Air Monitoring Action Levels Calculator

PIDs measure ionization, not a specific chemical, and their factory calibration (usually isobutylene) responds differently to other compounds than a true concentration of that compound would. The Correction Factor is a multiplier -- published by the instrument manufacturer for dozens of common chemicals -- that converts the raw isobutylene-equivalent reading into an estimated true concentration of the actual substance. Using 1.0 (isobutylene) for an unknown or different compound will misstate Corrected Reading, sometimes substantially.

Ambient air rarely reads zero on a PID -- vehicle exhaust, nearby industry, or even biogenic VOCs can produce a nonzero upwind reading that has nothing to do with the site being monitored. Subtracting that upwind Background Reading from the Corrected Reading isolates Net Above Background, the portion attributable to the work being done, which is the figure that should actually be compared against site action levels rather than the raw instrument number.

No. OSHA's own hazardous waste operations standard, 29 CFR 1910.120 Appendix B, describes when each PPE level applies in qualitative terms -- professional judgment about identified versus unidentified hazards, skin absorption risk, and splash potential -- and does not publish fixed ppm breakpoints from a direct-reading instrument. This output is a commonly taught illustrative screening ladder, useful for training and discussion, not a citable regulatory table.

Action Level 1 and Action Level 2 are numbers YOU set, pulled from your site's own approved Health and Safety Plan, so Action Level 1 Exceeded and Action Level 2 Exceeded reflect a real, site-specific decision someone with authority already made. The Generic PPE Level Screen is this calculator's own illustrative default ladder, shown for context, and should never override the site-specific action levels you actually entered.