CIH General 5 — Questions and Answers
Question 1: What is the assigned protection factor (APF) for a full-face air-purifying respirator according to OSHA?
- 10
- 25
- 50 (Correct answer)
- 1000
Correct answer: 50
OSHA assigns an APF of 50 to full-face air-purifying respirators, meaning they can reduce exposure to 1/50th of ambient concentration.
Question 2: In quantitative fit testing, which method uses a particle counter to measure aerosol penetration through a respirator?
- Isoamyl acetate test
- Bitrex test
- PortaCount test (Correct answer)
- Saccharin test
Correct answer: PortaCount test
The PortaCount uses condensation particle counting to quantitatively measure how many ambient particles penetrate the respirator seal.
Question 3: Which chemical form presents the greatest inhalation hazard for a substance with a very low vapor pressure at room temperature?
- Vapor
- Gas
- Aerosol/mist (Correct answer)
- Pure liquid
Correct answer: Aerosol/mist
When a low-vapor-pressure liquid is dispersed as an aerosol or mist, fine droplets remain airborne and can be inhaled deeply.
Question 4: Under the OSHA Respiratory Protection Standard (29 CFR 1910.134), how often must employees who wear tight-fitting respirators be fit tested?
- Every 6 months
- Annually (Correct answer)
- Every 2 years
- Only at initial assignment
Correct answer: Annually
OSHA requires annual fit testing for tight-fitting respirators to account for changes in facial structure and respirator condition.
Question 5: What is the primary purpose of biological monitoring in occupational health?
- To detect workplace air contaminants above PELs
- To assess total worker exposure from all routes including skin and ingestion (Correct answer)
- To replace air sampling requirements
- To measure employer compliance with OSHA standards
Correct answer: To assess total worker exposure from all routes including skin and ingestion
Biological monitoring measures biomarkers in blood, urine, or exhaled air to capture total body burden from all exposure routes.
Question 6: A chemical that requires a higher concentration to produce the same toxic effect as another chemical is described as having:
- Lower toxicity (Correct answer)
- Higher potency
- Greater bioavailability
- A smaller safety factor
Correct answer: Lower toxicity
A chemical requiring more dose to produce a given effect has lower toxicity (less potency) compared to one requiring less dose.
Question 7: Which ACGIH TLV category is set to prevent narcosis, irritation, or other acute effects from short-term exposure peaks?
- TLV-TWA
- TLV-STEL (Correct answer)
- TLV-C
- TLV-BEI
Correct answer: TLV-STEL
The TLV-STEL (Short-Term Exposure Limit) is a 15-minute TWA that should not be exceeded to prevent acute effects.
CIH General 5
What is the assigned protection factor (APF) for a full-face air-purifying respirator according to OSHA?