Over a million Americans in three Southwestern states have been warned to close their windows and limit outdoor activity due to a hazardous cloud of airborne toxins. Air quality alerts have been issued for parts of Texas, New Mexico, and Arizona as dust storms have caused a significant spike in harmful particles.
El Paso, Texas, the largest city affected with a population of nearly 900,000, is at the center of the air quality emergency. The affected zone spans approximately 200 miles along the border. The U.S. Environmental Protection Agency (EPA) has classified the air in the entire El Paso metropolitan area as 'unhealthy,' with a section near Fort Bliss designated as 'very unhealthy.' The Air Quality Index (AQI) in northern El Paso reached 411, a level at which the EPA advises everyone to avoid outdoor physical activity.
The primary pollutant identified is PM10, a type of fine particulate matter composed of tiny solid particles or liquid droplets less than ten micrometers in diameter. While larger than PM2.5, PM10 can still penetrate deep into the lungs, causing inflammation, breathing difficulties, and exacerbating existing respiratory conditions like asthma. AccuWeather warned that exposure can lead to eye and throat irritation, coughing, and more serious health effects with prolonged exposure.
Data from IQAir indicates that the pollution is being driven by winds moving north from Mexico. The geography along the U.S. southern border, including regular dust storms originating from the Chihuahuan Desert, is a significant factor. Pollution from vehicles and industrial sources in Ciudad Juárez, Mexico, a city with over 1.6 million residents, also contributes to the air quality issues. The American Lung Association previously gave El Paso an 'F' grade for ozone pollution in 2025.
In New Mexico, cities including Las Cruces, Silver City, Deming, and Lordsburg are experiencing air quality levels considered harmful to sensitive groups. These groups include individuals with lung or heart disease, older adults, pregnant women, children, and those who work outdoors. Approximately 250,000 people in New Mexico are impacted.
Smaller areas of 'unhealthy' air have also been reported in Arizona, primarily over the Maricopa Indian Reservation south of Phoenix. The EPA's classification highlights the widespread nature of the air quality degradation affecting a significant portion of the U.S. Southwest.