Carbon monoxide modeling and mobile source air toxics analysis

Challenge

The additional travel lanes contemplated as part of the project alternatives will have the effect of moving some traffic closer to nearby homes, schools and businesses. Therefore, under each alternative there may be localized areas where ambient concentrations of Mobile Source Air Toxics (MSAT) could be higher under certain Build Alternatives than the No-Build Alternative.

Solution

A quantitative analysis of mass air toxic emissions from the travel study area of the proposed project was completed by following the +/- 5 percent “link by link” methodology and by using the latest version of the EPA’s mobile emission factor model (MOBILE6.2). The travel study area used for the MSAT analysis is the same area as the MPA within the North Central Texas Council of Government (NCTCOG) Region.

Benefit

The analysis indicates a decrease in MSAT emissions for both the Build and No-Build Alternatives for the design year of 2035 versus the 2012 base year. Total MSAT emissions under a Build scenario are predicted to decrease by 32 percent between 2012 and 2035.