1 / 42

Real-time Exposure Assessment

Real-time Exposure Assessment. Terri A. Pearce, Ph.D. Occupational Safety and Health Administration Oklahoma City Area Office. Real-Time. Instantaneous Absolute, Average, Rolling average Near real-time Processor delay, lag for data transmission Adjusted After data interpolation.

savea
Download Presentation

Real-time Exposure Assessment

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Real-time Exposure Assessment Terri A. Pearce, Ph.D. Occupational Safety and Health Administration Oklahoma City Area Office

  2. Real-Time • Instantaneous • Absolute, Average, Rolling average • Near real-time • Processor delay, lag for data transmission • Adjusted • After data interpolation

  3. Exposure Assessment • Source • Contaminant • Route of Entry • Monitoring method efficacy • Receptor • Proximity • Dose • Physiological construct

  4. NIOSH DREAM Workshop

  5. Six Monitoring Categories • Noise • Radiation • Gases and Vapors • Aerosols • Ergonomics • Biomonitoring and Surface Sampling

  6. AIHA Survey • 684 respondents (640 users) with most respondents from manufacturing and services sectors • 546 reported using DRMs as supplements to laboratory analysis with 445 also using DRMs as alternatives to conventional methods • Particle monitors used most often followed by gas and vapor monitors

  7. Choosing a DRM

  8. Future Needs • More contaminant specific • Multiple contaminants • More user friendly • Less cumbersome • Less expensive • Specific to unique hazards

  9. Sampling strategies

  10. Strategy development

  11. Types of Monitoring • Hazard zones • Emission points • Controls (pre- and post-implementation) • Tasks (work practice) • Exposure assessment

  12. Hazard Zones • Go/no go, safe/not safe • Accuracy, precision, and bias not as important if error is on side of most conservative (protective) decision • Established technology with good accessibility for workers

  13. Emission Points • Yes/no, high/low • Process emissions versus leak detection • May need to know background contaminant levels • Sensitivity may not be as important as specificity

  14. Controls • Before/after • Accuracy or bias may not be as important as precision • May follow-up with area or personal monitoring

  15. Tasks • Tasks/overall TWA • Process emissions versus work practice • Accuracy, precision, and bias all important • Comparability across monitors if evaluating more than one worker

  16. Exposure Assessment • Above/below OEL • Accuracy, precision, and bias are important, specificity is good too • Results consistent across time and concentration • Comparability among monitors and with conventional method

  17. Selecting a Method • Understand mission/objective • Regulatory requirements • Capabilities of the technology • Calibration status • User friendliness AIHA Real Time Detection Systems Committee

  18. Selection Logic Birch, M.E., T.A. Pearce, and C.C. Coffey: Direct-Reading Instruments for Gas and Vapor Detection (Publ. No. ASI18). American Conference of Governmental Industrial Hygienists (ACGIH): Cincinnati, OH, 2009.

  19. Monitor Selection • Active/Passive • Size • Weight • Durability • Alarms • Display • Intrinsic safety • Price • Ease of calibration/bump test • Sensor availability AIHA Real Time Detection Systems Committee

  20. Sensor Selection • Compatibility with monitor • Specificity for agent of interest • Service life • Price AIHA Real Time Detection Systems Committee

  21. Noise • Area versus personal sampling • Continuous versus impulse noise • Measurement mimics the physiological response

  22. Personal Dosimeters • Microphone placed in proximity to the ear • Provides the cumulative exposure over the course of the exposure period • Display allows for administrative control

  23. Sound Level Meters • Provides for identifying noise source and contributing frequency • Better at measuring impulse noise

  24. Applicability of Noise Monitor • Yes • Hazard zones • Emission points • Controls pre- and post-implementation • Hazards associated with specific tasks • Exposure assessment

  25. Radiation • Area versus personal sampling • Real-time and Near real-time • Measurement equates to the physiological response

  26. Area Survey Monitors • Real-time counters • Geiger-Muller • Ion chamber • Proportional

  27. Personal Dosimeters • Real-time • Pocket dosimeter • Digital electronic dosimeter • Audible alarm rate meter • Near real-time • Film badges • Thermoluminescent dosimeters

  28. Applicability of Radiation Monitor • Yes • Hazard zones • Emission points • Controls pre- and post-implementation • Hazards associated with specific tasks • Exposure assessment

  29. Gases and Vapors • Area versus personal sampling • Single versus multiple gases • Not a direct measure of physiological effect

  30. Single gas monitors • Mercury • Specific Sensors • carbon monoxide, chlorine, chlorine dioxide, hydrogen cyanide, hydrogen sulfide, nitrogen dioxide, phosphine and sulfur dioxide

  31. Multi-gas monitors • Configured with multiple sensors • Capable of detecting properties of individual gases • Photoionization • Flame ionization • Infrared • Gas chromatography • Mass spectrometry

  32. 4-gas Monitors • Confined Space Regulation • Oxygen deficiency • Combustible gases and vapors (LEL) • Toxics • Carbon Monoxide • Hydrogen Sulfide

  33. Applicability of Gas/Vapor Monitor • Yes • Hot zones versus safe zones • Maybe • Emission points • Controls pre- and post-implementation • Hazards associated with specific tasks • No • Exposure assessment

  34. Aerosols • No monitor is particle specific • Measure in mass or particle count/volume of air • Not a direct measure of physiological effect

  35. Mass monitors • Area versus personal • May have integrated filter for subsequent analysis

  36. Particle counters • Area monitors only • Total versus size differentiating • Coincidence errors at high concentrations

  37. Applicability of Aerosol Monitor • Maybe • Hot zones versus safe zones • Emission points • Controls pre- and post-implementation • Hazards associated with specific tasks • No • Exposure assessment

  38. Respirator Fit-testing • Aerosol monitor used to determine appropriateness of personal protection

  39. Ergonomics • NIOSH lifting equation • Capabilities for measuring force strength on actual muscles

  40. Biomonitoring • Personal sampling only • Parameter measured is or approximates the physiological response

  41. Surface Sampling • Area versus personal sampling • Connections to physiological response may be possible

  42. Terri A. Pearce, Ph.D.pearce.terri@dol.govOklahoma City Area Office55 N. Robinson, Suite 315Oklahoma City, OK 73102405-278-9560

More Related