US lawCaliforniaStatutesCode hscDivision 26Part 1Chapter 239047.2Cal. HSC § 39047.2Cal. HSC § 39047.2Last amended: 1999Year: 2025Length: 10 wordsOfficial source “PM2.5” means particulate matter 2.5 microns and smaller in size.PreviousCal. HSC § 39047NextCal. HSC § 39047.5