Certified Industrial Hygienist (CIH)
Examination Practice Exam Questions
And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A
Instant Do wnload Pdf
1. The most efficient instrumental technique for the qualitative determination
of the elemental content of a dust sample is:
A) High performance liquid chromatography
B) Gas chromatography
C) X-ray diffraction
D) UV spectrophotometry
E) Atomic absorption spectrophotometry
F) Emission spectroscopy
Correct Answer: F
Rationale: Emission spectroscopy is used for qualitative determination of
elemental content. Atomic absorption is quantitative, while X-ray diffraction
identifies crystalline compounds.
2. In a work area, noise levels are 95 dBA for two hours, 90 dBA for four hours,
and 80 dBA for two hours. Does this exceed OSHA limits?
A) Yes
B) No
,Correct Answer: A
Rationale: Using the OSHA noise dose calculation: 95 dBA for 2 hours = 2/4 = 0.5;
90 dBA for 4 hours = 4/8 = 0.5; 80 dBA for 2 hours = 0. Total dose = 1.0 (100%). This
is at the limit and exceeds allowable limits.
3. A respirator protection factor of 100 means:
A) The concentration outside should not exceed 100 times the TLV
B) The respirator will last 100 times longer than PF 1
C) The concentration inside is not expected to exceed 1/100th of the concentration
outside
D) A and C only
E) All of the above
Correct Answer: D
Rationale: A protection factor of 100 means the respirator reduces contaminant
concentration to 1/100 of the outside level, and the outside concentration should
not exceed 100 times the exposure limit.
4. Which is NOT a limitation of chemical cartridge respirators?
A) Prohibited in oxygen-deficient atmospheres
B) Limited to less than 10 times the TLV
C) Limited to less than 5 times the TLV without a fit test
D) Prohibited in IDLH atmospheres
E) All are limitations
,Correct Answer: E
Rationale: All listed items are limitations of chemical cartridge respirators. They
cannot be used in oxygen-deficient or IDLH atmospheres and have concentration
limits.
5. A room requires 5 air changes per hour for ventilation. Which statement best
describes the situation?
A) Not sufficient since 10 air changes is only "fair" ventilation
B) Adequate if only solvents with TLV >200 ppm are used
C) A 3 sq ft fan must exhaust at 5000 cfm
D) Fan selection depends on knowing room dimensions
E) The room is very large
Correct Answer: D
Rationale: Fan selection and speed depend on room volume. Air changes per hour
= (cfm × 60) / room volume. Without room dimensions, fan requirements cannot be
determined.
6. Which is NOT a simple asphyxiant?
A) CH₄
B) N₂
C) Ar
D) C₂H₄
E) C₂H₂
, Correct Answer: C (Argon)
Rationale: Argon is a simple asphyxiant. Methane, nitrogen, ethylene, and
acetylene are also asphyxiants.
7. Which form of silica has the lowest TLV?
A) Crocidolite
B) Cristobalite
C) Chrysotile
D) Tridymite
E) Crystalline quartz
F) Fused silica
Correct Answer: D
Rationale: Tridymite is a high-temperature polymorph of crystalline silica with a
very low TLV. Crocidolite and chrysotile are asbestos minerals.
8. One machine generates 98 dBA and another produces 96 dBA. What is the
new combined reading?
A) 97 dBA
B) 98 dBA
C) 99 dBA
D) 100 dBA
Correct Answer: D
Examination Practice Exam Questions
And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A
Instant Do wnload Pdf
1. The most efficient instrumental technique for the qualitative determination
of the elemental content of a dust sample is:
A) High performance liquid chromatography
B) Gas chromatography
C) X-ray diffraction
D) UV spectrophotometry
E) Atomic absorption spectrophotometry
F) Emission spectroscopy
Correct Answer: F
Rationale: Emission spectroscopy is used for qualitative determination of
elemental content. Atomic absorption is quantitative, while X-ray diffraction
identifies crystalline compounds.
2. In a work area, noise levels are 95 dBA for two hours, 90 dBA for four hours,
and 80 dBA for two hours. Does this exceed OSHA limits?
A) Yes
B) No
,Correct Answer: A
Rationale: Using the OSHA noise dose calculation: 95 dBA for 2 hours = 2/4 = 0.5;
90 dBA for 4 hours = 4/8 = 0.5; 80 dBA for 2 hours = 0. Total dose = 1.0 (100%). This
is at the limit and exceeds allowable limits.
3. A respirator protection factor of 100 means:
A) The concentration outside should not exceed 100 times the TLV
B) The respirator will last 100 times longer than PF 1
C) The concentration inside is not expected to exceed 1/100th of the concentration
outside
D) A and C only
E) All of the above
Correct Answer: D
Rationale: A protection factor of 100 means the respirator reduces contaminant
concentration to 1/100 of the outside level, and the outside concentration should
not exceed 100 times the exposure limit.
4. Which is NOT a limitation of chemical cartridge respirators?
A) Prohibited in oxygen-deficient atmospheres
B) Limited to less than 10 times the TLV
C) Limited to less than 5 times the TLV without a fit test
D) Prohibited in IDLH atmospheres
E) All are limitations
,Correct Answer: E
Rationale: All listed items are limitations of chemical cartridge respirators. They
cannot be used in oxygen-deficient or IDLH atmospheres and have concentration
limits.
5. A room requires 5 air changes per hour for ventilation. Which statement best
describes the situation?
A) Not sufficient since 10 air changes is only "fair" ventilation
B) Adequate if only solvents with TLV >200 ppm are used
C) A 3 sq ft fan must exhaust at 5000 cfm
D) Fan selection depends on knowing room dimensions
E) The room is very large
Correct Answer: D
Rationale: Fan selection and speed depend on room volume. Air changes per hour
= (cfm × 60) / room volume. Without room dimensions, fan requirements cannot be
determined.
6. Which is NOT a simple asphyxiant?
A) CH₄
B) N₂
C) Ar
D) C₂H₄
E) C₂H₂
, Correct Answer: C (Argon)
Rationale: Argon is a simple asphyxiant. Methane, nitrogen, ethylene, and
acetylene are also asphyxiants.
7. Which form of silica has the lowest TLV?
A) Crocidolite
B) Cristobalite
C) Chrysotile
D) Tridymite
E) Crystalline quartz
F) Fused silica
Correct Answer: D
Rationale: Tridymite is a high-temperature polymorph of crystalline silica with a
very low TLV. Crocidolite and chrysotile are asbestos minerals.
8. One machine generates 98 dBA and another produces 96 dBA. What is the
new combined reading?
A) 97 dBA
B) 98 dBA
C) 99 dBA
D) 100 dBA
Correct Answer: D
