NCED Emissions Control & Environmental Compliance 3 — Questions and Answers
Question 1: A catalytic converter reaches light-off temperature at approximately what degree Fahrenheit during cold start?
- 100°F
- 250°F
- 400–600°F (Correct answer)
- 900°F
Correct answer: 400–600°F
Catalytic converters become effective (reach light-off) at roughly 400–600°F, which is why cold-start emissions are highest before the catalyst warms up.
Question 2: Which Clean Air Act section established the Acid Rain Program targeting SO2 and NOx reductions from power plants?
- Title I
- Title III
- Title IV (Correct answer)
- Title VI
Correct answer: Title IV
Title IV of the 1990 Clean Air Act Amendments created the Acid Rain Program with a cap-and-trade approach to reduce SO2 and NOx emissions from electric utilities.
Question 3: A technician notices a vehicle's exhaust smells strongly of rotten eggs (hydrogen sulfide). This odor most likely indicates:
- Rich air-fuel mixture causing incomplete combustion
- A failing catalytic converter unable to convert H2S from sulfur in fuel (Correct answer)
- A stuck-open EGR valve
- A lean misfire condition
Correct answer: A failing catalytic converter unable to convert H2S from sulfur in fuel
A sulfur or rotten-egg odor indicates the catalytic converter is not properly converting hydrogen sulfide produced from sulfur compounds in gasoline.
Question 4: Which EPA program requires facilities that use, store, or release extremely hazardous substances above threshold quantities to submit Risk Management Plans (RMPs)?
- EPCRA Section 313
- CAA Section 112(r) (Correct answer)
- RCRA Subtitle C
- CERCLA Section 103
Correct answer: CAA Section 112(r)
CAA Section 112(r) requires facilities with extremely hazardous substances above threshold quantities to develop and submit Risk Management Plans to prevent accidental releases.
Question 5: What does the lambda (λ) value of 1.0 represent in engine emissions management?
- Maximum fuel enrichment
- Stoichiometric air-fuel ratio (perfect combustion balance) (Correct answer)
- Lean detonation threshold
- Idle air-fuel ratio for diesels
Correct answer: Stoichiometric air-fuel ratio (perfect combustion balance)
Lambda = 1.0 represents the stoichiometric air-fuel ratio (14.7:1 for gasoline), where the ideal balance exists for the three-way catalytic converter to reduce all three major pollutants.
Question 6: Under EPA's Prevention of Significant Deterioration (PSD) program, a major new source in an attainment area must install which type of emission control?
- Reasonably Available Control Technology (RACT)
- Best Available Control Technology (BACT) (Correct answer)
- Lowest Achievable Emission Rate (LAER)
- Maximum Achievable Control Technology (MACT)
Correct answer: Best Available Control Technology (BACT)
PSD requires major new sources in attainment areas to apply Best Available Control Technology (BACT), determined on a case-by-case basis.
Question 7: Which diagnostic code category indicates an emission-related fault that will illuminate the Malfunction Indicator Lamp (MIL) on the first occurrence?
- Type A MIL code (Correct answer)
- Type B MIL code
- Type C pending code
- Type D informational code
Correct answer: Type A MIL code
Type A codes are the most severe emission-related faults and illuminate the MIL immediately upon the first detection of the fault.
NCED Emissions Control & Environmental Compliance 3
A catalytic converter reaches light-off temperature at approximately what degree Fahrenheit during cold start?