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Biologically Derived Airborne Contaminants: Bioaerosols and TLVs ®

Biologically Derived Airborne Contaminants: Bioaerosols and TLVs ®. Kenneth F. Martinez, MSEE, CIH Chair, ACGIH ® Bioaerosols Committee NIOSH. Where ?. Microorganisms. Obligate parasites (must have a living host) viruses bacteria rickettsia

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Biologically Derived Airborne Contaminants: Bioaerosols and TLVs ®

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  1. Biologically Derived Airborne Contaminants: Bioaerosols and TLVs® Kenneth F. Martinez, MSEE, CIH Chair, ACGIH® Bioaerosols Committee NIOSH

  2. Where ?

  3. Microorganisms • Obligate parasites (must have a living host) • viruses • bacteria • rickettsia • Facultative saprophytes (will utilize dead organic material) • fungi • bacteria

  4. Size Ranges of Microorganisms

  5. Mechanisms for Microbial DispersalLinear Distances

  6. Microbiological Concerns • Infections • Immunologic Reactions • Toxic Effects

  7. Infectious Disease • Pathogenicity • Virulence • Relationship between virulence (V), numbers of pathogens or dosage (D), and resistant state of the host (RS) • Colonization • Invasiveness V * D Infectious Disease = RS

  8. Infectious DiseaseTerminology • Portal of entry • Exposure vs. infection • Clinical vs. subclinical or asymptomatic infection • Carrier state • Opportunistic infection • Human pathogen vs. virulence • Immunosuppression

  9. Infectious DiseasePathways • Respiratory • Oral (via ingestion) • Contact • Penetration • Vectors (via insect bite)

  10. Allergic Disease • Allergic rhinitis • Allergic asthma • Allergic bronchopulmonary aspergillosis • Extrinsic allergic alveolitis (hypersensitivity pneumonitis)

  11. U.S. Disease Prevalence • 1 of 5 Americans suffer from allergic disease • Indoor allergens responsible for significant share • Environmental control reduces disease severity Source: NHLBI, 1991

  12. Allergen Exposure Dust Mites Molds Animal Dander Pollen Allergenic Chemicals Genetic Predisposition or Susceptibility Allergic Disease Immunologic Sensitization Mild Moderate Severe (Death) Other Exposures Viruses Air Pollution Tobacco Smoke Source: Pope AM, et al., eds., 1993

  13. Important Mycotoxins

  14. Where Are We?

  15. Classification of Occupant Complaints • Sick Building Syndrome • Building-Related Disease • Occupant Discomfort

  16. Sick Building SyndromeNon-specific Symptoms • Headache • Eye, nose, throat irritation • Sneezing • Fatigue and lethargy • Skin irritation • Dizziness and nausea • Cough • Chest tightness

  17. Legionnaires Disease Pontiac Fever Humidifier Fever Hypersensitivity Pneumonitis Anthrax Building-Related Disease • Known etiologies • Related to identifiable exposure

  18. No numeric criteria for interpreting environmental measurements!

  19. Why Not Scientifically Supportable? TotalCulturable or Countable Bioaerosols • Not a single entity • Human responses cover wide range • No single sampling method exists • No exposure/response relationships exist

  20. Why Not Scientifically Supportable? Specific Culturable or Countable Bioaerosols - other than infectious • Data are derived from indicators rather than actual effector agents • Concentrations vary widely • Low statistical power in cause-effect relationship studies

  21. Why Not Scientifically Supportable? Infectious Culturable or Countable Bioaerosols • Dose-response data limited to a few agents • Air sampling limited to research • Administrative and engineering controls remain the primary defenses

  22. Why Not Scientifically Supportable? Assayable biological contaminants • Some dose-response relationship data available • Experimental studies • Epidemiologic surveys • Assay methods improving • May be appropriate in the future

  23. Questions? • Pat Breysse • Lisa Brosseau • Larry Lowry • Tom Bernard • Ken Martinez

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