Dehumidifiers and Asthma: FAQ

Link to Can Dehumidifiers Help with Asthma Symptoms?Can Dehumidifiers Help with Asthma Symptoms?

Yes, dehumidifiers can assist in managing asthma symptoms by lowering indoor humidity levels. High humidity encourages the growth of dust mites and mould, which are common triggers for asthma (Arlian et al., 1999; Mendell et al., 2011). By keeping humidity between 30% and 50%, dehumidifiers make it harder for these allergens to thrive, which may ease asthma symptoms.

However, dehumidifiers are not a complete solution on their own and should be used alongside your regular asthma treatments, as scientific evidence about their direct benefits on asthma is still limited (Wright et al., 2009).

Link to How Does Indoor Dampness Affect Asthma?How Does Indoor Dampness Affect Asthma?

Indoor dampness can worsen asthma by promoting the growth of mould and dust mites (Arlian et al., 1998; Mendell et al., 2011). Damp environments increase the number of these allergens in your home, leading to more frequent or severe asthma attacks (Billings & Howard, 1998). Keeping your home dry can help reduce these triggers.

Link to Do Dehumidifiers Reduce Asthma Triggers Like Dust Mites and Mold?Do Dehumidifiers Reduce Asthma Triggers Like Dust Mites and Mold?

Yes, dehumidifiers can help reduce asthma triggers by making the environment less suitable for dust mites and mould (Arlian et al., 1998; Peat et al., 1998). Dust mites love humid conditions, and lowering humidity below 50% can greatly decrease their numbers (Arlian et al., 1999).

Controlling moisture also limits mould growth. However, while dehumidifiers can reduce these allergens, they should be part of a broader asthma management plan that includes medications and other environmental controls.

Link to Is Dry or Humid Air Better for Asthma?Is Dry or Humid Air Better for Asthma?

Neither extremely dry nor overly humid air is ideal for asthma. Very dry air can irritate your airways, potentially worsening symptoms (Reinikainen & Jaakkola, 2001). High humidity can promote the growth of dust mites and mould (Mendell et al., 2011). The optimal indoor humidity level for people with asthma, or anyone, is between 30% and 50% (Arlian et al., 2001). Maintaining humidity in this range helps reduce asthma triggers while keeping airways comfortable.

Link to What Is the Best Indoor Humidity Level for Asthma?What Is the Best Indoor Humidity Level for Asthma?

As previously mentioned, the ideal indoor humidity level for managing asthma is between 30% and 50% - a range that minimises the growth of dust mites and mould and reduces exposure to common asthma triggers. Using a dehumidifier with a built-in humidistat can help you monitor and maintain the ideal humidity level in your home.

Link to Are There Risks to Using Dehumidifiers for Asthma?Are There Risks to Using Dehumidifiers for Asthma?

Overusing dehumidifiers can make the air too dry, which might irritate your respiratory system and make your asthma symptoms worse (Reinikainen & Jaakkola, 2001). Regularly checking your indoor humidity levels helps keep them within a healthy range.

Link to What Other Ways Can Help Manage Asthma Related to Indoor Dampness?What Other Ways Can Help Manage Asthma Related to Indoor Dampness?

Besides using dehumidifiers, you can:

• Control Moisture: Fix leaks, improve ventilation, and make sure your home has proper drainage to prevent dampness (American Thoracic Society, 1997; Rose, 1994).
• Reduce Allergens: Use dust mite-proof covers on bedding, wash bedding regularly in hot water, and keep indoor humidity below 50% (Peat et al., 1998).
• Remove Mold: Clean visible mould with appropriate cleaning agents and repair damp areas to prevent mould growth (Williamson et al., 1997).
• Improve Ventilation: Use exhaust fans and open windows when possible to reduce indoor humidity and pollutants (Øie et al., 1999).
• Clean Regularly: Vacuum and dust your home frequently to reduce allergens.

Link to Is There Scientific Evidence Supporting Dehumidifiers for Asthma?Is There Scientific Evidence Supporting Dehumidifiers for Asthma?

Scientific evidence on the effectiveness of dehumidifiers in improving asthma symptoms is limited. While they can lower humidity and reduce allergen levels, studies haven't consistently shown major improvements in asthma symptoms using dehumidifiers alone. (Wright et al., 2009; Singh et al., 2013). Therefore, dehumidifiers should be one part of a broader strategy to manage asthma.

Link to Where Can I Find Reliable Information on Asthma and Indoor Dampness?Where Can I Find Reliable Information on Asthma and Indoor Dampness?

Reliable resources include:

• American Thoracic Society (ATS): Offers guidelines on achieving healthy indoor air and managing moisture problems (American Thoracic Society, 1997).
• Environmental Protection Agency (EPA): Provides information on indoor air quality and mould remediation.
• Healthcare Providers: Your doctor or asthma specialist can give personalised advice on managing asthma related to indoor environments.

References

• American Thoracic Society. (1997). Achieving healthy indoor air: Report of the ATS Workshop. American Journal of Respiratory and Critical Care Medicine, 156(3 Pt 2), S33–S64.

• Arlian, L. G., Confer, P. D., Rapp, C. M., Vyszenski-Moher, D. L., & Chang, J. C. (1998). Population dynamics of the house dust mites Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei at specific relative humidities. Journal of Medical Entomology, 35(1), 46–53.

• Arlian, L. G., Neal, J. S., & Vyszenski-Moher, D. L. (1999). Reducing relative humidity to control the house dust mite Dermatophagoides farinae. Journal of Allergy and Clinical Immunology, 104(4), 852–856.

• Billings, C. G., & Howard, P. (1998). Damp housing and asthma. Monaldi Archives for Chest Disease, 53(1), 43–49.

• Mendell, M. J., Mirer, A. G., Cheung, K., Tong, M., & Douwes, J. (2011). Respiratory and allergic health effects of dampness, mould, and dampness-related agents: A review of the epidemiologic evidence. Environmental Health Perspectives, 119(6), 748–756.

• Peat, J. K., Dickerson, J., & Li, J. (1998). Effects of damp and mould in the home on respiratory health: A review of the literature. Allergy, 53(2), 120–128.

• Reinikainen, L. M., & Jaakkola, J. J. (2001). Effects of temperature and humidity fluctuations on indoor air quality and health. Indoor Air, 11(2), 65–73.

• Rose, W. B. (1994). Recommendations for remedial and preventive actions for existing residential buildings. In H. R. Trechsel (Ed.), Moisture Control in Buildings (pp. 321–347). ASTM International.

• Singh, M., Jaiswal, N., & Cochrane Airways Group. (2013). Dehumidifiers for chronic asthma. Cochrane Database of Systematic Reviews, (6), CD003563.

• Williamson, I. J., Martin, C. J., McGill, G., Monie, R. D., & Fennerty, A. G. (1997). Damp housing and asthma: A case-control study. Thorax, 52(3), 229–234.

• Wright, G. R., Howieson, S., McSharry, C., McMahon, A. D., Chaudhuri, R., Thompson, J., & Thomson, N. C. (2009). Effect of improved home ventilation on asthma control and house dust mite allergen levels. Allergy, 64(11), 1671–1680.

• Øie, L., Nafstad, P., Botten, G., Magnus, P., & Jaakkola, J. J. (1999). Ventilation in homes and bronchial obstruction in young children. Epidemiology, 10(3), 294–299.