Air Emissions, Permitting, and Monitoring
What the exam tests
Air questions test source classification, permit applicability, emission calculations, control efficiency, and monitoring obligations. Expect the Clean Air Act programs: SIP requirements, New Source Performance Standards, NESHAP and MACT standards for hazardous air pollutants, Title V operating permits, and New Source Review or PSD permitting.
Core rules
- Title V major-source thresholds include 100 tons per year of any criteria pollutant, 10 tons per year of a single hazardous air pollutant, or 25 tons per year of combined hazardous air pollutants; nonattainment areas can have lower thresholds.
- PSD major-source thresholds are commonly 100 or 250 tons per year depending on the source category and attainment status.
- Applicability is generally based on potential emissions, not last year’s actual emissions.
- Emission estimates use activity rates, emission factors, fuel data, and control efficiency. Monitoring may include CEMS, stack testing, opacity readings, or leak detection and repair.
- Records must support reported emissions, deviations, and compliance certifications.
Worked example
A boiler operates 2,000 hours per year and emits 10 lb/hr of NOx uncontrolled. Annual uncontrolled emissions are 20,000 lb, or 10 tons. With 80% control, potential emissions are 2 tons per year. If the same facility emits 11 tons per year of a single HAP, it is a major source for HAP purposes even though its criteria-pollutant potential is low. The reasoning is that major-source thresholds apply separately to criteria pollutants and HAPs.
Traps
Using actual emissions when potential emissions control applicability; ignoring fugitive emissions; assuming a permit exemption applies without checking source category; confusing opacity percent with Ringelmann number; failing to account for CEMS downtime; and reporting rounded values that hide an exceedance.