What happens to the mold spores we inhale?

I'm guessing when we exhale, many of them are expelled back out to the environment.

But given that disease can be caused by mold exposure, I'm also guessing that we do not immediately expel a percentage of them.

Molds can colonize in the lungs, causing detrimental effects. Can they colonize elsewhere in the body?

For mold spores that do not colonize inside the body, what happens to them? Are they expelled? If so, by what mechanisms? Are they alive or dead when they are expelled?

  • $\begingroup$ I think spores can cause problems only in immunodeficienc individuals. $\endgroup$ Commented Feb 11, 2016 at 12:00
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    $\begingroup$ @OleksandrPapchenko You may think it, but if you research it, you will quickly learn that is not true! $\endgroup$ Commented Feb 11, 2016 at 22:03
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    $\begingroup$ Maybe I'm reading too much into this post, but I think there may be too many questions here. Like asking about other parts of the body? I also don't know why you ask, "are they dead or alive when expelled?" It's not like our lungs autoclave the air we exhale or bombard the spores with UV light or anything. How would simple inhalation/exhalation kill mold spores? $\endgroup$ Commented Feb 12, 2016 at 5:10
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    $\begingroup$ @anongoodnurse You're jumping to conclusions. We likely only expel some of the spores immediately via the air we exhale. The question specifically asks by what mechanisms we expel the rest of the spores and if they are alive or dead at that point. So to answer the question, you need to look at all mechanisms, not just the exhalation of air. $\endgroup$ Commented Feb 12, 2016 at 8:20

1 Answer 1


Mold spores are capable of landing and becoming dormant. Unless conditions are severe enough, mold spores will not just simply die off; they will essentially wait for conditions to improve and once those conditions do improve, they will take root and grow. When it comes to the human body, it all depends on the type of mold and the overall health of the host. The body is designed with natural defense mechanisms - mucous, enzymes, beneficial bacteria, filaments, etc. - against airborne particles and microorganisms. Basically, you'll never know if a sneeze or cough - other forms of defense - saved you from a miserable existence as a mold host.

As for whether or not mold spores are expelled from the body, that is not so easily answered. Mold spores can sometimes teem in the millions, especially around a dense infestation (such as grain silos or a house that has structural mold rot). Research has concluded that farmers (who make up 30% of victims who suffer respiratory illness in the U.S. alone), for example, inhale up to 750,000 mold spores per minute. The odds aren't exactly in their favor when it comes to expelling mold spores simply by exhaling.

(I write for MoldBlogger, by the way. If you have anymore questions or are curious about other mold-related scenarios, feel free to check it out.)


Here are some of the sources where a lot of this information can be read about.

National Institute for Occupational Safety and Health. Agricultural Safety. Centers for Disease Control and Prevention website. https://www.cdc.gov/niosh/topics/aginjury/. Published June 19, 2014. Updated December 15, 2014. Accessed February 1, 2017.

Glen H. Hetzel, et al. Farmer’s Lung: Causes and Symptoms of Mold and Dust Induced Respiratory Illness. National Agriculture Safety Database website. http://nasdonline.org/1853/d001796/farmer-039-s-lung-causes-and-symptoms-of.html. Published 2005. Accessed February 1, 2017.

Dennis J. Murphy. Agricultural Safety and Health: Farm Respiratory Hazards. PennState Extension website. http://extension.psu.edu/business/ag-safety/health/e26. Published 2017. Accessed February 1, 2017

Also, please feel free to check out a simple post that summarizes this type of information: Occupational Respiratory Diseases: The Farmer, His Lungs, and Mold

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    $\begingroup$ Great that you took the time to answer an old question +1. Could you add your sources to this answer to allow other users to background-read on your topics covered? $\endgroup$
    – AliceD
    Commented Feb 13, 2017 at 8:48
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    $\begingroup$ Thank you. Sources have been added. I will keep an eye out for more sources that I've used in my own research and return to edit again at some point. $\endgroup$
    – TheDemsk
    Commented Feb 13, 2017 at 20:13

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