Can Mold Grow in Alcohol?

Whether there are strange masses floating in one’s bottle of whiskey or if a sanitation professional wishes to know their cleaning chemicals more closely – it is quite a common question to wonder whether alcohol can act as a breeding ground for cultures of mold.

The particular answer to whether mold can grow in alcohol depends on the particular concentration strength of the alcohol, how it was stored, and whether any other additives have made their way into the alcohol’s mixture.

Fortunately, most forms of alcohol cannot grow mold due to the simple fact that it is inhospitable to most forms of life – especially to that of mold and similar fungal bodies. 

However, this is not always the case, especially in drinking liquors that have extra ingredients added to it that dilute its relative concentration strength, and as such it is good for one to be cautious if they suspect mold is growing in their beverage.

Why do Food Products Grow Mold?

mold on food

Mold is a type of microorganism specifically belonging to the fungi branch of microbial life, with a particular preference for growing in wet or otherwise moisture rich environments such as food or beverages.

Mold will usually grow on the surface of food or drinks by way of said food products becoming contaminated with mold spores, microscopic cells produced by larger colonies of mold that are responsible for spreading the specific lineage of the mold’s species.

This type of fungi is especially common in food and drinks due to the conditions that must be met in order for the mold spores to propagate properly – that being the presence of moisture, a nutritive source, heat and proper air flow; all of which may be found in certain alcoholic beverages and similar fluids.

At What Percentage Can Alcohol Grow Mold?

As previously mentioned at the beginning of this article, most forms of alcohol cannot grow mold due to its concentration strength making the propagation and survival of most life forms impossible once submersed in said alcohol.

This becomes less true the lower the concentration strength of the alcohol is, a characteristic that is generally achievable by the dilution of the otherwise pure alcohol with water, adulterants, excipients or additional food purpose ingredients that alter the sensory characteristics of the alcohol.

Generally, the percentage strength per unit volume of 17% is the absolute maximum possible concentration that mold or other microbial life may survive in an ethanol alcohol solution – though even this particular concentration is rather hostile to mold, and will require specific conditions be met in order to host life in any form.

Can Mold Grow in Beer?

Whether or not alcohol can grow in a can or bottle of beer will depend on two factors; that being the particular alcohol concentration percentage of the beer and the method in which it was stored.

Typically, most common store-bought beers will clock in at around 5-6% alcohol by volume, placing it significantly lower than disinfectant grade alcohol or other alcoholic beverages that are not susceptible to the growth of microbiological life such as mold.

This can equate to the majority of beers being at risk of developing mold cultures, especially if stored in a warm environment and exposed to the open air.

However, the majority if not all commercially produced beer brands hold their products to stringent quality standards and as such if the packaging of the beer and the conditions it is stored in are ideal, it is quite unlikely that any sort of mold will grow in the beer.

Can Mold Grow in Spirits and Liquors?

can mold grow in spirits

One standard unit of spirits or liquor in the United States is measured at 1.5 ounces of 40% ABV – significantly higher than the ceiling of 17% percentage strength per unit of volume required to eliminate any risk of growing mold cultures or other microbial life.

As such, unless the spirit or liquor has been incorporated into a cocktail or other mixed beverage that lowers the total alcohol concentration of the drink itself, it is unlikely that any sort of microbial life can develop in the alcoholic fluid.

This is all the more so if the spirit or liquor has been kept preserved in the proper manner, such as in an air-tight container away from direct sunlight and other factors that may denature or otherwise weaken the strength and function of the alcohol itself.

Can Mold Grow in Wine?

Unlike spirits and liquors, wine generally has a significant amount of sugar present in its ingredients, and as such is far more susceptible to growing mold and similar fungal cultures than other kinds of alcoholic beverages.

The majority of standard wines possess an alcohol by volume percentage of about 12%, which is sufficiently high enough to ward off the presence of most species of mold, but will not always guarantee that no mold at all can develop.

This is especially applicable if the correct conditions for the development and growth of mold cultures is met, with the wine being left out in the open in a warm room being the worst possible way of storing it for the purposes of avoiding microbial life.

