol is, like other VOCs, concentrations can build up in enclosed spaces like basements, attics, and even whole homes if they are not ventilated.

Image source: (17) 

How do mycotoxins and mVOCs overlap?

Mycotoxins are only found in solid or liquid form, while mVOCs are gaseous.  However, mycotoxins and many mVOCs are both toxic products of mold.  Therefore, overlap exists in the toxic category, but the science community doesn’t think that mVOCs should be called mycotoxins.   Why?

1. The condition of secondary metabolites: mycotoxins are all secondary metabolites, encoded by clustered genes that are easy to detect in genomic data. Only some fungal volatiles (e.g., the terpenoids) are secondary metabolites. 18 

2. There already are other classes of toxic metabolites made by fungi that are not called mycotoxins. Terms like “antibiotic,” (compounds toxic to bacteria), “mushroom poison” (compounds made by mushrooms) and “phytotoxin” (compounds toxic to plants, or confusingly, made by plants19) are used to label certain other categories of fungal products with toxigenic properties. 18 

3. Since many of the VOCs that have been studied are breakdown products of fatty acids, mediated by lipoxygenases, or are made by simple biotransformation steps from amino acids, we are not certain whether the VOCs we detect in profiles from growing fungi are the direct products of fungal metabolism or are merely incidental breakdown products.18

For these reasons, one article proposes the name “volatoxin” for those mycotoxins which are volatiles.18  Whatever they are officially named, mVOCs have the potential to be harmful to humans, especially if they are allowed to accumulate in a closed space.

Mold Naturally found outside vs trapped indoors

Mycotoxins and mVOCs found outside are normally diluted due to the abundant circulation of fresh air around and through them.  It is entirely different indoors.  Just as CO2 can build up from exhalation of inhabitants in a closed space, mVOCs from mold can also become concentrated in closed atmospheres, and mycotoxins become airborne whenever mold is disturbed, even from the airflow created when a window or door is opened.  

Where are these high concentrations found?  Spaces like the following are ripe for “biohazard” conditions concerning mVOCs and mycotoxins: 

• Damp basements

• Enclosed crawl spaces

• Attics with leaky roofs or otherwise high ambient humidity

• Backyard sheds

• Non-climatized storage units

• Vacation homes that are closed up without air conditioning or ventilation

• Homes damaged by natural disasters or neglect, that are abandoned

• Commercial buildings that have not been occupied or climatized in some time

The combination of lack of ventilation (for dilution) and excess humidity and darkness makes these spaces the perfect environment to grow mold and all of the toxins it emits.

How does Polar Ionization affect mycotoxins and mVOCs?

Our Polar Ionization uses Carbon Brush style Needlepoint Ionization to split the normal water vapor (H2O) in the air into millions of positive Hydrogen ions and negative Oxygen ions, without the production of ozone.  These natural ions are in proper balance and are stable enough that they can last a minute or longer as they travel in the airflows of an HVAC system or room giving them sufficient time to interact with air and surface contaminants in large buildings. Ions are any molecule or atom where the number of electrons does not equal the number of protons. These ions are very effective against a wide range of particulate, biological and chemical contaminants.  

Due to their type and stability they:

• can provide purification for large areas with reasonable upfront costs and no ongoing replacement parts 

• can react with both airborne and surface based contaminants opening up many new applications for safe active sanitization of occupied spaces.

• Remove static electricity, and as such are able to travel much further than negative ions.  

• Due to their balanced nature, they do not create unwanted ozone unlike devices that produce negative only ionization

Ability of Polar Ionization to protect against Mycotoxins and Mold Related Particulates

Mycotoxins can be transmitted through ingesting contaminated food, or they can become airborne, attached to spores of mold (conidia) or fragments of conidia.  According to a 2005 study 20, mycotoxins from Stachybotrys Chartarum (specifically trichothecene mycotoxins) were found on intact spores, which are larger (about 5 microns in diameter) as well as fragments of mold and other smaller particles (1.2 microns and below). These mycotoxins are known to react primarily with mucous membranes of the upper respiratory tract and eyes, leading to irritating erythema, inflammation, and pain. 20  In an earlier study, Trichothecene mycotoxins were found on Stachybotrys atra conidia of 5 micron diameter on average, indicating that these mycotoxins are easily respirable.21

The term PM2.5 is often used to refer to particulates 2.5 microns and less in diameter. For reference, a human hair is around 50-100 microns (μm) in diameter.  The human body has many natural defenses against large particulates like these.  In general, we consider extremely small PM2.5 contaminants to be far more dangerous and difficult to remove than larger particulates. Even smaller, 0.3 microns are considered the Most Penetrating Particle Size (MPPS) due to their difficulty to capture.  A HEPA filter's efficiency rating is specifically tested at 0.3 microns (not larger or smaller particles) because it is addressing a variant of the filter's minimum efficiency. 

Polar Ionization removes particulates from the air primarily through making them group together making them larger, heavier, and often with a negative or positive charge.   Those same larger, heavier, and charged particles can not stay airborne for long and are relatively easy to trap in a mechanical filter or easily vacuumed up from the ground after they settled.   Polar Ionization can quickly remove well over 95% of airborne particulates (including spores) without any physical mechanical filtration whatsoever (HEPA).  Due to its mode of action, it can also improve the filter rating of any mechanical filter used in the same space by several levels.  The use of mechanical filtration in addition to Polar Ionization is often unnecessary, however it can improve the speed of removal of particulates especially with those with high sensitivities.  At HypoAir we are quick to recommend redundancies in air purification where the needs of the occupants require faster removal of particulates and when finances allow. 

Numerous case studies conducted by independent labs show how mold spore counts (and thus by inference, mycotoxins carried on the mold spores)  were dramatically reduced in the air of closed environments by employing HypoAir’s Polar Ionization without additional filters.22 

Ability of Polar Ionization to break down mVOCs

The Polar Ions are also effective at breaking down VOCs & odors at a molecular level, specifically gasses with electron volt potential below 11. This is by design as the power output is capped at 12.07eV in order to prevent the formation of ozone since oxygen has an electron volt potential of 12. Formaldehyde (CH2O) for example has 10.88 as its electron volt potential and can be dismantled down into harmless carbon dioxide (CO2) and water vapor (H2O).  Similarly Ammonia (NH3) with an electron volt potential of 10.07 is broken down into harmless nitrogen (N2) and water vapor (H2O) (nitrogen naturally makes up about 78% of earth’s atmosphere).   Due to the method of production and stability of the ions, no ozone is produced in this process and the theoretical issue of incomplete oxidation or unintended byproducts is addressed with net VOC reduction.  One example showing proof of these breakdown reactions was obtained by measurement before and after installation of a bi-polar ionization device in the HVAC system of Houston Methodist Hospital, which reduced Total VOCs (TVOCs) to acceptable levels with activation of the device after many months of poor air quality complaints and failure of carbon filters to adequately clean the polluted air intake.23

The following are electron volt potentials of some of the most common mVOCs in water-damaged buildings24:  

Additional efficacy against more complex chemical compounds and high concentrations of odors can be found with our products that combine Polar Ionization with Activated Carbon, AHPCO and/or our TotalClean i2 spray.

Ability of Polar Ionization to Neutralize Biological Contaminants on Surfaces and in the Air

Polar Ionization has been well tested in our products and in other devices that produce the same type of ions to neutralize certain bacteria, mold, and viruses in the air and on surfaces.  Polar Ionization & Mold Spores in particular have been tested many times, including a 99.50% kill rate tested by GCA over a 24 hour period. 25 The Polar Ions are effective at disrupting these biological contaminants by breaking down their surface proteins which results in inactivation or lysis.  The efficacy of Polar ionization on viral (Feline Coronavirus, Coxsackie Virus, Polio Virus, SARS Coronavirus) and other biological threats (TB, MRSA, VRE, C. Diff) has been proven for years by a wide range of independent studies with more information, sources, and studies found on hypoair.com.

