Mold isn’t just unsightly. It can prove to be a serious health hazard if left untreated. Various mold species can grow undetected for weeks, months, or even years in homes all year round. Mold spores are known to have an adverse impact on the indoor air quality but they are often more dangerous than common pollutants such as dust and smoke.

Here in this post, we will shed light on the seven most common types of mold found in homes, potential health implications they can cause, and various ways homeowners can prevent them. Read on.

1. Alternaria

One of the most common allergenic molds found in homes, Alternaria typically grows anywhere dampness can be found.

A velvet-textured mold with dark brown/green hairs, Alternaria is generally found in carpets, wallpapers, window frames, and HVAC systems. It can also be found in bathtubs, showers, and under (leaking) sinks.

Exposure to this mold can cause allergies, asthma, and pulmonary diseases.

This mold species takes root and spreads to different areas of a building due to water damage. Since it spreads rapidly, quick mold remediation is advisable. The best way to prevent the growth of this mold in homes is to get water damage investigated and repaired by professionals.           

2. Stachybotrys

A toxigenic mold, Stachybotrys is commonly referred to as Black Mold. Black or dark-greenish in appearance, it generally grows in laundry rooms and basements or on wet carpets and bathroom ceilings. Most homeowners find this mold species on cellulose materials such as cardboard, wood, wicker, etc.

Black Mold can cause fatigue, headache, respiratory issues, and skin/eye irritation.

Black Mold thrives in damp areas that maintain high humidity levels for weeks. Therefore, the best way to prevent the growth of black mold in homes is to keep the relative humidity (RH) level below 50%. It is also important to prevent moisture accumulation in the basement and crawlspace.

3. Aspergillus

An allergenic and toxigenic mold, Aspergillus is common in American households. There are more than 185 different species of this mold, appearing in different colors/textures.

This mold can cause allergic reactions and worsen existing lung conditions. Some species of this mold are known to produce afltoxin, a dangerous carcinogen (cancer causing agent).

Experts recommend the use of HEPA-certified air filters to prevent the entry and accumulation of Aspergillus spores. It is important to close the windows when there’s a construction (or digging) activity going on nearby.

Once inside a home, it can grow in damp walls and wet surfaces. Aspergillus is known to have long, flask-shaped mold spores. The mold colonies can appear as thick walls of mold on contaminated surfaces. It can also grow on piles of dead leaves or compost piles.

4. Aureobasidium

An allergenic mold, Aureobasidium is usually found in grout or caulking in kitchens or bathrooms. It can also grow on painted walls and wooden furniture or behind wallpaper as long as its spores can find moisture.

Pink or black in color, Aureobasidium can cause hay fever, hypersensitivity pneumonitis (HP – a lung disease causing inflammation of the lung tissue), and asthma. Touching materials affected by this mold can result in dermatitis and rashes.

Known as tertiary colonizers, Aureobasidium spores require high amounts of moisture to germinate and grow indoors. The best way to prevent this mold is to ensure surfaces such as tile grout, window frames, shower curtains, kitchen cabinets, etc. are not left damp for a long duration of time. In case the RH inside a building is over 75%, this mold can also grow on painted surfaces.

5. Chaetomium

An allergenic and pathogenic mold, Chaetomium is found in buildings with extensive water damage.

It has cotton-like texture, gives off musty odor and can cause hay fever, asthma, and sinus problems. The mold changes color – from white to grey to brown and eventually black.

This mold is also believed to be carcinogenic (carcinogens are substances that promote the formation of cancer) and teratogenic (teratogens are substances that may cause functional or physical defects in the human fetus).

Cutting off moisture sources such as a water leak in the basement, attic, or roof is the best way to prevent the growth of Chaetomium.

6. Penicillium

A common household mold, Penicillium can grow anywhere its spores can find moisture. An allergenic mold, Penicillium is recognized by its velvety texture. The mold infestation has a distinct, blue or green appearance.

Exposure to Penicillium can cause lung inflammation or hay fever.

This mold is commonly found in homes and buildings with water damage. Its spores can become airborne and spread to different areas of a home such as wallpapers, carpets, mattresses, insulation, and ducting.

Homeowners should remedy water leaks or water damage quickly to prevent the growth of Penicillium. It can quickly spread from one room to another, if left untreated, even for a few weeks.

7. Fusarium

An allergenic mold, it is commonly found in the soil of home gardens and can grow indoors if mold spores land on wet or moist surfaces. Generally pink, reddish or white in color, Fusarium is known to cause allergic reactions.

According to researchers, prolonged exposure to this mold can even cause life-threatening health conditions such as brain abscess/infection.

Fusarium can grow and spread even at cold temperatures. If a mold test confirms the presence of this mold, immediate mold removal and remediation is necessary.

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