NOx Emissions and Lifetimes: Using DISCOVER-AQ to Evaluate CMAQ NO2 Through Use of Field Observations and Satellite Retrievals

A great deal of effort is expended at the state and federal level to forecast air quality episodes and to evaluate emissions control strategies that lead to attainment of the National Ambient Air Quality Standard for surface ozone. While air quality studies often focus on surface ozone, care must be taken to ensure that ozone precursors are accurately represented within the model framework. Recent analysis of surface measurements show that air quality models overestimate tropospheric NO2 in urban areas and underestimate NO2 in rural regions indicating possible problems with emissions inventories and/or chemical lifetimes. Our comparison of Community Multiscale Air Quality (CMAQ) model fields of NO2 in the mid-Atlantic region during summer 2011 to the Dutch Ozone Monitoring Instrument satellite retrievals of tropospheric column NO2 (DOMINO) lends further credence to this discrepancy. Here we explore possible ways to reconcile model and observations through use of data from ground based, aircraft, sonde, and satellite platforms obtained during the recent NASA DISCOVER-AQ mission and coordinated flights of the UMd aircraft. The ramifications proposed solutions to the model measurement discrepancy have on forecasts of surface ozone will be discussed.