CIH CIH Industrial Hygiene Sampling & Monitoring 2 — Questions and Answers
Question 1: Which instrument is most commonly used for real-time measurement of particulate matter in workplace air?
- Gas chromatograph
- Direct-reading aerosol photometer (Correct answer)
- Flame ionization detector
- Infrared spectrometer
Correct answer: Direct-reading aerosol photometer
Direct-reading aerosol photometers measure light scattering from airborne particles to provide instantaneous particle concentration readings.
Question 2: What particle size fraction is collected by an inhalable particulate matter sampler?
- Particles <1 µm
- Particles <4 µm
- Particles up to 100 µm aerodynamic diameter (Correct answer)
- Particles <10 µm
Correct answer: Particles up to 100 µm aerodynamic diameter
Inhalable particulate matter samplers collect particles up to approximately 100 µm that can be inhaled through the nose and mouth.
Question 3: The ACGIH threshold limit value (TLV-STEL) represents maximum exposure for what duration?
- 15 minutes (Correct answer)
- 30 minutes
- 60 minutes
- 4 hours
Correct answer: 15 minutes
The TLV-STEL is a 15-minute short-term exposure limit that should not be exceeded during any part of the workday.
Question 4: What is the purpose of a blank sample in an industrial hygiene sampling campaign?
- To calibrate the pump flow rate
- To detect contamination from media preparation or field handling (Correct answer)
- To measure the detection limit of the instrument
- To set the upper range of the analytical curve
Correct answer: To detect contamination from media preparation or field handling
Field and media blanks detect background contamination introduced during manufacturing, shipping, or field handling of sampling media.
Question 5: Which pump flow rate is typically used for collecting respirable dust using a 10-mm Dorr-Oliver cyclone?
- 0.5 L/min
- 1.7 L/min (Correct answer)
- 2.5 L/min
- 5.0 L/min
Correct answer: 1.7 L/min
The 10-mm Dorr-Oliver nylon cyclone is operated at 1.7 L/min to achieve the respirable size-selective cut point per NIOSH methods.
Question 6: What does a detector tube (colorimetric tube) measure in workplace air sampling?
- Particle mass concentration
- Approximate gas or vapor concentration via color change (Correct answer)
- Exact analyte identity using chromatography
- Radiation dose equivalent
Correct answer: Approximate gas or vapor concentration via color change
Detector tubes contain reagents that change color proportional to the concentration of a target gas or vapor, providing rapid semi-quantitative results.
CIH CIH Industrial Hygiene Sampling & Monitoring 2
Which instrument is most commonly used for real-time measurement of particulate matter in workplace air?