What Is Alternaria Mold? Health Risks and Concerns On Alternaria

Helen Skeates
Helen Skeates
23 min read

It is crucial to identify mold, know its potential hazards, and remove it immediately. With this, you should learn about what is Alternaria mold.

Whether you are going to stay in your house for many years or you’re anticipating selling it in the future, recognizing mold should be one of your priorities. Ranging from mild to massive contamination, mold can be toxic and can affect your living situation.

Did you know that if mold inspectors find the mold test positive, the house value drops by 3%? So, have your house well-treated and be vigilant for unsightly mold.

The Dark, Dirty Truth About Household Mold (And How to Rid Yourself of It)

Monsters of Mold

Mold comes in many different forms. Sometimes it can be detected by scent, but oftentimes it is odorless. Some of the most common types of mold found in homes include alternaria, aspergillus, and stachybotrys. Alternaria is an allergenic mold with a velvety texture. You might see it in the bathroom or near a sink as it is typically a sign of water damage. Aspergillus is another allergenic mold that can be toxic for people with weak immune systems. There are over a hundred species in various colors. Stachybotrys is the notorious black mold. This slimy mold is toxigenic and should only be treated by a professional. Though not all black-colored molds are the black mold, all molds still require immediate treatment.

Cozy Conditions

Mold thrives in damp, dusty, and stagnant conditions. So, it’s important to keep your home well ventilated, and at a relative humidity below 50%. The key to getting rid of mold is moisture control. But where exactly do these molds like to creep?

Alternaria Mold Characteristics, Risk Factors, and Removal Tips

It Came From Beneath

Next to the bread basket, the basement is the place you’re most likely to find mold indoors. You can prevent mold from hiding in your cellar by making sure your basement is primed and patched to protect from floods, and using a dehumidifier to keep your basement’s humidity level low.

Lurking Behind the Curtain

Shower molds can creep up in the corners where the tub meets the wall and also in the grouted or caulked crevices between tiles. Don’t wait for the shrieks of horrified bathers. Give your bathroom adequate ventilation and perform regular cleanings to remove the damp residue that helps mold breed.

Stalking Through Vents

Terrifying but true: Mold can enter your home via air conditioning vents. This isn’t surprising. Wherever dust and dampness collect, mold is bound to find what it needs for sustenance. The best solution for this mold? Replace your filters every two to three months and keep your vents dust-free. If you do find mold in your AC follow these tips.

The Tell-Tale Drip

Mold spawned from a sink pipe’s drip can turn any room’s air into a living nightmare. When you’re in the kitchen, laundry room, or bathroom, keep an ear out for eerie dripping sounds from underneath the drain. Patch up any cracks on the double, and sink-centric mold will be kept at bay.

Oozing Down From Above

Perforations in tile caulking can result in water seepage through ceilings, creating the perfect conditions for mold to spawn. Destroy this dastardly fiend’s habitat by conducting routine checks of tiles and tubs, and also of your home’s roof if you live in an area prone to hurricanes or strong gusts of wind.

Night of the Living Carpet

It doesn’t take a giant pool of water to turn your carpet into mold city. Over time, an inconspicuous, slow, festering collection of moisture and dirt can transform your flooring into a tropical island teeming with strange life-forms. Often, the only effective solution will be a full-on carpet replacement. So keep carpets clean and dry, and check shoes at the door.

Move Fast

Should you find mold in your home, clean it up promptly, and fix any water problems that have caused it. If you do experience water damage to your home, dry those areas within 24–48 hours to prevent mold growth. Whether you find mold on the ceiling, in the shower, or in your carpet, quick action is paramount.

A Silver Bullet for Mold

If the mold covers more than 10 square feet or you find any amount of the dreaded black mold call a professional—the Environmental Protection Agency recommends having an expert clean mold of this nature. You can handle cleaning small areas covered in common household mold with a DIY cleaner. First, protect yourself by wearing gloves, goggles, and a respirator before starting work. Next, spray down mold with a mixture of one cup vinegar, one cup borax, and a gallon of warm water. Let it sit for several hours, then use a file or toothbrush to scrape off the mold and discard it. Porous materials like ceiling tiles and carpet that have been exposed to mold, will need to be discarded. Decontaminate all your tools and clothes, and your home will be safe again.

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The Alternaria Species

Alternaria is dark-pigmented fungi with a brown or dark green appearance that can infect over 4000 plant species. They are widespread, with over 300 species known.

Every year, they do enormous harm to agricultural items, such as cereals, fruits, and vegetables. Alternaria is the culprit for rot in mango farms.

