- May 28, 2026
- By Daniela Benites
There was more than just an unpleasant smell to the orange haze that clouded East Coast cities and set off air quality alerts in more than 20 states at the peak of the 2023 Canadian wildfires in June 2023.
A new University of Maryland air quality study conducted by taking air samples in College Park during and after the episode for the first time found airborne chemicals known as aeruginosins, associated with toxic bacteria blooms, in wildfire smoke plumes. The research was led by Akua Asa-Awuku, chemical and biomolecular engineering professor and associate dean in the A. James Clark School of Engineering, and published Saturday in the journal American Chemical Society ES&T Air.
Aeruginosins are emitted by cyanobacteria—algae-like microorganisms found in lakes, rivers, ponds, estuaries and and other water bodies. When conditions are right, they create “blooms” often observable in the water surface that are linked to bronchitis, asthma, allergies, rhinitis and dermatitis when inhaled; accidental ingestion of contaminated water has been found to cause gastrointestinal symptoms.
While studies have not identified how wildfire plumes trigger the release of the toxins into the air, the findings raise new questions about the public health impact of wildfire smoke emissions, which previously had been shown to cause or worsen respiratory conditions such as asthma, and pose even greater risks for vulnerable groups such as children, seniors and those with underlying health conditions.
The study reported that aeruginosin was present in 12% of the air samples collected by Asa-Awuku’s research team in College Park—about 1,000 miles from the fire zone—with the presence of aeruginosins most prevalent during peak pollution, and decreasing as air quality improved.