Indoor air quality in preschools in the Republic of Srpska, Bosnia and Herzegovina: a pilot study

Background

Indoor air pollution is a significant public health challenge, particularly in preschool environments where children spend a large portion of their day. However, systematic monitoring data on indoor air quality in educational institutions in the Republic of Srpska are lacking, limiting evidence-based policy and preventive actions. This study aimed to assess comfort parameters, indoor air quality and identify key factors influencing children’s exposure.

Methods

A pilot study was conducted in ten preschool institutions across six geographical areas of the Republic of Srpska during summer (July 2024) and the heating season (November 2025) with the support of the UNICEF office in Bosnia and Herzegovina. Indoor concentrations of PM2.5, PM10 and CO₂ were measured using a portable monitoring device (Trotec BQ30). Data were analysed using descriptive statistics.

Results

The average concentrations of PM10 and PM2.5 measured indoors were compared between two periods. During the heating season, the mean PM10 and PM2.5 concentrations were 49.43 μg/m³ and 27.70 μg/m³, while in the non-heating season, they averaged 46.09 μg/m³ and 21.85 μg/m³. Elevated PM2.5 concentrations exceeding WHO guideline values were observed in 6/10 institutions during summer and 8/10 during the heating season. Regarding comfort parameters increased CO₂ levels (>1000 ppm) were recorded in 8/10 institutions during summer and 9/10 during the heating season, indicating inadequate ventilation. Deviations were present among preschools with higher occupancy density, insufficient ventilation and elevated outdoor air pollution.

Conclusions

This pilot study highlights indoor air quality challenges in preschool settings. The findings suggest further emphasize the need for continuous monitoring, improved ventilation, and targeted measures to protect children’s health, alongside system-level interventions to support evidence-based public health action and policy development.

Key messages

• Indoor air quality in preschool settings is frequently compromised, with elevated PM2.5 and CO₂ levels indicating significant exposure risks for children, particularly during the heating season.

• Improving ventilation and establishing routine indoor air quality monitoring are essential measures to support evidence-based interventions and protect children’s health in educational settings.