• Determine whether project/action is in need of a quantitative hot -spot analysis. A hot - spot analysis is required only for projects of local air quality concern. The following describes the types of projects/actions that might require a hot-spot analysis for CO, PM$_{10 }$ and PM$_{2.5}$, respectively: 

− As stated in 40 CFR 93.123(a)(1) a quantitative CO hot -spot analysis should be considered for the following types of projects: 

“(i) For projects in or affecting locations, areas, or categories of sites which are identified in the applicable implementation plan as sites of violation or possible violation;(ii) For projects affecting intersections that are at Level-of- Service (LOS) 90 D, E, or F, or those that will change to LOS D, E, or F because of increased traffic volumes related to the project; (iii) For any project affecting one or more of the top three intersections nonattainment or maintenance area with highest traffic volumes, as identified in the applicable implementation plan; and (iv) For any project affecting one or more of the top three intersections in the nonattainment or maintenance area with the worst level of service, as identified in the implementation plan.” 

Furthermore, 40 CFR 93.123(a)(2) states: 

“…In cases other than those described above, the demonstrations required by § 93.116 may be based on either:(i) Quantitative methods that represent reasonable and common professional practice; or (ii) A qualitative consideration of local factors, if this can provide a clear demonstration that the requirements of § 93.116 are met.” 

− 40 CFR 93.123(b)(1) defines the projects of air quality concern that require a quantitative PM$_{10 }$and PM$_{2.5 }$hot-spot analysis as: 

“(i) New highway projects that have a significant number of diesel vehicles, and expanded highway projects that have a significant increase in the number of diesel vehicles; (ii) Projects affecting intersections that are at LOS D, E, or F with a significant number of diesel vehicles, or those that will change to LOS D, E, or F because of increased traffic volumes from a significant number of diesel vehicles related to the project; (iii) New bus and rail terminals and transfer points that have a significant number of diesel vehicles congregating at a single location; (iv) Expanded bus and rail terminals and transfer points that significantly increase the number of diesel vehicles congregating at a single location; and (v) Projects in or affecting locations, areas, or categories of sites which are identified in the PM 10 or PM 2.5 