Every year, there is at least 20% of yield loss in agriculture due to Alternaria fungi. They do not only invade homes, but they also destroy acres worth of crops.

What Are Common Types Of Alternaria? 

Studies are still in progress concerning Alternaria species. Today, there are around 250 species known to science.

Here are some common types that might be lurking behind your drywalls:

Alternaria alternata is the type of mold commonly found outside the house, but it can also be found indoors. A. alternata spores depend on windy, dry, and warm days.

They pose a problem for people with breathing problems. In a geographical sense, they thrive in tropical zones and sub-tropical zones.

Some other types are Alternaria stemphyloides, Alternaria geophilia, and Alternaria teunissima. These are specific epithets from the Alternaria genus, but limited studies emerge.

Where Do They Usually Grow? 

Mold is a familiar nemesis to homes and buildings. They can grow in particular conditions, such as damp and dark places.

Most mold species cannot thrive below 40 degrees Fahrenheit. Typically, mold grows in temperatures between 77 degrees Fahrenheit and 86 degrees Fahrenheit, especially when high humidity levels.

Alternaria mold requires minimal moisture to develop. Experts say that Alternaria species grow on minimum value water activity (aw) = 0.65.

This type of mold is found on clothing, carpets, windows, doors, and basements. If your clothes are left damp, expect mold colonies in 24 hours.

Usually, you can find Alternaria in plants and plant-based spoiled meals. They are tagged as outdoor mold, but they can cause serious health concerns when they enter your house.

Health Risks and Concerns On Alternaria

According to Marta F. Gabriel, the Alternaria alternata spores are a well-known biological contaminant and a prevalent source of powerful air allergens in environmental samples. Being exposed to Alternaria is most likely to happen outdoors.

Alternaria: An Indoor Air Quality Contaminant - YouTube

When inhaled, people suffering from asthma and lung problems have increased allergy severity. Alternaria mold should not be underestimated as they pose high-risk factors, especially when exposed to these.

Also, the Alternaria species has been associated with hypersensitivity pneumonitis. It is also studied to cause extrinsic asthma.

The acceptable mold level inside an establishment is 200-500 spores, and if the level exceeds 1000 spores, you should deal with it right away.

How Do You Look For This Mold?

One notable sign of this mold is its scent. Once you smell some musty smells emanating from the furniture, then it must be mold.

Other mold types have appearances of green, black, and white, while Alternaria mold has brown to dark green. Alternaria has tiny fuzzy hairs, be careful as you should not touch them.

How To Prevent Alternaria Mold?

It goes without saying that the efficient way to prevent mold invasion is to keep your house clean and do regular maintenance. You will find Alternaria mold sitting on the surface of air conditioning systems, such as the vents and pipes.

If you’re looking to sell your precious home in the future, advertise it for lease, or live your life peacefully in it, you might want to do some cleaning first.

Unlike mildew and other bacteria, mold can penetrate the insides of the object it is clinging to. Alternaria mold, in particular, has long strands of hyphae buried deep into the thing.

First, if you’re working on furniture, let it dry under the sun. On the other hand, if you work on walls and parts of the house that can’t be brought outside, clean it with a HEPA-grade vacuum.

Second, dilute a mixture of detergent and bleach in a bucket of warm water. Scrub it off until the mold is gone.

Third, spritz a little bit of white distilled vinegar over the surface if you fancy homemade cleaning solutions. Spritz it with mold remover for better results.

Lastly, let the furniture or clothing dry. It might not be a 100% guarantee that Alternaria won’t come back, but at least you took matters to remove it.

Check out these articles if you want to know more about “how to clean mold from air conditioner coils” and “how to prevent mold in garage”.

How to Rid Your Home of Mold

Mold is difficult to remove on your own, particularly if you or a member of your household has health problems. If you think you have mold growing in your home, call a mold remediation company right away. The U.S. Environmental Protection Agency (EPA) recommends hiring a professional if mold covers an area larger than 3 feet by 3 feet, if you have mold in your HVAC system, if the mold was caused by contaminated water or sewage, or if you have any health concerns.

Some homeowners try to remove large mold growths with bleach. Most bleach products are made up of 96 percent water and only 4 percent chlorine. It is not effective on non-porous materials like drywall, wood, or carpet. Be sure to use the proper personal protective equipment like safety goggles, a mask or respirator, rubber gloves, and boots. Here is more on personal safety equipment.

If you rent your home, call your property owner or landlord at the first sign of mold. If possible, take pictures of the damage. If you have problems reaching someone to help, contact your community’s health board or local department of health.

