General Practice Flashcards

Which sampling method is most appropriate when a worker's exposure varies significantly throughout the shift?

Answer: Full-period consecutive sampling

Full-period consecutive sampling captures the entire shift variability and provides the most representative TWA exposure estimate.

The ACGIH TLV-STEL is defined as a concentration that should not be exceeded for more than how many minutes at a time?

Answer: 15 minutes

The ACGIH TLV-STEL is a 15-minute TWA concentration that should not be exceeded at any time during the workday.

A noise survey reveals a worker is exposed to 95 dBA for 4 hours and 90 dBA for 4 hours. Using OSHA's permissible noise formula, what is the dose?

Answer: 125%

At 95 dBA the limit is 4 hours (4/4=1.0) and at 90 dBA the limit is 8 hours (4/8=0.5); combined dose = 1.0 + 0.5 = 1.5 = 150%.

Which administrative control is most effective for reducing cumulative chemical exposure when engineering controls are not feasible?

Answer: Job rotation among workers

Job rotation distributes exposure among multiple workers, reducing any single worker's cumulative dose when source elimination is not possible.

What does a real-time aerosol monitor measure that a gravimetric filter method does not provide?

Answer: Continuous time-resolved concentration data

Real-time aerosol monitors provide continuous, time-stamped concentration readings, allowing identification of peak exposure events during a shift.

In industrial hygiene, the term 'action level' under OSHA standards typically represents what fraction of the PEL?

Answer: One-half (50%)

OSHA action levels are generally set at one-half (50%) of the PEL to trigger monitoring, medical surveillance, and training requirements.

Which route of entry is most significant for lead exposure in a smelting operation?

Answer: Inhalation of lead fume and dust

Inhalation of airborne lead fume and dust is the primary route of occupational exposure in high-temperature smelting operations.