Kimberly A. Prather

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.

Abstract The Tijuana River, at the US-Mexico border, discharges millions of gallons of wastewater daily—sewage, industrial waste, and runoff—into the Pacific Ocean, making it the dominant source of coastal pollution in this region. This study examines how such wastewater influences coastal aerosols by tracking spatial gradients from near the border northward.

Is the air we breathe safe? This seemingly straightforward question is often unanswerable because regulations, monitoring approaches, and reporting structures cannot keep up with the rapid human-induced shifts to the planet and atmosphere. The air is becoming more burdened by pollutants from new sources such as intense fires at the wildland-urban interface, an ever-expanding area where human development meets natural habitats.