Does Exposure To Sunlight Kill Dust Mites?

Of the many ways to kill dust mites, there are suggestions that exposure to sunlight can be an effective measure. But is it? It depends on various factors before you could kill off the mites with sunlight.

Elements Of Sunlight That Could Potentially Kill Dust Mites

The sun, at its peak, is often associated with the blistering heat. In some of the hottest US cities, temperature could hit 100 F. Heat is associated with killing dust mites and you’ll be asking if the sunlight is hot enough to do so.

Another potential element that kills dust mites is the UV spectrum from the sun. The sunlight contains UV-A, UV-B, and UV-C, with UV-C being the most potent for killing dust mites but also harmful for humans.

At the top of the atmosphere, the sunlight contains about 8% UV.  However, most of the UV-C and part of UV-B are filtered off by the atmosphere. Therefore, very little natural UV remains when the sunlight hits the earth.

It’s unlikely that the amount of UV on the earth’s surface is sufficient to kill dust mites.

Does Sunlight Kill Dust Mites?

Sunlight does kill dust mites, but not through direct contact with sunlight. Instead, trapping the heat from the sun will lead to dehydration of dust mites, which eventually kills them off. Considering that 75% of dust mites’ body weight is contributed by water, prolonged sunlight exposure becomes a very effective method.

Researchers have backed up this theory with a very detailed experiment. In the study, carpets that are infested with dust mites are placed face-down on a concrete slab and exposed to the sun. On the 2nd hour of exposure, massive movements of the mites are observed, possibly due to hydration.

After 3 hours of exposure, no live mites are remaining in the carpet. It is interesting to note that the temperature of the carpet, which is flipped against the concrete surface, increased to 131F while humidity decreased to 24%.

The figures show how the heat trapped in the carpet has made the surrounding very dry. The low humidity also causes dust mites to dehydrate and ultimately perished.

Sunlight Exposure Have No Effect To Dust Mite Allergen

While the mites are effectively killed off, sunlight exposure apparently does nothing to denature the allergen. Dust mite allergen, Der p I, remain unaffected despite the increase in temperature and reduced humidity.

This suggests that a higher temperature is needed to denature the allergen and low humidity has no effect on it. You’ll still need to remove or denature the allergens after exposing carpets, rugs, or other household items to sunlight.

Factors That Could Affect Mortality Rate Of Dust Mites To Sunlight

Just because the sun is out doesn’t mean you could replicate the same mortality rate of the study. The experiment was carried out in Sydney, which has a temperature of around 25°C in the summer.

The sunlight needs to be adequately hot and you’ll need to expose the items for at least 3 hours. Also, the placement of the item is important. Areas that are infested with mites are placed face down to ensure the heat is trapped and the temperature builds up.

For example, placing your pillow under the sun may only kill mites that are lingering on the bottom side.

If you’re living in apartments where you can’t get enough sunlight, then you’ll have difficulty implementing the same method. Also, if you’re placing the rug, or carpet in the open air, you’ll need to be wary of a sudden change in weather, particularly if you’re in tropical countries.

Final Thoughts

Sunlight is proven to be effective in killing dust mites, provided that you’re doing it the right way. With sufficient heat and exposure, all of the mites will die. However, it’s important to remember that the allergen remains and will still cause allergies.

Leave a Comment