visiblemold.jpeg (image_90S7su2.webp)When the weather outside is frightful, many of us spend more time inside.  While this time can be delightful, sometimes the indoors have issues lurking that can impact our health. We’re talking about mold – particularly in homes where mold can be seen or smelled.

What Are Molds?

Molds are members of the Fungal Kingdom, a group of living organisms that are neither plants nor animals and can take on many shapes and sizes.  Molds are fungi that grow in multicellular filaments called “hyphae,” which can spread over walls and other surfaces to form visible colonies. Other fungal organisms grow as mushrooms or as single-celled yeasts or alternate between mold and yeast forms.  

Some molds are good, like Penicillium which produced the first penicillin antibiotics.  Others, like Aspergillus, are not, and can cause food to spoil and generate harmful toxins.  Some molds cause serious infections in people with compromised immune systems and some molds can trigger allergic responses including severe asthma exacerbations. 

Is Visible Mold a Problem?

If you see or smell mold in your home, it is because there is enough moisture  (perhaps around leaky plumbing fixtures or on basement walls) to allow mold to grow out of control.  Molds are everywhere, indoors and out, but if they have grown to the point that you can actually see or smell them in your home, you have a moisture problem.  

It is a “problem” because living in a home where mold can be seen or smelled has been associated with an increased incidence of asthma in children [Quanash 2012], an increased risk of asthmatic exacerbations, decreased lung function in non-asthmatics [Hernberg 2014], and an increased risk of developing rhinitis and rhinoconjunctivitis [Jaakkola 2013].  

 How Are Illnesses Associated with Visible Mold?

  1. Molds can trigger allergic responses.

  • This includes acute responses such as allergic rhinitis or asthma exacerbations, but can also include chronic allergic diseases such as hypersensitivity pneumonitis which can result in fevers, weight loss and pulmonary fibrosis or emphysema.
  1. Molds produce volatile organic compounds that can cause even non-allergic health effects.

  • Some of these compounds are responsible for the moldy smell, some may be classified as “mycotoxins” and be irritating to skin or nasal passages, or have other health effects.
  1. The moisture that led to increased visible mold growth can also lead to increased invisible bacterial growth.  These invisible bacteria can produce hazardous substances of their own.

  • Identifying the species of visible mold is not generally helpful. The species that are visible may not be directly causing health problems.
  1. The increased humidity that led to increased levels of mold growth may have also increased the level of dust mite allergens or airborne particles in your home.

  1. Wet building materials themselves can release harmful chemical substances into the air.

What Does All This Mean?

Visible mold is a sign of potential problems for everyone, not just those who test positive for mold allergy.  

Here are some recommendations from the Environmental Protection Agency to reduce mold in your home:

  1. Fix the source of water problems or leaks to prevent mold growth.

  2. Reduce indoor humidity (to 30-60%) to decrease mold growth by: 

  • Venting bathrooms, dryers and other moisture-generating sources to the outside
  • Using air conditioners and dehumidifiers,
  • Increasing ventilation,
  • Using exhaust fans whenever cooking, dishwashing or cleaning.
  1. Clean and dry any damp or wet building materials and furnishings within 24-48 hours to prevent mold growth.

  2. Clean mold off hard surfaces with water and detergent, and dry completely. Absorbent materials such as ceiling tiles that are moldy may need to be replaced.  

  1. Prevent condensation: Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof, or floors) by adding insulation.

For more information, visit https://www.epa.gov/mold.

The Bottom Line

It is not possible to reduce mold exposure completely, and individuals who are allergic may experience symptoms even when visible mold has been eliminated. For susceptible individuals, medications to prevent or treat allergic rhinitis, conjunctivitis and asthma are particularly important.  Allergy shots may also be useful. 

If you think you or someone you love may have health effects from mold exposure, talk to one of our doctors and see if either you or your home would benefit from some additional interventions.