Wine’s ability to grow mold is secondary to the fact that it can expire, however, and as such one must calculate for both factors so as to retain the quality and edibility of the wine if they are not consuming it immediately.

Can Rubbing Alcohol Grow Mold?

Most forms of rubbing alcohol (be it isopropyl, ethanol, or a mixture) are significantly more concentrated in terms of alcohol concentration than alcoholic beverages and as such are not only incapable of developing mold cultures but can also be used to kill mold on other surfaces.

This is especially noticeable in a medical or otherwise sterile setting that requires a quick acting and efficient disinfecting compound that itself does not expire or can otherwise be compromised by the presence of microbial life.

Is Cloudy Liquor a Sign of Mold?

Generally, liquor that is cloudy or has “floaties” present in its fluid are not host to a mold culture – especially if the liquor has been stored in an appropriate manner and is of a rather high alcohol by volume concentration.

This is especially applicable in whiskey, brandy or similar brown alcohols with a rather high presence of certain compounds that are a consequence of improper storage, an improper distillation process or simple ingredient additives.


  • Rogawansamy S, Gaskin S, Taylor M, Pisaniello D. An evaluation of antifungal agents for the treatment of fungal contamination in indoor air environments. Int J Environ Res Public Health. 2015 Jun 2;12(6):6319-32. doi: 10.3390/ijerph120606319. PMID: 26042369; PMCID: PMC4483703.
  • Korukluoglu, M., Sahan, Y. & Yigit, A. The fungicidal efficacy of various commercial disinfectants used in the food industry. Ann. Microbiol. 56, 325 (2006). 

Does Alcohol Kill Fungi?

One of the most common uses for alcohol in its more pure forms is that of a germicide and sterility agent, with certain types and percentages of alcohol being deemed appropriate for the purposes of killing certain types of microbial life in the correct setting.

Among these types of microbes specifically targeted through the use of alcohol is that of fungi – eukaryotic microorganisms that may take the form of mold, yeast or mushrooms, depending on the particular species.

Fungi can and is regularly killed or otherwise rendered inert through the use of alcohol, especially in hospital or clinical settings wherein sterilization is of utmost importance. 

However, not all types of alcohol are created equal, and stringent standards of quality apply when using alcohol to disinfect and sterilize an area.

What Sort of Alcohol Can Kill Microbes?

Depending on what type of microbe is to be killed as well as the surface that is being disinfected, the particular formulation and percentage concentration of alcohol that is required will also change.

More easily accessible formulations of alcohol such as 60-80% isopropanol rubbing alcohol for the purposes of skin disinfection are the most commonly used – especially for killing any microscopic fungi that may be present on the individual’s skin.

When specifically disinfecting surfaces that contain significant populations of fungal spores or fungal colonies, it is best to utilize non-ethanol formulated alcohol at a moderate to high concentration percentage, as ethanol alcohol has been shown to not completely kill certain types of fungal species.

This is especially applicable in a clinical setting wherein even a small volume of fungal spores or fungal colonies present on medical implements can lead to fatal cases of infection.

How Does Alcohol Kill Microbes?

The particular mechanism of alcohol that is responsible for its wide reaching and effective ability to kill microbes is that of its protein denaturing effect.

When denaturation takes place between alcohol and a microbial life form, the alcohol affects any protein compounds present in the microbe’s cellular structure – essentially destroying the cell wall’s capacity to retain its shape and thereby rupturing and exposing the contents of the microbe’s cells.

The time it takes to do this and whether or not the alcohol is sufficiently powerful enough to pierce the structure of the microbe’s body will depend on a variety of factors such as what formulation of alcohol is being used as well as what type of microbial life is undergoing the denaturing.

In the case of fungi, yeasts are generally found to be far more susceptible to alcohol induced protein denaturation than other types of fungi – primarily due to the thickness and molecular complexity of the protein based structures encompassing said other types of fungi. 

Is it Hard to Kill Fungi with Alcohol?

It is actually quite easy to disinfect a surface contaminated with fungal life forms – so long as the proper tools are utilized for a sufficient enough period of time.

