Grantee Research Project Results
Final Report: Indoor Air Quality in Large Office Buildings in the Midwest
EPA Grant Number: R824795Title: Indoor Air Quality in Large Office Buildings in the Midwest
Investigators:
Institution: University of Iowa
EPA Project Officer: Chung, Serena
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $635,257
RFA: Indoor Air Quality in Large Office Buildings (1995) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Objective:
This study used standardized methods to characterize indoor air quality (IAQ), building design and operation, psychosocial factors, and human perceptions of IAQ and symptoms in six large office buildings located in the Midwestern U.S. The aims of this study were to: 1. Collect baseline data to characterize: the physical, mechanical, and environmental factors that influence L\Q; human exposures to carbon dioxide, carbon monoxide, temperature, relative humidity, noise, illumination, organic chemicals, respirable particulates, and microorganisms; occupant perceptions of IAQ, psychosocial attributes of the workgroup, and occupant productivity; and 2. To evaluate relationships among these parameters. Six large office buildings in metropolitan areas were selected in Iowa (#1,#2), Minnesota (#4,#5,#6), and Nebraska (#6). Sampling was conducted over a one week period in each building, in each of four seasons. The building design, air handling system, air flow patterns and velocities, and building operation were characterized. Carbon dioxide, carbon monoxide, temperature, relative humidity, light, and noise were monitored using direct reading instruments and data-loggers inside each building. Simultaneous outdoor measurements of these parameters were also made. Airborne concentrations of culturable bioaerosols, volatile organic compounds, formaldehyde, acetaldehyde, and PM10 particulates were also made. Airborne endotoxins and total microorganisms (culturable plus non-culturable bacteria and fungi) were evaluated. In addition to employee perceptions and symptoms, data on the psychological characteristics of employees and the psychosocial characteristics of the work group as a whole were collected using a questionnaire based upon the EPA BASE questionnaire with additions from other standardized questionnaires. Data was entered into the EPA data management program for inclusion in the EPA's national IAQ data base (IADCS).Summary/Accomplishments (Outputs/Outcomes):
Sampling was initiated in November 1996 and completed in October 1998. Each of the six study buildings was sampled once during each season, with the exception of building #2. Access to building #2 during the fall season was not available to a laborlmanagement dispute. Results of the study are described in detail in the publications and theses listed below. Some further analysis and preparation of additional manuscripts for publication continues. In summary:Air flow rates and percent recirculation were quite variable, with the proportion of outdoor air provided to occupants ranging from 10 to 79 CFMlperson during the first round of sampling. Carbon dioxide (C02), carbon monoxide (CO), and temperature were within ranges anticipated for non-problem buildings. Building geometric mean carbon dioxide concentrations ranged from 218 ppm to 608 ppm. No differences in C02 were found between seasons. Concentrations of carbon monoxide were consistently near 1 ppm, with one indoor exception of 6 ppm and one outdoor reading of 26 ppm. Indoor temperatures were fairly consistent between buildings over all seasons, ranging from 20 C to 25 C. Relative humidity was low during the heating season, ranging from 11.7% to 24.0%, and moderate during the more humid summer months ranging up to 63% indoors. Indoor geometric mean concentrations of total volatile organic compounds (TVOCs), ranged from 51) to 361 1lglm3. There were significant differences between buildings, but not between seasons. The most prevalent compounds included: xylene, toluene, 2-propanol, limonene, heptene, and heptane. Geometric mean formaldehyde concentrations ranged from 1.9 to 19.8 uglm3, and mean acetaldehyde levels ranged from < 3.0 to 10.2 uglm3. Airborne concentrations of culturable bacteria and fungi were low, with no samples exceeding 352 CFUlm3 in any building, during any season. Bioaerosol concentrations outdoors were usually higher than indoors, and this was especially true for fungi with outdoor levels reaching up to 4,452 CFUlm3. Concentrations of thermophilic bacteria never exceeded 66 CFUlm3 at any location, during any season. Total (direct count) bioaerosols were more variable, ranging from 509 to 10,745 orgslm3 (during the first season of sampling). Geometric mean endotoxin concentrations ranged from 0.5 to 3.0 EUlm3 (also during the first season of sampling). Respirable particulates (PM-10) were generally low (3 to 71 uglm3), with one building geomekic mean value of 164 uglm3. This one elevated indoor value coincided with an elevated outdoor measurement of 136 uglm3. Noise levels ranged from 48 to 58 dBA, with mean light values ranging from 134 to 594 lux. There was a significant difference in noise levels between buildings. In general a greater variability was seen between sampling locations within buildings for particulates, bioaerosols, and VOCs compared to comfort parameters such as C02 which had low geometric standard deviations between locations. Indoor concentrations of VOCs and particulates were generally higher than outdoor concentrations, while bioaerosols concentrations were typically highest outside. A number of correlations were found among environmental parameters. Most notably, C02 was found to correlate positively with TVOCs and aldehydes reinforcing the importance of ventilation as a control.
