Evaluation of the AIRPACT2 modeling system for the Pacific Northwest Abdullah Mahmud MS Student, CEE Washington State University

Introduction/Motivation Research objective Modeling system Evaluation approach Results Summary Acknowledgements Presentation outline

 Air Indicator Report for Public Access and Community Tracking (AIRPACT) version 2 is a numerical air quality modeling system for the Pacific Northwest  AIRPACT was developed during  Updated to AIRPACT2 in September 2003 by incorporating air toxics, and expanding the domain Introduction

 Next day air quality forecasts  Long term simulation record  Public education –Web products available daily to enhance public awareness –Detailed picture of air pollutant behavior— neighborhood air quality –Provides ‘what-if’ view of potential control strategies –Ideal academic resource Motivation

Evaluate model performance in order to understand the strengths and weaknesses of the modeling system, and find ways to improve it AIRPACT2 follows a classical photochemical modeling system that includes met, emission, and chemistry & transport components Research objectives Modeling system

MCIP&CALMET (met preprocessor) u, v formatted for each layer of CALMET u, v formatted for each layer of CALMET 3D met field: u, v, w, T, BL variables 3D met field: u, v, w, T, BL variables O3, VOC, NOx, primary PM Air toxics O3, VOC, NOx, primary PM Air toxics IC/BC (NCEP GFS) Landuse, terrain Landuse terrain IC/BC of gaseous & PM species, chemical mechanism, dry deposition MM5 (met model) SMOKE (emissions processor) Hourly speciated & gridded emissions Hourly speciated & gridded emissions Annual/monthly emissions, landuse & land cover CALGRID (transport & photochemical model) Model Evaluation Tool

AIRPACT2 animations

Evaluation approach  No standards for model evaluation, although some guidelines are available  Compare gas phase modeled mixing ratios, and particulate concentrations with those of measured  Extract model data for a 3x3 grid matrix for surface layer  Apply statistical metrics

Air quality monitoring stations

Evaluation metrics Mean Bias (ppb) Fractional Bias (%) Mean Error (ppb) Fractional Error (%)

Results  Ambient O 3 mixing ratios, and PM 2.5 concentrations for Sep 2003 were obtained from Washington Department of Ecology telemetric data network, and from ODEQ  Air toxics data were obtained from the Urban Air Toxics Measurement Campaign in Seattle for Sep – Oct 2003  Data were analyzed temporally and spatially

Enumclaw, WA Carus. OR Episode Non-episode Better forecasting capability Model over-predicts, although captures the diurnal pattern Hourly O 3 simulations

Ranked O 3 performance Relatively better performance at higher levels Over- estimates at lower mixing ratios

8-h max O 3 prediction performance statistics (September 2003)

O 3 time series (Sep 2003)

Air toxics simulations

Air toxics simulations at Seattle Beacon Hill site (Sep-Oct 2003) Ratio analysis

Long-term simulations (monthly average air toxics)

PM 2.5 simulations PM 2.5 time-series (Sep 1-15, 2003) CALGRID misses secondary formation of PM 2.5

Summary Airpact2 Evaluation –Good performance for O 3 during episodes –Over-estimation of non-episode O 3 mixing ratios –Over-estimation of air toxics (single site sub-grid effects?) –Captures trends and relative ratios for most species Conversion to CMAQ underway –Continue Sept 2003 evaluation for comparison to CALGRID with 4-km resolution –Expanded domain: Idaho, Oregon, Washington, southern BC with 12 km resolution –Evaluation of regional S, N, & Hg deposition

Acknowledgements  Joe Vaughan, Jack Chen, Jeremy Avise, Brian Lamb, and Hal Westberg  NW-AIRQUEST supports AIRPACT2  NW International Air Quality & Environmental Science Technology Consortium –17 local, state and federal agencies –Environment Canada & other Canadian agencies –WSU, UW, and UBC  Mission: provide sound science in support of regional air quality management