The circadian rhythm of total volatile organic compounds, carbon dioxide, and formaldehyde concentrations and the physical parameters in rooms with and without air-related irritation symptoms

In office environment exposure to volatile organic compounds (VOCs) and formaldehyde (HCHO) may cause symptoms. One room with and without reported occupants’ symptoms were selected in a large office building. The aim was to follow the circadian rhythm of the total volatile organic compounds (TVOC), HCHO and carbon dioxide (CO₂) concentrations and the temperature (T) and relative humidity (RH). Both rooms (no occupants) were monitored online (24/7) for one week in summer 2014. The room with reported occupants’ symptoms had high T, and showed pulses of TVOC, HCHO and CO₂ during night, however the measured concentrations did not explain indoor problems. Formaldehyde and TVOC pulses were linked to the T increase and lack of ventilation. The TVOC, HCHO and CO₂ values were <230 μg/m³, < 40 μg/m³ and <450 ppm, respectively. Building monitoring provides valuable data on the emission and conditions of buildings and help to detect ventilation dysfunctions.