The stated purpose of the…

The stated purpose of the Guideline to Address Odour Mixtures in Ontario (Guidelines) is for the Ministry of the Environment, Conservation and Parks and the regulated community to have guidance on anticipating, preventing, and addressing odour issues that could be of concern to local residences. OWMA and its members believe further consultation is crucial before finalization.

Most significantly, the Draft Guideline to Address Odour Mixtures in Ontario should affirm that Odour Units are an inappropriate legal compliance and enforcement tool. As odour and offensive of odour is subjective, it is not possible for odour unit measurement to apply a fair and consistent approach to odour of all types. As acknowledged in Section 8.0 of the Technical Bulletin, an odour assessment showing less than 1 OU at a receptor cannot guarantee that no adverse effects will occur. Section 6.0 of the Technical Bulletin states that ambient air monitoring is not a requirement of an odour assessments, but field surveys and communication engagement results can be useful. This again implies that odour studies will need to be based on subjective means. Direct language is needed on how odour investigations will be performed in the field to assess odour to a standard so that it can be assessed against an appropriate objective scale.

Further, if source testing shows compliance with required standards, does this mean the facility is in compliance regardless of whether the odour is offensive to some? Would there be an appeals process or a reassessment process in these scenarios?

More clarity is needed on testing procedures to make sure the testing is objective and factors in different types of odours and different testing procedures and methods for these types of odours. Clear language is also needed on the process neighbouring commercial and private residences should follow if odour sources are a nuisance, but all technical odour assessment requirements are met.
While OWMA agrees with the ministry’s emphasis in the Draft Odour Guideline and Draft Technical Bulletin on reliance on best management practices, technical benchmarking, and identifying best available odour control technology, there should be additional emphasis on using site- and source- specific solutions for odour management as an effective way to reduce actual odour emissions and actual adverse effects.

Odour is subjective and any attempts at measuring odour units is plagued with uncertainty and unreliability due to inconsistency in sampling, dilution, calibration, standardization of panelists and odour laboratories, and meteorological data and dispersion modelling.

In the case of waste management and processing facilities, where some level of harmless odour is inherent and expected, odour unit measurement and enforcement rarely, if ever, results in any meaningful environmental protection or mitigation of adverse effects.

The use of odour units as a regulatory compliance and enforcement standard is contrary to the Draft Odour Guideline’s goal of “reducing regulatory uncertainty for any facility with potential odour issues.” OWMA recommends that odour units should not be incorporated in Environmental Compliance Approvals and other regulatory tools as a legal compliance limit.

Detailed recommendations are included in the enclosed supporting document.