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Building Assessment Survey and Evaluation (BASE) Study

Study Overview

Contents

What is the BASE Study?

The Building Assessment Survey and Evaluation (BASE) study was conducted over a five-year period from 1994-1998, to characterize determinants of indoor air quality (IAQ) and occupant perceptions in representative public and commercial office buildings across the U.S. This study provides normative IAQ data and baseline symptom rates in typical office buildings and establishes standardized testing protocols.  The data collected as part of this study allow examination of relationships of symptoms and building characteristics; allow for the development of hypotheses to investigate sick building syndrome; and provide a stronger scientific basis for policy makers to develop guidance on building design, construction, operation and maintenance.

The BASE study used a standardized protocol to collect extensive indoor air quality data from 100 randomly selected public and commercial office buildings in 37 cities in 25 States.  The data collected provide normative IAQ data and baseline symptom rates in typical office buildings and includes general information regarding the building itself, indoor pollutant concentrations, basic occupant statistics, occupant health symptoms and perceptions of indoor air quality, and the design, maintenance and operation of building heating, ventilating, and air conditioning (HVAC) systems. 

Buildings included in the sample were randomly selected from cities with populations greater than 100,000 within 10 climatic regions in either winter or summer. Buildings with highly publicized indoor environmental quality problems were excluded.

Information from the 100 buildings studied as part of BASE including several publications describing the study and summarizing preliminary results are available on this website. In addition, the raw data from this study are now available to researchers and others interested in IAQ and office buildings.

This study was conducted by the BASE Workgroup of EPA's Office of Radiation and Indoor Air.

What Were the Goals and Objectives of the Study?

The primary goal of the study was to address a significant data gap that existed regarding baseline indoor air quality (IAQ) and occupant perceptions in large public and commercial office buildings. One of the major objectives of the BASE program included providing a database and summary information of IAQ-related parameters in office spaces for the research, building professional and policy-making communities to help further the understanding of indoor air quality (IAQ) and the role of environmental factors in occupant perceptions of IAQ and health symptoms.

Why Did EPA Conduct This Study?

Early IAQ research in office buildings in the United States focused on evaluating buildings whose occupants had significant complaints about IAQ.  Since IAQ baseline information from typical buildings was sparse, no reference existed with which to compare the “problem” buildings. Therefore, the EPA designed the BASE study as a cross-sectional study of office buildings without regard to IAQ complaints. The study encompasses three major areas of investigation: comfort and environmental measurements; building and heating, ventilation, and air conditioning (HVAC) characterization; and an occupant questionnaire.

What Type of Data Were Collected?

A representative listing of core parameters (for definitions, see the glossary of terms) collected are listed below:

Environmental Monitoring Building and HVAC Characteristics Occupant Survey
Building Checklist HVAC Checklist
  • Particles (PM10,  PM2.5)
  • VOCs
  • Formaldehyde
  • Bioaerosols (air, visible growth)
  • Radon
  • Temperature
  • Relative Humidity
  • Carbon Dioxide
  • Sound
  • Light
  • Carbon Monoxide
  • Use
  • Occupancy
  • Geographical Location
  • Ventilation (equipment, operation schedule)
  • Construction
  • Outdoor Sources
  • Smoking Policy
  • Water Damage
  • Fire Damage
  • Renovation
  • Pest Control
  • Cleaning Practices
  • Type Specifications (air handler, exhaust fans)
  • Filtration
  • Air Cleaning Systems
  • Air Washers
  • Humidification Systems
  • Maintenance Schedule
  • Inspection Schedule
  • Supply Air Flow Rate
  • Percent Outdoor Air
  • Outdoor Air Intake Rate
  • Supply Air (temperature, relative humidity)
  • Exhaust Fan Rates
  • Local Ventilation Performance
  • Natural Ventilation
  • Measurements (if needed)
  • Workplace Physical Information
  • Health and Well-being
  • Workplace Environmental Conditions
  • Job Characteristics
  • Occupant Demographics

How Can I Obtain the BASE Raw Dataset?

To obtain the BASE data on CD-ROM, please read and sign the Notification Prior to Use Data Form (PDF, 2 pp, 19KB About PDF).  You can fax or mail the completed form to:

US EPA
Indoor Environments Division
BASE Workgroup
1200 Pennsylvania Avenue, NW MC (MC 6609J)
Washington, DC 20460
Phone:  (202) 343-9370
FAX: (202) 343-2393

Please review your form before you submit it as incomplete forms will delay processing.  Please forward all comments and questions concerning the BASE study to the BASE Workgroup BASEworkgroup@epa.gov

The data have undergone documented quality assurance procedures and all reasonable efforts have been made to ensure the validity of the data.  However, it is expected that anomalies may be discovered as further analysis is made.   Therefore, EPA plans to maintain a list of all requesters of these data in order to track how data are being used and to be able to provide updates and information on any major anomalies identified.

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