Think about all the places you walk in a day. Mostly likely that includes a parking lot somewhere, wherever you work, and the grocery store. Maybe you stopped at a gas station or took your dog on a walk around the block. Now, think about all the different things you step on in those places. While you probably are thinking of things like mud, car oil, or the stray grape someone dropped at lunch, there are many other things that hide in dust that are a little more worrisome for your health.
Chemicals that can cause cancer and other health problems collect on the bottom of your shoes when you are out and about and, if you wear your shoes around the house, these chemicals end up in your household dust. Scientists have shown that the average adult American eats the equivalent of 34 adult aspirin tablets of dust every year. (1) And unsurprisingly, for those of you with kids, you know everything goes in their mouths and they spend so much time on the floor, that they eat about twice the amount of dust, the equivalent of 1 tablet of adult aspirin every 5 days. There are no scientific studies on how much dust your furry loved ones eat, but based on how much time they spend on the floor, and then licking themselves, you can bet that it's a lot too.
Common contaminants that make their way into the dust in your house via your shoes include lead, flame retardants, and pesticides. Small flakes of lead from old lead paint also often end up on sidewalks and soil outside. While the dangers of lead paint have been known for a very long time, people often only think to cover it or remove it from inside their homes, but forget about the outside. That means when old paint from the outside of the homes starts peeling, it often contains flecks of lead that end up settling on the paths outside that we walk along all of the time.
Similarly, pesticides are very good at getting on your shoes. Pesticides are often applied in community areas, like parks, sidewalks, and street medians. These are all typically knee height or lower, perfect for accidentally brushing up against and getting stuck to shoes.
Flame retardants, frequently found in furniture and electronics, like computers and televisions, are key abusers of collecting in dust and then entering your body. Offices with lots of computers and electronics are often choke full of flame retardants and are one of the major ways they end up on your shoes.
Flame retardants, lead, and pesticides are just a few of the main worries that end up in dust that settles on the ground. Others include industrial grade adhesives from things like carpets and exhaust from cars in parking lots and sidewalks. Because dust settles on the ground, we disturb it when we walk and then it gets on our shoes. If we wear those shoes throughout our homes, the dust can then end up settling on the floor of our homes.
The Good News is...
One the easiest way to limit the amount of harmful substances we ingest through household dust is by taking our shoes off and using a doormat. Taking off your shoes at the door helps keep all of those chemicals and other dirt remnants out of your home. Studies have found that people who take their shoes off at the door have significantly lower amounts of many different chemicals in their homes and bodies than people who wear their shoes inside all of the time. (2)
But what about my feet? If you prefer to wear shoes around the house for the arch support or because your toes get cold, consider having a pair of shoes or slippers you only wear in the house, then switch shoes when you get home. As if you needed another excuse to get some cozy slippers!
1) U.S. EPA. Update for Chapter 5 of the Exposure Factors Handbook: Soil and Dust Ingestion. US EPA Office of Research and Development, Washington, DC, EPA/600/R-17/384F, 2017
2) https://www.ncbi.nlm.nih.gov/pubmed/24657158
