Re‐examination of the 2003 North American electrical blackout impacts on regional air quality

Abstract

Aircraft measurements have been utilized to capitalize on the 2003 North American electrical blackout as an unplanned event providing a unique opportunity to assess the impacts of power plants on air quality. Here we adopt a modeling approach using CMAQ with a direct sensitivity technique, DDM‐3D, to quantify how emissions reductions from different sources impacted ozone and particulate matter. Simulated air quality fields were able to reproduce both the regular surface observations and airborne measurements before and during the blackout. Sensitivity results show that blackout‐linked power plant SO2 emissions reductions led to a sulfate concentration reduction of 22% at Selinsgrove, Pennsylvania, while power plant NOx emissions reductions had very limited (∼4%) impacts on O3. These results are lower than the estimates presented in previous studies. Results also suggest that over much of the region, on‐road mobile NOx emissions reductions linked to the blackout had a larger impact on O3.