The most complete data on symptoms and psychosocial measures was collected during the first round of sampling in each building. Participation rates averaged around 55% for the first round, and dropped off during subsequent rounds. During the first round of data collection a total of 373 individuals completed questionnaires. 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 which used similar questionnaires. Participants reported a high latitude for making decisions, but lower perception of skill discretion, psychological job demands, or decision authority. They also reported a low perception of job security. The workforce also exhibited an elevated level of obsessive compulsive, paranoid-ideation, interpersonal sensitivity, depression, somatization, anxiety, and hostility characteristics compared to standardized populations. While participants viewed themselves as functioning well in their social work environment, they perceived their well-being to rank low. Significant relationships between exposure to environmental parameters and increased number of symptoms were most prominent for males (temperature, carbon monoxide, noise, aldehydes, particulates, and endotoxin), and less significant for females (relative humidity, and endotoxin). This is the first time that low level exposure to endotoxin has been associated with symptoms in this type of environment. Importantly, lower scores on psychosocial scales were significantly related to increased symptoms in females, but not for males. Trends in symptoms and psychosocial parameters over time in this population is currently under analysis.
Conclusions:
Although quite variable, ventilation and the rates of outdoor air delivered to occupied spaces met or exceeded ASHRAE guidelines for commercial buildings. In general, environmental parameters were within ranges recommended for non-problem buildings. Airborne concentrations of volatile organic compounds, particles, and microorganisms were low compared to problem buildings. Upper respiratory and musculoskeletal symptoms were however, elevated during the winter season in this population. Psychosocial characteristics of this population also differed from standard US populations especially in regards to obsessive-compulsive, psychotism, somatization, and anxiety scores. The differences between males and females for associations between symptoms and environmental parameters or psychosocial parameters are important for prevention and management of IEQ problems.Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 15 publications | 2 publications in selected types | All 2 journal articles |
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Reynolds SJ, Black DW, Borin SS, Breuer G, Burmeister LF, Fuortes LJ, Smith TF, Stein MA, Subramanian P, Thorne PS, Whitten P. Indoor environmental quality in six commercial office buildings in the midwest United States. Applied Occupational and Environmental Hygiene 2001;16(11):1065-1077. |
R824795 (Final) |
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Subramanian P, Breuer GM, Reynolds SJ. Low molecular weight carbonyls in large midwestern office buildings. International Journal of Environmental Analytical Chemistry 2000, Volume: 76, Number: 3, Page: 215-239. |
R824795 (Final) |
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Supplemental Keywords:
RFA, Scientific Discipline, Health, Air, Toxics, Geographic Area, Midwest, particulate matter, Health Risk Assessment, VOCs, Risk Assessments, Biochemistry, indoor air, Atmospheric Sciences, Biology, EPA Region, building related illness, monitoring, fungi, Iowa, particulates, PM10, buildings, ambient air, workplace, microorganisms, human exposure, carbon monoxide, inhalation, office, sick building syndrome, Region 7, carbon dioxide, IARelevant Websites:
http://www.public-health.uiowa.eduProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.