Slide1 l.jpg
This presentation is the property of its rightful owner.
Sponsored Links
1 / 130

TLV ® and BEI ® Committees: The Decision Making Process Presented at AIHce May 13, 2003, Dallas, TX Bill Wells PhD, CIH, CSP, Moderator PowerPoint PPT Presentation


  • 252 Views
  • Uploaded on
  • Presentation posted in: General

TLV ® and BEI ® Committees: The Decision Making Process Presented at AIHce May 13, 2003, Dallas, TX Bill Wells PhD, CIH, CSP, Moderator Dennis Casserly, PhD, CIH & Marilyn Hallock, CIH Monitors. Forum Overview. Pat Breysse: Introduction Lisa Brosseau: TLV ® -CS Committee

Download Presentation

TLV ® and BEI ® Committees: The Decision Making Process Presented at AIHce May 13, 2003, Dallas, TX Bill Wells PhD, CIH, CSP, Moderator

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


TLV® and BEI® Committees:

The Decision Making Process

Presented at AIHce

May 13, 2003, Dallas, TX

Bill Wells PhD, CIH, CSP, Moderator

Dennis Casserly, PhD, CIH & Marilyn Hallock, CIH Monitors


Forum Overview

  • Pat Breysse: Introduction

  • Lisa Brosseau: TLV®-CS Committee

  • Larry Lowry: BEI® Committee

  • Tom Bernard: TLV®-PA Committee

  • Ken Martinez: Bioaerosols Committee


ACGIH,® the TLVs® and BEIs®

Patrick N. Breysse, PhD, CIH

Johns Hopkins University

Bloomberg School of Public Health

Chair, ACGIH®


What Is ACGIH®?

  • Membership Society(founded in 1938)

  • Not-for-profit, Non-governmental Association(501(c)(6) organization)

  • Multi-Disciplinary Membership

  • Traditionally Neutral on Public Positions


MembershipApril 2003

Government

& Academia

Private Industry

& Others


Membership by Profession, 2003


Technical Committees

Committees provide the creativity, initiative, and technical expertise that has made ACGIH® what it is today and what it will be tomorrow.

.


Core Mission


ACGIH® Statement of Position

ACGIH® is not a standards setting body.

TLVs® and BEIs®–

  • Are an expression of scientific opinion.

  • Are not consensus standards.

  • Are based solely on health factors; it may not be economically or technically feasible to meet established TLVs® or BEIs®.


ACGIH®Statement of Position

TLVs® and BEIs®–

  • Should NOT be adopted as standards without an analysis of other factors necessary to make appropriate risk management decisions.

  • Can provide valuable input into the risk characterization process. The full written Documentation for the numerical TLV® or BEI® should be reviewed.


Conflict of Interest

  • Basis for Conflicts of Interest:

    • Employment

    • Financial benefit

    • Personal

    • Professional

  • Avoid perceived as well as real conflict of interest


Conflict of Interest

  • Committee members serve as individuals

    • they do not represent organizations and/or interest groups

  • Members are selected based on expertise, soundness of judgement, and ability to contribute


COI Process at ACGIH®


Today’s Roundtable

  • Chemical Substances - TLV

  • Biological Exposure Indices (BEI)

  • Physical Agents – TLV

  • Bioaerosols Committee


ACGIH® TLVs® for Chemical Substances Committee Update

Chair: Lisa M. Brosseau, ScD, CIH

Associate Professor

University of Minnesota

School of Public Health


Overview

  • TLV®-CS Committee has 20 members and 3 member-candidates, who volunteer time towards developing scientific guidelines and publications

    • Primary goal is to serve the scientific needs of industrial hygienists

    • Committee expenses (travel) are supported by ACGIH®

    • Time is donated by the members


Committee Structure

  • Chair and Vice Chair

  • Three Subcommittees, Chair and Co-Chair

    • Dusts & Inorganics (D&I)

    • Hydrogen, Oxygen & Carbon Compounds (HOC)

    • Miscellaneous Compounds (MISCO)

  • Administrative Subcommittees

    • Communications and Outreach

    • Membership

    • Notations

    • Chemical Substance Selection

  • Staff Support

    • Liaison, Clerical, Literature Searching


Chemical Substance Subcommittees

  • Approximately 10 members on each

  • Membership from academia, government, unions, industry

  • Membership represents four key disciplines:

