Slide 23 of 24

The scatter in the data in Slide 22 (most evident for benzene) contrasts the consistent trend of the data in the above slide. The contrast implies that the choice of placement of seals can affect VOC emissions. The variation of effect on stripping efficiency implies an optimal placement of seals may be possible, but determining the optimal condition would be difficult. However, the variation seen with grouped placement is relatively small. This implies the effect of sealed drain placement is small compared to the effect of increasing the number of sealed drains.