How can we reduce dust mites and dust mite allergen in our homes? Ian Cull,PE,CIH, owner of Indoor Science, a Chicago-based air quality consulting company, has some useful advice for homeowners who need help formulating a plan to control indoor dust mite allergen levels.
This is the first article written by Ian Cull for Exhale. It is part of a 4-part series pertaining to controlling allergen levels in the home. Each article will focus on a different group of allergens – pets (cats and dogs), pests (mouse and cockroach), and pollen.
Reducing Dust Mites in Your Home
If you just got a report back that states you have elevated allergens, your first thought is probably “Now what?” The answer depends on the type of allergen you have present. Before coming up with strategies for cleaning up and removing allergens, it is important to understand why they are there in the first place. Otherwise, those allergens might easily come back. This is the first in a series to help you come up with a plan to control various allergens. In this article, I will cover dust mites and a future article will cover pets (cat, dog), pests (mouse, cockroach), and pollen.
Dust mites are very small arachnids that like to eat shed skin cells. They are common in areas where you spend a lot of time, such as in your bed. Because you can’t stop shedding skin cells, they can be a challenge to control.
You might pick up dust mites by sitting in a chair at a restaurant or conference room and bring it home. In a large study, 84% of homes had detectable levels of dust mite allergen. Unlike bed bugs, dust mites do not bite. They eat your skin cells after they have sloughed off. Their feces is the critical source of allergens that can trigger hypersensitivity diseases.
Dust mites also need moisture in the form of airborne humidity. By keeping the relative humidity below 50%, dust mites will not be able to survive. That can be a challenge under the bed covers as perspiration keeps humidity high. The best thing you can do in the morning is to NOT make your bed immediately. That gives the bedding time to dry out.
People that sleep on their stomach breath humidity into a pillow or mattress. By sleeping on your back, a pillow will experience less humidity and therefore be less likely to harbor dust mites.
Mattress and pillow encasements act like a big filter to prevent dust mites from getting in. They also prevent dust mites that already found their way in from getting out. And more importantly, they prevent the dust mite feces from coming out. Dust mites are about 0.3 millimeters (mm) in length but their feces is closer to 0.02 mm. One study found that dust mite allergens were blocked below detectable limits by fabrics with a pore size less than 0.01 mm in size. Encasements alone do not solve the problem but should be part of the overall strategy.
To control dust mites, it is important to wash bedding weekly with hot water at 130°F (or higher). Many hot water heaters do not allow for temperatures exceeding 120°F to prevent scalding. In that situation, you may need to rely on the high heat of the dryer. You need to maintain the 130°F temperature for at least 10 minutes to effectively kill the dust mites.
Some recommend putting stuffed animals in the freezer for a day to kill dust mites. If you try this, be sure to also wash the item because freezing alone doesn’t remove the allergens.
There is debate regarding the benefit of removing carpeting if you have elevated dust mites in a home. Carpeting with accumulated skin cells can be an ideal habitat for dust mites, especially in a humid climate. Generally, carpet removal should be considered a second line of defense after trying other strategies.
If you don’t want to remove your carpeting or upholstered furniture, it is important to keep them clean. This can be done with a high-efficiency vacuum cleaner. There are chemicals designed to kill dust mites, but some studies show that their clinical efficiency is limited.
If you have an elevated dust mite level in your home, don’t panic. By keeping your home clean and dry using the strategies above, you’ll be able to kill off the dust mites and remove their potent allergens.
About the Author
Ian Cull, PE, CIH is the owner of Indoor Science, a Chicago-based air quality consulting company. He and his team investigate air quality issues in homes, offices, and schools including mold and other allergens. Mr. Cull previously served as the Technical Director of the Indoor Air Quality Association. With over 20 years of experience, Mr. Cull has been invited to speak around the world including Asia, Europe, South America, and Australia.