    • Industrial hygiene

    • Toxicology

    • Occupational Medicine

    • Occupational Epidemiology


Core TLV® Principles

  • Focus on airborne exposures in occupational settings

  • Utilize the “threshold” concept

  • Primary users are industrial hygienists

  • Goal is towards protection of “nearly all” workers

Technical, economic, and analytic feasibility are NOT considered


Committee Actions in 2003

  • Adopted TLVs® for 22 substances

  • Proposed 6 new TLVs®

    • (listed on the Notice of Intended Changes (NIC))

  • Revised 7 adopted TLVs® (listed on the NIC)

  • Proposed withdrawing TLVs® for methane, ethane, propane, butane and liquified petroleum gas. (Will also withdraw iso-butane.)

    • All to be replaced with a proposal for Aliphatic Hydrocarbon Gases, Alkane (C1-C4)

  • Revised 3 proposals for TLVs® and retained on the NIC


Committee Actions in 2003 (Cont’d)

  • Adopted a new Appendix E for Particulates (Insoluble or Poorly Soluble) Not Otherwise Specified (PNOS)

  • Developed new Documentation for 2 substances (no change in values)

  • Changed the name of one TLV® and kept on the NIC with revised recommendations

  • Retained 4 proposed TLVs® on the NIC

  • Withdrew 2 proposed TLVs® from the NIC


Committee Actions in 2003 (Cont’d)

  • Proposed withdrawal of Appendix B: Substances of Variable Composition

  • Proposed revision of Appendix C: Threshold Limit Values for Mixtures

  • Proposed a new Appendix F: Commercially Important Tree Species Identified as Inducing Sensitization


Substances and Issues Under Study in 2003

  • 115 chemical substances currently under study

  • Issues under study include:

    • Ceiling limits, excursions, and STELs

    • Notations for reproductive effects

    • Skin notation

    • Reciprocal Calculation Procedure, Group Guidance Values for refined C5 - C15 aliphatic and aromatic hydrocarbon solvents and constituent chemicals


Particulates(Insoluble or Poorly Soluble) Not Otherwise Specified

  • The recommendations are guidelines (not TLVs®) for limiting exposure to insoluble particles:

    • 3 mg/m3 (respirable)

    • 10 mg/m3 (inhalable)

  • Apply to particles that:

    • Do not have a TLV®

    • Are insoluble or poorly soluble in water or lung fluid

    • Have low toxicity (not genotoxic, cytotoxic, etc.)

    • Only toxic effects are inflammation or “lung overload” mechanisms


ProposedNew Appendix C: TLVs® for Mixtures

  • In the absence of other information, assume additivity of substances having similar effects

    • Same outcomes, same target organs or systems

the TLV® for the mixture has been exceeded.


ProposedNew Appendix C: TLVs® for Mixtures

  • Recommends using the TLV®Documentation, as well as the TLV® Basis information in the book

  • Where possible, only combine TLVs® having a similar time basis

    • Table showing appropriate combinations of different types of TLVs®


ProposedNew Appendix C: TLVs® for Mixtures

  • Limitations and Special Cases

    • Do not use when suspect inhibition or synergism

    • Take care when considering mixtures of A1, A2, or A3 carcinogens

    • Not appropriate for complex mixtures with many different components (e.g., gasoline, diesel exhaust)


Committee Activities

  • Notations

    • Complete re-write of Introduction to the TLV®-CS section of the book

    • Improved definition and categorization of TLV® Basis

  • Communications

    • Symposia on substances under study

  • Membership

    • Recruitment, especially of physicians and epidemiologists

    • Bill Wagner Award & member recognition

  • Chemical Substance Selection

    • Refining the selection process


Committee Activities

  • Sponsored symposium on TDI (Spring 2002)

  • Attended ACGIH® symposium on oil mists and metalworking fluids (Fall 2002)

  • Plenary talk on TLVs® at AIOH in Australia (Winter 2002)

  • Co-sponsored a colloquium on Workplace Chemical Exposure Standards with IRSST in Montreal (Spring 2003)


Committee Plans

  • Co-sponsor symposium on enzymes (Spring 2004)

  • Roundtables on TLVs® at other professional meetings (SOT, ACOEM)

  • Joint meetings with ACGIH® BEI® and AIHA WEEL Committees


Questions?


