Common environmental bacteria found in classrooms may negatively affect pediatric respiratory health, according to European study data.
RT’s Three Key Takeaways:
- Bacterial Exposure Link: Classroom dust containing elevated levels of Streptomyces and Mycobacterium species is associated with measurable reductions in lung function among school-aged children.
- Measurable Spirometry Reductions: Higher bacterial concentrations correlated with statistically significant decreases in forced vital capacity, forced expiratory volume in one second, and peak expiratory flow.
- Facility Maintenance Priority: Healthcare and respiratory experts emphasize that prioritizing indoor air quality through improved ventilation, moisture control, and routine cleaning is vital to protect developing lungs.
Common bacteria found in classroom dust are associated with reduced lung function in children, according to research presented at ERS 2026.
The study, presented by Dr Soutrik Banerjee from the Department of Environmental and Prevention Sciences at the University of Ferrara in Italy and technology company Alten SA, evaluated whether specific bacterial strains present in school environments affect pediatric respiratory health.
“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 Banerjee, researcher at the University of Ferrara. “However, much less is known about whether the types of bacteria growing in classroom dust are linked to children’s lung function. We were particularly interested in two bacterial groups, Streptomyces and Mycobacterium spp, which are found in soil, dust and water systems. We wanted to see whether higher exposure to these bacteria in the classroom is associated with children’s lung health across Europe.”
Evaluating Lung Function Across European Classrooms
Researchers analyzed data from the SINPHONIE study, which evaluated classroom dust samples across 22 European countries and nearly 300 classrooms to quantify levels of Streptomyces and Mycobacterium species.
Investigators also assessed the lung function of participating students using standard spirometry testing, which measures the volume of air the lungs can hold as well as exhalation speed. The research team adjusted the findings for age, gender, body mass index (BMI), passive smoking, pet allergens, socioeconomic indicators, school building age and region, and local outdoor air pollution levels.
The analysis revealed that children in classrooms with higher concentrations of Streptomyces experienced a 0.08-liter reduction in forced vital capacity (FVC). In addition, children in rooms with higher levels of Mycobacterium exhibited a 0.06-liter lower forced expiratory volume in one second (FEV1), as well as a 0.13-liter-per-second lower peak expiratory flow (PEF).
“Although the reductions we found were modest for each child, they are statistically significant and could be important for the wider population,” said Banerjee, researcher at the University of Ferrara. “Children are exposed to school indoor environments every weekday and a mild to moderate reduction in lung function today may be a pre-cursor to preventable lung disease in later life.”
Banerjee noted that dust-borne bacteria may irritate airways or trigger immune and inflammatory pathways, or they could serve as markers for broader environmental issues such as dampness, inadequate ventilation, poor cleaning protocols, or outdoor soil intrusion.
“The bacteria may either have a direct biological effect, or they may be indicators of other indoor environmental factors that influence lung function,” said Banerjee, researcher at the University of Ferrara.
Implications for School Indoor Air Quality
Commenting on the findings, independent experts highlighted the operational relevance of the study for facility management and pediatric healthcare.
“This large European study shows that children’s lungs seem to suffer when two common types of bacteria are growing in dust in their classrooms,” said Alexander Möller, head of the European Respiratory Society pediatric assembly and professor of pediatric pulmonology at the University Children’s Hospital Zurich.
“While not all bacteria are harmful, these findings suggest that the classroom environment is important in children’s lung health and they support the idea that healthy school buildings matter,” said Möller, head of the European Respiratory Society pediatric assembly. “The practical message is not that schools should become sterile environments. Rather, schools should focus on good indoor air quality: adequate ventilation, control of dampness and mould, regular cleaning and proper building maintenance.”
“Children spend a lot of their time in the classroom, so it’s important that we understand how to keep this environment safe and healthy,” said Möller, professor of pediatric pulmonology at the University Children’s Hospital Zurich. “This study suggests that investment in indoor air quality, building maintenance and monitoring of environmental conditions in classrooms is money well spent.”
