“What am I, hard of smelling?”—Elaine Benes on Seinfeld
All it takes is a momentary lapse in concentration. When you are in the laboratory and take a direct sniff of the chemicals you are using, you run the risk of damaging your mucous membranes or your lungs.
When it is necessary to smell chemicals in the lab, the proper technique is to cup your hand above the container and waft the air toward your face.
Try not to breathe in the air through your nose, but bring in just enough to make sense of the smell—much like the approach you would take when someone asks you to do a breath check or when you're debating eating dairy beyond its expiry date.
Below you can watch the technique in action on YouTube:
There are many unpleasant smells that are imposed on us in life. At the very least we owe it to ourselves not to let the things we choose to smell cause injury.