What Does the Border Sound Like?
A Sonic Exploration of Pollution in San Ysidro, CA
August 12, 2026 | 8:52 AM
TAGS:
BORDER, GEOGRAPHY, ENVIROMENT, SOUND, HEALTH, CULTURE
After a short walk through palms trees and murals, the local dog-walker tells me the story of her asthma diagnosis. Attempting to speak above the loudly noise of cars passing, Alvarez shares how following a 45 minute bus commute to her local hospital, she “ended that day receiving the devastating news of an adult-onset asthma diagosis”. Adult onset asthma is defined as breathing difficulties occuring after the age of 20, often occuring in spaces of “long-term exposure to air pollution.” Unfortuntely, Ramona’s story is one of many in San Ysidro - home to the world’s busiest land border crossing.
Filled with constant traffic and visitors, San Ysidro sees up to “50,000 vehicles and 25,000 pedestrians cross daily” (South County Economic Development Council, 2013). Sandwhiched between the large bustling cities of San Diego and Tijuana, San Ysidro is home to a transnational community of 28,000 residents. This transnational movement can also be reflected in all aspects of life at the border. Whether the bilingual signs, the US-Dollar to Peso money exchange centers, or the multinational music heard around every corner, San Ysidro is the epitome of what crossnational life looks like. Similarly, the educational and health systems in the region also create a push and pull of pedestrian and car traffc. Along with the poetics and beauty of crossnational life, so too are the burdens and challenges of the region .
Most popularly, in 2018, Imperial Beach, a small beach town neighborhing San Ysidro, sued the U.S International Boundary and Water Comission for inadequetly protecting crossnational communities and waters from sewage contamination in the Tijuana River. Simiarly, San Ysidro faces a number of traffic induced noise pollution, which often go unreglated. Residents of San Ysidro often note the intense and disturbing presence of constant traffic, border patrol and survelience cameras. With higher exxposure to long-term cardiovascular and respiratory health problems, air pollution often manifests in everyday inconvencies such as indoor pollution, haze-filled skies and,the focus of today’s soundscape, noise pollution. San Ysidro residents are exposed to high levels of particulate matter (PM). PM is the result of heavy pollution causes pollutant particles to linger in the forms of solid or liquid particles such as dust, dirt, soot, and smoke. Particulate matter 2.5m (PM2.5) is when PM particles are smaller than 2.5 micrometers, making them small enough to be inhaled. This is extremely concerning because San Ysidro has ranked in the top 5% of the highest PM2.5 levels in the state. High amounts of exposure to particulate matter are known to cause severe side effects such as premature mortality, heart and lung disease, asthma, and respiratory issues, with worse rates seen in vulnerable groups of people such as the elderly, children, those with previous health conditions and those that are outside (and therefore more exposed to these particles) such as the unhoused or laborers.
“Every [inhaler] pump reminds me that the city, [and] the people I voted for, forgot me and my home. It is not just a river problem, its one in our air.”
WHAT IS SOUND ECOLOGY?
Using a microphone (also known as a sound recorder), the supplement sound piece “Sonics of the Border” documents the noise of San Ysidro. Using a technique known as soundwalking, the piece is a compilation of the sounds of the region including bird songs, traffic noises, and the sounds of everyday life at the border. A soundscape defines space through sound. Considering the “why”, the “ifs” and the “how” of a place through what you can hear.
Soundscape ecology is a strategic way of understanding the sonic relationships in the world around us. In an acdemic journal article published by BioScience in 2025, argues that there is a direct link between how healthy environments and ecosystems are and the types of sounds in a place (categorized as unpleasent and pelasant, as natural/industrial). For example, if we consider how bird populations dim in the presence of industrial workyards, or how humans develop tinitus when exposed to loud sounds of traffic, then community and environmental health projects should consider the sonics of the world when defining health, prosperity and when envisioning health futures of the loudest communities.
SYNTHESIS:
References:
Ilmarinen, P., Tuomisto, L. E., & Kankaanranta, H. (2015). Phenotypes, Risk Factors, and Mechanisms of Adult-Onset Asthma. Mediators of Inflammation, 2015, 1–19. https://doi.org/10.1155/2015/514868
GSA San Ysidro POE. (2020, October 10). San Ysidro Port of Entry - South County EDC. South County EDC.
https://southcountyedc.com/san-ysidro-poe/