Scheduled Break

Take a minute to stretch!


Biological Exposure Indices (BEIs®)Process and Use

Larry K. Lowry, Ph.D.

Chair, ACGIH® BEI® Committee

The University of Texas Health Center at Tyler


Where are we going today?

  • Current definitions of the BEI®, 2002

  • The development of BEIs®

  • The key – Documentation

  • Examples

  • Biomonitoring without limits

  • Current and future issues

  • Resources


Biological monitoring. Why?

  • Assess exposure and uptake by all routes

    • TLV® not protective – skin

    • Includes workload

    • More closely related to systemic effects

  • Assess effectiveness of PPE

  • Legal or ethical drivers

    • Regulations

    • Control workers’ compensation costs


“Guidelines” for biological monitoring – The BEIs®


The BEIs® – 2003

BEIs® are intended for use in the practice of industrial hygiene as guidelines or recommendations to assist in the control of potential workplace health hazards and for no other use.


The BEI® – Definition

  • Biological monitoring … entails measurement of the concentration of a chemical determinant in the biological media of the exposed and is an indicator of the uptake of the substance.

  • The BEI® determinant can be the chemical itself; one or more metabolites; or a characteristic reversible biochemical change induced by the chemical.


BEIs®

  • Represent levels of determinants that are most likely to be observed in specimens collected from a healthy worker who has been exposed to chemicals to the same extent as a worker with inhalation exposure to the TLV®-TWA.

  • Generally indicate a concentration below which nearly all workers should not experience adverse health effects.


Current basis for BEIs®

  • Bio-equivalent to TLV® (traditional)

    • “BEIs® represent levels of determinants that are most likely to be observed in specimens collected from a healthy worker who has been exposed to chemicals to the same extent as a worker with inhalation exposure to the TLV®-TWA.”

  • Most of the BEIs® are based on TLVs®


Current basis

  • Indicators of early, reversible health effect

    • Approach developed in late 80’s as relationships did not always exist between airborne exposure and biomonitoring determinant.

  • Examples:

    • CO, Acetyl cholinesterase inhibiting pesticides, Cd, Pb, Hg, Hexane-MnBK


The BEI® CommitteeLarry Lowry, Ph.D., U TX Health Center at Tyler – Chair

  • Phil Edelman, MD, CDC – Vice Chair

  • Mike Morgan, Sc.D, CIH, U. of WA – Past Chair

  • Joe Saady, Ph.D., VA Division of Forensic Science

  • Leena Nylander-French, Ph.D, CIH, UNC, Chapel Hill

  • John Cocker, Ph.D., HSE, UK

  • K. H. Schaller, Dipl. Ing., Univ Erlangen, Germany

  • M. Ikeda, Ph.D., Kyoto Ind Health Assoc, Japan

  • Gary Spies, CIH, Pharmacia

  • Glenn Talaska, Ph.D., CIH, Univ of Cincinnati

  • Jan Yager, Ph.D., EPRI


BEI® development

  • Volunteer assigned document

  • Prepares draft Documentation

  • Sources of data

    • Human laboratory & workplace data

      • Limited use of animal data

    • Simulation modeling with verification

    • Published peer-reviewed data

  • Draft Documentation discussed in committee meetings, e-mail


Develop

Select

Review

Assign

BEI®?

No

Feasibility

Chemical

Data

Author

Yes

Prepare

Review

Discuss

Select

Draft

Draft

Justification

Determinant

Return to

Revise

Yes

Author

No

Final

Document

Development Process


How are chemicals selected?

  • Chemicals with human data

  • Potential for dermal absorption

  • Availability of adequate lab methods

  • Recommendations by others

  • Interest/experience of committee member


The Documentation

  • Who is the audience?

    • The practicing occupational hygienist or other practicing occupational health professional

  • What the Documentation is

    • Justification supporting the BEI®

    • Practical information on sampling, background, etc.