For more info about our proprietary products and technologies, please visit www.hypoair.com

References:

1. Indoor Environmental Quality: What is Mold? (n.d.). Retrieved from https://www.cdc.gov/niosh/topics/indoorenv/whatismold.html

2. Sapkota, A. (18 January 2022). Primary vs Secondary Metabolites- Definition, 12 Differences, Examples. Retrieved from https://microbenotes.com/primary-vs-secondary-metabolites/

3. Bennett, J. W., Klich,  M. (2003). Mycotoxins. Clinical Microbiology Reviews, 16(3), 497–516.  https://doi.org/10.1128%2FCMR.16.3.497-516.2003

4. Rea, W.J. (2018). A Large Case-series of Successful Treatment of Patients Exposed to Mold and Mycotoxin. Clinical Therapeutics, 40(6), 889-893. https://doi.org/10.1016/j.clinthera.2018.05.003

5. Bloom, E., Nyman, E., Must, A., Pehrson, C., Larsson,  L. (2009).  Mycotoxins produced by molds in water-damaged indoor environments.  Journal of Occupational and Environmental Hygiene, 6(11), 671–678. http://dx.doi.org/10.1080/15459620903252053

6. Trichodermol (T3D3717). (n.d.). Retrieved from http://www.t3db.ca/toxins/T3D3717

7. Verrucarol (T3D3723). (n.d.). Retrieved from http://www.t3db.ca/toxins/T3D3723

8. Vieira, T., Cunha, S., Casal, S. (2015). 25.3.3 Sterigmatocystin. In V.R. Preedy (Ed.), Coffee in Health and Disease Prevention (pp. 225-233). Elsevier Inc.

9. Islam, Z., Harkema, J.R., Pestka, J.J. (2006). Satratoxin G from the black mold Stachybotrys chartarum evokes olfactory sensory neuron loss and inflammation in the murine nose and brain. Environmental Health Perspectives, 114(7), 1099-1107. https://doi.org/10.1289/ehp.8854

10. Gliotoxin. (n.d.). Retrieved from https://healthmatters.io/understand-blood-test-results/gliotoxin

11. Ferk, F., Speer, K., Mišík, M., Nersesyan, A., Knasmüller, S. (2015). Chapter 66 - Protective Effects of Coffee Against Induction of DNA Damage and Cancer by Aflatoxin B1. In V.R. Preedy (Ed.), Coffee in Health and Disease Prevention (pp. 587-596). Elsevier Inc.

12. Korpi, A., Järnberg, J., Pasanen, A-L. (2009).  Microbial volatile organic compounds.  Critical Reviews in Toxicology, 39(2), 39-193. https://doi.org/10.1080/10408440802291497 

13. Kreja, L., Seidel,  H-J. (2002). Evaluation of the genotoxic potential of some microbial volatile organic compounds (MVOC) with the comet assay, the micronucleus assay and the HPRT gene mutation assay.  Mutation Research, 513(1-2), pp. 143-150.  https://doi.org/10.1016/s1383-5718(01)00306-0

14. Inamdar, A.A., Masurekar, P., Bennett, J.W. (2010).  Neurotoxicity of fungal volatile organic compounds in Drosophila melanogaster. Toxicological Sciences, 117, pp. 418–426. https://doi.org/10.1093/toxsci/kfq222

15. Inamdar, A.A., Hossain, M.M., Bernstein, A.I., Miller, G.W., Richardson, J.R.,  Bennett, J.W. (2013). The fungal derived semiochemical 1-octen-3-ol disrupts dopamine packaging and causes neurodegeneration. Proceedings of the National Academy of Sciences USA, 110, 19561–19566. https://doi.org/10.1073/pnas.1318830110

16. Inamdar, A.A., Moore, J.C., Cohen, R.I., Bennett, J.W. (2012).  A model to evaluate the cytotoxicity of the fungal volatile organic compound 1-octen-3-o1 in human embryonic stem cells. Mycopathologia, 173, 13–20.  https://doi.org/10.1007/s11046-011-9457-z

17. Morse, R., Acker, D. (22 February 2017). Indoor Air Quality And Mold Prevention Of The Building Envelope. Retrieved from https://www.wbdg.org/resources/indoor-air-quality-and-mold-prevention-building-envelope

18.  Bennett, J.W., Inamdar, A.A., (2015). Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins? Toxins (Basel), 7(9), 3785–3804. https://doi.org/10.3390%2Ftoxins7093785

19.  A.Graniti (1972). “The evolution of the toxic concept in plant pathology.” In: Wood R.K., Ballio A., Graniti A., editors. Phytotoxins in Plant Diseases (pp. 1–18). Academic Press.

20. Brasel, T. L., Douglas, D. R., Wilson, S. C., Straus, D. C. (2005).  Detection of Airborne Stachybotrys chartarum Macrocyclic Trichothecene Mycotoxins on Particulates Smaller than Conidia.  Applied and Environmental Microbiology. 71(1),  114–122.  https://doi.org/10.1128%2FAEM.71.1.114-122.2005

21. Sorenson, W. G., Frazer, D.G., Jarvis, B.B., Simpson, J., Robinson,  V.A. (1987). Trichothecene Mycotoxins in Aerosolized Conidia of Stachybotrys atra. Applied and Environmental Microbiology, 53(6), 1370-1375. https://doi.org/10.1128%2Faem.53.6.1370-1375.1987

22. Milburn, D. Case Studies, Mold Focus_Part 1. (n.d.) Retrieved from https://docs.google.com/presentation/d/1RSgZYhSq0M_-fzlPUP1Q8z2btVuDi8so/edit#slide=id.p1

23. Schurk, D. Houston Methodist Hospital Test Study Results Needle Point Bi-Polar Air Ionization for VOC Remediation. (n.d.). Retrieved from http://www.victordistcontrols.com/wp-content/uploads/2014/03/Methodist_Hospital_VOC_Remediation_Project_Test_Results_2014.pdf

24. Electron Volt (eV) Potential Chart for Industrial Gases: UNDERSTANDING eV POTENTIAL PAPER. (n.d.). Retrieved from https://egeda.be/wp-content/uploads/2020/11/Electron-Volt-potential-chart.pdf

25. Waddell, C. GPS Reports on Pathogen Testing,(n.d.) Retrieved from https://gpsair.com/uploads/customer-resources/Service-Logic/White-Paper-GPS-Reports-on-Pathogen-Testing-03-2020.pdf

Optimizing Your Window Air Conditioner for Maximum Clean, Cool Air

Global average temperatures have exceeded recorded highs several times in the last month, and articles on ways to keep cool are proliferating!  In this article, I don’t have any “new” way to keep cool, but if you are among those blessed with a simple window air conditioner, let us help you make it work just as well and as efficiently as the day you bought it!

Window air conditioners are the humble yet hard-working appliances that many households can’t do without.  As one of the oldest cities in the US, New York City has an abundance of window units because about 75 percent of the buildings throughout the five boroughs were constructed before 1960, according to the NYC Department of Buildings.  (Why about a quarter of US households are stuck with ugly and loud window AC units)  The cost of retrofitting these old buildings with central air conditioning is way too high, so window air-conditioning units are the solution, and continue to be for many households across the US.  However, even if your window air conditioner is an older unit, a little time and effort can go a long way in helping it cool better, work less (lower your energy bill), and put out better quality air! 

If you have the option of upgrading your window air conditioner, there are many worthy options out there, including those with inverter motors, which save a lot of energy and control humidity better.  (To understand better what inverter technology is, check out our article here.)  Unfortunately, no one has combined an inverter air conditioner and premium filtration, but you can get premium filtration on a new air conditioner with the Friedrich Kuhl units.  These units cool (and some also heat) rooms by heat pump, with smart controls (wifi enabled and smart home compatible) AND they have MERV 13 filters available (a MERV 13 bracket kit is needed).  Until manufacturers put inverter units and premium filtration together, we have to put premium filtration in priority!

If your existing window air conditioner has a few more years of life, it helps (although not necessary) to know how a window air conditioner works.  In the first part of our article “What kind of air conditioner do you have?” we explain the workings of this type of unit.  A key lesson is knowing that unless you have a ventilation lever on your unit, there is no mixing of indoor and outdoor air.  (Check out this video to find out how to find and operate a ventilation lever.)  Therefore, the air conditioner is not pulling in outside air, it’s only recirculating indoor air.  Whatever dust, pet dander and microbes are floating around your apartment can get lodged in the air conditioner and grow into disgusting science experiments that will negatively affect your air quality!

Therefore, a clean evaporator coil is super-important.  The evaporator coils are what change your hot and humid indoor air into cooler and drier air.  Because most window air conditioners come with a flimsy clean-able filter that would qualify somewhere between MERV 1 through 4, what really ends up filtering the air is the coil–because after a season of running constantly, so much dust and dirt go through the cheap filter and get lodged in the coil!  This is not only disgusting, it’s unhealthy.  Therefore, if you’ve operated your window unit for more than one summer and never cleaned the coil, please start with this step to eliminate the majority of grime that’s lodged there.  (Be sure to have help removing the air conditioner from the window, especially if you live on an upper story!) 

After you’ve cleaned your unit (and the included filter), check that it is blowing cold air well.  It should blow air that is 15-20 degrees colder than the air it takes in.  To measure this, simply use a portable temperature gauge above the unit (out of the stream of cold air) as the intake temperature, and then move the thermometer directly into the cold air coming out, and note the difference (it’s also helpful to note the difference in humidity, to know that it’s actually removing moisture as well!).  Our portable humidity sensors will give both temperature and humidity.  If the difference in inlet and outlet temperatures does not approach 15 degrees F for a clean AC unit, then you can check into getting the refrigerant topped up.  This is best done by a licensed HVAC technician.

