Kelley C. Barsanti

1. Introduction Click to copy section linkSection link copied! The Tijuana River (TR) flows through a binational watershed, with about 75% of its drainage area located in Mexico and the remaining 25% within the United States (Figure 1B). (1) The rapid industrial growth of the Mexican city of Tijuana, (2) combined with poor wastewater management, has significantly affected the TR, leading to a continuous influx of urban runoff, industrial effluents, and untreated sewage into the river.

Editor’s summary Intense industrial and urban wastewater pollution has plagued the Tijuana River for decades, causing long-term closure of neighboring beaches. Rico et al. showed that surging wastewater flows in the summer of 2024 enhanced water-to-air hydrogen sulfide (H2S) transfer at a turbulent hotspot, leading to nighttime atmospheric H2S peaks thousands of times greater than typical urban levels.

Abstract Fires in the wildland-urban interface (WUI) are a global issue with growing importance. However, the impact of WUI fires on air quality and health is less understood compared to that of fires in wildland. We analyze WUI fire impacts on air quality and health at the global scale using a multi-scale atmospheric chemistry model—the Multi-Scale Infrastructure for Chemistry and Aerosols model (MUSICA).