Airborne Concentrations of Volatile Organic Compounds, Formaldehyde and Ammonia in Finnish Office Buildings with Suspected Indoor Air Problems

Abstract

A database of indoor air concentrations of volatile organic compounds (VOCs) (n = 528), formaldehyde (n = 76), and ammonia (n = 47) in office environments was analyzed to suggest interpretation guidelines for chemical measurements in office buildings with suspected indoor air problems. Indoor air samples were collected for VOCs from 176 office buildings, 23 offices for formaldehyde, and 14 office buildings for ammonia in 2001–2006. Although the buildings had reported indoor air complaints, a walk-through inspection by indoor air specialists showed no exceptional sources of indoor air pollutants. The measurements of chemical pollutants did not indicate any clear reason for the complaints. The geometric mean concentration of total volatile organic compounds (TVOC) was 88 μg m−³ in office rooms and 75 μg m−³ in the open plan offices. The mechanical supply and exhaust ventilation significantly (p < 0.004) decreased the indoor air concentration of TVOC. The highest mean concentration and frequency distributions were determined for the individual VOCs. The most common VOCs found in ⩾ 84% of the indoor samples include toluene, xylene (p,m), 1-butanol, nonanal, and benzene. According to concentrations, the most abundant VOCs were 2-(2-ethoxyethoxy)ethanol, acetic acid, 1,2-propanediol, and toluene. The geometric mean concentration of formaldehyde and ammonia in the office buildings was 11 μg m−³ (3–44 μg m−³ and 14 μg m−³ (1–49 μg m−³, respectively. On the basis of statistical analyses, the guideline value indicating a usual concentration of the pollutant in office buildings is 70 μg m−³ for TVOC, 7 μg m−³ for most individual VOCs, 10 μg m−³ for formaldehyde, and 12 μg m−³ for ammonia… The guidance value suggested for TVOC is 250 μg m⁻³, for formaldehyde 15 μg m−³, and for ammonia 25 μg m−³. If the guidance value is exceeded, this may indicate the existence of an exceptional source and the need for additional environmental investigations. The levels should not be used for the evaluation of health risks. The guideline values are applicable in a subarctic climate for modern, urban office buildings.

Keywords:

• guidance value
• guideline value
• indoor environment
• VOC

ACKNOWLEDGMENTS

The authors warmly thank the indoor air researchers of FIOH Uusimaa for their excellent field investigations and laboratory work. We especially wish to thank Juha Svinhufvud and Mari Rothberg for their valuable comments and advice concerning the chemical analysis.