In everyday life, household dust is referred to as just that – dust. Normal, everyday, harmless dust. It all pretty much looks the same, and can be found pretty much all over the place. But, have you ever stopped to think about what's really in there?
Well, two gentleman were very interested in this question, and worked quite hard to flesh it out.
David Layton and Paloma Beamer, professors of environmental policy at the University of Arizona, set out to determine what the seemingly ever-present material consists of.
They drew on information collected from a large scale study of areas in the Netherlands and the United States. They found that, in general, dust is comprised of the following materials:
- shed bits of human skin
- animal fur
- decomposing insects
- food debris
- lint and organic fibers from clothes
- bedding and other fabrics
- tracked-in soil
- particulate matter from smoking and cooking,
Alarmingly, the researchers also found various toxins in household dust, such as lead, arsenic, and even DDT.
"There are more [components]," Beamer says. "Dust is a hodgepodge of all sorts of things. It would probably be impossible to make a list of all the possible items."
This list is only part of the story, however, since different components of different sizes behave differently and elicit different responses from occupants. In order to better understand the introduction, deposition, and release of dust particles, the team developed a computer algorithm that looks at the source, size, toxicity, entrance and exits routes of various types of dust particles.
The researchers found that approximately 60% of household dust is brought in from outside – through windows and doors, from pets, and chiefly, from people bringing them in on their persons and shaking them off.
Arsenic is a naturally-occurring metal that comes mostly from volcanic activity, but can also be the result of human activities. This could be of special concern, considering that arsenic has been found to have a profound effect on neurological development in children. Lead particles are most likely the remnants of lead-based paint that may or may not have been removed. Especially in porous surfaces, the dust can serve as kind of a timeline of different chemicals and materials introduced to the home since its construction.
The good news is that about 80% of this dust can be removed by cleaning regularly. Also, the use of a vacuum with a High Particulate Efficiency Air (HEPA) filter can help small particles from being redistributed throughout the home and improve indoor air quality. There really is little need for alarm as long as the space remains reasonably clean.
To read more about the study, please read "Migration of contaminated soil and airborne particulates to indoor dust" from http://pubs.acs.org.
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