TUESDAY, Sept. 8, 2026 (HealthDay News) — Kids spend hours every day in the classroom — and what they're breathing in could affect their lungs, according to a new study.

"We know that indoor air quality in schools can be affected by pollutants, humidity, ventilation, temperature, dampness and biological agents like fungi and bacteria," said study author Dr. Soutrik Banerjee of the University of Ferrara in Italy. "However, much less is known about whether the types of bacteria growing in classroom dust are linked to children's lung function."

His team studied nearly 4,800 schoolchildren across 22 European countries, looking at their exposure to bacteria in classroom dust.

They found that kids exposed to higher levels of two common types of bacteria had slightly reduced lung function.

In simple terms, those children couldn’t blow out quite as much air — or blow it out as quickly — during breathing tests.

Researchers say the exposure may irritate children's airways or trigger immune and inflammatory responses.

"The bacteria may either have a direct biological effect, or they may be indicators of other indoor environmental factors that influence lung function," Banerjee said in a news release.

Those other factors could include dampness, ventilation, cleaning practices or outdoor dust getting inside.

The bacteria — Streptomyces and Mycobacterium — are widespread in the environment, including in the U.S., and can be found in places like soil, dust and water.

This study was observational, so more research is needed to determine what is driving the link.

The findings were presented Sunday at a meeting of the European Respiratory Society in Barcelona, Spain. 

Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.

More information

The American Lung Association has more on air quality and children's respiratory health.

SOURCE: HealthDay TV, Sept. 8, 2026