Mold spores are essentially microscopic fungus seeds, so small that they can easily become airborne and inhaled. These particles are everywhere, both in the household and outdoors, so there is no way that mold can be entirely avoided.
For most people, molds don’t pose a health hazard. The human immune system usually prevents fungus from growing on and in the body. Molds can, however, in those with sensitivities, trigger an out of control immune response, an allergic reaction.
Respiratory Mold Allergies
People who have respiratory allergies year-round, even during freezing and dry weather, may have an allergy to mold, as well as to household dust mites and the dander of indoor pets. Although mold allergies can occur throughout the year, they are usually most severe during warm, wet weather and from mid to late summer, when conditions are best for fungal growth and reproduction. By contrast, dust mite and pet allergies often make the sufferer consistently miserable, regardless of season.
When Are Mold Counts Highest?
Ambient moisture enhances both growth and spore production of fungi. So spore counts typically rise with rainfall, fog and damp, night time conditions. Fusarium, Phoma, Cephalosporium, and Trichoderma are types of fungi that release more spores when conditions are damp.
Spores of many fungi are distributed by the wind. This dry spore dispersal increases as wind speed rise and relative humidity falls. Spores of Cladosporium, Alternaria, Epicoccum, Helminthosporium, Rhizopus, Aspergillus, and Penicillium peak during these types of conditions.
Overall, in North America, airborne fungi are at extremely low levels when outdoor temperatures are below-freezing, and, in temperate regions, at peak levels in late summer and early autumn.
However, fungi also grow in indoor environments, and indoor growth can cause year-round allergic symptoms. Soiled furniture upholstery, poorly maintained mist vaporizers, dirty garbage containers and foam products, such as mattress pads, pillows and foam mattresses encourage indoor fungal growth. Damp basements, molding around windows, shower curtains, and plumbing fixtures are also prime sites for indoor fungal growth.
Reducing the Severity of Mold Allergies
Because spores can’t be entirely eliminated from the environment, those who are allergic to molds can experience unrelenting allergy symptoms. But it is possible to reduce exposure to mold and thereby minimize the body’s allergic response to it.
Local weather services often post mold counts, so that those with allergies can elect to spend more time indoors on days when the mold count is high. To reduce the severity of allergies to indoor molds, install a high quality, and frequently replaced filter to the home heating and cooling ventilation system, keep indoor humidity levels low, fix any leaking fixtures and pipes, and regularly clean surfaces that are prone to moisture, such as garbage containers and bathrooms.
For more information on the molds that can trigger allergies, see the Suite101 articles:
Mold Allergy: Which Fungi Cause Allergies?
Mold Allergy: Symptoms and Treatment
Mayo Clinic (June, 2009) Mold Allergy
Asthma and Allergy Foundation of America (2005) Mold Allergy.
Huang, Shih-Wen (2009), Mold Allergies, MDeMedicine from MDWeb
WebMD (2009) Mold Allergy.
Please note: The information in this article is not to be followed as medical advice, diagnosis or treatment. Please consult with your physician or primary health practitioner for information regarding your own personal health and necessary treatments. This article was originally published in Suite101 online magazine.