Respirator selection
Ozone respirator selectionO3
Water and air disinfection/ozonation, welding fume, laser printers/photocopiers, and semiconductor and food processing.
These are federal OSHA limits. The PEL shown is the federal OSHA value. About two dozen states run their own OSHA-approved plans, and some — notably California (Cal/OSHA) — enforce lower or additional exposure limits. If you work under a state plan, check your state's PEL and enter it as a custom limit in the calculator.
Cartridge (limited use): Chemical cartridge (activated carbon) — work use only up to 1 ppm; gas mask ESCAPE ONLY — Black band
An APR fitted with the correct cartridge is only adequate up to its MUC (below) — the cartridge must be able to capture ozone. CORRECTED: APR is limited to a chemical cartridge respirator up to 1 ppm ONLY — NOT up to the 5 ppm IDLH as previously stated. Between 1 ppm and above, and at/above the 5 ppm IDLH, supplied air/SCBA is required; the gas mask is escape-only. Strong OXIDIZER; no ozone-specific NIOSH cartridge color; olfactory fatigue degrades odor warning — confirm manufacturer approval. You must establish a change-out schedule; never rely on taste or smell. See the cartridge & filter guide.
Calculator for Ozone
Result
Enter a concentration and an exposure limit to see the
compliant respirators and their Maximum Use Concentration.
Hazard ratio = concentration ÷ OEL · Minimum APF must meet or exceed it · MUC = APF × OEL (capped at IDLH). Source: OSHA 29 CFR 1910.134(d)(3)(i)(A), Table 1 — Assigned Protection Factors. Last verified 2026-07-16.
Maximum use concentration for Ozone by respirator
MUC = APF × the OSHA PEL (0.1 ppm), capped at the IDLH (5 ppm). Use this as a reference for the highest concentration each respirator class may be used at.
| Respirator | APF | MUC (ppm) |
|---|---|---|
| Air-Purifying Respirator · Quarter mask | 5 | 0.5 |
| Air-Purifying Respirator · Half mask | 10 | 1 |
| Supplied-Air Respirator (Airline) · Half mask · Demand | 10 | 1 |
| Self-Contained Breathing Apparatus · Half mask · Demand | 10 | 1 |
| Powered Air-Purifying Respirator · Helmet / hood | 25 | 2.5 |
| Powered Air-Purifying Respirator · Loose-fitting facepiece | 25 | 2.5 |
| Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow | 25 | 2.5 |
| Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow | 25 | 2.5 |
| Air-Purifying Respirator · Full facepiece | 50 | 5 |
| Powered Air-Purifying Respirator · Half mask | 50 | 5 |
| Supplied-Air Respirator (Airline) · Full facepiece · Demand | 50 | 5 |
| Supplied-Air Respirator (Airline) · Half mask · Continuous flow | 50 | 5 |
| Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure | 50 | 5 |
| Self-Contained Breathing Apparatus · Full facepiece · Demand | 50 | 5 |
| Powered Air-Purifying Respirator · Full facepiece | 1,000 | 5IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow | 1,000 | 5IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure | 1,000 | 5IDLH |
| Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure | 10,000 | 5IDLH |
Notes
NIOSH REL Ceiling 0.1 ppm (sole REL in current NPG). OSHA PEL 8-hr TWA 0.1 ppm (Table Z-1). IDLH 5 ppm. NPG conversion 1 ppm = 1.96 mg/m3; MW 48.0. Do not publish the older workload-dependent REL values (e.g., 0.20 ppm heavy work up to 2 hr) — they are from superseded criteria documentation, not the current NPG.
Sources
- https://www.cdc.gov/niosh/npg/npgd0476.html
- https://www.cdc.gov/niosh/idlh/10028156.html
- https://www.osha.gov/annotated-pels/table-z-1
Data confidence: high. Values are cited from OSHA and NIOSH but should be verified against the current source and a qualified professional before use. See how this works.