Though ethanol alcohol at a percentage over 50% is enough to kill some types of fungi, it is the use of 70% isopropyl alcohol that is most often recommended for the purposes of truly removing most traces of fungi and other microbes from a surface.

This is due to the fact that ethanol is more geared towards killing viruses enveloped in a protective protein layer, a form of microbial life several steps removed from that of fungus and therefore making isopropyl alcohol the more effective tool in killing the aforementioned life form.

Does Alcohol Kill All Fungi?

Though alcohol is an extremely effective disinfecting agent in regards to its germicidal and fungicidal abilities, it is not entirely foolproof, and either due to random chance or a certain type of fungal species with a particularly thick envelopment – it is possible for fungal species to survive alcohol disinfection.

This is more applicable if the sort of alcohol that was used is either of too high or too low a concentration, both of which will not act sufficiently enough in the manner of protein denaturation to wipe out every fungal spore and fungal colony of a surface.

What Percentage Alcohol Kills Fungi?

70 percent isopropyl alcohol
Editorial Credit: MikeEdwards /

Bright Future Recovery outlines that alcohol is usually diluted to a percentage below 100% with either water or a similarly neutral compound for the purposes of improving its microbe killing abilities or preventing skin irritation, if external skin usage is the purpose of the alcohol based product.

The particular percentage recommended by most reliable sources is that of 70% isopropyl alcohol, especially in regards to the killing of fungal spores and other types of fungal life.

This is due to the fact that any percentage of isopropyl alcohol that is too concentrated may result in the alcohol failing to fully penetrate the cell wall’s protein structures, only damaging the fungal cell wall instead of fully rupturing and destroying it.

By addition of this characteristic of 70% concentrated isopropyl alcohol, the addition of water as a diluent compound will also allow the alcohol to denature enzymatic proteins alongside the normal denaturing ability of alcohol in concerns to structural proteins.

Can Alcohol Kill Fungal Infections on the Skin?

Though alcohol is normally used as a disinfecting agent on non-biological surfaces such as tables or equipment, it is possible for isopropyl alcohol of the correct percentage concentration to be used in order to kill skin level fungal infections.

Much like if one were disinfecting a surface that was not skin, it is best to make use of isopropyl alcohol that is at a 70% concentration strength with the other 30% primarily being water so as to avoid any allergenic or adverse effects.

To do so, one simply needs to apply the alcohol directly to the area with a fungal infection, leaving the alcohol to dry or soak for a short period of time so as to kill any fungal colonies that it comes into contact with.

This, of course, will only be effective if the fungal infection is only at the surface, and deeper infections will not be affected or touched by the use of topical alcohol application.


  • Widmer A, Frei R. 2011. Decontamination, Disinfection, and Sterilization, p 143-173. In Versalovic J, Carroll K, Funke G, Jorgensen J, Landry M, Warnock D (ed), Manual of Clinical Microbiology, 10th Edition. ASM Press, Washington, DC. doi: 10.1128/9781555816728.ch11
  • Ribeiro MM, Neumann VA, Padoveze MC, Graziano KU. Efficacy and effectiveness of alcohol in the disinfection of semi-critical materials: a systematic review. Rev Lat Am Enfermagem. 2015 Jul-Aug;23(4):741-52. doi: 10.1590/0104-1169.0266.2611. PMID: 26444178; PMCID: PMC4623738.
  • LOEWENTHAL K. The Antifungal Effect of 70% Ethyl Alcohol: A Laboratory Study. Arch Dermatol. 1961;83(5):803–805. doi:10.1001/archderm.1961.01580110091014

Are All Black Mold Species Toxic: Color Explained

Many homeowners, especially in the US, have been indoctrinated that black mold is dangerous as it decreases air quality and can be potentially toxic. This belief has been exacerbated by years of media portrayal and marketing.

Academic studies provide insufficient data supporting that black mold species pose any critical threat to human health. With countless species of mold exhibiting a dark or black pigmentation, one genus in particular has accumulated negative perception – Stachybotrys. Two species under that genus, S. chartarum and S. chlorohalonata, are colloquially called “black mold” in the United States. While these species do produce mycotoxins, insufficient evidence supports the association of this mold to poor health.

