By substance
Respirator selection by substance
Pick a common US workplace substance to see its OSHA PEL, NIOSH IDLH, and the OSHA-compliant respirators with each one’s maximum use concentration — pre-filled into the calculator.
Gases & vapors (ppm)
AcetoneC3H6O
PEL 1,000 ppmIDLH 2,500 ppm
AmmoniaNH3
PEL 50 ppmIDLH 300 ppm
BenzeneC6H6
PEL 1 ppmIDLH 500 ppm
Carbon dioxideCO2
PEL 5,000 ppmIDLH 40,000 ppm
Carbon monoxideCO
PEL 50 ppmIDLH 1,200 ppm
ChlorineCl2
PEL 1 ppmIDLH 10 ppm
Ethylene oxideC2H4O
PEL 1 ppmIDLH 800 ppm
FormaldehydeHCHO (CH2O)
PEL 0.75 ppmIDLH 20 ppm
Hydrogen chlorideHCl
PEL 5 ppmIDLH 50 ppm
Hydrogen cyanideHCN
PEL 10 ppmIDLH 50 ppm
Hydrogen fluorideHF
PEL 3 ppmIDLH 30 ppm
Hydrogen sulfideH2S
PEL 20 ppmIDLH 100 ppm
Isopropyl alcohol (2-Propanol, IPA)(CH3)2CHOH (C3H8O)
PEL 400 ppmIDLH 2,000 ppm
MethanolCH4O
PEL 200 ppmIDLH 6,000 ppm
Methyl ethyl ketone (2-Butanone, MEK)CH3COCH2CH3 (C4H8O)
PEL 200 ppmIDLH 3,000 ppm
Methylene chloride (Dichloromethane)CH2Cl2
PEL 25 ppmIDLH 2,300 ppm
Nitric acidHNO3
PEL 2 ppmIDLH 25 ppm
Nitrogen dioxideNO2
PEL 5 ppmIDLH 13 ppm
OzoneO3
PEL 0.1 ppmIDLH 5 ppm
StyreneC8H8
PEL 100 ppmIDLH 700 ppm
Sulfur dioxideSO2
PEL 5 ppmIDLH 100 ppm
Tetrachloroethylene (Perchloroethylene)C2Cl4
PEL 100 ppmIDLH 150 ppm
TolueneC7H8
PEL 200 ppmIDLH 500 ppm
Xylenes (o-, m-, p-isomers)C8H10
PEL 100 ppmIDLH 900 ppm
Particulates (mg/m³, N/R/P filters)
CadmiumCd
PEL 0.01 mg/m3IDLH 9 mg/m3
Hexavalent chromium (Cr(VI))Cr(VI) (varies by compound; e.g., CrO3, chromates)
PEL 0.01 mg/m3IDLH 15 mg/m3
LeadPb
PEL 0.05 mg/m3IDLH 100 mg/m3
ManganeseMn
PEL 5 mg/m3IDLH 500 mg/m3
Particulates not otherwise regulated (PNOR)— (catch-all for inert dusts without a specific standard)
PEL 15 mg/m3
Respirable crystalline silicaSiO2
PEL 0.05 mg/m3IDLH 50 mg/m3
Wood dust— (cellulosic organic particulate; species-dependent)
PEL 15 mg/m3
Welding fumesmixture
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Don’t see your substance? Use the main calculator and enter your own exposure limit and IDLH.