Revised estimates for continuous shoreline fumigation: a PDF approach

Area of Science:

• Atmospheric Science
• Environmental Engineering
• Fluid Dynamics

Background:

• Coastal areas face unique air pollution challenges due to shoreline emissions.
• Understanding pollutant dispersion is crucial for environmental and health impact assessments.
• Existing models often simplify atmospheric boundary layer complexities.

Purpose of the Study:

• To develop and validate a probability density function (PDF) fumigation model for air pollutant dispersion from tall stacks on shorelines.
• To investigate pollutant dispersion within the stable layer and the thermal internal boundary layer (TIBL).
• To incorporate advanced turbulence characteristics, including skewed vertical velocity PDFs and finite Lagrangian integral time scales.

Main Methods:

• Utilized a PDF fumigation model with independent lateral and vertical dispersion assumptions.
• Modeled TIBL growth parabolically and turbulence as homogeneous and stationary.
• Employed a skewed bi-Gaussian vertical velocity PDF, informed by Weil's solutions.
• Incorporated finite Lagrangian integral time scales and Weil and Brower's convective limit.

Main Results:

• The model accurately simulates pollutant dispersion, particularly during fumigation events.
• Finite Lagrangian integral time scales reduce initial vertical dispersion, shifting maximum concentrations downwind.
• Reduced initial dispersion leads to higher concentrations at greater distances.
• Model predictions show good agreement with Nanticoke field experiment data.

Conclusions:

• The revised PDF fumigation model provides a robust tool for assessing air quality near coastlines.
• The model's ability to capture TIBL dynamics and turbulence effects enhances dispersion predictions.
• Validation against experimental data confirms the model's reliability for real-world applications.