This article will briefly discuss molds, black molds, mycotoxins, and what the color of the species indicates.

Mold Explained

mold colony

Molds are a group of fungi, not unlike the common mushroom, that are capable of growing in almost any surface – as long as the surface achieves all the necessary conditions. They are multicellular organisms which distinguish them from bacteria. Molds also grow as filamentous colonies, unlike other fungal groups that exclusively grow as yeasts.

While the growth of mold on a wall is distinctly visible, fungi are present everywhere. Fungi produce spores, microscopic cells that are capable of lying dormant until the necessary conditions are met for the spore to grow. Being ubiquitous, spores are found in drinking water and in the air. On average, studies reveal that every breath of air contains between 1-10 spores – which means a person can inhale between 20,000-200,000 spores every day.

While fungal spores are especially prevalent in the environment, they pose little threat to humans in particular as the human body is not the ideal environment for fungi to grow in. Like any organism, mold requires water, food, and oxygen to thrive.

Because of the living conditions required by mold, they are most often found growing on moist or damp wooden surfaces such as wallboards, ceiling tiles, and cardboard. Granted, as long as there is organic matter for them to consume and the other pre-requisites are met, mold can grow (e.g., dust found on concrete).

Like most fungi, molds are highly morphologically diverse. This means that molds can be of any size and shape. While some species are restricted to certain morphological characteristics, some species can have a wide array of morphological features depending on their environment. One of these morphological features that will be expounded on is color.

Not all molds produce relatively toxic compounds that can lead to serious health issues. However, molds constitutively contribute foreign materials in the air (e.g., spores, hyphae, etc.) that can cause allergic reactions and respiratory irritations.

Molds have been commonly attributed to damp building-related illnesses (DBRI) (also known as sick building syndrome). These include a wide array of respiratory, immunological, and neurological symptoms that are commonly associated with a specific building. While inadequate cleaning methods are the primary culprit of DBRI, the occurrence of mold is a subsequent factor.

Black Mold

In the United States, the name black mold is often used to refer to two specific species of mold: Stachybotrys chartarum (previously Stachybotrys atra) and Stachybotrys chlorohalonata. However, these are by all means not the only species of mold that can exhibit a dark or black pigmentation.

Other genera such as Aspergillus, Cladosporium, and Nigraspora all include multiple species that can produce colonies exhibiting dark or black pigmentation. This is why the Centers for Disease Control and Prevention (CDC) reports that while molds can pose as a health hazard to people with weaker immune systems and children prone to developing asthma, color is not an indication of how dangerous a mold may be.

Concern for Stachybotrys species arose from numerous studies. A 1998 paper published in the Archives of Pediatrics and Adolescent Medicine studied the incidence of acute pulmonary hemorrhage in infants with respect to fungal exposure. With an emphasis on S. chartarum, the study found that five out of the ten infants with acute pulmonary hemorrhage lived in homes with viable S. chartarum spores in the air.

A 2003 paper published in Clinical Microbiology Reviews discussed that the concern for Stachybotrys (emphasized with S. chartarum) has been brought up by numerous studies associating the fungus with serious illness. However, the review concludes that most of these studies suffer from methodological flaws and inconsistencies, thus making their findings inconclusive.

While being regarded by the general public as a serious health hazard, the most common symptoms caused by black mold contamination include dizziness, nasal congestion, flu-like symptoms, sore throat, chronic coughing, and skin rashes. The more extreme symptoms that have presented in special cases include asthma attacks and lung complications.



Mycotoxins refer to the naturally occurring compounds fungi produce that have toxic properties. These mycotoxins are often secondary metabolites, which means that fungi produce them as a result of their metabolic activities, but they are not necessarily needed for survival.

Oftentimes, mycotoxins are more of a concern in agriculture. Specific fungal genera such as Fusarium and Alternaria grow on agricultural crops and stores. These are problematic because contaminated agricultural products are then unsafe to consume, conferring economic loss to the farmers.