Next, it’s not too hard to upgrade your current filtration so that the air coming out of your air conditioner is cleaner than the air that goes in!  Here are some options:

• Frigidaire now offers MERV 14 filters for some of its models.  Check the link in the overview for compatibility.
• You can cut a regular HVAC filter to fit as per this video (make sure you use painter’s tape around the edges to prevent air leaking around the filter), or 
• You can have a custom filter bracket made for your window AC, and change the filter in it often. Since the louvers in front just thwart air flow, you can actually remove the louvered panel and fit the filter inside (if it has a rectangular filter), or you can fit the filter over the louvers and secure it to the front with double-sided tape.  In order to specify the correct size for your window unit, determine which louvers are the “intake” (moving air into the unit), and measure the area covering and slightly outside of them, so that the frame and tape will seal but not cover a lot of the louvered space. 
• You can make your own frame from 1” aluminum “u-channel” and rivets, and purchase the filter material in bulk or cut to size (these media pads are equivalent to MERV 8 and will filter a lot more dust than the cleanable factory filter!)

Finally, placing a Germ Defender or Mobile Air Angel near the air conditioner will not only help to freshen the room as ions are carried with the fresh air, it will also help to keep the coils cleaner as ions are sucked into the air conditioner by killing microbes and mold spores inside it.

If your space is feeling stuffy from being closed up all the time due to hot weather, chances are CO2 levels are rising.  Fresh air ventilation is important, so go ahead and use that ventilation lever on your window air conditioner, or crack the windows in the morning or evening when temperatures are more tolerable.  If you live in an urban or dusty area, use our window ventilation filters to get fresh air without the particulates.  May our window air conditioning units live long, cool lives!

Keeping Your Vacation Home Fresh

It doesn’t matter whether your “vacation home” is a pull-behind trailer, or a luxurious condo, or a humble cabin in the mountains:  when you “get away” to a relaxing place, you don’t want to spend your precious vacation time trying to figure out how to get musty smells out or remove mold from the linens because the climate inside suffered while you were away.  Here are our tips to make it welcoming and low-maintenance!

First of all, humidity is the most important factor you’ll want to control in order to keep out mold, and you’ll want to keep the humidity under 60% all the time.  If the outside climate humidity rises over 60%, that climate will come inside and settle into soft surfaces, making them a perfect habitat for mold growth. You can only control humidity inside effectively by having a tight envelope, which means sealing up passages where outside air can penetrate in.  If no one will be living there while you’re away, you won’t need fresh-air ventilation, so make your get-away home as tight as possible by sealing windows, doors, attic doors, and other penetrations.  

Also, remember that relative humidity and temperature are closely linked.  For example, if you leave an air conditioner set on 82 degrees and the humidity rises to 80%, you may be at risk of mold forming in less than 2 weeks!  (If you’re wondering how that calculation came to be, check out this fun dew point calculator.)  In addition, relative humidity in a space will increase as temperature is lowered.   Air conditioning will naturally take some of the humidity out of the air, but there are a number of factors that can allow humidity to remain high even when your air conditioner is on. 

Here are some options to keep the humidity under control while you’re not there:

• If you have wi-fi available in your vacation home, now’s the time to take advantage of technology that can pair with existing units like mini-splits, window or portable air conditioners to enable you to monitor climate and control them remotely.  Cielo is a company that has a number of products that can help you maintain the right humidity and temperature remotely. 

• Alternatively, if you do not have wifi or app-enabled monitoring, you’ll need to choose a temperature for setting your air conditioner.  Although it’s tempting to set the temperature just under the temperature of melting plastic (haha) to conserve energy, don’t do it!  Setting the thermostat as high as 85 degrees can cause short run times and not allow the air conditioner to remove enough humidity from the air, creating an atmosphere for mold growth.  (No, You Shouldn’t Set Your Thermostat to 85F.  Here’s Why.)  For that reason, it’s ok to set it 7-10 degrees above the temperature you normally keep it while you’re staying there IF you also take into account the outdoor temperature and humidity.  There’s no magic formula for determining this ideal energy-saving-yet-mold-preventing temperature setting, but think about it: if your vacation space is in a hot, humid climate like the southeast US, you’ll want to set the maximum indoor temperature lower than the average outdoor temperature to make the air conditioning come on often enough to remove humidity.  

• Thirdly, if you don’t have a humidity control setting on your air conditioner, or even an air conditioner at all, it’s best to purchase a dehumidifier with a humidistat and set it to 60% maximum humidity.  This will ensure that humidity is being controlled, no matter what temperature the interior rises to!  Think of this dehumidifier as insurance against mold: if your air conditioner was to stop working, the dehumidifier can still keep your space mold-free if it’s suitably sized for your space.  Check out our article on different types and sizes of dehumidifiers, and be sure to set up a portable dehumidifier with a drain into a lower tub or sink that condensate can safely drain all the time.

• Leave doors to rooms and closets open for best air circulation.  Just like air purifiers, portable dehumidifiers cannot reach behind closed doors.  

• Use ceiling fans in rooms and portable fans elsewhere to keep air circulating while you’re away, which will reduce the water content in all your furnishings by evaporation.  ““Evaporation increases the humidity of the atmosphere that immediately surrounds the liquid. This humid air takes some time to dissipate into the rest of the atmosphere. The presence of a breeze, a powerful wind, or some other form of air circulation can speed up this process and make the environment of the liquid less humid. Therefore, by decreasing the humidity of the liquid’s surrounding, a powerful breeze or wind can increase the rate at which the liquid evaporates.” (Factors Affecting the Rate of Evaporation)  This is why disaster restoration companies use powerful fans to move air over wet surfaces, increasing evaporation and removal of water.  With less water in your furnishings, the chance of mold growth is reduced.   You can even add air circulation to any space that has a light socket, such as closets and pantries, by removing the light bulb and screwing in a light socket fan (which come in different designs with exposed or enclosed blades).

• Make sure your air conditioning and dehumidifier drains are clear and a clean air filter is in place before you leave!  Many homeowners have come on vacation to find their air conditioner or dehumidifier drain pan overflowing and dripping onto ceilings, floors, and other inconvenient places–what a mess that can also turn into hazardous mold!  As a homeowner, make sure to check these drains and change the filter several times during the air conditioning season, or arrange for someone to do the same while you’re away. 

• Window air conditioners need deep-cleaning sometimes.  If a musty smell is coming from the air conditioner when the fan cycles on, then you’ll know that dust has infiltrated the cooling coils, absorbed moisture, and is nourishing mold growth.  Check our article on how to deep clean it and restore the fresh smell.

• If you can, shut off water at the main valve to avoid any possible leaks, and switch off the breaker to the hot water heater if it’s electric (turn off gas if it’s gas).  This will avoid water leaks under sinks, which can make a nasty moldy mess!  If you don’t do this, at the very least shut off water to the washing machine, because burst water hoses at the washer are the single largest cause of home flooding.  (Leaving the House for 3 Days or 3 Months? 5 Must-Dos Before Your Trip)

• Bipolar ionization units like our Germ Defenders, Mobile Air Angels and Whole Home Ionizers are a great way to keep mold away too.  At the very least, plugging a Germ Defender into the bathroom will send out ions to kill mold spores in this small space where air circulation can be a challenge.

• Leaving a portable HEPA filter with activated carbon running is not a bad idea, either.  Activated carbon will help avoid that “musty” smell.  According to firesafeliving.com,  “plug-in” scent devices are not a fire hazard if you leave them plugged in while you’re away, but we at HypoAir don’t recommend them because a) many plug-ins use toxic chemicals like phthalates and formaldehyde, and b) the freshener will dry out before you return anyway, leaving an appliance running on your wall.  What’s better: make your own reed diffusers with your favorite essential oil (or combination of oils) and place them throughout your space for a safe, no-mess fresh scent!

These extra steps may seem to take more time on those days you’re packing up to leave your vacation home, but when you come back to a home that is ready for relaxing as soon as you open the doors and windows, it will be worth it!

How to safely remove old carpet

Upon testing my bedroom carpet as part of a series of mold tests in my home, I found this:

I scheduled time to remove the carpet the next week.  Now, how do I do this safely?

Research revealed two extremes:

1. removing the carpet with no breathing equipment and no dust abatement (although this guy has some great tips, I cringe at the way he’s throwing the carpet around with no dust mask)

2. removing the carpet with breathing equipment, a zillion garbage bags and gallons of mold eliminator (this method is costly and WET!) 

