Stinky Breath

Does my breath smell bad? Be honest!

This is Sandra Tsing Loh with the Loh Down on Science.

Worrying about bad breath is the WORST! And you can’t ask just any stranger to check it for you. But Hamin Shin and researchers from KAIST and Samsung in South Korea want to help.

Is it something you ate? Not necessarily! Chronic bad breath, or halitosis, happens when someone exhales a chemical called hydrogen sulfide. It’s associated with a swampy smell, like rotten eggs! 

The researchers learned that another chemical — tungsten oxide — can react with hydrogen sulfide. So they made a thumb-sized device that contains tiny particles of tungsten oxide. They compared the device against an existing tool used to diagnose halitosis.

When volunteers blew into the device, the tungsten oxide reacted, showing that the stinky chemical was present! The sensor was almost NINETY PERCENT accurate! And it’s simpler and more affordable than current methods.

Someday soon, you won’t have to rely on your friends to smell your breath anymore — you can test your own! 

Until then…who wants gum?


Shin, H., Kim, D., Jung, W., Jang, J., Kim, Y. H., Lee Y., Chang, K., Lee, J., Park, J., Namkoong, K., Kim, I. Surface Activity-Tuned Metal Oxide Chemiresistor: Toward Direct and Quantitative Halitosis Diagnosis. ACS Nano, ASAP (2021). https://doi.org/10.1021/acsnano.1c01350

Photo credit: Jens Rother / Alamy Stock Photo