Figure 1.2 replicates Figure 5.1 from the main body of this report; it presents a comparison of PM2.5 emissions from several alternatives analyzed. A strategy to mitigate emissions from passenger vehicles is shown to be relatively ineffective compared to a strategy focused on commercial vehicles because PM2.5 emissions are predominantly generated by the commercial vehicle. Emissions for a hypothetical scenario, in which no vehicle delay occurs at the border crossing, is shown to establish that about half of the PM2.5 emissions are the result of border crossing delay; this estimate effectively sets a maximum emission reduction benefit that could be accrued by any combination of projects.