I had to find a solution in the median.  Here’s what I came up with for my situation (I am moderately sensitive to mold). 

Supply list:

• Respirator with extra set of filters

• Heavy gloves

• Old clothes

• Knee pads

• TotalClean concentrate (or several pre-mixed spray bottles)

• Clean garden sprayer

• Rags

• Plastic sheeting and painters tape for taping off vents and covering heavy furniture

• Old towels to block under door

• Heavy duty garbage bags (also known as contractor bags)

• Carpet knife with extra blades or utility knife with extra blades

• Duct tape

• Pliers for pulling carpet

• Nail puller to remove staples in padding

• Pry bar and hammer to remove tack strips

• HEPA vacuum with new bag for cleanup

• Air Angel and/or Germ Defender: helps with dust and mold mitigation

Prep, prep, prep…it’s tedious but so worth it.  

• Move whatever furniture, clothing and decor you can easily move, into another room. I took the long-overdue opportunity to get a new mattress, so I could escort my old one to the dump!

• Use dollies on furniture that is too heavy or large to move out of the room.

• Turn off the HVAC and cover any ceiling, floor or wall registers with plastic sheeting and painter’s tape

• Measure TotalClean concentrate and water into garden sprayer at 1:7 parts respectively or empty pre-mixed spray bottles into sprayer.

• Block under door(s) with old towels so that dust doesn’t migrate through the house.

• Open window and remove screen if you plan to toss the carpet out of the window (also block off the area below)

• Turn on the Air Angel and/or Germ Defender to help dust particles clump together and fall to the floor; the ions also destroy mold and bacteria on contact

• Suit up with all protective gear including your respirator!

My strategies for minimizing dust will be to dampen a section of the carpet with the sprayer; cut the carpet into a  manageable section, remove it, and do the same three steps for the carpet pad underneath.  You’ll want to make the least number of cuts, because cutting through the carpet releases a lot of dust and fibers into the air.  I realize that this method will only wet the top of the carpet and not the cut edge or bottom, but short of soaking the carpet and subfloor, I found this is the best solution.  I liked the idea of tossing the carpet out of the window on a good weather day and bagging or binning it outside so that I didn’t drag the bags through the house.  I removed the carpet, padding and staples as I went, because I had a heavy piece of furniture left in the room and did not want to move it around more than necessary.

1. Starting in one corner, use the sprayer to dampen the carpet in a 2’x8’ section.  Cut just inside that section with the carpet knife.  

2. Use pliers to grab the carpet in the corner and wrestle it from the tack strips. If you can’t get it out, try cutting the corner out with your knife and pulling out just the corner.

3. Roll it up gently and dispose of it in a contractor bag (or toss it out a window!)  If bagging it, then you can use the duct tape to keep it rolled tightly.

4. Spray the carpet pad underneath and cut it.

5. Dispose of it in the same way.

6. Remove staples holding the padding to the floor with the nail puller.

7. Remove tack strips using the pry bar and hammer.  They are super-sharp!  (If you plan on replacing with new carpet and the tack strips are not rusty or damaged, you can leave them in place).  

Repeat steps 1-5 until the whole room is devoid of carpet and padding!  If you can handle more than 2x8’ of damp carpet at a time, you can  Then, use a HEPA vacuum to thoroughly vacuum the floors to remove dust.  You will want to wipe down the walls, window(s) and ceiling fan with TotalClean because dust is now everywhere.  Finally, you can remove the sheeting from your register(s) and change clothes and shower–you earned it!  It’s best to add a bit of EC3 Laundry Additive to your clothing when washing it to avoid spreading mold to any of your clean clothing. 

If you have a new floor already scheduled for installation, good for you! Make sure that the subfloor dries out completely before 48 hours have passed, and definitely before installing new flooring (use of the sprayer makes it unlikely to soak the subfloor).   If you haven’t picked out new flooring yet, you can remove/replace any nails or screws that are sticking out, use a non-toxic floor paint, and/or use an area rug to cover over any rough areas until that day comes.  Try not to wait too long, however, so that excessive wear of the subfloor doesn’t occur.  

The unintended consequences of turning down the thermostat this winter

According to the Energy Information Administration and their Winter Fuels Outlook report, it will cost 27 percent to 28 percent more than 2021/2022 to heat your home with oil or gas.  If you heat with electricity, prices may rise by as much as 10 percent, because much of our electricity is generated from oil and gas. (Newsweek.com)

When you have a fixed or unstable budget, the decision to lower or turn off heat during the winter is not easy.  The other components of our budgets–food, housing, transportation and medical care–aren’t as flexible as those extra blankets, mittens and hats, so down the thermostat goes.  This is where what you don’t know might hurt you.

It’s not only the air temperature that changes when the heat source turns off.  Air holds a certain amount of water vapor, also called humidity, and warmer air can hold more water vapor than cooler air.  When the air cools, water vapor in the air will tend to condense on any surface that is lower than the dewpoint temperature.  That’s why you see condensation on windows and around door frames in winter: these are the points that tend to conduct cold temperatures from the outside, and moisture from the air is condensing on them.  Persistent moisture is mold-feeding moisture, and before you know it, there is a mold problem.  Even worse is that mold could be forming in places you can’t readily see, like inside walls, attics and basements, because the air temperature has dropped and cooler air just can’t hold the moisture of warmer air.   Cooler air can easily reach humidity levels of 80% or more, giving that “damp” feeling and over time, exposing the home to mold growth.  

There is a myth that when a room is not being used, it’s best to turn off heat (close registers) and close it off from the rest of the house (close the door) to save money.  If this is done without any ventilation or air circulation, it’s also a recipe for mold, because without air circulation, water vapor in stagnant air will be absorbed by furnishings and allow mold to take root.  If you need to limit heating in your home, try to leave doors to unused rooms at least cracked and leave a fan running in the room, because dynamic airflow limits moisture ingress due to evaporation. For more on finding and fixing areas prone to mold in the winter, check out our article.

If high humidity is not a problem, low humidity might be.  Low humidity can damage all kinds of decor in your house by shrinking and drying, from wood flooring, wallpaper, and furniture to fine instruments like pianos and guitars and artwork.

Then, there’s your body.  Stress due to cold is a real problem for the elderly and those with pre-existing medical conditions like asthma or heart disease.  It also makes people more likely to use alternate heating methods that could be unsafe.  Small room heaters are often known to tip over and cause fires, and electric blankets can actually cause burns.   Falling asleep on a bunched-up blanket is a common cause of burns, according to Bell, a plastic surgeon who treats many burn patients. He explains that when a hot blanket rests on the same body part for an extended period, the skin can burn. “These burn accidents usually happen because someone has fallen asleep on a bunched-up area of the blanket,” he says.  Unfortunately, people with diabetes are more vulnerable to burns from electric blankets because their condition makes them less sensitive to heat. “Electric blankets are also not recommended for infants, young children or anyone who is paralyzed or incapable of understanding how to safely operate them,” says Bell.  People with urinary incontinence also should not use electric blankets because wetness and electricity don't mix. (ul.com)  If you do use an electric blanket, follow all the safety guidelines of UL Solutions (previously Underwriters Laboratories) so that you don’t become one of these statistics!

When home heating costs rise, air quality can also worsen due to particulates in the air.  In Europe, the impacts of inflation and fuel scarcity due to the Russian-Ukrainian war is particularly hard on middle and lower income families, and they turn to alternative sources like burning wood, coal and even garbage in indoor stoves.  These stoves impact indoor and outdoor air quality.  Indoors, reloading a stove that is already burning fills the air with particulates, and combustion gasses can leak out of improperly-sealed doors and exhaust pipe fittings, exposing inhabitants to dangerous levels of carbon monoxide and particulates.   Outdoors, European cities that typically have poor air quality during the winter may have even worse this winter. A recent study from Greece showed that wood burning was responsible for almost half of the cancer-causing air pollution in Athens and a new study from New Zealand has showed an increase in serious respiratory infections when wood smoke built up in an area. (TheGuardian.com)  If you live in one of these areas, it doesn’t matter whether you are the one burning wood–you will still be breathing its effects. 

If you feel financial pressure to lower the thermostat this winter, here are some practical ways to keep the air warmer and less humid in your home (Prof Cath Noakes from the University of Leeds):

• Move seating away from cold windows
• Use thick curtains at night, but allow the sun to come in during the day
• Ensure radiators or ventilation registers are not covered or blocked by furniture
• Ventilate using high-level windows can reduce cold drafts
• Ventilating after a shower or when cooking can prevent moisture buildup which can lead to damp and mold.