Stachybotrys species have been found to produce certain mycotoxins, specifically macrocyclic trichothecene mycotoxins. However, these are especially uncommon. Even warned as the dangerous kind of black mold, not all kinds of S. chartarum produces these mycotoxins. As of now, there are only two types, or chemotypes, of S. chartarum that produce mycotoxins. One has been found to produce highly toxic macrocyclic trichothecene mycotoxins while the other chemotype produces less toxic atranones and simple trichothecenes but not macrocyclic trichothecenes.

Even when some fungi have been known to produce deadly mycotoxins that would cause food to be unsafe to eat, these fungi exhibit different cases depending on the environment. A 2005 review published in Applied Microbiology and Biotechnology reports that fungi such as Penicillium and Aspergillus are major contaminants of food and feed products. However, the same fungi were observed to produce different sets of mycotoxins when isolated from damp buildings.

While there are reports of toxic mold causing serious or rare health issues such as pulmonary hemorrhages or even memory loss, the CDC and the World Health Organization (WHO) agree that these reports are rare and the studies linking molds to these health issues have been insufficient.

A 2010 review published in the Applied Occupational and Environmental Hygiene called upon the assessment of industrial hygienists to inspect both residential and commercial buildings for molds and mycotoxins. The review and the assessments confirm that while there are reports of high levels of mold capable of conferring poor health and hazardous health issues, the average levels of mold in mold-contaminated buildings were insufficient to induce health issues as reported in some literature.

Final Thoughts

By all means, studies unanimously agree that mold can produce foreign materials that can lower the quality of indoor air – possibly triggering respiratory irritation and allergic responses.

The worst-case scenario would be for immunosuppressed individuals as fungal infections are commonplace and potentially life-threatening. But for the majority of the population with adequate immune systems, mold is not a critical situation. For overall safety, it is still recommended as the best course of action to remove any mold that has been detected to prevent it from spreading and growing into a more probable health hazard.


Which Household Mold Species are Dangerous?

Mold spores are around you at all times. There are also potentially hundreds of thousands of mold species to exist. Some species of mold are harmless, while others are capable of producing pathogens and mycotoxins.

Molds are typically classified based on their health effects on humans. Molds can be allergenic, pathogenic, and toxigenic. Allergenic molds cause problems in people who have allergies to certain species of mold. Where-as pathogenic molds can cause infections in humans, even in good health. Toxic molds actively produce chemical poisons with the intentions of harming other organisms.

Some mold species pose little to no harm to otherwise healthy people, while some produce mycotoxins that are unsafe to humans. It’s important to have a better understanding of the aforementioned classifications as apposed to a specific species of mold (there are hundreds of thousands).

How Molds are Classified

As noted above, molds are typically classified based on their likeness to cause adverse health symptoms in humans. Molds are either allergenic, pathogenic, or toxigenic. Just the same, dust can also be closely connected to the occurrence of allergic reactions. This comparison between dust and mold will surely clear things out for you.

allergic reaction boy


Molds that are classified as allergenic are apt to affect people who have allergies or are predisposed to asthmatic symptoms.

People who are allergic to a specific mold species can experience severe reaction when they come into contact with it (via inhalation, ingestion, or dermal contact). When the body comes into contact with the mold it has an inflammatory response in the upper respiratory tract.

It’s estimated that 20 to 30 percent of the population is susceptible to mold-based allergic reactions. However, most healthy people are unaffected by small amounts of exposure.


Our bodies’ immune system is able to fight off pathogens, however, pathogenic molds are referred to as opportunistic. Meaning, they tend to target people who have compromised immune systems like the elderly, infants, and people who take immunosuppressants.


Unlike the other two mold species, molds that are toxigenic actively work to produce harmful chemicals called mycotoxins. The purpose of these chemicals is to intentionally harm other organisms.

Both mature mold growth and mold spores can contain mycotoxins. As a result you can become exposed to it via inhalation, ingestion, and skin contact.

Dangerous Types of Mold

brick wall monochrome mold

As noted above, mold classifications typically help to outline which species have a likeness to cause harm to humans and be deemed “more dangerous.” However the following species are mentioned more than others in regards to their overall level of danger in humans.

Stachybotrys chartarum aka ‘Black Mold’

Stachybotrys chartarum aka “Black Mold” or “Toxic Black Mold” is one of the most recognized indoor molds. Stachybotrys chartarum takes on a greenish-black appearance.

