This post is also available in: Svenska
We received a thought-provoking question from a reader:
Thanks for your interesting and informative blog! I wonder, what does dust consist of? I have read that it contains heavy metals. Is this true?
Professor Agnes Wold answers these questions.
What is dust?
This topic is interesting. Dust is what falls from the air. So, I cannot imagine heavy metals would be floating around in the air in an ordinary home.
Does dust cause infections or allergies?
One hundred years ago, it was thought that there were a lot of bacteria in dust (SPOILER ALERT: there aren’t). Women were urged to consistently clean and scrub to prevent these infectious diseases. Obviously, without effect. Infectious diseases are spread between humans, or between humans and animals. Not via dust.
Infectious diseases decreased drastically for 100 years and almost no one died from infections anymore. All of a sudden, dust became the focus as a cause of allergic diseases. This increased aggressively during the 20th century. There was talk of “dust allergy”. This term is completely wrong because dust is not a substance. Dust consists of all sorts of particles that fall from the air. In a barn it consists of plant parts, in a workshop it consists of metal particles, and at home it is the sand and hairs and flakes of the skin, and more. “Dust allergy” was meant to refer to allergies towards mites that live on our dead skin. Of course, like everything else in a home, they are present in dust. But no more there than anywhere else.
It’s a concern that now people are starting to worry about the presence of heavy metals in the dust. The interesting thing is that all these (so far completely wrong) notions about the danger of dust, always result in the same call to women: Clean up!
Dust mites – an air purifier!
About 10 years ago, the Swedish National Board of Health and Welfare had the silly idea to write in brochures that “cleaning is important to combat the spread of infections and allergies”. And unfortunately, the Swedish National Institute of Public Health also had this among its “advice for preventing allergies”. I was called to action. On national TV, I had to explain that cleaning certainly did not help against infections and allergies. After the program, I was contacted by a group of ventilation and civil engineers who took care of properties in Mölndal and Gothenburg. We had a very nice chat.
They told me that dust mites can only occur if there is perfect humidity in a home. If it is too hot and dry, the dust will not fall to the floor. This can be observed in a bathroom with underfloor heating – there is no dust mites! Furthermore, the dust mites act as air purifiers as they attract particles in the air. Just like when crystals are formed in a saline solution, they must have something to stick to.
So now you know that dust mites are a sign of a perfect indoor climate. Do not touch it – especially if it is lying and sleeping under your bed! 😉
Warm greetings from Agnes Wold