Using observations and source specific model tracers to characterize pollutant transport during FRAPPÉ and...

Area of Science:

• Atmospheric Science
• Air Quality Research
• Environmental Modeling

Background:

• Transport phenomena significantly influence air quality in complex terrain like the Colorado Northern Front Range Metropolitan Area (NFRMA).
• Terrain-induced flows and recirculation patterns in the NFRMA can lead to the mixing of diverse emission sources, complicating air quality assessments.

Purpose of the Study:

• To investigate air pollution transport processes within the NFRMA during the FRAPPÉ and DISCOVER-AQ campaigns.
• To analyze the connection between transport patterns and air quality in the NFRMA.
• To characterize pollution movement from the NFRMA to mountainous areas and its recirculation potential.

Main Methods:

• Utilized the Weather Research and Forecasting (WRF) Model with inert tracers to simulate atmospheric transport.
• Compared model outputs of winds and tracers with observational data from the FRAPPÉ and DISCOVER-AQ campaigns.
• Analyzed specific pollution transport events, including one on August 12, 2014, using aircraft data.

Main Results:

• The WRF model accurately represented measured winds and inert tracer concentrations, validating its performance.
• Model tracers effectively supported the analysis of surface winds, ozone concentrations, and emission interactions.
• Distinct air mass separations were observed during upslope events, with northern areas influenced by oil and gas emissions and southern areas by urban emissions.

Conclusions:

• Pollution originating in the NFRMA can impact adjacent mountain areas east of the Continental Divide.
• Pollutants can "spill over" the Continental Divide, affecting valleys to the west.
• The study highlights the complex interplay of terrain, emissions, and transport in shaping regional air quality.