Emissions Control & Environmental Compliance Flashcards

A vehicle has a P0401 code (EGR flow insufficient). Which emission primarily increases when EGR flow is inadequate?

Answer: Oxides of nitrogen (NOx)

EGR reduces combustion temperature by diluting the intake charge with exhaust gas; insufficient EGR flow allows temperatures to rise, increasing NOx formation.

Under EPA's Greenhouse Gas Reporting Program, which sector is the single largest contributor to U.S. greenhouse gas emissions?

Answer: Transportation

As of recent EPA data, transportation surpassed electricity generation to become the largest U.S. GHG-emitting sector, primarily from cars and trucks burning fossil fuels.

A facility's air permit requires continuous emission monitoring (CEMS) for SO2. The CEMS experiences a data gap due to malfunction. How should missing data typically be treated per EPA regulations?

Answer: Treated as the highest potential emission rate for that period

EPA's missing data substitution procedures for CEMS generally require using the highest emission value measured in the most recent quality-assured data period, ensuring conservative accounting.

Which refrigerant, now phased down under the AIM Act, replaced R-22 in HVAC systems but still has a global warming potential (GWP) of approximately 2,088?

Answer: R-410A

R-410A replaced R-22 but itself has a high GWP of ~2,088, prompting the AIM Act to phase it down in favor of lower-GWP HFO alternatives.

What is the maximum allowable sulfur content (in parts per million) for Tier 3 compliant gasoline sold in the U.S. as of 2017?

Answer: 10 ppm

EPA's Tier 3 fuel standards require a maximum annual average sulfur content of 10 ppm in gasoline, enabling more effective catalytic converter performance.

An environmental auditor finds a facility is not required to obtain a Title V permit because its actual emissions fall below major source thresholds. The facility may still require a permit under which program?

Answer: Minor Source / State/local air permit program

Facilities below major source thresholds are typically regulated as minor sources under state or local air permit programs, which still require permits for construction or operation.

Which parameter does the OBD-II misfire monitor track to detect cylinder misfires that could damage the catalytic converter or increase HC emissions?

Answer: Crankshaft angular velocity (deceleration) between power strokes

The misfire monitor measures crankshaft deceleration between firing events; a misfiring cylinder causes a detectable drop in rotational speed compared to normal firing cylinders.