  • What the Documentation is not

    • An extensive review of toxicological data

    • A novel research approach to setting guidelines


The Documentation – contents

  • Basis of the BEI®

  • Uses and properties

  • Absorption

  • Elimination

  • Metabolic pathways & biochemical interactions

  • Possible non-occupational exposure

  • Summary of toxicology


For each index or BEI®

  • Analytical methods, sampling, and storage

  • Levels without occupational exposure

  • Kinetics

  • Factors affecting interpretation

    • Analytical procedures and sampling

    • Exposure

    • Population

  • Justification – the key

  • Current quality of database

  • Recommendations and references


The notations

  • B - Background levels expected

  • Nq- Nonquantitative

    • Biol. monitoring recommended, no BEI®

  • Ns- Non-Specific

    • Needs confirmation

  • Sq Semiquantitative (but specific)

    • Screening test

    • Confirmatory tests


Practical applications

  • Bioavailability of metals – Chromium

    • Chromium VI (water soluble) fume

  • Specificity and Sensitivity – Benzene biomonitoring

    • t,t-Muconic acid in urine (t,t-MA)

    • S-Phenylmercapturic acid in urine (SPMA)


Bioavailability of metals – Chromium

  • Physical properties and solubility

    • Cr (III), very insoluble particulates

    • Cr (VI) insoluble particulate – the lung carcinogen

    • Cr (VI) water soluble

      • Fume as generated in MMA arc welding

      • Mist as generated in electroplating

  • Health effects of Cr (VI) water soluble

    • Fume – lung irritant

    • Mist – chrome ulcers on skin, mucus membranes


Biological monitoring of Cr exposure

  • Cr (III) inappropriate – not bioavailable

  • Cr (VI) insoluble – not bioavailable

  • Cr (VI) water soluble

    • If fume, use BEI® based on welding studies

    • If mist, bioavailability less

      • See chrome ulcers at “acceptable” BEI® values


Biomonitoring of benzene


Biomonitoring at the current TLV®

  • t,t-Muconic acid in urine (t,t-MA)

    • Good sensitivity (to 0.1 ppm benzene)

    • HPLC methodology

    • Considerable variability in populations

  • S-Phenylmercapturic acid in urine (SPMA)

    • Ultimate sensitivity (to 0.01 ppm benzene)

    • GC/MS methodology

    • Good data base, but expensive


Biological monitoring without limits

  • What about substances absorbed through the skin and with chronic systemic health effects that occur after a long lag time such as cancer?


The traditional approach

  • Cannot relate to airborne limits, TLVs®

    • Irrelevant

  • Cannot relate to skin absorption

    • Difficult to quantitate dermal dose

  • Cannot relate to health effect

    • Often wrong timeline

  • What to do?


The BEI® approach

  • Rationale

    • Biological monitoring is essential to assess dermal exposure

    • How do you correlate dermal dose with a biomarker of exposure?

  • Nq Approach

    • “Biological monitoring should be considered for this compound based on the review; however, a specific BEI® could not be determined due to insufficient data.”


Criteria for an Nq

  • Dermal route of exposure significant

  • Good measurement methods

  • Good qualitative data on human exposure and biomarker concentration

  • Poor quantitative data relating exposure & biomarker

  • Long lag time, exposure to health outcome

  • Low or no background in general population


If criteria are met, then

  • Develop full Documentation

  • Describe sampling and analysis

  • Define background levels

  • Describe justification for biomonitoring

  • Note the lack of quantitative data

  • Cite guidance values from literature

  • Publish BEI® as Nq (no value)


Examples – MBOCA

  • Principal route of exposure – dermal

  • Alleged health effect in humans – cancer

  • Good methods and human data on exposure-response

  • Industry practice guidance from the HSE


Health and Safety Executive, UK

  • Scientific basis to justify guidance values

  • Use "yardstick or benchmark" approach

  • Issues

    • Results – no "safe" or "unsafe" exposure levels

    • Results – estimates of exposure areas and allow intervention to reduce exposures

    • No legal status

  • Examples – MBOCA and MDA


The “yardstick or benchmark” approach

  • Good analytical methods

  • All specimens analyzed by one laboratory or with a single method

  • Establish "best industry practice" using an upper 90% confidence limit of the "best" industries

  • Benchmarks – guidance value to provide users with assessment of their results


Current issues

  • Carcinogens?

    • Is there a safe level of exposure?

    • The German EKA approach

  • Mixtures and interactions

    • Metabolism/toxicokinetics on pure chemical

    • Workers exposed to mixtures

    • How does this effect BEI®?

