This Interval is a phantom Interval in that it actually happens outside of the Period. It begins the date the component was monitored (9/1) and ends when the actual Period begins. Since it is a Phantom Interval there are not emissions for this Interval.
200 PPM reading on 9/1 BEFORE the start of the period. We are going to use this PPM to help calculate the emissions in the first Interval- until we have a Profile change or a PPM. In this case- a PPM event on June 30.
LL Valve with Correlation Equation and 200 PPM = (200^.746) x 2.29E-06. There are not emissions in this Interval, but we are going to use this RefHER to help calculate the estimated HER when the Period begins.
Since this is a Phantom Interval we have not emissions, but we do have the RefHER that we calculated.
First day of Period with the component Active. We have an emission from 9/1 and we have another PPM reading on 6/30. But what is the estimated emission rate on 1/1?
The HER for the 9/1 PPM event (.000119) and the HER for the 6/30 event (.000236) are charted. The slope of the line is determined and the intercept of the line on 1/1 is identified (.00016595).
The average of the calculated HER for the sloped line on 1/1 and the actual HER for the PPM reading (500) that begins the next Interval.