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2.10 Air Quality

The proposed project is consistent with the description included in the 2006 RTIP and

therefore conforms to the RTIP and RTP. Approval of the 2006 RTIP and its air quality
conformity analysis by the FHWA and FTA means that the proposed project conforms to

the RTIP and RTP.

Carbon Monoxide: The project site is in a federal CO and PM 10 nonattainment areas,

and, consequently, the project must be evaluated for CO and PM 10 effects at a project
level. The Transportation Project-Level Carbon Monoxide Protocol, UCD-ITS-97-21

(the Protocol), University of California, Davis, December 1997 (UC Davis Institute of
Transportation Studies 1997) provides procedures and guidelines for use by agencies to

evaluate the potential local level CO effects of a transportation project. Per the Protocol,
the project is satisfactory for local CO concentrations and no further analysis is required.

A description of the process used to reach this conclusion is provided in the Air Quality

Impact Analysis: Golden Valley Road Bridge, Santa Clarita, California (EDAW 2006c).

Particulate Matter - PM 10 and PM 2.5: A hot spot analysis is defined in 40 CFR 93.101
as an estimation of likely future localized PM 2.5 or PM 10 pollutant concentrations and a

comparison of those concentrations to the relevant air quality standards. A hot spot

analysis assesses the air quality effects on a scale smaller than an entire nonattainment or
maintenance area, including, for example, congested roadway intersections and highways

or transit terminals. Such an analysis is a means of demonstrating that a transportation
project meets Clean Air Act conformity requirements to support state and local air quality

goals with respect to potential localized air quality effects. When a hot spot analysis is
required, it is included within the project-level conformity determination made by the

FHWA or FTA.

Based on the project traffic report (Katz, Okitsu & Associates 2005), a conservative

estimate of the maximum Average Annual Daily Traffic (AADT) on Newhall Ranch
Road/Golden Valley Road is 50,000. Further, a diesel truck traffic fraction on the

roadway is likely 2 to 3 percent. Therefore, the Golden Valley Road Bridge Project is not
a project of air quality concern, and no qualitative PM 10 or PM 2.5 analysis is required by

the FHWA.

Page 2.10-16 Golden Valley Road Bridge EA
City of Santa Clarita