AQS Meteorology & Atmospheric Science Flashcards

What is the significance of the planetary boundary layer (PBL) height in daily air quality cycles?

Answer: It grows during daytime heating, increasing dilution volume, and collapses at night

The PBL height expands as daytime solar heating drives convective mixing, allowing greater dilution; it contracts after sunset, concentrating any overnight emissions near the surface.

Which meteorological parameter is used in the AERMOD dispersion model to characterize boundary layer turbulence?

Answer: Monin-Obukhov length

AERMOD uses the Monin-Obukhov length to characterize the thermodynamic state of the surface boundary layer and compute turbulence profiles for dispersion calculations.

Calm wind conditions (< 1 m/s) present a challenge for Gaussian dispersion models because:

Answer: The models assume non-zero wind speed for plume transport direction

Gaussian plume models require a defined transport wind direction and speed; near-calm conditions violate this assumption and require alternative puff or variable-wind approaches.

The urban heat island effect influences urban air quality primarily by:

Answer: Enhancing vertical mixing during the day but intensifying nocturnal inversions at the urban fringe

Urban heat islands promote daytime convective mixing over city cores but can create convergence zones and enhanced nocturnal inversions at urban edges, complicating pollutant patterns.

What is 'wet deposition' in the context of atmospheric pollutant removal?

Answer: Removal of pollutants from the atmosphere via precipitation (rain, snow, fog)

Wet deposition removes gases and particles from the atmosphere when they are scavenged by precipitation, transporting pollutants to Earth's surface via rain, snow, or fog.

Which dispersion model is the EPA's preferred regulatory model for near-field (< 50 km) industrial sources in the US?

Answer: AERMOD

AERMOD (American Meteorological Society/EPA Regulatory Model) is the EPA's preferred near-field steady-state Gaussian dispersion model for regulatory permit applications.