  • Biomarkers of effect – irreversible effects?

  • Data gaps – lack of human data

  • Animal data – should this be used?


Skin absorption Justification for BEI®

  • Existing BEIs® for substances with substantial skin absorption

    • MBOCA – Nq

    • EGME/EGMEA – Nq

    • EGEE/EGEEA – 100 mg/g creatinine

      • (based on TLV® of 5 ppm)

      • Is this a valid approach?

    • Are Nq notations appropriate?

    • Should a chemical without a “skin” notation have a BEI®?


The future

  • As TLVs® drop, BEIs® based on TLVs® drop

    • Cannot distinguish exposure at TLV® from background

  • What do we do for substances that have no human data?

  • What is the future of modeling techniques?

    • Can these modeling techniques be validated?

  • Should animal data be used?

  • What about mixtures?


Other guidelines


GermanyThe BATs from the DFG


The HSE – UK Biological monitoring guidelines


Guidance from WHO – How to do biological monitoring


Other GuidelinesNew edition, 2001


Your questions please

Thank you for your attention


Scheduled Break

Take a minute to stretch!


ACGIH® TLVs® for Physical Agents Committee Update

Vice-Chair: Thomas Bernard

University of South Florida

College of Public Health


TLV®Physical Agents Committee

Process for Hazardous Agent Selection and Decision Making


Mission

To foster, solicit, collect and evaluate data on potential health hazards of exposures to physical agents. When appropriate, recommend ACGIH® Threshold Limit Values® for physical agents.


2002 PAC

Harry Mahar

Maurice Bitran

Thomas Bernard

Gerald Coles

Anthony Cullen

Daniel Johnson

John Leonowich

William Murray

Bhawani Pathak

Robert Patterson

Thomas Tenforde

Carla Treadwell

Consultants:

Thomas Adams

Thomas Armstrong

Gregory Lotz

Martin Mainster

Gary Myers


Overview

  • Physical Agents

  • Process

    • Committee Activities

    • TLV® Development

  • Future

    • Format

    • Agents


Disclaimer

The opinions expressed here are those of the author

and not of

his employer,

the Physical Agents Committee or

the ACGIH® Worldwide.


Physical Agents

It’s the Movement of Energy


Risk of Health Effects

  • What is the nature of the energy?

  • How much energy?

  • What is the interaction with tissue?


Nature of Energy

  • Electric and Magnetic Fields

  • Photons

  • Kinetic Energy

    • Pressure

    • Vibration

    • Mechanical

  • Heat


Amount of Energy

  • Total Amount of Energy Absorbed

    • What does it take to raise water temperature?

  • Rate of Absorption (Power or Intensity)

    • How fast does the temperature rise?

  • Normalized to Surface Area

    (e.g., mJ/cm2, mW/cm2)


Interactions

  • Electric and Magnetic Fields

    • Induce Currents

    • Align Molecules

    • Vibrate Molecular Bonds

  • Photons

    • Vibrate Molecular Bonds

    • Disrupt Molecular Bonds


More Interactions

  • Mechanical Disruption of Tissue

    • Pressure

    • Vibration

    • Force Applications

  • Loss of Tissue Function

    • Thermal: Gain or Loss of Heat


Bernard Watt-O-Meter

{Not Accepted, or Considered Acceptable, by Any Authority}

Power Limits for Various Exposures [mW/cm2]

Electric and Magnetic Fields170,000

Radiofrequency/Microwave1.0

Infrared Light10

Blue Light0.0001

Ultraviolet Light0.0012

Ionizing Radiation0.00000003

Noise0.00003

Heat Stress30


Exposure

  • Energy Distribution in the Immediate Environment

  • The distribution is usually described as Power or Intensity (directly or through a surrogate) versus Frequency or Wavelength in Bands


Exposure Threshold

  • Total Energy

    • Ability to Absorb Energy

  • Rate of Energy (Power or Intensity)

    • Ability to Dissipate Absorbed Energy

      In a Band

      Integrated Over All Bands


Process

Committee Activities

Development of TLVs®


Representation

  • Usually one or two members with an expertise for a particular agent (e.g., a small portion of the electromagnetic spectrum)

  • Small committee to maintain a working and collegial group. We meet as a whole.