It’s sometimes harder to detect high humidity in the winter because of the lower temperatures, so don’t take a risk–keep one or more humidity sensors in your home for monitoring it.  Our bipolar ionizers like the Germ Defender, Air Angel or Whole Home Polar Ionizer actually deter mold even if humidity temporarily goes too high, making them great investments for all seasons. 

Finally, if you have a warm home, sharing it with your elderly, disabled or disadvantaged friends for a meal or a few hours could make a huge impact in their lives.  Helping them to purchase safe heating appliances and understand how to keep humidity at manageable levels also will help them to live healthier.  Warmth is not always about containment, but allowing it to radiate to others. 

Ancient homebuilding 101: How did ancient people prevent mold in their homes?

Mold is an ancient problem, the most infamous account of which is in the 14th chapter of the book of Leviticus in the Bible.   Although it’s described as a “plague of leprosy” in the King James translation (verse 34), the references to “ingrained streaks, greenish or reddish, which appear to be deep in the wall” (verse 37 in New King James translation) are hallmarks of mold.  Indeed, some scholars investigating the meaning of the Hebrew word “Tsara’at” that was translated “leprosy” have inferred from ancient skeletal evidence and modern symptoms of mold exposure that a better translation may have been “mold”.  (Mold: “Tsara’at,” Leviticus, and the History of a Confusion).  Going forward with this assumption, the prescription for mold in the ancient Hebrew home was inspection (by the priest), identification (by shutting up the house and seeing if the mold grew), remediation (empty the house of everything valuable, remove the stones and plaster, and replace them with new stones and plaster), reinspection and cleansing, and in the case of last resort, demolition (complete dismantling and removal of the house). 

Has the problem (or plague) of mold gotten worse since ancient times?  Maybe so.  After World War II, a housing boom generated the need for faster and cheaper construction and made gypsum wallboard (drywall) much more popular than plaster as a building material.  Drywall is composed of compressed gypsum between two layers of durable paper. Gypsum readily absorbs water and dries slowly, while paper supports mold growth very readily. Since mold growth can occur within 24-48 hours of a water event, according to the US EPA, this is a perfect recipe for mold growth (just add water!).

The housing boom also caused quality of construction to decrease as volume increased, allowing for water problems to happen more frequently. “Back in the days of plaster, brick and stone construction, we didn’t have mold problems like we do now. This is in part because mold doesn’t grow on those materials very easily, if at all. Drywall, on the other hand, is like a Petri dish. What’s worse is that drywall is an ideal growth medium for Stachybotrys, the black toxic mold referenced above, because of its high cellulose content. Nearly every mold will grow on drywall given the right moisture levels, but Stachybotrys has a field day with it.  The final component of the perfect storm, which has made mold into the problem we now face as a society, here and internationally, is that our buildings are built so tightly, in the name of energy efficiency. Ever since the fuel crisis in the 70’s, there has been a huge push to reduce energy usage and create a more comfortable living environment. We have walls stuffed thick with fluffy insulation. Having a small utility bill is a bragging right at cocktail parties.” (A Brief History of Mold)

We can see that there are three things we need to consider in homebuilding to prevent the dreaded “m” word: design (for natural ventilation), construction technique (to avoid water intrusion and decay) and materials.  Here are two examples of how ancient people incorporated these mold-fighting aspects into their homes, knowingly or unknowingly:  one is from Israel and the other is from Egypt.

Building techniques in first-century Israel:

According to nazarethvillage.com, villagers in Israel often built homes on the bare ground.  They could dig into soft limestone to make caves for water or wine storage, but often just used what the topography offered.  “Building on sloping bedrock requires great care in setting the first course, starting from the lowest part of the foundation and working upwards step by step. The bedrock footing is flattened and slightly stepped, but does not need to be completely level. By fitting stones into the uneven footing, the force of gravity will secure the buildings onto the bedrock. Using the land as the ancients did makes a lot of sense – there is less to dig and less to build.”  (Site Excavation)  The mortar used to hold the stones together was primarily earth, chalk (calcium carbonate), leftover straw (to add strength and reduce cracking) and a small amount of hydrated lime for durability.  The chalk is excellent at absorbing excess moisture from the air (reducing humidity inside), while the lime also inhibits fungal growth (keep reading for more benefits of lime!).  (Mortars for building and plastering in antiquity)

House windows in first-century Galilee were typically placed relatively high in the wall for maximum ventilation and privacy. Ventilation, as we know, can discourage mold by allowing ions in the fresh air to reach interior surfaces. (Windows)  The same principles were used in design of the homes, which featured a central courtyard with rooms added around it; thus fresh air could flow through the rooms whenever doors were opened to the courtyard. 

Preparing the house for plastering inside requires placing “small chinkstones and mortar to fill cracks and create a flat substrate for the interior plaster. Although obscuring the beautiful view of exposed stone masonry, interior plaster was necessary for insulation and to prevent household pests from taking over.  Plasters also improve interior lighting by brightening up the colours of the walls. We discovered that mixing chalk with the earth plaster gives a bright yet warm tonality to the home. The homes of more wealthy residences and public buildings – such as our synagogue – were finished in white lime plaster and occasionally painted.” (Interior Plaster)

Building techniques in ancient Egypt:  The following facts were taken from the article Homes and Mud-Brick Construction in Ancient Egypt, which references the report by Virginia L. Emery, University of Chicago, UCLA Encyclopedia of Egyptology 2011, escholarship.org:

Unfired mud brick houses were common in ancient Egypt, from the simplest abodes to the grandest of palaces.  Mud brick had several advantages over stone:

• Brick ingredients were available virtually everywhere (sand, clay, and silt combined with chopped straw or dung as temper and binding agent)
• Mud bricks are quicker to fabricate than quarrying stone, making them more economical in that sense
• Mud bricks are quicker and easier to build with because they don’t require the trimming or fitting that building with hewn stone demands. 

“Mud-brick walls could be constructed directly on an unprepared ground surface, though more commonly were provided with brick foundations and wall footings laid in trenches upon a bed of sand... Occasionally, particularly along high- traffic routes, the base of the wall at ground level was protected by a footing of stone, in an effort to minimize the undercutting of the wall due to water or wind damage and traffic; stone elements also could be included in the wall proper, being most common at the quoining of building corners.”

The article Mudbricks give clues to understanding the Bible, which referenced the article Mud Bricks and the Process of Construction in the Middle Bronze Age Southern Levant, confirms that unfired mudbricks are susceptible to water damage.  Water can dissolve the bricks as well as weaken them, especially near the base of the walls. Several strategies are used to help minimize water damage. Typically, the construction techniques in the Ancient Near East involved building a stone foundation of 2-3 courses of stone upon which mudbricks were then placed to the desired height. The stone foundation does two things:  it minimizes the capillary action of water and salts seeping into the lower courses of bricks; it also helps reduce the erosive effect of water splashing from the roof back onto the bricks or from water running in the street.  Another aspect of mudbrick preservation was regular plastering and re-plastering the walls, which helped retard the effects of moisture and erosion, as well as the intrusion of plants, insects, and animals. 

How do these natural building methods defeat mold?

Mud-brick, which is also called adobe in areas of Spanish influence, can still be an economical way to build. Many people think that mud-brick invites mold and dampness into your home, however, it actually inhibits mold in several ways.  Ideal conditions for mold or rot are caused when a building material absorbs moisture and is unable to later release it, or when moisture is not absorbed but condensates on a surface. Here are the ways mud-brick and other earth building techniques inhibit mold, according to Earth Building School:

• Creating thermal mass:  Thermal mass regulates temperature by absorbing heat when it is available, storing it and slowly releasing it when ambient temperatures drop.  Keeping temperatures higher and more constant reduces condensation and dampness, because cold air holds less moisture and so will condensate on windows and walls.Earth is one of the best thermal mass materials available, because of its slow reaction time and because it naturally regulates humidity.  It is easy to retrofit earthen building elements to your existing home: Earthen plaster over drywall, inbuilt cob furniture or mudbrick feature walls - let your imagination run free while creating a beautiful, healthy living space.
• Clay regulates humidity: You can't beat clay when it comes to balancing indoor humidity at optimum levels of 40-60% RH. A solid wall of earth bricks can absorb up to thirty times the moisture of conventional burnt bricks and a 30mm (1-3/16”) thick surface coating of clay is more than enough for daily buffering.  
• Naturally anti-fungal: Finally, natural finishes such as clay, lime plasters or Tadelakt (Moroccan plaster) are naturally anti-fungal.  These are good finishes in areas that are often damp, such as kitchens and bathrooms.  Lime is highly alkaline (high pH) and inhibits mold growth. It can be used to fix mold problems in old buildings (once permanent water damage has been remedied) and is a good and very hygienic choice for bathrooms - even in splash areas such as hand basins and showers.  Lime plaster is water resistant and can be applied as Tadelakt, for a totally waterproof result.  Working with lime - especially in situations where waterproofing is required - is a bit more technical, so it is advisable to get a skilled person onto the job. 

