Potential sources of occupants’ symptoms in the case building
| Feature | Measured/evaluated value | Comparison to guidelines |
|---|---|---|
| Ventilation rate | The condition assessment reports estimate the ventilation rates to be much lower than the design values. Furthermore, air flow in some of the natural ventilation air shafts has reversed the direction of the ventilation. Hence, air flows from the attic to the classrooms. The calculated value for ventilation rate is 2.7 dm3/s per person | The calculated ventilation rate is much less than Finnish recommendations (6 dm3/s per person) |
| CO2 | CO2 varied between 1,000 and 2,000 ppm during the occupied hours (8–16) in the studied rooms, while in three classrooms the maximum concentration reached 2,000 ppm almost every day | Much above the standard values (600–1,000 ppm) |
| Air pressure | The building was under negative pressure for almost the whole of the measurement periods (measured in February and March). Range +28 to −40 Pa, range of averages −2.8 to −11.8 Pa | The building is designed to be under slight negative pressure. The variation of values can be mainly ascribed to opening windows and operating times of mechanical ventilation |
| Air humidity | Range of RH values 14%–42% (measured in spring) | Mainly within the range of normal level |
| Room temperature | Range of room temperatures 17.7 °C −24.5 °C (measured in spring) | Mainly within the range of normal level |
| NO2 | Not measured | |
| SO2 | Not measured | |
| O3 | Not measured | |
| VOC | 111 µg/m3 (measured in one classroom) | Slightly above WHO guideline but within the normal range according to Finnish guide. The concentrations of the individual compounds contributing to total VOC substances remained below the recommended action level |
| Particulate matters | The measured levels of harmful pollutants, such as fungi and microbes, were less than 100 spores/g | The values do not exceed the normal level defined in Finnish guidelines |
| The concentration of mineral wool fibre was lesser than 0.1 fibre/cm2 (14 days) | ||
| Formaldehyde | Not measured |
| Feature | Measured/evaluated value | Comparison to guidelines |
|---|---|---|
| Ventilation rate | The condition assessment reports estimate the ventilation rates to be much lower than the design values. Furthermore, air flow in some of the natural ventilation air shafts has reversed the direction of the ventilation. Hence, air flows from the attic to the classrooms. The calculated value for ventilation rate is 2.7 dm3/s per person | The calculated ventilation rate is much less than Finnish recommendations (6 dm3/s per person) |
| CO2 | CO2 varied between 1,000 and 2,000 ppm during the occupied hours (8–16) in the studied rooms, while in three classrooms the maximum concentration reached 2,000 ppm almost every day | Much above the standard values (600–1,000 ppm) |
| Air pressure | The building was under negative pressure for almost the whole of the measurement periods (measured in February and March). Range +28 to −40 Pa, range of averages −2.8 to −11.8 Pa | The building is designed to be under slight negative pressure. The variation of values can be mainly ascribed to opening windows and operating times of mechanical ventilation |
| Air humidity | Range of RH values 14%–42% (measured in spring) | Mainly within the range of normal level |
| Room temperature | Range of room temperatures 17.7 °C −24.5 °C (measured in spring) | Mainly within the range of normal level |
| NO2 | Not measured | |
| SO2 | Not measured | |
| O3 | Not measured | |
| VOC | 111 µg/m3 (measured in one classroom) | Slightly above WHO guideline but within the normal range according to Finnish guide. The concentrations of the individual compounds contributing to total VOC substances remained below the recommended action level |
| Particulate matters | The measured levels of harmful pollutants, such as fungi and microbes, were less than 100 spores/g | The values do not exceed the normal level defined in Finnish guidelines |
| The concentration of mineral wool fibre was lesser than 0.1 fibre/cm2 (14 days) | ||
| Formaldehyde | Not measured |
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