Causes of Indoor Air Quality Problems in Schools

ORNL/M-6633/R1

Causes of Indoor Air Quality Problems in Schools

Summary of Scientific Research Revised Edition

Charlene W. Bayer, Ph.D., Principal Research Scientist and Branch Head Georgia Tech Research Institute Atlanta, Ga.

Prepared by SEMCO, Inc., Columbia, Mo. under Subcontract Number 86X-SV044V

Prepared for the Energy Division Oak Ridge National Laboratory Oak Ridge, Tennessee 37831-6285 managed by UT-Battelle LLC for the U.S. Department of Energy under contract DE-AC05-00OR22725

Sidney A. Crow, Ph.D., Associate Vice President for Research and Sponsored Programs Georgia State University Atlanta, Ga. John Fischer, Technology Consultant SEMCO, Inc. Columbia, Mo.

May 2000

{ CONTENTS List of Illustrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Preface to Revised Edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Acronyms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix 1

School Facilities and Indoor Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3

IAQ Investigations Conducted in School Facilities . . . . . . . . . . . . . . . . . . . . . . . 5

4

Factors Determining Growth of Microorganisms . . . . . . . . . . . . . . . . . . . . . . . Growth of Fungi in HVAC Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Toxin Production by Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Production of Volatile Emissions by Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

Humidity Control and the Impact on IAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Impact of High Space Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Impact of Low Space Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6

VOCs and Other Chemical Compounds That Affect IAQ . . . . . . . . . . . . . . . . . . 31

7

Control of Indoor Environments with HVAC Systems . . . . . . . . . . . . . . . . . . . 37

8

Impact of IAQ on Productivity and Satisfaction in the Learning Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

9

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

19 20 21 22

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

iii

{ LIST OF ILLUSTRATIONS Figure 1

Space humidity measured by Downing at three operating modes with and without the dual-wheel total energy recovery systems . . . . . . . . . . . . . . . . . . . 9

Tables 1 2 3 4 5 6

Impacts of ASHRAE Standard 62-1989 on classroom humidity levels in three Florida cities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alternative technologies to meet ASHAE Standard 62-1989 in Florida schools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ontario Ministry of Labor findings on relationships between extent of complaints regarding IAQ and CO2 levels and ventilation rates . . . . . . . . . . Maryland’s requirements for outdoor air ventilation rates in schools . . . . . . Particulate matter levels in schools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cost vs benefit comparison for providing desirable IAQ in schools . . . . . . . .

v

27 28 33 34 36 46

{ PREFACE TO REVISED EDITION Since this report was first published, a number of new articles reporting the results of research on IAQ in schools have appeared in journals and conference proceedings. Several of these articles deal with the impact of indoor airborne contaminants on students’ health. As a result of this additional research, particularly the healthrelated papers, we decided to update and revise this literature review summary report. The text of this revised report contains summaries of these recent IAQ articles, with 50 new items added to the References. In addition, we have expanded the discussion of carbon dioxide in response to concerns about this section in the first version of the report.

vii

{ ABBREVIATIONS AND ACRONYMS ASHRAE cfm cfu CO CO2 DWERS ERV HVAC IAQ MVOC NO2 NOx PM10 PM2.5 ppm RH SBS TERS VAV VOC

American Society of Heating, Refrigerating and Air-Conditioning Engineers cubic feet per minute colony-forming unit carbon monoxide carbon dioxide dual-wheel total energy recovery system energy recovery ventilator heating, ventilation, and air-conditioning indoor air quality microbial volatile organic compound nitrogen dioxide oxides of nitrogen particulate matter of