Evaluation of the NOAA National Air Quality Forecast Capability

Air quality is determined by the extent to which ambient air has no harmful pollutants that can affect human health, ecological systems, and/or visibility (WHO, 2006). Primary air pollutants are emitted into the atmosphere whereas secondary air pollutants form in the atmosphere. The operational NOAA National Air Quality Forecast Capability (NAQFC) utilizes the Community Multiscale Air Quality (CMAQ) model, which is driven by the NCEP Global Forecast System (GFS) meteorological model (AQMv6). An Air Quality Model (AQM) v7 has been developed and is under experimental testing at NOAA. AQMv7 couples the CMAQ-based chemistry model with the FV3-based atmosphere model within the Unified Forecast System (UFS) frame. This model transitions from the offline-coupled GFS-CMAQ system to an online-coupled UFS-based online-CMAQ and is showing promising improvements in predicting hourly PM 2.5 and the daily maximum 8-hr averaged ozone concentrations.

This project aims to evaluate the NOAA air quality model meteorological and atmospheric chemistry predictions from the summer of 2022. Specifically, analyzing the July 20-22, 2022 ozone exceedance event affecting metropolitan NYC and Long Island—the most widespread ozone event of the season. Using the EPA Photochemistry Assessment Monitoring System (PAMS) and the AirNow air quality datasets, detailed chemistry measurements were used to analyze the performance of the model. Analysis was performed for ozone, NO2, and NO chemical compounds. Overall, there are mixed results for predictions using the AQMv7 when compared to the v6 for the high impact ozone case of July 20-22, 2023. However, though predictions improved for the exceedance case, the model produced unfavorable results in non-exceedance areas, producing conflicting results.