Proposed 2013 Updates to Alberta’s Air Quality Model Guideline

1. Proposed 2013 Updates to Alberta’s Air Quality Model Guideline Frauke Spurrell, Wally Qiu and David Lyder CPANS Luncheons November 2012

2. Purpose of Air Quality Model Guideline • The AQMG is used to ensure consistency in the use of dispersion models in air quality assessments. • The objectives are to: • Provide for uniform benchmarking, • Provide a structured approach to selection and application of models, • Ensure that there is a sound scientific basis for the use of alternatives, when alternatives are appropriate, and • Detail the required content of assessments submitted to the department.

3. Levels of Modelling • There are three levels of assessment: • Screening assessment- this is utilized to determine an initial impression of the highest concentrations that are likely to occur. • Refined assessment– due to its higher level of sophistication, more closely estimates actual air quality impacts of single or multiple sources. • Advanced assessment- treats specific processes in greater detail using an alternative or modified model. Justification for use and modelling details should be verified with AENV prior to submission.

4. Accepted Regulatory Models

5. Proposed Changes to AQMG: Baseline Concentrations, Inputs and Outputs

6. Proposed Changes to AQMG: NO2/NOx Conversion Methods • OLM Method • Hourly time series of O3 for each month added into Appendix D (no longer maximum seasonal rates) • Different series for urban and rural settings • ARM Method • Specifications for selecting appropriate downwind monitors to determine equilibrium NO2/NOx ratio • 0.7 default value if no monitoring data available

7. Proposed Changes to AQMG: Meteorological Data • Meteorology - Screening • More sophisticated meteorological grid provided inside of AERSCREEN (MAKEMET) • Meteorology – Refined/Advanced • One year of on-site data (not modelled meteorology) • 90% complete • Fill in upper air data • Five years of modelled data (2002 – 2006) as provided by ESRD • No other data sets accepted

8. Proposed Changes to AQMG: Models • Use of AERSCREEN as recommended model for screening purposes • A formula is provided for calculating alternate averaging periods • Added guidance on CALMET switch settings and version • Use the current version and recommended model switches available on TRC Solutions website • Deviation from default requires discussion prior to modelling and additional modelling (see CALPUFF) • Use as much prognostic data as possible; CALMET may not be used on its own

9. Proposed Changes to AQMG: Models • CALPUFF model • Use current version available on TRC Solutions website and recommended model switches (default model) • Deviation from current model with recommended switches requires duplicate modelling with default model for comparative purposes (maximum, distribution, time series, statistics); the Director still has the right to select default modelling results

10. Next Steps… • The revised Air Quality Modelling Guideline is being prepared for posting • There will be a 60 day public comment period once the updated guideline is posted