What gives a smell its character?

Old-book aroma and paper degradation volatiles (VERIFIED): Research on historic paper has measured volatile organic compounds released during material degradation and linked those emissions to the characteristic smell of old books. Scope: Supports the role of paper degradation volatiles; individual books and libraries can differ by materials, storage and environment.

Petrichor and rain on dry ground (VERIFIED): The scientific literature has used the term petrichor for the characteristic earthy odour associated with rain acting on dry mineral and soil environments. Scope: Historical scientific framing of petrichor; this does not mean every rainy environment has one identical chemical profile.

1. Open a material page and read the entries it produces. What do they share, and what differs?

Smell only things you know are safe. Never smell unknown substances, chemicals, gas, smoke from fires or anything that could be harmful, and waft gently instead of inhaling hard. If you have a smell-related health concern, ask a medical professional.

Introduction to Smell is free, like all of SmellBook Learn. It describes perception and cultural association, quotes scientific findings only from VERIFIED claims with their scope, and is not medical advice. Lessons on the biology of smell will be added when registered sources support them.