This session invites submissions on producing atmospheric composition forecasting from daily to sub-seasonal to seasonal scales. This includes development and implementation of both research and operational deterministic air quality forecasting systems, ensemble approaches for probabilistic air quality forecasting, chemical data assimilation, bias correction, machine-learning and other techniques to improve initialization, emission, physical and chemical processes, and post-processing of air quality forecasting systems to improve forecasting skill and decision-making support.

As new challenges emerge in air quality modeling and forecasting, innovative techniques offer exciting opportunities to advance our understanding of the complex interactions between air quality, meteorology, and the climate system. Meanwhile we are facing a growing need to provide tools which can rapidly and reliably inform both the public and policy makers of the ways in which air quality might change, responding to questions of environmental justice and compounding environmental stressors. This session focuses on innovative techniques in atmospheric and air quality modeling, such as trustworthy artificial intelligence/machine learning, physics-infused machine learning, new approaches to model-data fusion, GPU-accelerated computing, and cloud computing.

Measurements provide real-world data to validate and constrain models, while models offer a framework for situating often sparse or intermittent measurements within a broader context. This session highlights work integrating measurements and models for physical and chemical processes in the atmosphere as they relate to air quality. A range of measurement types are considered, including in-situ and remote sensing measurements from surface, airborne, and satellite platforms. A variety of methods for measurement integration are also considered, including data assimilation, data fusion (including machine learning approaches), and use of measurements for model evaluation and validation.

In this session, we invite submissions from the latest observational and modeling studies with the focus on advancing our understanding of meteorology and atmospheric chemistry as a coupled system. Relevant topics include but are not limited to: (1) Coupled meteorology and chemistry feedbacks across scales (e.g., land-atmosphere coupling, PBL mixing, cloud microphysics, dynamics, etc.), (2) Studies designed to investigate meteorology and air quality interactions across multiple pollutant species (e.g., aerosols and reactive gases), (3) Biogenic emissions and their impacts on regional and global air quality, (4) Combined effects of meteorology and chemistry and their associated broader societal impact (e.g., health burden, environmental justice, etc.).

The linkages between the atmosphere's constituents and meteorology are dependent on the level of knowledge and methodology used to represent chemical and physical processes within the models.  These processes are sometimes scale-dependent, with different scales necessitating different approaches.  They may also be scale independent, applicable to all resolutions and modeling domains.  In this session, we focus on new modeling systems and process representations that span all scales of atmospheric modeling.  A particular focus is on fundamental processes - those which have a key influence on the predicted state of the atmosphere, yet may be addressed through novel process representation.

Unique or extreme events such as wildfires, stratospheric ozone intrusions, dust storms, cold air pools, and pandemics can have notable and sometimes dramatic impacts on meteorology and air quality. Further, while typically episodic and unique in nature, climatological projections have them occurring more frequently and the enormity of their impact, spatially, temporally, and in terms of creating hazardous conditions, affect millions of lives. In this session we invite abstracts that probe the underlying physics and chemistry of extreme events with the goal of understanding their impact on air quality and meteorology. Possible topics include, but are not limited to, recent high-impact wildfires, pandemics, and other notable events such as dust storms, stratospheric ozone intrusions, and cold air pools.