Whether the building is constructed with mud-brick or stone, these are the “bones” of the walls; plaster is placed over the brick or stone, and then the final interior and exterior finishes give them the protective “skin” that really preserve the construction from the elements.  Let’s dive into the finishes of Limewash and Tadelakt to find out why they are so good at inhibiting mold.

Limewash:  This ancient paint has so many physical benefits, and topping it off, has a soft and warming aesthetic that is causing a resurgence in its popularity.  Chemically, limewash is calcium hydroxide mixed with water.  Calcium hydroxide, also known as quicklime, is a naturally-occurring mineral that is soft and easy to mine from the ground (nature also “excavates” lime deposits with water, producing caves with fantastic formations inside).   Adding just the right amount of water causes the mixture to heat up (an exothermic reaction) that can be used immediately or left to cool down and thinned out with more water.  Here are some benefits of applying limewash in your interior or exterior finishes:

• Limewash applied to stone and wood prevents rot and erosion while allowing the structure to “breathe” and release moisture.
• Limewash is a natural pest repellent: the active ingredient, calcium hydroxide, discourages many types of worms, beetles and even mosquitoes from infesting the structure.
• Lime is a farmer’s friend because it naturally deodorizes.  Lime provides free calcium ions, which react and form complexes with odorous sulfur species such as hydrogen sulfide and organic mercaptans found in animal and biological waste.  Thus, waste odors are not “covered over” with lime, but actually destroyed.  (Uses of Lime/Environmental/Animal Waste)
• The high pH of limewash (10-13) makes it anti-fungal, anti-viral and anti-bacterial when it’s wet.  When dry, the pH lowers to neutral; however certain commercial limewashes like Lime Prime by Earthpaint have proprietary resins/polymers that allow the active ingredients to rehydrate and raise the pH again, so that it continually fights mold.
• Limewash (and the plaster beneath it) are naturally incombustible.  This property was recognized at least as far back as 1212, when the King of England decreed that buildings that survived the terrible London fire must be plastered and limewashed immediately to prevent future fires.
• Limewash prevents rust on iron surfaces.  This makes it even easier to apply, as masking off hardware is not necessary unless for aesthetic purposes.
• Limewash is cheap and easy to make on your own.  You’ll just need to purchase calcium oxide (also called burnt lime or quicklime) from a supplier, and be sure to wear the proper clothing and protective gear to guard against chemical burns.  There is plenty of tutorials online, and this article from a long-established UK building conservation company also describes the process.
• Finally, if you prefer skip the DIY and use commercially prepared limewash, Earthpaint, a company that prides itself in only offering non-toxic paints and wood finishes, has a set of products that can specifically tackle damp areas and mold remediation areas: Lime Prime and Lime Seal.  These are also great on unprimed drywall in any location.

Tadelakt: Sometimes referred to as Moroccan plaster, tadelakt is a traditional plaster indigenous to the Marrakesh region of Morocco that can be used as a stylish wall covering and alternative to tiles. It can be used indoors and on exterior walls.  Tadelakt-plastered walls create a solid, waterproof surface that is seamless, has no grout lines and is resistant to mold, which are some of the reasons why this traditional plaster style has become so popular in contemporary, minimalist homes. (Tadelakt: What you Need to Know About Moroccan Plaster)

Tadelakt is applied in several coats and finished using a special technique. "The final stage of polishing is done by using a plastic trowel, Japanese trowel or a traditional Moroccan application which requires a special polishing stone," explains Ian Kozlowski, Founder of Decor Tadelakt.  It's the final stage of applying tadelakt that makes the resulting surface waterproof.  Valentin Tatanov, manager at Tadelakt London explains: "The olive oil soap that is rubbed into the surface of the product chemically reacts with the lime to form calcium stearate."

This waterproof membrane makes Tadelakt appropriate for use in shower enclosures and wet room ideas (where shower walls are not necessary and the entire room can be wetted and drained).  The seamless application means that details like benches, windowsills and shower niches are easy to create.

Tadelakt is relatively low maintenance;  it can be cleaned simply by rinsing with water because the surface resists dirt and mold. "In the shower, squeegeeing down the walls after each shower is all that is needed to maintain the tadelakt shower walls," explains Decor Tadelakt's Ian Kozlowski.  What's even better from a non-toxic standpoint, you must avoid using commercial bathroom cleaners on tadelakt, especially any containing bleach or harsh solvents, as this may destroy its waterproof quality. 

Just like a wooden countertop or cutting board needs periodic maintenance to keep it looking great, water-resistant and bacteria free, "regular recoating with soap solution ensures that the tadelakt stays in excellent condition for years to come," suggests Valentin. 

For these reasons, we shouldn't be afraid to experiment with limewash and tadelakt in our homes as the "new" anti-microbial coating.  They've stood the test of time!

Breaking down Mycotoxins and mVOCs with Enzymes and Non-Toxic Cleaners

If you haven’t read our white paper on mold, mycotoxins and mVOCs, you should!  While discussing the meanings of these scientific terms with our team, we thought it would be even more helpful to break it down to the vernacular.  Mold is like most other living organisms that excrete waste products.  Mycotoxins are not similar to excrement, in that they are not secreted because of normal growth, development or reproduction of the mold (they are secondary, not primary metabolites).  They are chemicals secreted in offense and defense, and in stressful situations.  Thus, mycotoxins are like sweat–the toxic sweat of mold (yuck!).  They can be sent aloft into the air on mold spores (which are also released whenever the mold is stressed or physically agitated), or even smaller fragments of mold and dust, which are all easily breathed in.  

Microbial Volatile Organic Compou0nds (mVOCs) are gasses as a product of growth, development or reproduction (some are primary metabolites), and as a signal to other microbes around them (secondary metabolites).  This means that mold uses mVOCs to communicate and affect the behavior of other molds around it, even as a competitive tool to directly exert antimicrobial activity (suppressing or eliminating potential enemies). (Volatile affairs in microbial interactions)  As such, mVOCs are akin to body odor–the toxic body odor of mold, which it uses to intimidate other mold!   Although they are meant to signal other microbes, even humans can recognize the smell of some mVOCs in that musty, earthy smell that is a tell-tale sign of mold.

It has been shown that the mycotoxins can be eliminated by various physical means such as thermolysis (destruction by intense heat), radiation treatment and low-temperature plasma (bipolar ionization).  They can also be destroyed by chemical methods such as oxidation (removal of electrons), reduction (addition of electrons), hydrolysis (breakdown by reaction with water), alcoholysis (breakdown by reaction with alcohol), absorption and adsorption, and biological methods by using living things like bacteria or other molds. (Enzymes for Detoxification of Various Mycotoxins: Origins and Mechanisms of Catalytic Action)  Only two  of these methods are permitted to mitigate mycotoxins in foods, however, contamination of raw materials with chemicals and/or products of side reactions limit their use.

Alternatively, using enzymes to detoxify mycotoxins mostly avoids these problems. Various enzymes can also be combined to treat the combinations of mycotoxins that are produced by some molds.  For example, cytochromes are enzymes that include a number of compounds consisting of an iron-containing molecule bonded to a protein (cancer.gov).  Cytochromes are usually used within mammals as detoxifying agents of multiple toxic compounds, including mycotoxins.  Cytochromes in the human liver are able to convert aflatoxin B1 (a cancer-causing mycotoxin) into Aflatoxin M1, which is 10 times weaker in carcinogenic potency.  In turn, glutathione s-transferase, another enzyme in our bodies, leads to the excretion of aflatoxins from the body (2016 study).   

Since the enzyme-based approach for degrading mycotoxins in homes is new, there aren’t that many commercial products on the market.  In fact, Green Home Solutions claimed in 2022 that it was the “is the only professional remediation company that combines the ANSI/IICRC standards for mold remediation with a state of the art proprietary disinfectant/ fungicide that not only kills bacteria and molds, but continues to work by breaking down the allergenic protein structures into harmless amino acids.”  It is only available for professional use, but their product description shows that several enzymes are combined for maximum effect on the broad range of mycotoxins that may be found in a home:

• AMYLASE is an enzyme that digests the mold’s outer membrane or cell wall. It dissolves and causes the insides to leak out.
• LIPASE is another enzyme in our product formula which attacks and breaks down the fatty lipids inside of and in between the mold membranes.
• PROTEASE breaks down allergenic proteins at the mold’s core or nucleus, eliminating them from the air you are breathing.

