Since about 1980, asthma prevalence and asthma-related hospitalizations and deaths have increased substantially, especially among children. Of particular concern is the high mortality rate among African Americans with asthma.

Recent studies have suggested that indoor exposures--to dust mites, cockroaches, mold, pet dander, tobacco smoke, and other biological and chemical pollutants--may influence the disease course of asthma. To ensure an appropriate response, public health and education officials have sought a science-based assessment of asthma and its relationship to indoor air exposures.

Clearing the Air meets this need. This book examines how indoor pollutants contribute to asthma-- its causation, prevalence, triggering, and severity. The committee discusses asthma among the general population and in sensitive subpopulations including children, low-income individuals, and urban residents. Based on the most current findings, the book also evaluates the scientific basis for mitigating the effects of indoor air pollutants implicated in asthma. The committee identifies priorities for public health policy, public education outreach, preventive intervention, and further research.

Contents

• THE NATIONAL ACADEMIES
• COMMITTEE ON THE ASSESSMENT OF ASTHMA AND INDOOR AIR
• PREFACE
• ACKNOWLEDGMENTS
• EXECUTIVE SUMMARY
• 1. MAJOR ISSUES IN UNDERSTANDING ASTHMA
  • ORIGIN OF THE STUDY
  • SUMMARY OF THE INDOOR ALLERGENS REPORT
  • DEFINITIONS OF ASTHMA
  • CLINICAL PRESENTATION OF ASTHMA
  • RISK FACTORS FOR ASTHMA
  • TRENDS IN THE PREVALENCE OF ASTHMA
  • MECHANISMS OF ASTHMA
  • EVALUATING THE EFFECTIVENESS OF INTERVENTIONS TO REDUCE ASTHMA
  • REFERENCES
• 2. METHODOLOGICAL CONSIDERATIONS IN EVALUATING THE EVIDENCE
  • EVALUATING THE EVIDENCE
  • SUMMARIZING CONCLUSIONS REGARDING THE EVIDENCE
  • ASSESSING EXPOSURES TO AGENTS IN INDOOR AIR
  • OTHER CONSIDERATIONS
  • REFERENCES
• 3. PATTERNS OF ASTHMA MORBIDITY AND MORTALITY
  • THE BURDEN OF ASTHMA
  • MORTALITY
  • UTILIZATION OF HEALTH CARE SERVICES
  • PREVALENCE
  • SEVERITY
  • TRENDS IN RISK FACTORS
  • TWIN, ADOPTION, AND MIGRANT STUDIES
  • SOCIOECONOMIC STATUS VERSUS RACE OR ETHNICITY
  • ASTHMA RATES IN GERMANY—A NATURAL EXPERIMENT
  • REFLECTIONS ON THE TRENDS
  • REFERENCES
• 4. PATHOPHYSIOLOGICAL BASIS OF ASTHMA
  • AIRWAY INFLAMMATION IN ASTHMA
  • THE AIRWAY SMOOTH MUSCLE IN ASTHMA
  • THE GENETICS OF ASTHMA
  • CONCLUSION
  • REFERENCES
• 5. INDOOR BIOLOGIC EXPOSURES
  • ANIMALS
  • COCKROACH
  • HOUSE DUST MITES
  • ENDOTOXINS
  • FUNGI
  • INFECTIOUS AGENTS
  • HOUSEPLANTS
  • POLLEN
  • REFERENCES
• 6. INDOOR CHEMICAL EXPOSURES
  • NITROGEN DIOXIDE
  • PESTICIDES
  • VOLATILE ORGANIC COMPOUNDS
  • FORMALDEHYDE
  • FRAGRANCES
  • PLASTICIZERS
  • OTHER CHEMICAL EXPOSURES IN THE INDOOR ENVIRONMENT
  • REFERENCES
• 7. EXPOSURE TO ENVIRONMENTAL TOBACCO SMOKE
  • DEFINITION OF ENVIRONMENTAL TOBACCO SMOKE (ETS)
  • FACTORS CONTROLLING EXPOSURE TO ETS
  • EVIDENCE OF A RELATIONSHIP BETWEEN ETS AND ASTHMA
  • CONCLUSIONS REGARDING THE HEALTH IMPACTS OF ETS WITH RESPECT TO ASTHMA
  • EVIDENCE REGARDING MEANS OF SOURCE MITIGATION OR PREVENTION
  • CONCLUSIONS REGARDING ETS SOURCE CONTROL OR MITIGATION: FEASIBILITY AND BENEFITS
  • RESEARCH NEEDS
  • REFERENCES
• 8. INDOOR DAMPNESS AND ASTHMA
  • INDOOR WATER SOURCES AND REMOVAL PROCESSES
  • INDOOR DAMPNESS AND RESPIRATORY DISEASE
  • DAMPNESS CONTROL
  • RESEARCH NEEDS
  • REFERENCES
• 9. ASTHMA AND NONRESIDENTIAL INDOOR ENVIRONMENTS
  • BUILDING-RELATED ASTHMA
  • STUDIES OF SCHOOLS
  • CONCLUSION
  • RESEARCH NEEDS
  • REFERENCES
• 10. IMPACT OF VENTILATION AND AIR CLEANING ON ASTHMA
  • THEORETICAL BACKGROUND
  • BUILDING VENTILATION
  • PARTICLE AIR CLEANING: INTRODUCTION AND REVIEW OF CONVENTIONAL PRACTICE
  • REFERENCES
• 11. SUMMARY OF RESEARCH RECOMMENDATIONS AND OVERALL CONCLUSIONS
  • PATHOPHYSIOLOGIC BASIS OF ASTHMA
  • ANIMAL ALLERGENS
  • COCKROACH
  • HOUSE DUST MITES
  • ENDOTOXIN
  • FUNGI
  • INFECTIOUS AGENTS
  • PLANTS
  • NITROGEN DIOXIDE (NO2)
  • PESTICIDES
  • PLASTICIZERS
  • VOLATILE ORGANIC COMPOUNDS
  • FRAGRANCES
  • ENVIRONMENTAL TOBACCO SMOKE (ETS)
  • INDOOR DAMPNESS, MOISTURE PROBLEMS, AND MOISTURE CONTROL
  • NONRESIDENTIAL INDOOR ENVIRONMENTS
  • VENTILATION
  • AIR CLEANING
  • OVERALL CONCLUSIONS
• APPENDIX A THEORETICAL CONSIDERATIONS RELEVANT TO THE INFLUENCE OF VENTILATION AND AIR CLEANING ON EXPOSURES TO INDOOR-GENERATED POLLUTANTS
• APPENDIX B WORKSHOP SUMMARIES
• APPENDIX C COMMITTEE AND STAFF BIOGRAPHIES

Support for this study was provided by the U.S. Environmental Protection Agency (contract no. X825863-01-3). The views presented in the book are those of the Institute of Medicine Committee on the Assessment of Asthma and Indoor Air and are not necessarily those of the funding organization.

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.