Mention air pollution, and most people think only of outdoor air quality. We rarely question the quality of air in our homes, but we should. According to the Environmental Protection Agency, the concentration of air pollutants in our homes can be two to five times higher than what is typically found outdoors.

Have you thought about your home’s indoor microbiome? It’s a complex community comprised of all the living microorganisms, including bacteria, viruses, fungi and other single-celled organisms. All living things—people, pets, pests, air, water and areas of active microbial growth indoors—impact air quality.

What contaminants are in our homes and how did they get there? The matter includes not just dust and dirt from people and pets shedding hair and skin. About a third is from outside, either blown in or tracked in on the soles of our shoes. 

THE INSIDE STORY

When outdoors, many unsanitary things attach to the bottom of our shoes. Consider how much visible dirt is on the soles of our shoes, such as mud, sand, gravel, debris from outdoor parks, and residue from all the other unclean places we walk on in a day. Not to mention city sidewalls covered in spit, gum and bird droppings, and public restroom floors covered in contaminants.

Numerous studies have shown that bacteria, fungus and viruses on the bottom of shoes do not wear off the more we walk. These contaminants cling to shoe soles and eventually end up on our home’s tile, wood and carpet floors. Scientists have discovered that whatever microbe is on the soles of our shoes transfers to our floor 90% of the time. And if we have carpet, that number rises to 99%.

When we wear shoes indoors, we spread all those icky substances throughout our home, contaminating indoor air and exposing us to harmful germs. Therefore, it’s important to clean more frequently.

The decision to wear or not wear street shoes in our homes carries significant weight. It’s customary in many cultures to remove shoes before entering a home. This tradition not only keeps the space cleaner, it also protects the health of everyone inside. Another obvious benefit is that by leaving our shoes at the door, we prevent dirt and contaminants from tainting our floors, ultimately reducing the time and effort spent on cleaning and vacuuming.

FOOTWEAR MATTERS

However, walking barefoot indoors does come with its own set of health risks. Being shoeless or wearing smooth-sole slippers indoors can increase the likelihood of accidents. Shockingly, more than half of falls among older adults occur when they are barefoot or wearing only socks or slippers.

To minimize the risk of falls, older adults should consider wearing sneakers or other sturdy shoes that are for indoor use only. Leaving outdoor footwear at the door and slipping into something more comfortable yet sturdy, with good traction, can help maintain stability.

It’s important to create a habit of removing shoes at the entrance of our home. To make this easier, design experts suggest creating a welcoming entryway space. This can include a bench for sitting while putting on or removing shoes, as well as shoe storage shelves or baskets to safely store footwear and keep them out of the way.

For guests, one way to help enforce the shoeless rule is to hang a sign inside the door or on a welcome mat with a message such as “Leave your worries and your shoes at the door.”

Providing indoor slippers, maintaining visibly clean floors and offering shoe covers for those not ready for a barefoot environment can all help guests feel more comfortable. 

An old African proverb beautifully illustrates this concept: “When you leave your shoes at the doorstep, you leave your troubles behind.” Removing shoes before entering a home is not only a courteous gesture but also a simple yet effective way to keep floors free of bacteria, chemicals and other harmful substances often found on shoe soles.