Indoor Environmental Quality in Six Commercial Office Buildings in the Midwest United States

Abstract

The aims of this study were to characterize physical, mechanical, and environmental factors influencing indoor environmental quality (IEQ) in commercial office buildings; document occupant perceptions and psychosocial attributes; and evaluate relationships among these parameters. Six large office buildings in metropolitan areas were selected in Iowa, Minnesota, and Nebraska. Comprehensive sampling was conducted over one week in each building, during all four seasons. This paper presents the study methods and selected results from the first round of sampling (November 1996 to April 1997). Air flow and recirculation rates were quite variable, with the proportion of outdoor air provided to occupants ranging from 10 to 79 CFM/person. Carbon dioxide, carbon monoxide, and temperature were within ranges anticipated for nonproblem buildings. Relative humidity was low, ranging from 11.7 to 24.0 percent. Indoor geometric mean concentrations of total volatile organic compounds (TVOCs) ranged from 73 to 235 microg/m3. The most prevalent compounds included xylene, toluene, 2-propanol, limonene, and heptane. Geometric mean formaldehyde concentrations ranged from 1.7 to 13.3 microg/m3, and mean acetaldehyde levels ranged from <3.0 to 7.5 microg/m3. Airborne concentrations of culturable bacteria and fungi were low, with no samples exceeding 150 CFU/m3. Total (direct count) bioaerosols were more variable, ranging from 5010 to 10,700 organisms/m3. Geometric mean endotoxin concentrations ranged from 0.5 to 3.0 EU/m3. Respirable particulates (PM10) were low (14 to 36 microg/m3). Noise levels ranged from 48 to 56 dBA, with mean light values ranging from 200 to 420 lux. Environmental parameters were significantly correlated with each other. The prevalence of upper respiratory symptoms (dry eyes, runny nose), central nervous system symptoms (headache, irritability), and musculoskeletal symptoms (pain/stiffness in shoulders/neck) were elevated compared to other studies using similar questionnaires. Importantly, psychosocial factors were significantly related to increased symptoms in females, while environmental factors were more closely correlated with symptoms in males. Endotoxin concentrations were associated with symptoms in both males and females. These data will help to identify and quantify the relative role of factors that contribute to sick building syndrome. The data collected in this study may also be used to evaluate the effectiveness of current building operation practices, and can be used to prioritize allocations of resources for reduction of risk associated with IEQ complaints.

Gender differences in office occupant perception of indoor environmental quality (IEQ)

“…However, before generalising it is prudent to examine potentially confounding factors. Many contributors to the SBS research literature have emphasised the inclusion of psycho-social or work-related factors when investigating sex differences [30,37,46,61]. That is, the frequently reported female occupants' health symptoms or complaints could be influenced by personal or occupational characteristics unrelated to indoor environment such as job-related stress, lack of control of work, low job pride resulting from low position within the organisational hierarchy.…”

Efficacy of a Detector Tube Method in Formaldehyde Measurement

“…Reynolds et al 13) reported that geometric mean concentrations of HCHO and CH 3 CHO in six commercial office buildings ranged from 5.0-13.3 µg/m 3 and 3.0-7.5 µg/m 3 , respectively. Also, Ikeda et al 4) reported that the mean concentrations of HCHO and CH 3 CHO in 53 rooms in a newly built condominium were 83.4 ± 5.6 µg/m 3 and 46.6 ± 3.2 µg/m 3 , respectively.…”

Evaluation of indoor air quality concerns at an outpatient medical clinic in a shared-use building - West Virginia.

“…Typical levels of CO in offices are between 0-5 ppm [Illinois Department of Public Health 2011]. Average CO levels found in a study of six office buildings located in the United States ranged from 1-1.5 ppm [Reynolds et al 2001]. Another study of 56 European office buildings reported average CO levels that ranged from 0.5-1.9 ppm [Bluyssen et al 1996].…”