Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments

http://dx.doi.org/10.1289/ehp.1510037



Table 2. Average indoor environmental conditions simulated in each room of the TIEQ lab.
Variable Day 1
Green+
Day 2
Moderate CO2
Day 3
High CO2
Day 4
Green
Day 5
Conventional
Day 6
Green+
Date 4 November 5 November 6 November 11 November 12 November 13 November
Day of the week Tuesday Wednesday Thursday Tuesday Wednesday Thursday
Room 502 503 502 503 502 503 502 503 502 503 502 503
Abbreviations: TIEQ, Total Indoor Environmental Quality; TVOCs, total volatile organic compounds.
aA constant air flow rate of 40 cfm/person was maintained on all study days, with 100% outdoor air used on days 1, 2, 3, and 6 and 50% outdoor air and 50% recirculated air used to achieve an outdoor air ventilation rate of 20 cfm/person on days 4 and 5. bAverage concentration from 1400 to 1700 hours was 926 ppm, but lower CO2 concentrations in the morning hours during the approach to steady state led to a lower average CO2 concentration.
Experimental parameters
CO2 (ppm) 563 609 906 962 1,400 1,420 761b 726b 969 921 486 488
Outdoor air ventilation (cfm/person)a 40 40 40 40 40 40 20 20 20 20 40 40
TVOCs (μg/m3) 43.4 38.5 38.2 28.6 32.2 29.8 48.5 43.5 506 666 55.8 14.9
Other environmental parameters
Temperature (°C) 23.9 24.5 22.4 23.9 21.3 22.0 22.9 23.7 21.8 22.5 20.7 21.3
Relative humidity (%) 31.0 30.4 34.2 31.6 38.7 38.3 34.3 33.3 39.6 38.3 27.8 26.8
NO2 (μg/m3) 57.9 58.9 53.2 54.1 60.8 58.4 51.3 45.6 54.6 50.8 56.5 55.5
O3 (μg/m3) 3.42 21.2 14.4 13.0 1.37 0.00 6.85 238 1.71 1.37 4.11 6.85
PM2.5 (μg/m3) 2.38 3.49 3.35 2.58 2.97 2.42 1.26 1.83 1.68 1.34 1.26 1.38
Noise (dB) 51.3 49.9 49.7 48.8 52.5 48.8 49.6 48.7 51.1 48.8 50.5 49.2
Illuminance (mV) 2.95 2.70 2.89 2.83 2.31 2.04 3.11 2.93 2.74 2.51 2.39 2.28
Irradiance (mV) 9.07 8.76 9.45 9.37 6.00 6.05 9.90 9.60 8.30 8.14 6.70 6.82