Travelmath.com, a site that helps people calculate the driving and flying time between cities, ranked some of the dirtiest places in airports and airplanes, based on 26 samples gathered by a microbiologist sent to examine five airports and four flights.
Unsurprisingly, they found that airports and airplanes are dirtier than the average home. But the places where they found the most germs in airports and on airplanes might surprise you.
The samples gathered show that bathrooms in airplanes and airports actually have fewer germs than other things we consider far less innocuous. On the airplane, the dirtiest place by far was actually the tray table. Their tests found that the tray table had 2,155 "colony forming units" -- a measure of the number of bacteria or fungal cells that are able to multiply -- per square inch. That compares to 285 on the overhead air vent, only 265 on the lavatory flush button, and 230 on the seat belt buckle.
In the airport, the findings were similar: The tests found that drinking fountain buttons had 1,240 colony forming units per square inch, compared to only 70 on bathroom stall locks.
Here is their ranking of the six locations:
1. Tray table - 2,155 CFU/sq. in.
2. Drinking fountain buttons - 1,240 CFU/sq. in.
3. Overhead air vent - 285 CFU/sq. in.
4. Lavatory flush button - 265 CFU/sq. in.
5. Seatbelt buckle - 230 CFU/sq. in.
6. Bathroom stall locks - 70 CFU/sq. in.
Thankfully, all the samples were negative for fecal coliforms like E. coli, which can make people fatally ill.
Here's a snapshot of how those figures compare with other common household items, based on 22 households tested by the National Sanitation Foundation. Pet bowls, pet toys and home countertops are often dirtier than some things in the airplane and airport, while home toilet seats, cell phones and money are actually cleaner.
It might seem counterintuitive that bathrooms are cleaner than tray tables and countertops. The figures suggest that airlines and airports are actually doing a decent job of sanitizing rest rooms -- which is a good thing, since dirty bathrooms can easily spread disease.
The bad news is that airlines and airports don't appear to be doing a good enough job of cleaning other things. Travelmath points out that the pressure on airlines to board a plane quickly has increased in recent decades, meaning tray tables often don't get cleaned until the end of the day.
The tests suggest that airlines need to clean planes more often. But until that happens, you might want to avoid eating anything that comes in contact with your tray table.
Note: A previous version of this article cited the National Science Foundation rather than the National Sanitation Foundation. The post has been updated.