  • Leverage with outside experts


Updating TLVs®

  • PAC meets with outside experts

  • Members bring recommendations to the PAC for discussion

  • Consideration of actions taken by national and international committees or agencies


New TLVs®

  • Quintessential Example: Hand Activity

  • Formed a cadre of consultants

  • Convened a conference

  • Developed recommendation and Documentation

  • Presented to PAC and discussed

  • PAC voted after internal deliberations


Future

Format

Agents


Format

  • TLV® Book

    • Use of Flow Charts

    • Evolving (see Heat Stress and RF/MW)

  • Training

  • Documentation

    • Expanded and Focused (see HAL and Lifting)

    • Health Effects and Exposure Indices

    • Guidance (see Heat Stress)


Form

  • Physical agents have their own history and character with respect to measurement and exposure assessment

  • There is an underlying similarity among the physical agents that may be introduced


Example Set

  • Radiofrequency / Microwave Radiation

  • Optical Radiation (IR, Visible and UV)

  • Vibration (Hand-Arm and Whole Body)

  • Noise


1000

100

10

Energy

1

0.1

0.01

0.001

0.01

0.1

1

10

100

1000

Bands

Energy Distribution


1000000

100000

10000

Energy Limit

1000

100

10

1

0.001

0.01

0.1

1

10

100

1000

Bands

Energy Limits Within Bands

Emin


1000000

100000

10000

1000

Energy

100

10

1

PD

Exp Lmt

0.1

0.01

0.001

0.01

0.1

1

10

100

1000

Bands

Limits by Band

Is the limit exceeded within one or more bands?


1000

100

Sensitivity

10

1

0.1

0.001

0.01

0.1

1

10

100

1000

Bands

Sensitivity Curve

Sensitivity = Energy Limit / Emin


1

0.1

Filter Multiplier

0.01

0.001

0.001

0.01

0.1

1

10

100

1000

Bands

Hazard Function

Hazard Function = 1.0 / Sensitivity


1000

100

10

1

Energy

0.1

0.01

ED

E-eff

0.001

0.0001

0.00001

0.001

0.01

0.1

1

10

100

1000

Bands

Effective Exposure

Effective Exposure = Energy Distribution x Hazard Function


Total Energy

Multiplying

  • Energy Limits by Band

  • Hazard Function by Band

    and Integrating (Summing)

    Yields a Constant Value:

    A Total Energy Limit


Limit by Total Energy

Total Energy

  • In One Band

  • Under the Effective Energy Curve

    Compared to

    Total Energy Limit


In Summary

  • TLVs®

    • Limit Power (Ability to Dissipate)

    • Limit Total Energy (Ability to Absorb)

  • Limit by

    • Band

    • Total


Agents Under Review

  • Lasers

  • Vibration

  • Cold Stress

  • Altitude

  • Impulse Noise

  • ELF H-Fields

  • HAL

  • Lifting

  • WMSDs

  • Wide-Band RF


Scheduled Break

Take a minute to stretch!


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 DispersalLinear 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

V * D

Infectious Disease =

RS


Infectious DiseaseTerminology

  • Portal of entry

  • Exposure vs. infection

  • Clinical vs. subclinical or asymptomatic infection

  • Carrier state

  • Opportunistic infection

  • Human pathogen vs. virulence

  • Immunosuppression


Infectious DiseasePathways

  • 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 MitesMolds

Animal DanderPollen

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


Important Mycotoxins


Where Are We?


Classification of Occupant Complaints

  • Sick Building Syndrome

  • Building-Related Disease

  • Occupant Discomfort


Sick Building SyndromeNon-specific Symptoms

  • Headache

  • Eye, nose, throat irritation

  • Sneezing

  • Fatigue and lethargy

  • Skin irritation

  • Dizziness and nausea

  • Cough

  • Chest tightness


Legionnaires Disease

Pontiac Fever

Humidifier Fever

Hypersensitivity Pneumonitis

Anthrax

Building-Related Disease

  • Known etiologies

  • Related to identifiable exposure


No numeric criteria

for interpreting

environmental measurements!


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


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


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


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


Questions?

  • Pat Breysse

  • Lisa Brosseau

  • Larry Lowry

  • Tom Bernard

  • Ken Martinez


  • Login