ASP Industrial Hygiene and Health 2 — Questions and Answers
Question 1: What is the hierarchy of controls in industrial hygiene, from most to least effective?
- PPE, administrative controls, engineering controls, substitution, elimination
- Elimination, substitution, engineering controls, administrative controls, PPE (Correct answer)
- Engineering controls, elimination, PPE, substitution, administrative controls
- Administrative controls, PPE, elimination, engineering controls, substitution
Correct answer: Elimination, substitution, engineering controls, administrative controls, PPE
The hierarchy ranks: elimination, substitution, engineering controls, administrative controls, and PPE.
Elimination removes the hazard completely. Substitution replaces it with something less hazardous. Engineering controls isolate people from the hazard. Administrative controls change how people work. PPE is the last resort.
Question 2: What does TLV-TWA stand for and what does it represent?
- Total Liquid Volume - Total Water Amount
- Threshold Limit Value - Time-Weighted Average; the average airborne concentration for a normal 8-hour workday (Correct answer)
- Toxic Level Value - Total Worker Assessment
- Temperature Limit Value - Thermal Work Area
Correct answer: Threshold Limit Value - Time-Weighted Average; the average airborne concentration for a normal 8-hour workday
TLV-TWA represents the time-weighted average concentration for a conventional 8-hour workday and 40-hour workweek.
The TLV-TWA is established by ACGIH. It represents the airborne concentration averaged over 8 hours to which most workers can be repeatedly exposed without adverse effects.
Question 3: Which sampling method is preferred for assessing a worker's personal exposure to airborne contaminants?
- Area sampling using a stationary monitor
- Grab sampling with detector tubes
- Personal sampling using a pump and collection media worn by the worker (Correct answer)
- Visual observation of dust levels
Correct answer: Personal sampling using a pump and collection media worn by the worker
Personal sampling with a calibrated air pump and collection media in the worker's breathing zone provides the most accurate assessment.
Personal sampling involves attaching a calibrated pump to a worker's belt with collection media in the breathing zone, within 6-9 inches of the nose and mouth, capturing actual exposure throughout the shift.
Question 4: What is the primary health concern associated with prolonged exposure to respirable crystalline silica?
- Hearing loss
- Silicosis and increased risk of lung cancer (Correct answer)
- Dermatitis
- Lead poisoning
Correct answer: Silicosis and increased risk of lung cancer
Prolonged inhalation of respirable crystalline silica causes silicosis and significantly increases lung cancer risk.
Respirable crystalline silica causes silicosis when fine particles deposit deep in the lungs, triggering inflammation and progressive fibrosis. OSHA's PEL is 50 micrograms per cubic meter as an 8-hour TWA.
Question 5: What is biological monitoring in occupational health?
- Monitoring bacteria growth in the workplace
- Measuring chemicals or their metabolites in workers' blood, urine, or exhaled air to assess internal dose (Correct answer)
- Tracking biodiversity near the workplace
- Inspecting food handling practices
Correct answer: Measuring chemicals or their metabolites in workers' blood, urine, or exhaled air to assess internal dose
Biological monitoring measures biomarkers in workers' specimens to assess the absorbed dose of a substance.
Biological monitoring complements air monitoring by measuring what has actually been absorbed through all routes. ACGIH publishes Biological Exposure Indices (BEIs) as guidance values.
Question 6: What type of ventilation system captures contaminants at or near their source before they enter the worker's breathing zone?
- General dilution ventilation
- Local exhaust ventilation (Correct answer)
- Natural ventilation
- Recirculation ventilation
Correct answer: Local exhaust ventilation
Local exhaust ventilation captures airborne contaminants at or near the point of generation using hoods, ducts, and fans.
LEV uses a hood, ductwork, air cleaner, fan, and exhaust stack to remove contaminants before they disperse. It is more effective and energy-efficient than general dilution ventilation.
ASP Industrial Hygiene and Health 2
What is the hierarchy of controls in industrial hygiene, from most to least effective?