Indoor air quality analysis of residential buildings in northeast China based on field measurements and longtime monitoring

Abstract

Outdoor air contamination was frequently observed and focused in northeast China in winter when severe cold days are common and understanding dynamic characteristics of indoor air quality in this area is essential for occupants' ventilation strategies. Herein, using spectrophotometric method, GC-MS (Gas Chromatography-Mass Spectrometer) method, TSI DustTrak particle tester and Telaire 7001 CO2 tester, we investigated the concentration change of formaldehyde (HCHO), volatile organic compounds (VOCs), PM2.5 and CO2 of 21 houses for 4 seasons under 2 conditions (airtight and natural ventilation). Moreover, 6 houses were selected to install convenient sensors for longtime monitoring. Outdoor temperature, concentration of PM2.5, residents' opening window behavior, indoor infiltration rate, temperature, relative humidity and the furniture surface area were also recorded for comparison and correlation analysis. According to the detected results, worst indoor conditions were revealed that average concentrations of HCHO (autumn), TVOC (summer), PM2.5 (winter) and CO2 (winter) were 0.094 mg/m3, 0.924 mg/m3, 0.073 mg/m3, and 883 ppm, respectively. Indoor concentration of PM2.5, TVOC and CO2 exceeded the standard limit and they changed with seasonal characteristics. The observed 4 factors have different effects on indoor air quality. Based on this research, it is recommended that outdoor condition be considered while opening and closing window in winter and ventilation be strengthened in summer.