Heavily polluted Tijuana River drives regional air quality crisis

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. This example makes it clear that poor water quality can drastically affect air quality—an observation with important implications for global waterways.