While mold grows best in warmer seasons, it is possible for it to grow in your home year-round. If you believe you have mold inside your home, do not wait until it spreads, or your family becomes ill. You can schedule a free in-home consultation with an experienced mold removal company in your area to look for signs, and if necessary, perform an efficient and convenient removal. Whether you have indicators of mold or not, a professional evaluation can provide you with expert advice at no cost to you. To get started, follow this link to get a list of qualified mold removal professionals in your area. Depending upon the situation, your homeowners insurance policy may cover the removal costs.


What is mold?

Molds are neither plants nor animals. They are microscopic fungi, related to mushrooms, yeast, and mildew and they can be found everywhere. Fungi use enzymes to digest food, and reproductive cells called spores to reproduce. Molds play an important role in the decomposition of leaves, wood, and other dead plant matter. Mold puts the “blue” in bleu cheese, and mold is the original source of penicillin, one of the earliest and most widely used naturally-occurring antibiotics. Unfortunately, mold is also one of the most common allergens on the planet.

Where does mold grow?

Mold spores need moisture to colonize and grow. Molds can grow on wood, ceilings, wallpaper, paint, carpet, sheet rock, and insulation. More specifically, when conditions are right, molds only needs three things to survive: oxygen, a cellulose base food source, and moisture. They use their powerful enzymes to dissolve home materials in the same way that they dissolve decaying plant matter. An environment with high humidity (high levels of moisture in the air) sets the stage for extreme mold growth and thereby poses a risk to your health. Kitchens, bathrooms, garages, basements, and crawlspaces are notorious for mold growth. If any part of your home has experienced water damage, then you’ll certainly find mold there. The U.S. Environmental Protection Agency estimates that one-third to one-half of all U.S. buildings have areas damp enough for mold growth. Even though indoor humidity is generally lower in the winter, indoor mold allergy may be more prevalent during the winter in some homes due to tight, energy-efficient seals. Mold is pervasive outdoors as well, and depending on their location, many people suffer from seasonal mold allergies.

Is exposure to mold dangerous?

Mold growth can not only lead to structural damage to your home (like sagging floors), but it can also adversely affect your health. You can be exposed to mold by touching moldy materials, eating moldy foods, and breathing in microscopic mold spores in the air. You can inhale over a half million spores per minute without even knowing it. Mold allergy symptoms may include skin rash, runny nose, irritated eyes, cough, congestion, and aggravation of asthma.

A 1999 Mayo Clinic study found that allergic fungal sinusitis (AFS) was diagnosed in 93% of cases of chronic rhinosinusitis (CRS), a condition that affects an estimated 37 million Americans. According to a 2005 study, exposure to mold in damp homes can double the risk of asthma development in children.

Most health problems caused by molds are related to allergic reactions; however, molds can also invade the body as agents of infection. Allergic bronchopulmonary aspergillosis is a serious lung disease similar to pneumonia in which mold colonizes and grows in asthmatic mucus within the lungs. People with chronic lung diseases and compromised immune systems are more prone to fungal pulmonary infections.

What if I’m not allergic to mold, will it still affect me?

Yes. One very serious byproduct of mold colonization and growth are mycotoxins. Mycotoxins are powerful agents that many link to “sick building syndrome”. More to the point, mycotoxins can cause a range of symptoms in even health adults and children. This array of toxic byproducts has even been known to cause death in some of the most severe cases. We’ll touch on this mold FAQ again.

Which kinds of mold are allergenic?

Not all molds are allergenic. As with pollen, certain mold spores are allergenic because they are small enough to float in the air and evade the protective mechanisms of the respiratory system. The most common allergenic, indoor molds include AlternariaAspergillusChaetomiumCladosporiumFusariumMucorPenicillium, and Stachybotrys.

What is toxic mold?

First of all, “toxic mold” is a bit of a misnomer. Mold itself is not toxic; however, some toxigenic molds (“toxic molds”) produce poisons called mycotoxins, which can cause fatigue, nausea, headaches, eye irritation, and respiratory problems. Stachybotrys mold, also known as black mold, has been known to cause fatal lung bleeding in infants when combined with environmental cigarette smoke.

Toxigenic molds present the all same health problems as other molds, including allergy symptoms in sensitive individuals. Additionally, in some cases, highly toxigenic molds like Stachybotrys and Chaetomium have been blamed for fatigue, nausea, headaches, pulmonary hemorrhage, chronic bronchitis, multiple sclerosis, lupus, cancer, fibromyalgia, rheumatoid arthritis, learning disabilities, memory loss, and death.

Since they can cause neurological damage, mycotoxins are also neurotoxins, and they have allegedly been used as biological weapons. Some people believe that biological warfare involving mycotoxins contributed to the Gulf War Syndrome, the unexplained illness that affected many soldiers who fought in the Gulf War. Severe mycotoxicosis (mycotoxin poisoning) results in total exhaustion, weakness, loss of muscular coordination, shock, and death.

