Biologically Derived Airborne Contaminants: Bioaerosols and TLVs ® Kenneth F. Martinez, MSEE, CIH...
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Transcript of Biologically Derived Airborne Contaminants: Bioaerosols and TLVs ® Kenneth F. Martinez, MSEE, CIH...
Biologically Derived Airborne Biologically Derived Airborne Contaminants:Contaminants:
Bioaerosols and TLVs Bioaerosols and TLVs®®
Kenneth F. Martinez, MSEE, CIHChair, ACGIH® Bioaerosols Committee
NIOSH
AgricultureIndoor Environments
Biotechnology Health Care
Where ?Where ?
MicroorganismsMicroorganisms
• Obligate parasites (must have a living host)– viruses– bacteria– rickettsia
• Facultative saprophytes (will utilize dead organic material)– fungi– bacteria
Size Ranges of Size Ranges of MicroorganismsMicroorganisms
FungalSpore
Escherichia coli
PolioVirus
RabiesVirus
1 µm
Mechanisms for Mechanisms for Microbial DispersalMicrobial Dispersal
Linear DistancesLinear DistancesVery Short Medium Long
Motility Sewage Wind
Gliding Motion Ground Water Animal Vectors
Eroding Soil Water Currents
Inanimate Objects
Microbiological Microbiological ConcernsConcerns
• Infections
• Immunologic Reactions
• Toxic Effects
Infectious DiseaseInfectious 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 DiseaseInfectious DiseaseTerminologyTerminology
• Portal of entry• Exposure vs. infection• Clinical vs. subclinical or asymptomatic
infection• Carrier state• Opportunistic infection• Human pathogen vs. virulence• Immunosuppression
Infectious DiseaseInfectious DiseasePathwaysPathways
• Respiratory
• Oral (via ingestion)
• Contact
• Penetration
• Vectors (via insect bite)
Allergic DiseaseAllergic Disease
• Allergic rhinitis
• Allergic asthma
• Allergic bronchopulmonary aspergillosis
• Extrinsic allergic alveolitis (hypersensitivity pneumonitis)
U.S. Disease U.S. Disease PrevalencePrevalence
• 1 of 5 Americans suffer from allergic disease
• Indoor allergens responsible for significant share
• Environmental control reduces disease severity0% 10% 20% 30%
HP
ABPA
AllergicDermititis
Asthma
Sinistitis
AllergicRhinitis
Prevalence
Source: NHLBI, 1991
Allergen Exposure
Dust MitesMolds
Animal DanderPollen
Allergenic Chemicals
Other Exposures
Viruses
Air Pollution
Tobacco Smoke
Genetic
Predisposition
or Susceptibility
Immunologic
Sensitization
Allergic Disease
Mild Moderate Severe
(Death)
Source: Pope AM, et al., eds., 1993
Important MycotoxinsImportant MycotoxinsFungal Species Toxin
Aspergillus
Aspergillus parasiticus Aflatoxin
Aspergillus flavus
Aspergillus versicolor Sterigmatocystin
Aspergillus terreus Patulin
Citrinin
Fusarium
Fusarium moniliforme Zearalenone
Fusarium spp. Tricothecenes
Penicillium
Penicillium viridicatum Ochratoxin
Penicillium spp. Citrinin
Patulin
Stachybotrys
Stachybotrys chartarum (atra) Tricothecenes
Where Are We?Where Are We?
Outdoors2%
In Transit5%
Indoors93%
Classification of Classification of Occupant ComplaintsOccupant Complaints
• Sick Building Syndrome
• Building-Related Disease
• Occupant Discomfort
Sick Building SyndromeSick Building SyndromeNon-specific SymptomsNon-specific Symptoms
• Headache• Eye, nose, throat irritation• Sneezing• Fatigue and lethargy• Skin irritation• Dizziness and nausea• Cough• Chest tightness
Building-Related Building-Related DiseaseDisease
• Known etiologies
• Related to identifiable exposure
Legionnaires DiseasePontiac FeverHumidifier Fever
Hypersensitivity PneumonitisAnthrax
Why Not Scientifically Why Not Scientifically Supportable?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 Why Not Scientifically Supportable?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 Why Not Scientifically Supportable?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 Why Not Scientifically Supportable?Supportable?
• Some dose-response relationship data available– Experimental studies– Epidemiologic surveys
• Assay methods improving
• May be appropriate in the future
Assayable biological contaminants
Questions?Questions?
• Pat Breysse
• Lisa Brosseau
• Larry Lowry
• Tom Bernard
• Ken Martinez