Outdoor mold is often just as harmful as indoor mold and their removal or restriction should be as hasty as when they come indoors. Health risks include:

  • Asthma
  • Sneezing
  • Skin rashes
  • Dizziness
  • Headaches

These risks are especially detrimental to children, the elderly, and people with pre-existing respiratory illnesses. By controlling humidity and reducing mold growth, you can

  • Avoid damage to building materials and furnishings,
  • Save money and
  • Avoid potential health risks.

What is it?

They are part of nature, belong to the fungi kingdom, and live in damp places where oxygen is plentiful. Outdoor mold plays a role in nature by decomposing dead organic matter such as fallen leaves, dead trees, and other debris; however, indoor mold growth should be avoided.

Can outside mold make you sick?

mold outdoors

Mold usually generates allergic reactions and hay fever symptoms which, although annoying, are not as severe. However, in some cases, allergic reactions to mold can be more severe and include:


People with asthma may experience a worsening of their symptoms when exposed to mold and allergies. In some people, exposure to certain types of mold may also trigger an asthma attack.

Allergic fungal sinusitis

In some very rare cases, exposure to airborne mold spores can cause inflammation of the lungs. This can be triggered by vulnerability to allergenic dust at work.


Like all other allergies, mold allergy symptoms occur when a person’s hypersensitive immune system is activated.

When mold spores are inhaled, the body reacts to them as antibodies, triggering the production of histamine.

There are a number of factors that can lead to the development or (in the case of mold allergy) aggravation of the symptoms of mold allergy

  • Having a family history of allergies
  • Working in a mold-exposed environment
  • Living in a house with high humidity
  • Working or living in a building exposed to high humidity
  • Living in a house with poor ventilation

What is outdoor mold called?

Usually called spores, air currents cause the mold to circulate in the atmosphere in the form of dust. The two most common outdoor molds are Alternaria and Cladosporium. These mold spores can be measured in the spring months and peak in the fall.

Alternaria is the most common form of allergenic mold in the world. It includes more than 50 species, indoor and outdoor.

It is frequently found on window frames, textiles, carpets, and horizontal surfaces. Alternaria is most typically found in showers, bathtubs, and under sinks. It usually signifies water damage and spreads rapidly.

Cladosporium is one of the most common molds, there are more than 40 species, and it grows in both hot and cold conditions, making it one of the most resistant types of molds available.

What causes high outdoor mold spores?

mold types

Mold usually spreads with its lures, called spores, and grows rapidly both outdoors and indoors throughout the year. Some spores spread in dry, windy weather, while others spread in fog or dew when humidity is high. Mold spore counts are highest at night, especially when fog, humidity, or rain is present.

When agitated, these mold spores become airborne, triggering an allergic reaction in people who have a mold allergy.

How to remove it?

Depending on the surface you will have different ways to remove mold. However, we bring you a summary of how you should do it outdoors. Products that kill mold

In general chlorine bleach

Traditionally called bleach, household bleach (sodium hypochlorite) works best to destroy mildew and remove any discoloration.

Mix a solution of 1 cup of bleach per gallon of water, which you can spray directly on the mildew. Keep in mind that bleach is quite strong, and dilution is an important step before use. Although bleach removes mold discoloration, it also removes color from most surfaces. Use it sparingly and, if in doubt, test it first on a small, unnoticeable spot.

Bleach should never be combined with ammonia, be careful of inhaling dangerous fumes.

Hydrogen peroxide

 Less strong than bleach, hydrogen peroxide (3% to 10% solution) removes mildew and lightens stains. It has a bleaching effect and acts more slowly than bleach, but does not emit fumes or leave residues. With controlled use it can be used as a laundry stain remover, tooth whitening and to heal small wounds.

White vinegar

It works by breaking down the internal structure of mold and mildew. It is a mild acid so you will probably need to mix it with other household cleaners. You can use a mixture and form a paste by combining the vinegar with baking soda so that there is a scrubbing effect and its basic pH removes the mold.

Isopropyl alcohol

Rubbing alcohol may not be as strong as other mold-killing ingredients. But when diluted with equal parts water, rubbing alcohol cleans surfaces without damaging them and can help stop mold growth.

Safety Considerations

When removing outdoor mold, you should protect yourself from both the spores and the chemicals, so no matter how small your risk is, you should be careful. When removing mold have on:

  • Safety glasses
  • Safety goggles
  • Protective clothing
  • Respirator (or at least a face mask)

If you have a serious mold problem on your hands and also have respiratory problems or other negative health effects, it is best to call a professional.

How to remove mold from tile, brick, and grout

mold in walls

There are many effective cleaning products for removing mold and mildew from tile and grout, but if you want to do it yourself, follow these instructions.

Bleach with water.

  • Mix one cup of bleach with one gallon of water. Let the mixture sit for 15 minutes.
  • Using rags and a stiff-bristled brush, apply a good amount of the mixture to the areas affected by mold. Otherwise, use a sprayer or hydro jet to apply the solution to the surface.
  • Rinse and wipe dry, checking that all spores have been removed.
  • Try again if necessary, and be sure to leave the windows open if you can to allow the space to breathe.
  • Disinfect clothes with boiling water once you have finished scrubbing to prevent spores from spreading.
  • Throw away sponges after use. If you want to keep the brush, you will need to disinfect it.

Even though outdoor mold is easier to remove than indoor mold, you must control it, because it is a disease for your flooring, including the surrounding plants, do not let it proliferate.

Outdoor mold: How to get rid of this silent enemy was last modified: April 13th, 2023 by Vanessa Gallanti
Your opinion matters, leave a comment
Inline Feedbacks
View all comments