Like any mold, toxigenic molds thrive in warm, damp conditions. Houses that have been flooded represent the perfect environment for toxic mold growth.

How do I know if I have a mold problem?

If you see small, white, thread-like growths or clusters of small, black dots on the walls of your bathroom or basement, or if you smell a musty odor, then you most likely have a mold problem. In some cases, mold will actually grow within the walls of a house or building, making it more difficult to detect. Some mold, however, is hidden and cannot be easily detected by our senses.

Symptoms of mold allergy include runny nose, itchy nose, sneezing, fatigue, headache, congestion, sniffling, sore throat, itch eyes, and watery eyes. In children, mold allergy typically leads to recurrent respiratory infections.

If you can’t see or smell it, how will I know it’s there?

While you may find some online test kits and businesses offering inexpensive services, many of these aren’t worth the money you spend on them. The most basic of kits traditionally test for mold spores, which isn’t an accurate indicator of a mold problem unless the mold count is extremely elevated (we’ll touch on the mold count again in a subsequent Mold FAQ). Mold spores, as we mentioned in a mold FAQ above, are omnipresent. There will be few places where you find no mold spores in the air. A better assessment of a potential problem is a physical inspection, paired with testing as well as readings on the humidity level in the home. Severe mold problems are often not too difficult to miss, but it is generally best to use a license, reputable, and insured specialist who takes into account several factors. On the other side of this question, people often detect it by changes in how they feel. Symptoms of a mold allergy, covered in our All About Mold article, outlines some of the symptoms. These combined with an odor, high relative humidity in the home, recent flooding, leaking pipes, etc. are often a good first indicator.

How do I treat my mold allergy?

If you’re allergic to mold, the best method of treatment is to avoid contact with mold spores. Wear an allergy relief mask when working outdoors, and take measures to control mold growth inside your home. You can also talk to your allergist about pharmaceutical and immunotherapy treatment options.

How can I control the mold growth in my home?

In practical terms, just as you cannot kill every single dust mite in your home, you cannot get rid of every single mold spore, but with environmental control, you can get rid of enough of them to see improvement in your allergy symptoms.

Repair any leaks or problems leading to water build-up in your home immediately, and remove all materials that have been damaged by water (this includes wood, wall paper, carpet, etc.). Keep exterior surfaces of your home properly sealed, and avoid piling wood or leaves near your home, as they collect moisture. Scour sinks and tubs at least once a month, and wash out garbage receptacles frequently. Pay particular attention to cracks, seams, and grout in the kitchen, bathroom, and laundry areas. Getting rid of indoor plants can also reduce the number of mold spores in the air.

Make sure your home is adequately ventilated. Hidden mold can often grow inside HVAC systems. An allergy relief vent filter will trap the mold before it reaches you.

A HEPA air purifier will remove a minimum of 99.97% of all mold spores in your home, and a HEPA filtered vacuum cleaner will suck up microscopic mold spores deep in your carpet so that you can dispose of them.

Monitor the humidity in your home with a hygrometer, or humidity gauge. Keep your home’s humidity between 40 and 50 percent. Most importantly, use a dehumidifier to remove excess moisture from the air and control humidity.

Polyurethane and rubber foams, commonly used in bedding materials, are especially prone to fungus invasion. If you have polyurethane or rubber foam bedding, consider purchasing allergy relief bedding, which is specifically designed to block out allergens.

Use diluted bleach or the versatile, odorless House Wash or Vital Oxide to clean up visible mold growth, and use Sure Cote as a sealant to prevent future mold growth.

How should I clean up toxic mold?

The act of cleaning mold can increase the airborne spore level by ten-thousand times, which can result in severe illness and actually spread mold growth if done improperly. Such high levels of airborne mold spores warrant protective clothing, including gloves, goggles, and a HEPA respirator. If you suspect you have toxic mold in your home, then you should consider hiring a professional mold remediation expert to clean up the mold and safely dispose of it.

Will Opening Windows Reduce Mold?

What is a mold count?

Similar to the pollen count, a mold count tells us the number of mold spores counted in a standard volume of air over a 24-hour period at a given time and place. If you’re allergic to mold, stay indoors as much as possible when the mold count is high. Anymore, your local news and weather websites will actually post information about mold spore counts, particularly if they are high.


Mold is a natural fragment of the environment — they will appear just about anywhere. The important thing is you recognize what is Alternaria mold and how to deal with it.

Helen Skeates

Helen Skeates

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