This mold species is hydrophilic and requires high water content and low levels of nitrogen. It usually grows as a result of prolonged moisture exposure: water-damage, leaks, flooding, etc.

Black mold is also toxigenic and produces mycotoxins which are harmful when inhaled and ingested.


Another potentially harmful mold species frequently found in damp and water-damaged areas is Chaetomium. Many homeowners mistake Chaetomium for toxic black mold due to their striking similarities.

Chaetomium mold colonies grow rapidly, are cottony, and are usually white initially. The spores they release are bigger and heavier than the spores of many other mold species, so they’re less likely to become air-borne, except in cases where the mold has dried out and is disturbed.

Chaetomium molds are among the many molds that cause infections (pathogenic), especially to individuals with weakened immune systems. Causing skin and nail infections, internal lesions, cerebral infections, asthma, and allergic reactions.


It’s estimated that there are nearly 200 species of Aspergillus mold. This species of mold typically grows in warm climates when elevated levels of moisture are present.

Aspergillus usually has a velvety or powdery texture and their colonies can take on many colors depending on the species. The mold is commonly found in heating and air conditioning systems.

Symptoms of aspergillus exposure include allergic reactions as well as chronic sinusitis.


There are an estimated 250 species of Alternaria. This type of mold is one of the most common and is ubiquitous in nature.

At the start of growth, the surface of Alternaria colonies are greyish white, but darken and turn greenish-black or yellowish-brown with a pale-colored border when matured. Alternaria is highly airborne and grows rapidly.

Alternaria is known to cause asthmatic symptoms like coughing, wheezing, headache. High levels of Alternaria exposure is also associated with esophageal cancer.

asthmatic boy bed


There are roughly 300 species of Fusarium. This species of mold requires wet conditions in order to grow and is commonly found in humidifiers. However, most species of Fusarium are not found indoors.

The color of the Fusarium colonies varies from tan, white, and cinnamon to salmon, red-violet, pink, purple, or yellow, with texture ranging from flat-looking to hairy.

Fusarium infection can cause serious health problems including dermal reactions, asthma, and pulmonary problems like emphysema and pneumonia.


Penicillium is one of the most common fungi in the world and grows both indoors and outdoors. Like most species of mold, they tend to grow in colonies that range in color: including white, bluish-green, pink, and yellow, with a powdery texture.

When indoors, penicillium is most commonly associated with the spoilage of food-stuffs.

Where Toxic Household Mold Species Are Found

Mold thrives and spreads easily in warm, damp, and humid places, which explains why indoor molds frequently grow in areas with high water content and low ventilation like bathrooms, showers, and basements.

Toxic molds are also incredibly resilient, which means they can grow in practically all common building materials. They can grow well in wood and wooden surfaces as well as paper and paper products such as wallpaper, drywall, and cardboard. They can thrive in fabrics like carpets and upholstery and can also be found in other building products, including paint and insulation.

Most health problems associated with exposure to molds arise with long-term exposure and high levels of concentration.

Dust vs Mold: What’s the Difference?

Indoor air quality (IAQ) is said to be up to five time worse than outdoors. Both dust and mold have a negative impact on IAQ. While dust isn’t mold, mold actively uses dust as a vehicle for transmission and a nutrient source.

Mold is part of the fungi kingdom and are referred to as Hyphomycetes. Molds are eukaryotic micro-organisms that reproduce asexually (primarily) via spores. Unlike mold, dust is not an organism. Dust is comprised of organic and inorganic particle matter like dirt, pollen, dead skin cells, pet dander, and lint.

Both dust and mold are airborne pollutants that contribute to poor air quality. Apart from one being a living organism, they have distinct differences that are important to understand.

What is Mold?

Mold is part of the fungi kingdom. It’s a non-scientific term used for many types and species of fungi. Fungi comprise a large number of organisms and roughly 300,000 species. The United States Environmental Protection Agency (EPA) defines fungus as “types of plants that have no leaves, flowers, or roots.”

