Indoor air quality in low energy residential buildings in Lithuania

- The indoor air quality in low energy residential buildings was assessed.
- Pollutant concentration in buildings with various levels of completion was compared.
- Concentrations of VOCs were very high immediately after installation of interior.
- Decrease of BTEX concentrations was rapid and fell below limit values in one month.

The indoor environment was investigated in 11 newly built low energy residential buildings. Temperature, relative humidity, the concentrations of CO2, NO2, formaldehyde, volatile organic compounds (VOC), and semi-volatile organic compounds (SVOC, i.e. PAHs, PCBs, HCB) were measured. Despite of the low air exchange rate in most buildings (0.08-0.69 h−1), CO2 and many monitored VOC and SVOC concentrations were at typical indoor levels, while the concentration of formaldehyde (3.3-52.3 μg/m3) was elevated above the Lithuanian limit value. In several buildings, extremely high concentrations of VOCs were observed where the installation of interior surfaces and furnishing were done shortly prior the measurement campaign. Decrease of benzene, toluene, ethylbenzene and xylene (BTEX) sum concentrations was rapid and fell below Lithuanian limit values in one month. This study demonstrates the importance of checking indoor air quality before occupancy and avoiding moving into buildings before the complete installation of the interior. Selection of low-emitting building and finishing materials, furniture, cleaning products and ensuring effective work of mechanical ventilation will contribute to good indoor air quality in low energy buildings.