![Kundo-Quarzwecke clock.](http://static.sciencelearn.org.nz/images/images/000/003/745/full/1080_ART_03_1080_and_water_quality_Clock-PartsPerBillion.jpg?1674171813)
Parts per billion (ppb) is an extremely small unit of measurement. Using time as an example, 1 second in 32 years is 1 part per billion.
Parts per billion (ppb) is an extremely small unit of measurement. Using time as an example, 1 second in 32 years is 1 part per billion.