Air Quality Messaging and Forecast Challenges During The Historic June 2023 Canadian Wildfire Smoke Outbreak in the Mid-Atlantic Region

The early and explosive start to the 2023 Canadian Wildfire Season resulted in the transport of substantial amounts of near-surface smoke into the United States. During a typical fire season, the smoke concentrations reaching the Mid-Atlantic from Canada usually disperse, resulting in air quality remaining below unhealthy levels. However, in June 2023, two outbreaks of dense near-surface smoke, emanating from various wildfire complexes in Western Canada and Quebec, resulted in several days of Red and Purple Air Quality Alerts (AQA) across all Mid-Atlantic states. Pollution concentrations from fine particulates (Particulate Matter 2.5µm, PM2.5) reached record unhealthy values in parts of Maryland, Northern Virginia, and the District of Columbia. The historic and prolonged hazardous air quality in the National Capital Region brought increased media and public scrutiny to the process of air quality forecasting. Air quality forecasts and alerts are managed by individual states, each with its own rules and regulations governing how and when air quality forecasts or alerts are created. Air quality experts typically work within the state environment offices. The National Weather Service (NWS), using its robust weather dissemination systems, assists the states in the communication of AQAs to the public. This presentation provides an overview of the state-driven air quality forecast process, highlights historic PM2.5 values observed across the NWS Baltimore/Washington area of responsibility in June 2023, discusses messaging challenges that arose during these events, and explores improvements in collaboration between individual states and the NWS.