IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail


French name in the regulation: Ammoniac
CAS : 7664-41-7

Exposure Standards in RROHS regulation

Permissible exposure values (PEV)
ppm mg/m3 f/cc Notes
TWAEV 25 17 - -
STEV 35 24 - -
Ceiling - - - -
Simple asphyxiant Percutaneous
Minimum exposure Sensitizer
Prohibited use Prohibited recirculation

TWA adjustment for unusual work schedules

1B : No adjustment

CNESST – Toxicological Index Service

Consult REPTOX file: Ammonia



Method: IRSST - 49
Sampling device:
Sampling media required:

Flow rate: -
TWA sampling volume: -
STEL sampling volume: -
Remarks: Refer to the user's guide accompanying the instrument.
Principle: Direct reading instrument-Electrochemical cell (DRI-elec)
Remarks: Ammonia is quantified in the field with a direct-reading instrument (DRI). The minimum reported value is 2.1 mg/m³ (3 ppm). The reference method corresponds to calibration of the DRI.
IRSST. "Méthode d'étalonnage d'un instrument à lecture directe". Méthode 49. Non publiée.


Method: IRSST - 220-1
Sampling device:
Sampling media required:
2144 Tube of carbon pretreated with sulfuric acid 500/250 mg

Flow rate: 0,10 - 0,5 L/min
TWA sampling volume: 24 L
STEL sampling volume: 7,5 L
Remarks: These tubes have a limited shelf life. It is important to respect the expiration date printed on the package.
Principle: Ion chromatography with conductivity detection (IC-CD)
Precision (%): 4,04
Minimum reported value: 9,4 µg
Remarks: The ammonium ion (NH4+) is being analyzed, so all ammonium salts and some substituted ammoniums will cause interference. The analytical results are expressed as ammonia (NH3).
IRSST. "Analyse de l'ammoniac dans l'air". Méthode 220-1. Non publiée.
Following the amendment of Appendix 1 of the Quebec Regulation respecting occupational health and safety (RSST, RLRQ, c. S-2.1, r. 13), part of Quebec Occupational Health and Safety Act, which came into effect on March 26, 2020, the TWAEV, STEL and Ceiling values for certain substances are now expressed in ppm. For these substances, the IRSST performed the conversion calculations to express these TWAEV, TWA and Ceiling values in mg/m3, which thus appears in its Sampling Guide for Air Contaminants in the Workplace (Guide d'échantillonnage des contaminants de l'air en milieu de travail ) and the associated Substance Data Sheets. However, it is imperative to refer to the values expressed in the RSST which are legally binding.