Biomass, structure, and waste burning within the Wildland-Urban Interface (WUI) have caused significant destruction to communities around the world. In addition, emissions from these fires, which include hazardous air pollutants, have significant impacts on air quality and public health across multiple spatiotemporal scales. Successfully conducted field campaigns (e.g., Western Wildfire Experiment For Cloud Chemistry, Aerosol Absorption And Nitrogen (WE-CAN) and Fire Influence on Regional to Global Environments and Air Quality(FIREX-AQ)) and geostationary satellite observations (e.g., GOES AOD and FRP products), along with the extensive studies on fires over the U.S. (especially the WUI fires), have significantly pushed our understanding of fires and fire impacts on air quality forward. This presents a unique opportunity to apply the knowledge learnt from U.S. fires at the global scale. This project aims to quantify fire emissions and impacts on air quality in the WUI at major/representative urban areas globally by combining satellite observational data and a multi-scale modeling framework (the Multi-Scale Infrastructure for Chemistry and Aerosols; MUSICA) improved by field campaign measurements. Specifically, the proposed work aims to address the following questions: (1) What can we learn from the U.S. FIREX-AQ and WE-CAN field campaigns and GOES fire products, and do those lessons apply to the global domain? (2) What are the emissions from WUI fires and how are they different from wildland fires? (3) What are the impacts of WUI fire emissions over global representative urban regions?