Dispersion Modelling Reviews

Stag​​e 2

Review the dispersion m​​​odelling report. Metro Vancouver:

• checks to ensure that the dispersion modelling was conducted in accordance with the approved plan;
• carefully reviews the meteorology that was used to drive the dispersion model;
• analyzes tables and figures of the model results, looking for potential issues with the meteorology or inconsistencies b​etween the model inputs and expected results; and
• compares the results to Metro Vancouver ambient air quality objectives or criteria from other jurisdictions if Metro Vancouver does not have objectives for a given air contaminant.

This stage also ​typically involves several iterations of Metro Vancouver asking questions and the consultant responding. It is not uncommon for Metro Vancouver to uncover an issue that requires the consultant to remodel.

External re​​view

Once Metro Vancouver is satisfied that the dispersion modelling methodology and model results are reasonable, staff form conclusions on the potential effects on ambient air quality and then forward the report to the relevant health authority – Fraser Health or Vancouver Coastal Health – for their interpretation of the model results in terms of human health impacts, as Metro Vancouver is not an expert in that field. Metro Vancouver may also forwa​​rd the report to other agencies for their comments on potential effects to other environmental aspects, such as soil or water, if Metro Vancouver has received comments from concerned persons regarding those areas.

All comments received from other agencies are provided to the District Director for consideration when reviewing staff’s recommend​ation on a permit application.​​