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Why regular laundry washing is important to maintain a healthy home environment

    Many people can be allergic to dust mites, pet dander, and other allergens that can build up in bedding, clothes, and other washable items at home. Taking care of these items by washing them regularly is a fundamental part of maintaining a healthy home environment.

    Why regular laundry washing is important to maintain a healthy home environment

    If there are a lot of fabric covered items in your home, there may be dust mites living in them. Dust mites are small creatures (belonging to the spider family) that often live in bedding, carpets and stuffed toys. People can be allergic to dust mites and to their droppings. Dust mites like warm humid environments. Most dust mites are found in bedding where a build-up of dust, skin flakes and moisture can provide them with an ideal habitat for growth.

    If you have pets at home, their allergens can collect on clothes, furniture, and other surfaces. Pet allergens are very common indoors and can even be found in homes where there are no pets. In a national survey in the United States, cat allergen was found in 99% of the homes that were tested, and this included homes without cats. Cat dander can be carried around on people’s clothing and can be transferred to bedding, furniture, and other surfaces indoors.

    Bedding and clothing can keep accumulating allergens if they are not washed regularly. Avoiding triggers is a fundamental part of managing asthma and allergies so it’s important to take a proactive approach to a healthy home environment – regular washing with laundry detergent and hot water (130 degrees Fahrenheit) is one beneficial way to do this.

    CERTIFIED asthma & allergy friendly® laundry detergents can help to maintain a healthy home environment

    The asthma & allergy friendly® program is operated by Allergy Standards Ltd. in collaboration with the Asthma and Allergy Foundation of America. This program helps people to identify laundry detergents and other products that will make a genuine difference to their indoor environment. The program develops certification standards for relevant categories of products, and all certified products undergo testing to those standards. The certification mark is awarded only to those products that meet the criteria. In this way, the asthma & allergy friendly®  mark can help consumers to make an informed choice about products that they bring into their home.  

    Consumers want to be confident that a laundry detergent can remove allergens like dust mite allergens and pet allergens. Laundry detergents can contain irritant or allergenic ingredients that can impact on those with sensitive airways. The asthma & allergy friendly®certification program addresses these issues by testing laundry detergents to its scientific standards. Certified laundry detergents undergo testing in three key areas:

    1. Allergen removal 

    As part of the allergen removal test, cat allergens and dust mite allergens are added to clothing fabric. The fabric samples are placed in an environmentally controlled chamber for an incubation period. The samples are then washed in the laundry detergent as per the manufacturer’s instructions. The level of allergen left in the fabric after washing is measured and compared to a control. Washing in the laundry detergent must show a reduction in dust mite allergen levels of 95% or greater.

    1. Impact on indoor air 

    The second part of testing involves measuring the emission of volatile organic compounds (VOCs) into the air when the laundry detergent is applied to a test surface. VOCs are chemicals they easily become gases, and some VOCs can negatively impact health.

    This test is run in an environmentally controlled chamber to simulate real world conditions as much as possible. The laundry detergent is applied to a test surface in the chamber where the VOCs released are monitored to ensure that the emissions remain low.

    If a powder laundry detergent is submitted, the airborne particles generated during use in the chamber are also measured to ensure these remain low.

    1. Chemical testing 

    Laundry detergents can contain irritant or allergenic ingredients that can trigger or exacerbate symptoms in some people with asthma and allergies.

    The asthma & allergy friendly® program looks at all of the chemical constituents in the laundry detergent to ensure there are no added fragrances, and that there are no allergenic or sensitizing chemicals present, or that their concentration is low enough to warrant no concern for sensitive individuals.

    Testing is also carried out to check for residual chemicals in a fabric after it has been washed in the laundry detergent.

    Practical laundry tips for maintaining a healthy home environment

    It’s good to get into a routine of washing your sheets and blankets weekly in hot water (130 degrees Fahrenheit) to reduce dust mite and pet allergens. Wash stuffed toys once a week in hot water or if stuffed toys can’t be washed, place them in a sealed plastic bag in the freezer for 24 hr and then tumble dry in the dryer to remove dead dust mites. Wash clothing regularly and wash before use if it has been stored for a long time.

    Check humidity levels in your laundry room. If humidity is over 50% you may need to increase air flow or use a dehumidifier. Dust mites like warm humid environments so it’s important to keep humidity below 50% indoors. Leave washing machine doors open to help the machine to dry out between uses. If you have a dryer, make sure this is properly vented, and clean the lint trap after each use.

    Ensure you make an informed choice about the products you bring into your home. Look for products that have been independently tested and certified. The asthma & allergy friendly® certification mark is a helpful signpost when looking for laundry products that genuinely contribute to a healthy indoor environment.


    Arlian, LG, Vyszenski-Moher, DL, Morgan, MS. Mite and mite allergen removal during machine washing of laundry. J Allergy Clin Immunol. 2003;111(6):1269-1273.

    Cloutier, MM, et al., 2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. J Allergy Clin Immunol. 2020;146(6):1217–1270.

    ‘Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma–Summary Report 2007’, J Allergy Clin Immunol. 2007;120(5):S94–S138.

    Salo PM, Arbes SJ, Crockett PW, Thorne PS, Cohn RD, Zeldin DC. Exposure to multiple indoor allergens in US homes and relationship to asthma. J Allergy Clin Immunol. 2008;121(3):678-684.

    Tovey, ER, Taylor, DJ, Mitakakis, TZ, De Lucca SD. Effectiveness of laundry washing agents and conditions in the removal of cat and dust mite allergen from bedding dust. J Allergy Clin Immunol. 2001;108(3):369-374.

    Wilson JM, Platts-Mills TAE. Home environmental interventions for house dust mite. J Allergy Clin Immunol Pract. 2018;6(1):1-7.

    Dr Emer Duffy ASL Science Lead

    About Dr. Emer Duffy

    Dr. Duffy holds a PhD in chemistry from the University of Tasmania, Australia. She also holds a BSc (Hons) in analytical science from Dublin City University, and a BS in chemistry from the University of Kansas, USA.

    Dr. Duffy has significant scientific expertise. Besides her most recent publication detailed above, she also developed non-invasive approaches to study VOCs in human skin and was a frequent invited speaker on the topic at educational workshops and conferences, including the Gordon Research Conference on Skin Barrier Function.

    Emer has won several prestigious awards and fellowships during her career, including a Marie Skłodowska-Curie Individual Fellowship and the Irish Research Council Lindau Nobel Laureate Meeting Award. She currently serves on the management committee of the COST Action Indoor Air Pollution Network.

    In her role as Science Lead in Allergy Standards Dr. Duffy is responsible for leading ASL’s science team. She coordinates the company’s research activities, updates and develops the certification standards and oversees ASL’s scientific testing and consultancy work.