Radon level reduction in two kindergartens in Slovenia

Area of Science:

• Environmental Science
• Public Health
• Building Science

Background:

• High indoor radon concentrations pose a significant health risk, particularly in buildings with specific geological foundations.
• Kindergartens, housing vulnerable populations, require effective radon mitigation strategies.
• Sub-floor channels in buildings can act as pathways for radon accumulation.

Purpose of the Study:

• To assess the effectiveness of remedial actions for reducing high indoor radon levels in two kindergartens.
• To evaluate natural ventilation versus mechanical ventilation for radon mitigation in sub-floor channels.
• To determine if radon concentrations can be reduced to acceptable levels for child safety.

Main Methods:

• Conducted radon concentration measurements in two kindergartens with average levels around 2,000 Bq m-3.
• Implemented natural ventilation by opening sub-floor channels at both ends.
• Installed a fan system for mechanical ventilation in one kindergarten, operating for 20 minutes three times daily.

Main Results:

• Natural ventilation of sub-floor channels did not sufficiently reduce radon concentrations.
• Mechanical ventilation using a fan significantly reduced radon levels to an acceptable value.
• The effectiveness of radon mitigation varied based on building foundation (sedimentary gravel vs. fly ash/cinder fill).

Conclusions:

• Mechanical ventilation is an effective radon mitigation strategy for sub-floor channels in buildings.
• Targeted ventilation systems can successfully lower indoor radon concentrations to safe levels.
• Building foundation characteristics influence radon entry and accumulation, requiring tailored mitigation approaches.