Using Historical Information to Improve Emission Projections (or How to Avoid Being Doomed to Repeat History)

The poet and philosopher, George Santayana is often quoted as having said that “those who cannot learn from history are doomed to repeat it.” While he certainly did not have emissions forecasting in mind when identifying this conceit, it does have application to air pollutant emission projection practitioners. Under contract to the Lake Michigan Directors Consortium, E.H. Pechan & Associates, Inc. is performing a study to analyze whether recent historical evidence suggests that EPA’s emission projection guidance and tools may overstate future emission levels. The purpose of this ongoing study, which focuses on a set of Midwest region priority stationary source categories, is two-fold: (1) compare default EPA emission activity growth rates with recent historical emission activity growth rates; and (2) analyze whether past trends indicate that significant stationary source emission reductions may be expected to occur beyond those forecast by EPA’s projections methodology.