Six Reasons To Wear A Mask On Public Transportation

Photo of a crowded bus in an article about reasons to wear a mask.

You should wear a mask on public transportation. Here are six reasons why wearing a mask on public transportation is a good idea, approved by an epidemiologist.

One

Subway cars and buses have questionable ventilation and enclose, restrict, and crowd passengers.

A good, well-fitting mask like an N95 or a KN95 can provide an extra layer of protection.


Two

Masks don’t only prevent COVID, they also prevent flu, RSV, parainfluenza, and other respiratory viruses that might be surging at different times of the season.


Three

Train cars and buses are indoor spaces containing a cross-section of the community.

Viral transmission can happen on buses and trains amongst people from many parts of the community.

People who wouldn’t typically interact with each other.


Four

People over 65 who are immunocompromised or have a pre-existing health condition predisposing them to severe illness should always consider wearing a mask in closed, indoor, and crowded spaces like a train car or a bus.


Five

While there is no mandate to wear a mask on public transportation anymore, we can think of it not only as a layer of protection for ourselves but as something we can do to protect more vulnerable riders.


Six

If you have been exposed to somebody with COVID-19 in the last ten days, you should wear a mask on public transportation and in any enclosed indoor spaces.


There you go. Six reasons to wear a mask on public transportation. These apply to other crowded spaces as well.


Other Resources: Centers for Disease Control and Prevention Covid page.

Using CO2 Sensors

I’m a nerd and occasionally carry a portable CO2 sensor in my back pocket when I know I’ll be in smaller spaces.

CO2 sensors measure the carbon dioxide level in a space. Here’s a link (not affiliate) to what I use: https://a.co/d/4VBdt0h

As a reminder, carbon dioxide (CO2) has no color or smell, making it impossible to detect its presence and monitor levels without a dedicated CO2 gas sensor.

Portable CO2 Sensor

Here are guidelines for interpreting CO2 sensors. Portable sensors can display green, amber, and red lights. Here’s what they mean:

  • Green displays up to 1000 ppm
  • Amber displays between 1000 – 2000 ppm
  • Red displays anything over 2000 ppm

This helps you decide what action to consider, whether opening a window or maintaining more space between people. The goal is to keep the ppm level as low as possible. You can read more about CO2 ppm here.