Glossary
pH — Glossary
The acidity-alkalinity scale — a master switch controlling how volatile (and smelly) ammonia and other compounds are.
pH measures how acidic or alkaline a solution is, from 0 to 14. For pet odor it is a switch: alkaline conditions push ammonia into its volatile, smelly gas form; acidic conditions lock it into the odorless ammonium ion.
This is why alkaline cleaners can make a urine spot smell worse — they release more ammonia gas — and why vinegar temporarily suppresses the smell without removing the residue.