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 Facultative saprophytes (will utilize dead organic material) –fungi –bacteria

Size Ranges of Microorganisms

Mechanisms for Microbial Dispersal Linear Distances

Microbiological Concerns Infections Immunologic Reactions Toxic Effects

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

Infectious Disease Terminology Portal of entry Exposure vs. infection Clinical vs. subclinical or asymptomatic infection Carrier state Opportunistic infection Human pathogen vs. virulence Immunosuppression

Infectious Disease Pathways Respiratory Oral (via ingestion) Contact Penetration Vectors (via insect bite)

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

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

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

Important Mycotoxins

Where Are We?

Classification of Occupant Complaints Sick Building Syndrome Building-Related Disease Occupant Discomfort

Sick Building Syndrome Non-specific Symptoms Headache Eye, nose, throat irritation Sneezing Fatigue and lethargy Skin irritation Dizziness and nausea Cough Chest tightness

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

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

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

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

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

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