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Asthma Triggers: Gain Control


picture of faucet dripping, depicting the asthma trigger  - Molds

About molds and asthma

Molds are microscopic fungi that live on plant and animal matter. Molds can be found almost anywhere when moisture is present.

Molds create tiny spores to reproduce, just as plants produce seeds. Mold spores float through the indoor and outdoor air continually. When mold spores land on damp places indoors, they may begin growing.

For people sensitive to molds, inhaling mold spores can trigger an asthma attack.

Actions you can take

  • If mold is a problem in your home, you need to clean up the mold and eliminate sources of moisture.
  • If you see mold on hard surfaces, clean it up with soap and water. Let the area dry completely.
  • Use exhaust fans or open a window in the bathroom and kitchen when showering, cooking or washing dishes.
  • Fix water leaks as soon as possible to keep mold from growing.
  • Dry damp or wet things completely within one to two days to keep mold from growing.
  • Maintain low indoor humidity, ideally between 30-50% relative humidity. Humidity levels can be measured by hygrometers, which are available at local hardware stores.

Additional resources

picture of cover of the publication A Brief Guide to Mold, Moisture, and Your Home A Brief Guide to Mold, Moisture and Your Home
This Guide provides information and guidance for homeowners and renters on how to clean up residential mold problems and how to prevent mold growth. 

See also, EPA's Mold and Moisture Program

picture of cover of Flood Cleanup and the Air in Your Home Flood Cleanup and the Air In Your Home (PDF) (15 pp., 1.6 M)
Indoor Air Facts No. 8 Use and Care of Home Humidifiers (PDF) (3 pp., 33 K)
Explains that some types of home humidifiers can disperse microorganisms from their water tanks into the indoor air. Describes the different types of humidifiers and provides recommendations for their use and maintenance.
Environmental Asthma Triggers

For all EPA asthma resources and publications, visit the Publications webpage.

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