Table 1. Levels of indoor air pollutants, temperature and humidity over the study period.
| Standard | Period 1 | Period 2 | Period 3 | Period 4 | |
|---|---|---|---|---|---|
| Temperature (°C) | 25.6±1.3 | 26.1±0.9 | 25.8±1.3 | 22.5±1.9 | |
| Humidity (%) | 50.3±9.1 | 60.4±6.8 | 49.6±9.0 | 32.8±7.9 | |
| PM10 (μm/m3) | 100 | 43.7±1.4 | 65.6±1.3 | 41.1±1.6 | 48.5±1.6 |
| PM2.5 (μm/m3) | 25.6±1.4 | 32.9±1.6 | 15.3±1.9 | 19.8±2.0 | |
| PM1.0 (μm/m3) | 20.9±1.4 | 27.4±1.8 | 11.2±2.2 | 15.9±2.2 | |
| NO (ppb) | 7.3±1.9 | 4.5±2.1 | 5.3±2.3 | 16.0±2.0 | |
| NO2 (ppb) | 50 | 21.0±1.2 | 23.1±1.3 | 13.9±1.7 | 11.2±2.3 |
| NOx (ppb) | 29.5±1.2 | 28.9±1.2 | 20.5±1.6 | 28.9±1.9 | |
| Benzene (ppb) | 0.5±0.5 | 0.5±0.4 | 0.5±0.4 | 0.6±0.4 | |
| Toluene (ppb) | 3.6±0.7 | 42.5±0.7 | 5.3±0.7 | 3.8±0.7 | |
| Ethyl-benzene (ppb) | 0.7±0.5 | 1.8±0.7 | 0.7±0.5 | 0.8±0.5 | |
| Xylene (ppb) | 0.9±0.6 | 2.8±0.6 | 1.0±0.6 | 1.2±0.6 | |
| Styrene (ppb) | 0.4±0.4 | 0.7±0.5 | 0.5±0.4 | 0.5±0.4 | |
| TVOC (ppb) | 400 | 18.5±0.6 | 80.5±0.7 | 23.2±0.6 | 28.0±0.6 |
Standard levels for indoor air quality control in public use facilities are set by the Ministry of Environment, Republic of Korea.
All levels are written as geometric mean ± geometric standard deviation.
Periods 1 to 4 are described in the methods section.
PM10, particles < 10 μm in diameter; PM2.5, particles < 2.5 μm in diameter; PM1.0, particles < 1.0 μm in diameter; NO, nitrogen oxide; NO2, nitrogen dioxide; NOX, nitrogen oxide compounds; TVOC, total volatile organic compound; ppb, parts per billion.