Since we revealed the real nature of mycotoxins and mVOCs (they’re like toxic sweat and body odor), we thought you might like some real solutions you can use to get rid of these toxins in your home!   Elimination of the mold colony is first and foremost, so it’s best to contract an inspector if you can’t find or handle the problem yourself.  Getting rid of the bulk of mold will remove much of the mycotoxins and mVOCs, but mycotoxins can still be present in dust (they are very hardy and indestructible by heat), and mVOCs may be present in absorbent furnishings.  Here are some products and techniques that can rid your home of the remainder of these toxins.

• Several top mold inspection and remediation companies in the US (The Mold Pros, Indoor Environmental Systems, Inc.) use CleanSeal CS4 as a fog to kill mold and other microbes on contact, with no toxic or lingering chemicals.  Since CleanSeal CS4 is 72% alcohol, it evaporates quickly and exceeds the CDC standards for mitigating Coronavirus/COVID-19.   It’s also safe to use around people, pets, electronics and fabrics (when properly applied, the fog settles gently and evaporates quickly so that there are no water stains or damage).
• Likewise, E3 is a non-toxic solution also trusted by many mold remediation companies and mold awareness sites, such as moldfreeliving.com.  It is a solution with citrus and essential oils which evaporates quickly and can also be used in the laundry or directly on pets’ fur as a sanitizer from mold.  
• MoldStain T-Klear is recommended for all mold and mycotoxin products in use of a fogger or electrostatic sprayer.  
• Most MVOCs can be mitigated with activated carbon filters, because they are in a gas form and can flow through and be adsorbed by the carbon molecules.  You can try our Germ Defender with carbon filters, or purchase carbon filters for your standalone HEPA unit.  Mycotoxins, however, will not be affected by carbon filters because mycotoxins are attached to spores, fragments of spores, and dust, which are not captured by carbon filters.

If you can’t remove all of the mold, the next best thing may be encapsulation.  Encapsulation is a controversial method in that it does not physically remove the mold but surrounds it with a protective layer that does not allow it to release spores or mycotoxins into the environment anymore.  If encapsulation is done properly, though, it can be a safe method that allows homeowners to save wet drywall and wood that have not dried out completely, by sealing any mold that is present and not allowing more to grow.  As demonstrated by EarthPaints, encapsulation either needs to be applied to completely dry substrates, or with a solution that allows the substrate to completely dry over time.  Their Lime Prime paint is a non flammable mineral shield that saturates wood fiber cells and pozzolanically reacts with concrete and gypsum. Encapsulated Substrates dry out properly and in 30-60 days are ready for follow up after a flood. (earthpaint.net)  The problem with mold encapsulation is that it must completely coat surfaces in a space with a durable non-toxic product, and of course the space must be clean and dehumidified, or the mold will “break through” and continue growing as dust and moisture allow it to propagate.  For more information on whether encapsulation is right for a space in your home, this article by a building biologist is very helpful.

Are my windows causing my mold allergy?

If you viewed the results of my home’s mold plate testing, you probably saw the high count of mold colonies in my sunroom–which doesn’t even have air conditioning vents in it.   What the heck?  I was scratching my head until I remembered that I had placed the plate on a table only a few feet away from the exterior wall of windows.  There are 12 exterior windows in that room!

Here are some of the ways that windows can increase mold counts in your home:

• Direct water leaks:  if the seals or caulking fail on your window(s), they could allow water to run into the wall, where mold can grow.

• Drafty windows allow air to pass from the outside in, or inside to outside, where the temperature and humidity difference can surpass the dewpoint and cause condensation.  Condensation can occur on the windowsill or anywhere around the window that is not properly sealed.

• Outdoor mold can grow on the screens, because they retain dust and moisture.  When you open windows, air blowing through the screens will blow mold spores right into the room.

• Heavy window treatments create a micro-climate between the room and the window.  Although they are great at insulating the room from heat or cold, fabric curtains retain humidity/moisture, and also create a cold pocket of air without air circulation.  With drafty windows, air between long curtains and the wall can allow condensation, and offer the ideal darkness for mold to grow.    

In my case, I believe it was the drafty windows that allowed air to blow around the frames and carry mold into the room.

Here are some ways to get that mold count down:

• Check for leaks in your windows.  Here are some warning signs that a window is leaking and how to determine where it is leaking (video):

• Peeling paint on an interior window sill 

• Peeling paint on an interior wall near a window

• Rotting wood on the exterior window frame or sill

If you have any of these symptoms, it’s best to remove the outer siding materials and find out where the water is getting in, because cosmetic repairs will not fix the leak. 

• Decide whether to replace or reseal your windows.  It’s rarely an easy decision because replacing your windows is not likely to save you money, considering the cost of the windows and installation.  However, there are some ways to know that it’s time to replace them:

• Replacement: If your windows are extremely damaged by water infiltration, then it’s a good case for replacement. (ecohome.net)  There are many options for energy-efficient windows, available in wood, vinyl or composite (fiberglass or a combination of materials).  Like many products, the installation of the windows is just as important as the quality of the windows themselves. Quality installation is critical for an airtight fit and a continuous water barrier to prevent drafts, water damage and condensation.(efficientwindows.org)  To select windows, the National Fenestration Rating Council (nfrc.org) is a non-profit organization that gives consumers energy performance ratings and other useful information about windows, doors, and skylights.  You’ll also want to consider that new exterior windows that meet Energy Star standards fall under “qualified energy efficiency improvements” which can generate tax credits.  For windows purchased in 2022, you can claim the Residential Renewable Energy Tax Credit for 30% of the total cost, up to a maximum of $600 for exterior windows and skylights. (filemytaxesonline.org) In addition, check with your local power supplier to see if they have more incentives for replacing windows. If you do decide to replace, remember that higher-cost wood windows (which are clad in aluminum or vinyl for weather protection) are only as good as the seals and techniques of cladding them; if water penetrates the cladding, the windows can rot in just a few years.  In addition, the vinyl or aluminum skins on these windows do not permit passage of vapor from the interior to the exterior, so that condensation forms on the inside of the skin.  Condensation = rot! (video)

• Reseal:  If the windows and frames are in good shape, but you have airtightness problems, it’s most cost-effective to apply some sealing around them. Caulk, weatherstripping and caulking cord are all products made for these purposes, and this video shows how to apply them.  In order to know where the air is coming in, you can do the following (houselogic.com):

• Seal the house by locking all doors, windows, and skylights.

• Close all dampers and vents.

• Turn on all kitchen and bath exhaust fans.

• Pass a burning incense stick along all openings -- windows, doors, fireplaces, outlets -- to pinpoint air rushing in from the outside. Smoke Pencil Pro ($44) is non-toxic smoke pencil for this purpose.

• Clean your windows and screens!  On windows where screens are installed, a bi-annual cleaning will greatly reduce the amount of mold present.  In general it’s not better to wash the outside or the inside first, as long as both are done!  However, since outsides usually get dirtier than the insides, it may be easier to see inside dirt if you wash the outside first. You can use a bucket of warm water with a few drops of dish detergent on the outside with a long-handled brush and squeegee, and TotalClean or a mixture of one part white vinegar to two parts water in a spray bottle for the inside. 

• Get your drapes in order!  If drapes are causing condensation to form on or around your windows, this is not a good situation and it will lead to mold if left unchecked.  Here are some suggestions:

• Open the drapes during the warm part of the day so that temperatures between the room and window can equalize and dry out moisture. 

• Leave the ceiling fan running in the room to promote circulation. 

• True thermal curtains are made of 3-4 layers of material, including a vapor retarder that allows vapor to escape through the curtain.   Problems can occur if the curtains block vapor.  

If you still have a high mold count near your windows, it’s best to check with a qualified, reputable mold inspector to find out the source and be able to enjoy the sun and scenery through your windows instead of the mold!

What’s hiding in that pallet wall?

Another embarrassing but true story:  

Once upon a time in New Orleans, I rehabbed a house that was gutted post-Katrina.  In a neighborhood built in the 1950’s, I took down a few walls and set about making this little 1500 square foot home into my Pinterest dream.  No matter that the sloping floors would make a soup can roll from front door to back with no effort and amazing speed; all of the reclaimed furniture and materials available at that time were more than sufficient to supply the ideas that came into my head.  Some of my favorite places to go were the local “Green Project” or Habitat for Humanity stores.  Green Project had a small lumber yard of reclaimed wood and salvaged architectural pieces.  I don’t know whether I found this particular piece of wood there, or from the side of the road, but it looked perfect. 

My carpenter had framed in split-level bar countertops on either side of the newly opened-up kitchen, and to keep the cost of countertops low, I decided that the top of the bar would be reclaimed wood.  The chunk of wood I found was long enough for both tops, and the color of dark chocolate, a perfect contrast to the cream-colored kitchen.  I cut the pieces, sanded the edges, coated them with a few layers of varnish and set them outside to dry for a week or so.  Time to install!  They looked beautiful.

