Draft EA - San Diego International Airport

SAN DIEGO INTERNATIONAL AIRPORT – PROPOSED RUNWAY 9 DISPLACED THRESHOLD
4.5 Air Quality
The primary sources of guidance for assessing potential air quality effects are FAA Orders 1050.1E and the Air
Quality Procedures for Civilian Airports and Air Force Bases (Airport Air Quality Handbook). 11
Typically, an
emissions inventory is prepared for each reasonable alternative, including the No Action alternative.
Additional analyses, including dispersion modeling or roadway intersection hot spot analyses, are not typically
required if the estimated emissions of each criteria pollutant would not exceed thresholds listed in the general
conformity regulations. Information presented in the Airport Air Quality Handbook can be used to determine
whether an NAAQS assessment 12
should be performed for a proposed action.
4.5.1 REGULATORY STANDARDS AND CRITERIA
The CAA requires federal agencies to ensure that their actions conform to the appropriate SIP. Conformity is
defined as demonstrating that a project or action conforms to the SIP’s purpose of eliminating or reducing the
severity and number of violations of the NAAQS, and achieving expeditious attainment of such standards.
Federally funded and approved actions at airports are subject to the U.S. EPA’s general conformity regulations.
The U.S. EPA has published a final rule regarding general conformity determinations. 13
The final rule includes
annual emissions thresholds for nonattainment areas and maintenance areas that trigger the need for a
general conformity determination, and defines projects that are generally excluded from general conformity
requirements.
A conformity determination is required if one of the following occurs: (1) the total direct and indirect
pollutant emissions 14 resulting from a project are above de minimis 15 emissions threshold levels specified in the
conformity regulations, or (2) pollutant emissions from the project would be regionally significant (i.e., the
project would contribute 10 percent or more of the region’s total emissions for a criteria pollutant). A
conformity determination is not required if the differences in emissions between the proposed action and the
no action alternative are below the applicable de minimis threshold levels. If a conformity determination is
required, the regulation identifies the approaches for showing that an action/project conforms to the
appropriate SIP.
11
12
13
14
15
U.S. Department of Transportation, Federal Aviation Administration, Air Quality Procedures for Civilian Airports and Air Force Bases, Report
No. FAA-AEE-97-03, Washington, DC, April 1997, including the addendum, Report No. FAA-AEE-04-03, September 2004.
When a Proposed Action could cause or contribute to an exceedance of the NAAQS, pollutant concentrations are estimated for criteria
pollutants of interest through air dispersion modeling. The FAA’s Emissions and Dispersion Modeling System (EDMS) incorporates
algorithms from the U.S. EPA’s AERMOD dispersion model.
U.S. Environmental Protection Agency, 40 Code of Federal Regulations Part 93, Determining Conformity of Federal Actions to State or
Federal Implementation Plans, Subpart B, November 30, 1993, as amended.
Total direct and indirect emissions are the sum of the emissions increases and decreases associated with a proposed project, or the “net”
change in emissions anticipated to occur as a result of the proposed project (40 CFR 93.152).
Emissions are so small as to be negligible or insignificant. If a project/action has de minimis emissions, a conformity determination/
NAAQS assessment pursuant to the Clean Air Act Amendments of 1990 is not required (40 CFR 93.153c).
Draft EA
Environmental Consequences
[4-15]