SHP Environmental Health & Industrial Hygiene 1 — Questions and Answers
Question 1: What is OSHA's permissible exposure limit (PEL) for noise as an 8-hour time-weighted average (TWA)?
- 85 dB(A)
- 90 dB(A) (Correct answer)
- 95 dB(A)
- 100 dB(A)
Correct answer: 90 dB(A)
OSHA's PEL for occupational noise exposure is 90 dB(A) as an 8-hour TWA, with a 5 dB exchange rate.
Question 2: Which organization publishes Threshold Limit Values (TLVs) for chemical substances and physical agents in the workplace?
- OSHA (Occupational Safety and Health Administration)
- NIOSH (National Institute for Occupational Safety and Health)
- ACGIH (American Conference of Governmental Industrial Hygienists) (Correct answer)
- EPA (Environmental Protection Agency)
Correct answer: ACGIH (American Conference of Governmental Industrial Hygienists)
The ACGIH publishes TLVs annually as recommended guidelines for occupational exposure to chemical substances and physical agents.
Question 3: In the hierarchy of hazard controls, which method is considered the most effective for protecting workers?
- Administrative controls
- Personal protective equipment (PPE)
- Engineering controls
- Elimination (Correct answer)
Correct answer: Elimination
Elimination—completely removing the hazard—is the most effective control because it eradicates the risk rather than managing or reducing exposure to it.
Question 4: Indoor CO2 levels above what concentration are generally associated with inadequate ventilation and increased occupant complaints?
- 500 ppm
- 1,000 ppm (Correct answer)
- 2,000 ppm
- 5,000 ppm
Correct answer: 1,000 ppm
CO2 levels above 1,000 ppm typically indicate inadequate fresh air ventilation and are associated with occupant complaints such as headaches and reduced cognitive performance.
Question 5: Under OSHA's Hearing Conservation Amendment (29 CFR 1910.95), at what noise action level must employers implement a hearing conservation program?
- 80 dB(A) TWA
- 85 dB(A) TWA (Correct answer)
- 90 dB(A) TWA
- 95 dB(A) TWA
Correct answer: 85 dB(A) TWA
OSHA requires a hearing conservation program when employee noise exposures equal or exceed 85 dB(A) as an 8-hour TWA, triggering audiometric testing and hearing protection.
Question 6: In industrial hygiene air sampling, what is the primary advantage of personal air sampling over area (fixed-point) air sampling?
- It measures contaminant concentrations across a wider work area
- It directly assesses the worker's actual breathing zone exposure (Correct answer)
- It is less expensive and easier to conduct
- It provides continuous real-time data to a monitoring station
Correct answer: It directly assesses the worker's actual breathing zone exposure
Personal air sampling collects air from the worker's breathing zone throughout the work shift, directly measuring the individual worker's actual inhalation exposure.
Question 7: What does IDLH represent in the context of occupational health and industrial hygiene?
- Initial Dose Limit for Hazards — starting exposure limit for new workers
- Immediately Dangerous to Life or Health — concentration posing immediate threat within 30 minutes (Correct answer)
- Industrial Dust Level Hazard — threshold for particulate matter exposure
- Integrated Daily Limit of Hazardous substances — a 24-hour occupational exposure limit
Correct answer: Immediately Dangerous to Life or Health — concentration posing immediate threat within 30 minutes
IDLH (Immediately Dangerous to Life or Health) is the maximum concentration from which a worker could escape within 30 minutes without suffering escape-impairing or irreversible health effects.
SHP Environmental Health & Industrial Hygiene 1
What is OSHA's permissible exposure limit (PEL) for noise as an 8-hour time-weighted average (TWA)?