Power plant emissions dropped significantly over the Aura record, 2004-2014, particularly in the early part of the period.

The correspondence is generally great between changes/trends in OMI NO₂ levels and power plant NO_x emissions reported to the Continuous Monitoring Emissions System (CEMS).  However, there are many factors that can influence NO₂ levels above a power plant, including changes in regional background levels, other nearby sources, etc.  See Duncan et al. (2013) for a detailed discussion on this topic.