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Column originally published Feb 1, 2005

There Are Many Ways To Reduce Dust Indoors

Question: Our six-year-old son was recently diagnosed with allergies. He reacted strongest to dust and dust mites in the skin test. We have covered his bed with a dust mite cover. We wonder whether we should remove the carpet in his bedroom also, as recommended by our doctor. Some of our friends said that if there is no carpet for the dust to settle on, the dust will stay in the air and it can be worse for him. Please help us to make the best decision for our son.


The short answer for you is yes, you should remove the carpet from his bedroom. For the benefit of many parents and grandparents reading this column, I should explain in greater detail about dust mite allergy and how to avoid it.

Dust mite allergy is one of the most common allergy affecting children and adults in North America. When we talk about someone being allergic to dust, we are referring to the dust indoors. This has nothing to do with dust or dirt outside of the house.

The substance in the indoor dust that triggers allergy is actually the droppings (or stool) of the house dust mites. These dust mites are very tiny insects visible only under the microscope. They are totally harmless to humans except for those who are allergic to their droppings. They feast on the dead skin cells that fall off our body every day.

As you can imagine, we spend about one-third of our time in bed (and even longer for children). Therefore, about a third of our skin cells are shed when we are in bed as well as in our bedrooms. These dust mites flourish best in warm and humid locations, like in the mattress and pillow.

If there are carpets in the bedroom, that would be a favourite place for dust mites also. The tiny space between the fabric of the carpet is just the perfect place for dust mites to grow and multiply, with lots of food available. The worst thing is that their stool is collected in the carpet also. Vacuuming the carpet really doesn’t do very much. The dust mites and their stool are buried deep inside and vacuum cleaners usually don’t have the power to remove much of them. Worst of all, the rotating brush of the vacuum actually puts some of the dust particles in the air. This can trigger allergic conditions in those who are susceptible. Unless you have a vacuum cleaner that has a HEPA filter, the dust that it sucks in would just flies out the other end.

This is the reason why I always recommend families who have anyone with dust allergy and asthma to remove carpets at least from the bedrooms. Those families who have done it were always surprised by the amount of dust and dirt that they found inside and underneath the carpets. Some families would find a rather dramatic improvement in themselves or in their children’s health. Others would need to remove all the carpets from the house and other dust collectors, or they might have allergy to other things like mould or animal dander.

Your friends’ argument that if carpets are removed, dust would fly around more and could be worse sounds like a very logical advice. However, the truth is the opposite. Most families would try to control the dust on the floor if they can see it, but they can’t see it if it is hidden in the carpets. There are many commercial products that can pick up dust from floors. Even a simple damp mop can do the job. I also advise families to decrease clutters in their children’s rooms and to wipe the dust regularly from shelves and tabletops.

Since pillows and mattresses can harbour lots of dust mites and their dropping, it is advisable to reduce your son’s exposure when he is in bed. This can be done by encasing them in plastic covers with zippers that can completely seal the dust inside. Everything in bed can be washed weekly to remove dust particles.

I should mention here that soft toys like teddy bears can collect lots of dust in a similar fashion. I would suggest that you reduce the number of these toys in your son’s environment. Putting them in a plastic bag and putting away completely is the best solution. Ask your family and friends not to buy these toys as presents in future. If your son is very attached to some of them, keep as few of them around as possible, and put them in the washer and dryer once a week. Remember that large toys may not dry completely inside, and mildew can grow in the presence of moisture after washing.

Another place where you should look for dust is the forced-air heating system. The problem is that dust can get collected inside the duct system after a short time. Whenever the furnace fires up, heated air comes out of the rectangular vents together with loads of dust and dust mites. This is at least part of the reason why children with allergy and asthma get sick more often in winter time.

If your house is heated by forced-air system, you can reduce the amount of dust by implementing the following suggestions. Get a high efficiency filter for the furnace. Find out the dimension of the filter, and go to a hardware store and buy the best ones available, they are more effective in removing dust and mildew particles from the air before it gets heated up by the furnace.

Another important advice is to a hire duct cleaner before the furnace starts in the fall. These duct cleaners come with a long hose to remove the majority of dust from your duct system. Covering individual vents with filters or cheesecloth can also reduce the dust flying around.

Many families keep their house too warm so that they can wear short-sleeves inside in winter time. This is a poor choice and should be avoided. The higher the temperature we set at the thermostat, the more the furnace has to kick on. This will increase the dust circulation. Warm temperature is also not a great idea for anyone with asthma, because it can dry up the air and mucus in the lungs. It is far more healthy to lower the thermostat to 20 degrees centigrade, and wear long sleeves and a sweater indoors.

Because of the length of this column, I cannot discuss about other allergens that can also affect your son. If you want to get additional information, please refer to some of my previous columns.