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A crucial aspect of regional air quality modelling is the accurate characterisation of local meteorology, as this plays a significant role in the transport and chemical transformation of pollution across a region. This study explores the potential of The Weather Research and Forecasting (WRF) model as an alternative meteorological model to support near-time air quality predictions for the NSW Greater Metropolitan Region (NSW GMR). We develop an optimal WRF configuration for the NSW GMR by downscaling the latest Bureau of Meteorology (BOM) Australian Community Climate and Earth-System Simulator (ACCESS) Numerical Weather Prediction (NWP) data using a three nested domain setup with resolutions of 12km, 4km and 1 km by varying physical parameterisations including two cumulus schemes, two planetary boundary layer schemes, two microphysical schemes, two compatible shortwave and longwave radiation schemes and a standard land surface model. Thus, a set of 16 experiments were executed and evaluated on different days involving high ozone days, bushfire smoke, dust storms and heatwaves. Each simulation was initialised at 12UTC with a forecast horizon of four days, including three hourly updates of boundary conditions. All simulations were evaluated with metrics including Mean Absolute Errors (MAE) and Index of Agreement (IOA) calculated over selected stations operated by NSW Department of Planning, Industry and Environment (NSW DPIE) and BOM for surface and vertical variables (temperature (T), relative humidity (RH), wind speed (WS)) including precipitation (PRECIP) and planetary boundary layer heights (PBLH). Overall, results showed that the best configuration produced acceptable agreements at the surface for T (IOA > 0.8), RH (IOA > 0.7) and WSP (IOA > 0.6). Errors in PBLH were elevated in the mid-boundary layer but was within 100m where vertical profiles of temperature and winds were well simulated. Similarly, experiments with double moment microphysical schemes were better in simulating precipitation. Other performance metrics for the experiments conducted under different case days will also be discussed. [ABSTRACT FROM AUTHOR]

The need for fast responses options to manage the potential risks of exposure of population to pollutants from planned or unplanned activities is becoming critical and require a constant improvement in its management. The Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT) developed by the US National Oceanic and Atmospheric Administration (NOAA), is a complete system for computing both simple air parcel trajectories and complex dispersion and deposition simulations. These simulations include tracking and forecasting the smoke from prescribed burns and wildfires, dust, volcanic ash, the release of radioactive material, and pollutants from industrial incidents. The model can also be aggregated as a decisions support tool in the different phases of emissions events management. It has been tailored to run in New South Wales with finer spatial resolution meteorological data from Bureau of Meteorology to increase the accuracy of the trajectory and dispersion modelling. This system, called 'HYSPLIT in NSW', has been successfully configured to produce operational atmospheric trajectory and dispersion forecasts twice daily since July 2019. The system provides greater certainty in predicting the transportation of smoke from wildfires and hazard reduction burns, and is able to identify areas that are likely to be affected by regional dust storms and industrial incidents. 'HYSPLIT in NSW' also supports both research applications and emergency response events that require modelling the transport and dispersion of harmful pollutants released to the atmosphere (e.g., Port Macquarie peat fire in August 2019). It is an efficient modelling tool as it does not require huge amount of computing resources. The model is often applied to support the needs from air quality regulators or local emergency managers for air parcel trajectory and dispersion forecast. [ABSTRACT FROM AUTHOR]