In nature, molds are referred to as decomposers as they work to break down dead, organic materials like plants, trees, and various other detritus. In order for mold to grow and germinate, it needs an organic, carbon-containing nutrient source, like dust.

Regardless of mold species, most if not all indoor molds reproduce via spores. Spores exist all around us and can lay dormant for years. Once mold finds itself in the ideal conditions for germination, it will start to grow.

Ideal conditions for growth include moisture (water source), food source, and oxygen. Some molds also thrive in various ambient temperatures as well as lighting.

mold wall building

What is Dust?

In laymen terms, dust is a collection of tiny airborne particle matter. These particulates contain both organic and inorganic materials like dead skin cells, hair, bacteria, dead bugs, insect excrement, pollen, pet dander, food particles, etc.

The dust found in your house will depend on your environment. It’s also commonly believed that dust is primarily made of human skin, this is not true. Dust is primarily comprised of soot and airborne particles like pollen that are tracked inside.

How to Tell the Difference Between Mold and Dust

While mold test kits do exist, they can be expensive. Most people also want to be able to visually differentiate the two. However, you can use all your senses as means of evaluation.

Molds can grow in a variety of colors and are usually easily distinguishable. However, at their onset, it can be hard to see the difference between mold and dust. Mold also doesn’t wipe clean and germinate on whatever surface/nutrient source it’s on. Usually a damp cloth, if you’re able to wipe the surface clean, it’s likely not mold.

Besides being able to visually distinguish mold from dust, you can also smell the difference. Water Mold Fire (WMF) explains that mold has a distinct musty smell. It’s often compared to wet socks or rotten wood. Dust on the other hand will smell earthy, like dirt.

Gravity has more of an impact on dust than it does on mold. Gravity will pull dust to the top of a surface, rather than the bottom of it. If you find something growing on the bottom of a surface, it’s likely mold.

You can manufacture your own test with diluted bleach (1-part bleach, 16 parts water) and a cotton swab. Upon application of the swab, if you notice the spot quickly lightens (1-2 minutes) you can assume its mold. If it doesn’t change color, it’s likely dust or dirt.

Note: While bleach can kill some mold, the purpose of the test is to remove the color from the mold.

How to Improve Indoor Air Quality

The EPA notes that indoor air quality is 2 to 5 times worse than outdoors. This is especially problematic as Americans spend 90% of their time indoors.

Osha goes on to say that the most common causes of IAQ related issues are poor ventilation, lack of maintenance for heating and HVAC systems, and humidity.

woman sitting dusty air


By opening windows and doors, you allow the space to fill with fresh air and the potentially harmful air to leave the space. As low as humidity levels are maintained, the potentiality for the mold spores to germinate is minimal.

You can also make use of air purifiers to help filter indoor air. Air purifiers make use of filters like HEPA or High Efficiency Particulate Air filters. These filters are used to help remove dust as well as mold spores from the air.

HEPA filters are capable of filtering particles as small as 0.03 microns. Dust particles are between 2.5 to 10 microns and mold spores are sized between 1 to 30 microns.

These types of filters can also be integrated into air conditioning systems and furnaces. Typically, an HVAC and vents will use MERV (Minimum Efficiency Reporting Value) rated filters. A MERV rating of eight results in 70 to 85% of particles 3 to 10 microns in size being filtered.

MERV values range from 1 to 16. Essentially the higher the value, the more efficient the filter is.

These filters for both the furnace and air conditioning systems should be changed regularly. As they become pollutant laden, they lose their efficiency and can do more harm than good. It’s best to change air filters every 30 to 60 days depending on external factors.

Humidity and Moisture

Mold only grows in the presence of moisture. Higher humidity levels result warm air condensing on cold surfaces like plumbing and walls. Over time this process of condensation results in moisture/water build-up that mold uses to germinate.

The EPA details that indoor humidity levels should be kept below 60% and within the range of 30-50%.

In order to combat humidity and moisture build-up you can use a dehumidifier to remove water vapor from the air.

You can also work to insulate plumbing with closed-cell foam and duct-work with fiberglass to combat heat transfer and condensation. You should also ensure appliances like dryers are ventilated/exhausted properly.