Cars and trucks wait hours to cross, spewing harmful fumes while idling at international bridges. According to non-profit organization Casa Familiar, air quality monitor readings correlate directly with border wait times. The resulting emissions, including PM2.5 and black carbon, can trigger asthma, bronchitis and even cancer.

Long hours spent at the border are a result of increasingly thorough inspections following 9/11 as well as, more recently, the end of Title 42 in May. After the pandemic-era restriction on asylum-seeking expired, the Biden administration introduced a new regulation requiring migrants to make an appointment before approaching the border. While the policy was intended to reduce illegal crossings, it has created even more backlog in Northern Mexico.

Officials are exploring solutions to alleviate the high wait times, including building new ports of entry and expanded pedestrian access.