Equations for Calculating Exposure Management Objectives for Single Shift, Long-Term Average, and Dual Exposure Limits

Details

• Personal Author:
  Hewett, Daniel J.
• Description:
  The majority of exposure limits for gases, vapors, and particulates have as their implicit or explicit goal the control of exposures for each employee. A measure of noncompliance for a typical single shift, TWA exposure limit (or for a 'long-term average' exposure limit) is the probability that a randomly selected worker has a 95th percentile exposure (or mean exposure) greater than the single shift limit (or long-term average limit). The goal of an exposure management program should be to ensure that this probability is small, say 0.05 or less. One method for determining if this goal has been achieved is to directly estimate the probability of noncompliance through the application of resource intensive, repeat sampling of randomly selected workers, followed by components-of-variance analysis. Equations will be presented for calculating site specific exposure management objectives, that if met will help ensure that the exposure management goal is achieved. These equations were derived from a statistical model (which will be briefly discussed) designed to be applied to both conventional, single-shift TWA exposure limits and the less common 'long- term average' exposure limits. The objectives include a target group exceedance fraction, an alternative single shift limit, a target group geometric mean, and a target group mean. Each of these objectives can be evaluated using off-the-shelf sampling strategies, tolerable sample sizes, and robust data analysis procedures. If the site-specific control objective is met, the overall goal of exposure control for at least 95% of the employees is likewise achieved. Examples will be presented for single shift exposures limits, 'long-term average' exposure limits, and for dual limits, where both a single shift and 'long-term average' limit apply. [Description provided by NIOSH]
• Subjects:
  Occupational Health Particulate Matter Safety Solvents
• Keywords:
  Exposure-levels Exposure-limits Gases Particulate-dust Particulates Sampling Vapors Workers
• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  California ; OSHA Region 3 ; OSHA Region 9 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DRDS - Division of Respiratory Disease Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  52
• NIOSHTIC Number:
  nn:20022439
• Citation:
  American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California. Fairfax, VA: American Industrial Hygiene Association, 2002 Jun; :52
• Federal Fiscal Year:
  2002
• NORA Priority Area:
  Research Tools and Approaches: Exposure Assessment Methods
• Peer Reviewed:
  False
• Source Full Name:
  American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7203b1c2c945d49143603132c408dd1f2f75eb8bca31ff79bd323a5a2aa77c4bf82071b783b75b4de452d7c51c0b30d3ad1260e78fea0c17a7e96c1a62ecd4c5
• Download URL:
  https://stacks.cdc.gov/view/cdc/199220/cdc_199220_DS1.pdf
• File Type:
  [PDF - 485.69 KB ]