Throughout processing this wood, I did notice a “smell”.  It didn’t seem too strong, probably because I was doing the cutting, sanding and painting outside.  But soon after I installed it inside, the headaches started.  I had a constant strong headache most days for a week, until I made the connection and removed the wood.  Bingo!  Problem solved.  This was probably a decade before home VOC-testing equipment was available, but my brain and respiratory system was telling me that this wood was poisonous. Looking back, it was probably treated with creosote, which gave it the (beautiful!) dark brown color.  Creosote is derived from the distillation of tar from wood or coal and is used as a wood preservative. Pesticide products containing creosote as the active ingredient are used to protect wood used outdoors (such as railroad ties and utility poles) against termites, fungi, mites and other pests. (epa.gov) The EPA has also determined that coal tar creosote is a probable human carcinogen (over longer exposure periods).  Thankfully, I was the only one in the household who seemed to be affected.  

I’m still a fan of reclaiming wood and other materials, but I’m a little more cautious nowadays.  That’s the major drawback to most reclaimed wood: you just don’t know its history.  Whether it’s been soaked in smelly chemicals like creosote, or sprayed with non-odorous pesticides, or just sitting outside accumulating mold and insect droppings, it has a mysterious history that you may or may not be able to neutralize when you “reclaim” it.  Following are the main dangers of using some (not all) reclaimed wood (cdawood.com) indoors.  

• Like my experience above, reclaimed wood that has been treated with harsh chemicals, like paints or stains, or contains VOCs (volatile organic compounds), can release toxins into the air.  Unlike my experience, you may not always smell these VOCs or toxins, which is a “silent” risk.

• Wood is quite a porous material.  Mold and mildew can be hiding in the crevices of the wood, especially reclaimed wood that has a lot of “character” (read: cracks, knots and grains).  Mold and its toxic byproducts, mycotoxins and MVOCs, can make you quite sick and even spread to other parts of your home via dust and spores.  

• You could bring pests inside.  Anyone who’s lived in the southeastern US would be familiar with termites, possibly carpenter bees, and maybe carpenter ants.  These are all wood-loving pests that can hitch a ride into your home inside of the lovely reclaimed wood.  They generally exit or die when the wood is agitated or dried out.  But have you heard of powder-post beetles?  These tiny pests can spread to other wood furniture and even the framing of your home, reducing the wood to “powder”.  Imagine losing your grandma’s precious antique dresser, or your kitchen floor joists, to these destructive pests because you decided to “reclaim” some wood for a table top: not a good trade-off!

If part of the reason to use reclaimed wood is “saving money” (one of my original reasons for creating those bar tops), are you really saving if one or more of these problems surfaces because of using it?  Here are a few ways to be more cautious with reclaimed wood: (Brunsell.com)

• Consider the source: Grocery store palettes are likely to have been in close contact with food, so they run a higher risk of having bacteria (from spills), so don’t use them indoors.

• Check for signs of how the wood has been treated: Know if and how the wood’s been treated. Heat-treated wood, also known as kiln-dried wood, is generally marked with an “HT.” In terms of your health, HT wood is preferable to chemically treated wood. You forgo the chemicals, and the heating kills off bugs. 

• Consider the end-use of the wood:  If it will be in close contact with children, pets or food, it’s best to use new, untreated wood and opt for non-toxic finishes (like the paints and stains we mention in this article). 

If your gut says, I don’t know about this piece of wood, it might be best to listen to your gut!   Manufacturers have honed in on the reclaimed trend and created vintage looking wood and furniture from new materials.  

• CdA Wood in Coeur d’Alene, Idaho is one such company that has the slogan “Barn wood but better”.  They take new untreated wood and make it look like old barn wood without paints or stains, using a patented “Xcelerated” process.  In the words of the VP, they “age wood indoors without using paints or stains”.  

• Another company that values indoor air quality is EarthPaint.net.   All of their coatings are non-toxic, so you can start with new wood and get a fabulous aged finish without VOCs, mold, toxins or pests.   

• Here’s a slew of ways you can add “character” to new wood with tools and a little elbow grease; just substitute non-toxic finishes for the stains used in the last few slides.

• Did you know that charred wood naturally resists water, pests and further aging?  Developed by the  Japanese, Shou sugi ban is the art of preserving and finishing wood using fire.  Cedar wood works best for shou sugi ban because of its natural chemical properties, but you can also use shou sugi ban on pine, hemlock, maple, or oak.  This article tells you a little about the history and how to DIY your own burnt wood!  EarthPaint.net also has “Special Linseed Oil” similar to what is used in the article.  I’ve personally used shou sugi ban on some wood supports for my shower curtain, as well as an outdoor table. 

At HypoAir, we aim to bring the best of the outdoors inside.  We’re very selective, though, to make sure that hidden pollutants or pests don’t slip in with the good stuff…and with vigilance you can be too.  It’s time to raise the bar on reclaimed wood, to make it as healthy as it is beautiful!

Start Thinking Like a Home Inspector

If you own a home, you need to learn to think like a home inspector.  A home is a great investment, but if the outside elements start to penetrate the building envelope, your great investment can start to deteriorate and become toxic!

Sometimes, after an especially hard rain, there is a different smell in my house.  This tells me that rain is probably going where it shouldn't. According to commonsensehome.com, a natural home website, the first spots to check are the roof and attic, especially around any roof penetrations like chimneys and vent lines.  

Recently one morning after such a rain, I went in earnest search of leaks inside to find the source of the musty smell.  Not finding anything in the attic, I went to the room where the smell was the strongest, the laundry room.  I checked areas around the windows because there were shelves in front of them, hiding any potential damp spots.  Uh-oh– a couple of the windowsills were wet, indicating that more of the not-so-old (10 years) windows were leaking.  I checked the corner above which there was a valley in the roof (roof valleys can be a source of leaks in a hard rain if they are improperly installed/sealed).  Thankfully all the walls were dry.

There was a gutter outside this room, and I knew from past experience (rain during the daytime), that the volume of water flowing off the roof seemed to be too fast or too much for this particular gutter, because it would shoot right over the side and pour down next to the wall.  Thinking about it, I went up onto the flat portion of the roof over the laundry room.  There were no big branches or breaks in the flat roof, but a lot of leaves and acorns were up there!  Time to get to work with the broom or leafblower, and I removed a section of the leaf guard over the gutter to clean out the gutter.  I checked to see that the downspouts were clean.

Next, I looked up to see if there were any wet spots behind or below the gutters (this only works after the sun has been out for a bit).  Thankfully, that was not the case.  Looking down the walls, I saw that there were a lot of wet leaves piled up around the foundation.  Wet leaves around the foundation do not just cause a musty smell in the house.  They can allow insects like carpenter ants and termites to come in, using the leaves as a shield to keep their tunnels moist.  I got to work with the leafblower.  

Rain can seep into basements and crawlspaces, so if I had a  basement, I would check the walls for seepage.  Bring a bright light, gloves, and if necessary a respirator (basements can be dusty!) to make sure that you don’t leave any corners/spots hidden from view; try to move any stored boxes to get a peek at every square foot of wall.  It was only after moving some storage shelves in front of the laundry room windows that I discovered the leaking windows. (Crazy, I know, my goal is to build some cabinets so that the windows will not be covered up!)

If you can't find the source of the problem, reach out to a well-reviewed professional home inspector in your area.  Remember, professional home inspection is a service dedicated to helping you find and live in healthy homes--not selling you other products or services.  You can find accredited home inspectors in your state at The International Association of Certified Home Inspectors (nachi.org).

There are a lot of good sites to help you get thinking like a home inspector.  Here are some that we’ve discovered and reference frequently.  Don't be shy about contacting them with questions!  

• Inspectapedia.com: This website must have THOUSANDS of pages, but the “search” function is great, the website hosts answer questions very promptly (within 48 hours), and there is feedback from many homeowners and experts alike.  Highly recommended!
• Homeinspectorsecrets.com: Created by a home inspector, this site has a lot of guides about a variety of subjects.
• Familyhandyman.com: This website contains step by step instructions to correct any problems you may find around your home, and reviews products as well.   
• Thespruce.com: Although not technically about home inspection, this website contains a wealth of information on a variety of home improvement topics and often contains non-toxic, safer alternatives. Their Home Improvement Review Board is made up of licensed general and specialty contractors, journeyman electricians, and journeyman plumbers, so you know that you’re getting good advice.
• Energyvanguard.com: This website is written by a building scientist and has an extensive blog, so you can understand the “why’s” of the best building practices.  He also frequently incorporates how he investigates and solves problems at his own home.