AQS AQS Meteorology & Atmospheric Science 2 — Questions and Answers
Question 1: The Gaussian plume dispersion model assumes pollutants spread in what mathematical pattern crosswind?
- Uniform distribution
- Normal (bell-curve) distribution (Correct answer)
- Logarithmic distribution
- Exponential decay
Correct answer: Normal (bell-curve) distribution
Gaussian dispersion models assume a normal distribution of pollutant concentrations in both the horizontal and vertical crosswind directions from a plume centerline.
Question 2: Fumigation in air quality meteorology refers to:
- Deliberate disinfectant fogging indoors
- Rapid downward mixing of an elevated plume to ground level (Correct answer)
- Release of pollutants from soil
- Photochemical smog formation
Correct answer: Rapid downward mixing of an elevated plume to ground level
Fumigation occurs when an elevated plume is trapped beneath a temperature inversion and is mixed to the surface by turbulent eddies, causing sharp ground-level concentration spikes.
Question 3: What role does solar radiation play in ground-level ozone formation?
- It directly emits ozone from the sun
- It provides energy to drive photochemical reactions between NOx and VOCs (Correct answer)
- It destroys ozone precursors before they react
- It has no direct role in ozone chemistry
Correct answer: It provides energy to drive photochemical reactions between NOx and VOCs
Ultraviolet solar radiation catalyzes the photochemical reaction between nitrogen oxides (NOx) and volatile organic compounds (VOCs) to produce ground-level ozone.
Question 4: Sea breeze circulation typically affects coastal air quality by:
- Permanently dispersing pollutants offshore
- Recirculating inland pollutants back to coastal areas in the evening (Correct answer)
- Increasing ozone destruction rates
- Preventing formation of secondary pollutants
Correct answer: Recirculating inland pollutants back to coastal areas in the evening
Daytime sea breezes carry coastal pollutants inland; overnight land breezes can return processed pollutants seaward, causing recirculation and elevated concentrations.
Question 5: In Gaussian dispersion modeling, effective stack height accounts for:
- Stack diameter only
- Physical stack height plus plume rise due to buoyancy and momentum (Correct answer)
- Atmospheric pressure at the stack tip
- Local terrain elevation only
Correct answer: Physical stack height plus plume rise due to buoyancy and momentum
Effective stack height equals the physical stack height plus plume rise, which depends on exit velocity, temperature excess, and atmospheric stability.
Question 6: Which atmospheric stability class represents the most unstable (highly convective) conditions in the Pasquill-Gifford system?
- Class F
- Class D
- Class A (Correct answer)
- Class C
Correct answer: Class A
Class A represents extremely unstable conditions with strong insolation and light winds, promoting rapid vertical mixing and the greatest dilution of pollutants.
AQS AQS Meteorology & Atmospheric Science 2
The Gaussian plume dispersion model assumes pollutants spread in what mathematical pattern crosswind?