PyroGenesis Inc. — Regulatory Filings 2021

May 21, 2021

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May 21, 2021

Raymond Chabot Grant Thornton LLP Suite 2000 National Bank Tower 600 De La Gauchetière Street West Montréal, Quebec H3B 4L8 T 514-878-2691

Autorité des marchés financiers British Columbia Securities Commission Alberta Securities Commission The Manitoba Securities Commission Financial and Consumer Affairs Authority of Saskatchewan Ontario Securities Commission Financial and Consumer Services Commission (New Brunswick) Nova Scotia Securities Commission Office of the Superintendent of Securities, Service Newfoundland and Labrador The Office of the Superintendent of Securities (Prince Edward Island)

Dear Mesdames / Sirs:

Re: Notice of Change of Auditor – PyroGenesis Canada Inc.

We have read and reviewed the information contained in the Notice of Change of Auditor of PyroGenesis Canada Inc. dated May 21, 2021 (the “Notice”), which we understand will be filed pursuant to Section 4.11 of the National Instrument 51-102.

Based on our knowledge as of the date hereof, we agree with the statements contained in the Notice pertaining to Raymond Chabot Grant Thornton LLP.

Yours truly,

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