Thousands of residents across a part of Alabama – which includes the city of Tuscaloosa, home to the University of Alabama -have been advised to stay inside as levels of fine particle pollution (PM2.5) have reached “unhealthy” levels.

The alert was active as of Tuesday, March 3, 2026, at 2.45 a.m. ET, according to the AirNow Map, which the Environmental Protection Agency (EPA) uses to monitor and communicate air quality across America.

What Residents Should Do When Air Quality Is ‘Unhealthy’

When air quality reaches “unhealthy” levels, the EPA warns that everyone is likely to be affected and should take steps to reduce their exposure to the pollution.

People in sensitive groups, including the elderly, children, and those with existing heart and lung conditions, should be especially careful and avoid all outdoor activity until conditions improve.

Alongside reducing exposure to outdoor air, residents in the affected area of Alabama should also keep indoor air as clean as possible, including in their homes. They should use air filters and purifiers, keep windows and doors closed, and avoid burning candles, incense, or indoor fires and wood-burning stoves. 

This is because the EPA considers PM2.5 to be one of the most dangerous forms of air pollution. The particles are so small—2.5 micrometers or less in size (smaller than the width of a single strand of hair), they can be inhaled, traveling deep into the lungs and bloodstream, worsening existing health issues, like asthma, and triggering symptoms ranging from eye, nose, and throat irritation and coughing to shortness of breath and chest tightness. 

What’s Causing The Poor Air Quality Across Alabama 

While the EPA hasn’t established what’s causing the elevated levels of PM2.5 across Alabama, PM2.5 can come from a variety of sources, including dust from unpaved roads and construction sites, smoke from wildfires or smokestacks, or emissions from vehicles or power and industrial plants. 

How Air Quality Is Measured Across The US

The EPA uses the Air Quality Index (AQI) to measure the air quality across the country. The AQI is a standardized system that scores air quality on a scale from 0 to 500 — the higher the number, the more polluted the air—and categorizes the air from good to hazardous. 

The AQI categories: 

  • Good (0–50): The air quality is considered ok, as air pollution poses little or no risk. Outdoor activities are safe for everyone, including children, older adults, and people with asthma or heart and lung disease.
  • Moderate (51–100): The quality of air is acceptable, but there could be a minor risk for a small number of people who are unusually sensitive to air pollution. Most people can continue normal outdoor activities, though sensitive individuals may notice mild symptoms.
  • Unhealthy for Sensitive Groups (101–150): Members of sensitive groups may start to experience some adverse health effects, but the general public is less likely to be affected. Sensitive individuals are advised to limit long or intense outdoor activities.
  • Unhealthy (151–200): Everyone may begin to experience health effects, and members of sensitive groups may experience more serious symptoms. Outdoor activity should be reduced, especially any strenuous exercise.
  • Very Unhealthy (201–300): This level triggers a health alert. The risk of health effects increases for everyone. People are advised to avoid outdoor activities, and sensitive groups should remain indoors and follow medical guidance.
  • Hazardous (301–500): This represents emergency conditions. The entire population is at risk of serious health effects, meaning everyone should avoid all outdoor activity, remain indoors, and follow public health instructions.