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You might clean your shoes if you step on something muddy or disgusting. (Please bring your dog!) But when you get home, do you always take off your shoes at the door?
Lots of people don’t. For many, what you drag under your shoes is the last thing on your mind when one gets home.
We are environmental chemists who have spent a decade examining the indoor environment and the pollutants people are exposed to in their homes. Although our examination of the indoor environment, through our DustSafe software, is not yet complete, on the question of whether to put on or take off shoes at home, the science is leaning toward the latter.
It is better to leave dirt outside the door.
Read more: Dust in your home can be dangerous
People spend up to 90% of their time indoors, so the question of whether or not to wear shoes at home is not a trivial matter.
The focus of policy is usually on the external environment of the soil, air quality, and environmental public health risks. However, there is a growing regulatory interest in the issue of indoor air quality.
Not only does dust and dirt from people and pets build up inside your home, it’s hair and skin.
About a third of it is on the outside, either bulged or strung on the bottoms of the abusive shoes.
Some of the microorganisms found on shoes and floors are drug-resistant pathogens, including hard-to-treat hospital-associated infectious agents (germs).
Add in carcinogenic toxins from asphalt road debris and endocrine-disrupting lawn chemicals, and you might see the dirt on your shoes in a new light.
Read more: Dust comparison in 35 countries
Our work involved measuring and evaluating exposure to a range of harmful substances found indoors, including:
- Perfluorinated chemicals (also known as PFAS or “forever chemicals”, due to their tendency to remain in the body and not degrade) are ubiquitous used in many industrial and household products and food packaging
A strong focus of our work has included assessing levels of toxic metals (such as arsenic, cadmium and lead) in homes across 35 countries.
These contaminants – chief among them the dangerous neurotoxin lead – are odorless and colorless. So there is no way to know if lead exposure hazards are only present in your soil or water pipes, or if they are also present on your living room floor.
Science suggests that there is a very strong relationship between the lead inside your home and that found in your yard soil.
The most likely reason for this contact is dirt dripping from your yard or stepping on your shoes, and on the furry paws of your beloved pets.
This connection speaks of the priority of making sure that the material from your external environment stays completely there. (We have tips here.)
An article in the Wall Street Journal argued that shoes at home aren’t too bad. The author explained that Escherichia coli – dangerous bacteria that develops in the intestines of many mammals, including humans – is so widespread that it is ubiquitous. So it should come as no surprise that it can be wiped down on shoe bottoms (96% of shoe bottoms, the article noted).
But let’s be clear. Although it’s fine to be scientific and stick with the term E. coli, these things are, quite simply, the bacteria associated with feces.
Whether it’s us or Fido, it can potentially make us very sick if we’re exposed to high levels. And let’s face it – it’s just plain gross.
Why wander inside your house if you have a very simple alternative – take off your shoes at the door?
Read more: The pollen season becomes longer and more intense
So, are there drawbacks to having a shoe-free home?
Beyond the sometimes bumpy toe, from an environmental health standpoint, there aren’t many downsides to owning a shoe-free home. Leaving your shoes at the entry mat leaves harmful pathogens there, too.
We all know prevention is much better than cure, and taking off shoes at the door is an essential and easy preventative activity for many of us.
Need shoes for foot support? Easy – just have some “indoor shoes” that you never wear outside.
The issue of sterile home syndrome, which points to increased rates of allergy among children, remains. Some argue that it is linked to overly sterilized families.
In fact, some dirt is likely to be beneficial as studies have indicated that it helps develop the immune system and reduce the risk of allergies.
But there are better and less rude ways to do that than walking around inside in your dirty shoes. Get out, go for a walk, and enjoy the great outdoors.
Just don’t bring the dirtiest parts indoors to build and pollute our homes.
Read more: Do I really need a specific shoe for a specific sport?