7.3 Introduction to occupational exposure limits

Written by Imran Qureshi (NEBOSH)

NEBOSH IGC · Workplace hazards · 15 questions

Name: ____________________   Date: ____________

1. An 8 hour time-weighted average is used for:

   • A Radiation dose
   • B Long-term exposure limits
   • C Peak noise only
   • D Short-term limits

2. The purpose of an occupational exposure limit is to:

   • A Replace the need for controls
   • B Provide a benchmark for judging control
   • C Measure noise
   • D Ban substances

3. A limitation of exposure limits is that:

   • A They guarantee safety
   • B They apply to skin only
   • C They do not allow for combined exposure to several substances
   • D They are the same for all substances

4. A long-term exposure limit is normally averaged over:

   • A 1 minute
   • B 10 years
   • C 8 hours
   • D 1 week of rest

5. A short-term exposure limit usually relates to:

   • A A year
   • B A month
   • C A period of about 15 minutes
   • D A lifetime

6. TWA stands for:

   • A Total work area
   • B Toxic waste agent
   • C Time-weighted average
   • D Temporary working allowance

7. Why are time-weighted averages used?

   • A They replace limits
   • B The effect of many substances depends on the total dose over time
   • C They make limits higher always
   • D They are easier to remember

8. Occupational exposure limits are expressed as:

   • A Lux
   • B Airborne concentrations of a substance
   • C Kilograms
   • D Decibels

9. An exposure limit does not apply well to:

   • A A cold day
   • B A single, well known substance
   • C A short task
   • D Combined exposure to several substances

10. A limitation of exposure limits is that they:

    • A Cover every substance
    • B Include skin absorption always
    • C Cannot be measured
    • D Assume healthy adults

11. A measured level that is below the limit means that:

    • A The substance is harmless
    • B Controls can be removed
    • C Exposure meets the standard but is not necessarily safe
    • D No further action is needed ever

12. Exposure limits do not cover skin absorption unless:

    • A The limit is high
    • B The substance is a gas
    • C They carry an indication that skin absorption is a route
    • D The worker wears gloves

13. The purpose of an exposure limit is to:

    • A Increase output
    • B Ban all substances
    • C Replace the SDS
    • D Set a benchmark for judging whether controls are adequate

14. Measurements of airborne concentrations are compared with:

    • A The number of workers
    • B Recognised standards
    • C The company turnover
    • D The shift length

15. Why is a short-term exposure limit used as well as an 8 hour limit?

    • A To control short peaks of high exposure
    • B To make exposure measurement unnecessary
    • C To apply only to biological agents
    • D To replace the 8 hour limit