Energie Forma+, in collaboration with their contractor Groupe Magma Inc. (Magma), planned the construction and operation of a biogas plant in Salaberry-de-Valleyfield, Quebec. A certificate of authorization request was submitted to the MELCCFP for approval. This study aimed to assess the potential air quality impacts from the plant’s operations, focusing on key contaminants such as odour emissions, hydrogen sulfide (H₂S), and ammonia (NH₃).