General…

General
From a scientific standpoint Airzone supports MOECC efforts to include cumulative air quality (AQ) levels as part of the permitting system. This will (finally) align predicted AQ levels with AQ standards which, themselves, are based on total air exposure (and, therefore, cumulative by definition) and will ensure that “apples-are-compared-to-apples”.
However, the imposition of conditions for industrial facilities in the identified areas with high air quality (“stressed airsheds” for benzene and B(a)P) does not seem to be proportionate to each facility’s own contribution (as far as can be told from the information provided). There seems to be no predictable, transparent and verifiable (quantified) mechanism to account for an individual facility’s own contribution to airborne levels. This may cause unfair (too much or too little) impositions on some facilities. Ultimately, we suggest, the quantitative impact of individual facilities on AQ must be considered, even if (and after) BACTs are imposed.
We provide some additional comments of a more technical nature below.

Identification of Stressed Airsheds
1) In the document “Discussion Paper: Cumulative Effects Assessment in Air Approvals” Table 5.1 would seem to indicate that definition of these areas is based on a single year of monitoring data (2014). It is suggested that at least 5 years of the most recent data available be used to aide identification on a more reliable statistical basis.
2) In same document as above, the MOECC asks (p.16) for suggestions for future steps; we suggest that the MOECC consider PM2.5 as the next CEA contaminant, given its cited impacts on human health.

Imposition of Conditions on Facilities in Stressed Airsheds
1) Consideration should be given to management actions for facilities just outside of the stressed airsheds (even if they are outside the identified municipal boundaries) if they contribute significantly to AQ levels therein. The MOECC will have to define “significant” here. For reference, the Town of Oakville has defined “significant” in their regulatory system for PM2.5 increment levels, as well as “major emitters” (versus “minor” ones).
2) In the proposal Document “Proposal for Cumulative Effects Assessment (CEA) in Air Approvals”, p.8, a list of conditions is provided where the policy proposal would be triggered for expanding facilities. Further explanations may be required for the term “net increase in POI concentrations” (as it may not only just be the maximum POI location that contributes).
3) In same document as above, a list of requirements is provided for facilities required to attend a pre-submission consultation (p.8). Under sub-part “iv.” it is not clear if the provision of an ESDM report/modelling is optional or obligatory.
4) In same document as above, a list of requirements is provided for facilities required to submit a TBR (p.9). Under sub-part “c.” it is not clear if the maximum POI to be provided is before or after implementation of the suggested technology. In the same sub-part, it is not clear what “contaminant loading” means (airborne concentration?).

Modelling
1) We have not reviewed the modelling guides referenced as part of the modelling work but, unless already considered, we would suggest accounting for edge-effects of the modelling domain. The method used to estimate cumulative AQ levels in this work is to account for all significant sources (industrial and non-industrial). However, at the edges of the model domain, receptors will not receive emissions from all significant sources contributing to levels at those locations especially when winds come from “off-domain”.
To account for that, a certain “buffer zone”, around the domain edge, should be identified and within which modelling results are deemed not valid to identify Threshold Action Levels. Threshold Action Level boundaries should only be defined within the “area of validity” of the model results. If a larger area of validity is required the modelling domain can always be added to in the future to accommodate.
2) It seems that the predictions of MOECC’s multi-source model (MSM) were compared to measured data for 1 (modelled) year only. We suggest that the modelled predictions be extended to at least 5 years to determine year-to-year variations in modelled results and allow a more robust statistical comparison against measured data.
3) We would support the MOECC’s future intentions of utilizing the CALPUFF model, instead of AERMOD, given the dispersal distances used (up to ~20 km) and the domains being close to large water bodies where complex air flows can occur.

Miscellaneous
1) In the document “Addressing Cumulative Effects Assessment for Air Approvals in Ontario - Supplemental Discussion Paper: Rationale and Framework for Proposal for a First Step on the Assessment and Management of Cumulative Air Emissions”, the section entitled “Current Ministry Approaches to Cumulative Effects under O. Reg. 419/05” should include mention, and provide consequences of, the Lafarge case (2007).
2) In same document as above, p. 9/21, first paragraph requires more explanation as it is difficult to understand.
3) In same document as above, section 7.3 “Management”, p. 20/21, reference is made to land-use planning to address the wider context of cumulative effects. What may not be realized is that the Provincial Policy Statement already requires cumulative effects to be accounted for in planning decisions (although it is often not, for air quality, considered in practise).

[Original Comment ID: 212358]