AQS Mitigation Strategies 3 — Questions and Answers
Question 1: Fugitive dust emissions from an unpaved haul road are best controlled using which mitigation measure?
- Installing electrostatic precipitators along the road
- Applying chemical dust suppressants or watering the road surface (Correct answer)
- Constructing a concrete barrier wall
- Reducing truck payload limits
Correct answer: Applying chemical dust suppressants or watering the road surface
Watering or applying chemical suppressants binds surface particles and prevents wind and vehicle traffic from suspending dust into the air.
Question 2: Under EPA's Enhanced Inspection and Maintenance (I/M) program, what is the main vehicle emission control goal?
- Ensure catalytic converters are physically present
- Identify and repair high-emitting vehicles to reduce on-road fleet emissions (Correct answer)
- Mandate fleet electrification by model year
- Verify fuel economy meets CAFE standards
Correct answer: Identify and repair high-emitting vehicles to reduce on-road fleet emissions
Enhanced I/M programs test actual tailpipe emissions and OBD systems to find and repair gross emitters, reducing fleet-average emissions significantly.
Question 3: Stage II vapor recovery systems at gasoline service stations are designed to capture which pollutant during vehicle refueling?
- Carbon monoxide (CO)
- Volatile organic compounds (VOCs) / gasoline vapors (Correct answer)
- Particulate matter (PM10)
- Nitrogen oxides (NOx)
Correct answer: Volatile organic compounds (VOCs) / gasoline vapors
Stage II systems use a vacuum-assist or balance nozzle to recover fuel vapors displaced from the vehicle tank during refueling, preventing VOC release.
Question 4: Which agricultural practice is a direct mitigation measure for ammonia (NH3) emissions from livestock operations?
- Covering manure storage lagoons (Correct answer)
- Increasing stocking density indoors
- Irrigating fields more frequently
- Switching to antibiotic feed supplements
Correct answer: Covering manure storage lagoons
Covering manure storage lagoons prevents volatilization of ammonia, which is a precursor to secondary PM2.5 formation.
Question 5: A construction project near a non-attainment area must implement Best Available Control Measures (BACM) for fugitive dust. Which of the following is NOT a typical BACM for construction sites?
- Stabilizing disturbed soil with vegetation or mulch
- Operating equipment only during daylight hours (Correct answer)
- Covering haul trucks transporting loose material
- Minimizing disturbed area and phasing grading operations
Correct answer: Operating equipment only during daylight hours
Limiting operating hours to daylight is a noise control measure, not a recognized dust control BACM for construction sites.
Question 6: Energy efficiency improvements in industrial processes are classified as what type of air quality mitigation?
- End-of-pipe control
- Pollution prevention (Correct answer)
- Dispersion modeling
- Offset crediting
Correct answer: Pollution prevention
Efficiency improvements reduce fuel consumption and therefore combustion emissions at the source, making them a pollution prevention strategy.
Question 7: Which emission control technology is specifically used to reduce mercury (Hg) from coal combustion flue gas?
- Wet limestone FGD scrubber alone
- Activated carbon injection (ACI) (Correct answer)
- Selective non-catalytic reduction (SNCR)
- Low-NOx burners
Correct answer: Activated carbon injection (ACI)
Activated carbon injection adsorbs gaseous mercury in the flue gas stream; the mercury-laden carbon is then captured by a downstream particulate control device.
AQS Mitigation Strategies 3
Fugitive dust emissions from an unpaved haul road are best controlled using which mitigation measure?