Question: My sister always insists that we take our shoes off at the door. She says that it is cleaner and safer. I think that it is an old wives tale. Is there any data to support her claim?
Response: In the olden days (as my kids call them), taking your shoes off at the door was the norm. This custom is still the standard practice in Korea, Japan, and many other countries. Even in countries where shoes are generally worn indoors, related practices are followed, as door mats are often placed at entryways for people to wipe their feet before entry. These "shoe off" and "door mat" practices came about to reduce the amount of dirt that gets tracked into your home. Shoes clearly can be a source of substantial dirt, as is evident from the footprints left when you walk in shoes on a clean, wet floor. Not only can shoes bring dirt into your home, but they can also bring pesticides, lead, and other chemicals that can be present in dirt. The U.S. Environmental Protection Agency (EPA), for example, showed that people bring lawn pesticides into their homes on their shoes. These pesticide-laden shoes were a major source of pesticide exposures, especially for young children who spend a lot of time on the floor and who put dirty fingers, dust, and toys in their mouths. Somewhat surprising was that the study showed that indoor shoe-wearing was a larger source of children’s pesticide exposures than eating non-organic fruits and vegetables. Taking your shoes off and wiping your feet on a door mat or other carpeting before entering were found to be important pollutant reduction measures.
Even if you do not use pesticides on your lawn or have lead in your soil, you can still have pesticides, lead and other chemicals on your shoes from your travels to other lawns and other places. These pesticides and chemicals can stay on your shoes for quite some time. So, it clearly makes sense to listen to your sister (at least in this one case) and take your shoes off before you enter your home. For added insurance, you can put a door mat just inside your door to store the shoes or to have people wipe their feet before coming inside. Your home will not only be cleaner, but may also look better, especially if you chose a nice looking door mat, such as this one.
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Helen Suh MacIntosh is a professor in environmental health at Harvard University and studies how pollution behaves in the environment and how it affects people's health. Please keep in mind that her answers are just her interpretation of available information and should not be taken as the only viewpoint or solution to a problem. Use this column at your own risk. Having said this, please feel free to post any of your environmental health questions to Helen@TreeHugger.com. (Please use a descriptive email subject line and mention if you want to remain anonymous or not).