# PM2.5

> English word · Proper noun

## Definitions
1. Initialism of particulate matter 2.5, a pollution measurement of particles with a maximum diameter of 2.5 µm.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/pm2-5