BOARD MEETING DATE: July 11, 2003
AGENDA NO. 36

Implement FY 2002-03 Environmental Justice Enhancement I – 4: Continue to Develop Localized Significance Thresholds for Subregions of the Air District as Another Indicator of CEQA Significance

SYNOPSIS:

On September 13, 2002, the Governing Board approved the implementation of Environmental Justice Program Enhancements for FY 2002-03. Enhancement I-4 directed staff to continue developing localized significance thresholds through a stakeholder working group. Staff has met with the stakeholder working group three times and developed a proposal to implement Enhancement I-4. The proposal consists of the methodology used to develop subregional localized significance thresholds, as well as the look-up tables by subregion. Look-up tables may be used for projects smaller than or equal to five acres. Project-specific modeling is recommended for projects larger than five acres. Use of these significance thresholds is advisory, not mandatory.

COMMITTEE:

Mobile Source, June 27, 2003, Reviewed

RECOMMENDED ACTION:

Adopt the attached resolution

Barry R. Wallerstein, D.Env.
Executive Officer

Background

The concept of developing localized significance thresholds in a look-up table format was originally developed in response to the environmental justice initiatives adopted by the Governing Board in October 1997. In particular, Environmental Justice Initiative #4 directed staff to revise the CEQA Air Quality Handbook (Handbook) and establish a stakeholder working group comprised of local government planners; representatives of local councils of government; environmental groups; the building and construction industries; and other interested individuals to solicit input on the revised Handbook.

In 1998, the AQMD started a series of Handbook revision working group meetings. One of the issues identified by the stakeholders was a request to address localized air quality impacts. With respect to criteria pollutants, the existing Handbook only discussed localized impacts as part of focused CO "hotspots" analyses prepared for mobile sources.

Assessing localized air quality impacts requires using complex dispersion models. Therefore, to address the issue of localized significance, yet be sensitive to the fact that other public agencies might not have the expertise or adequate financial resources to perform complex dispersion modeling, in addition to the methodology itself, AQMD staff began developing a proposal to establish localized significance thresholds in a form similar to the regional significance thresholds, that is, based on the amount of pounds of emission per day generated by a proposed project that would cause or contribute to localized air quality impacts.

After developing the methodology for deriving localized significance thresholds (LSTs), staff presented in the fourth quarter of 2001 the concept, methodologies, and a preliminary evaluation on the use of LSTs at Governing Board Mobile Source Committee meetings. Because of concerns and issues raised by committee members, the Mobile Source Committee recommended that staff seek approval from the Governing Board before proceeding with further development of the LSTs. On February 1, 2002, the Governing Board directed staff to continue developing LSTs and report back to the Board for consideration and possible incorporation into the Handbook.

On September 13, 2002, the AQMD Governing Board approved the implementation of Environmental Justice Program Enhancement for FY 2002-03. In connection with approving the Environmental Justice Program Enhancement for FY 2002-03 the Board directed staff to implement 23 enhancements to the original Environmental Justice Program divided into three categories. Under Category I: Further-reduced Health Risks, Enhancement I-4 included a proposal to continue developing localized significance thresholds for subregions of the air district, as another indicator of CEQA significance.

Proposal

An air quality analysis normally separates a project’s emissions into construction and operational activity emissions because these two activities are typically sequential. Relative to the staff proposal, the emissions of primary concern from construction activities are NOx and CO combustion emissions from construction equipment¹ and fugitive PM10 dust from construction site preparation activities. The primary emissions from operational activities include, but are not limited to NOx and CO combustion emissions from stationary sources and/or on-site mobile equipment. Some operational activities may also include fugitive PM10 dust generating activities such as aggregate operations or earthmoving activities at landfills. Volatile organic compounds (VOCs) are considered to be ozone precursors. Since ozone is a pollutant of regional concern, LSTs are not applicable to VOC emissions. VOCs that are classified as air toxics are already subject to health risk assessment analysis procedures pursuant to the SCAQMD document Risk Assessment Procedures for Rules 1401 and 212.

¹ Construction equipment also emits PM10, but for simplicity these emissions should be combined with the fugitive PM10 dust when using the LSTs.

LSTs are derived using one of three methodologies depending upon the attainment status of the pollutant. For attainment pollutants, nitrogen dioxide (NO2) and CO², the LSTs are derived using an air quality dispersion model to back-calculate the emissions per day that would cause or contribute to a violation of any ambient air quality standard (AAQS) for a particular source receptor area (SRA). The most stringent standard for NO2 is the one-hour state standard of 25 parts per hundred million (pphm); and for CO it is the one-hour and eight-hour state standards of nine parts per million (ppm) and 20 ppm, respectively.

LSTs are developed based upon the size or total area of the emissions source, the ambient air quality³ in each SRA in which the emission source is located, and the distance to the sensitive receptor. LSTs for NO2 and CO are derived by adding the incremental emission impacts from the project activity to the peak background NO2 and CO concentrations and comparing the total concentration to the most stringent ambient air quality standards. Background criteria pollutant concentrations are represented by the highest measured pollutant concentration in the last three years at the air quality monitoring station nearest to the proposed project site.

²Although the district has not been designated as in attainment with the CO ambient air quality standards, it has not exceeded any CO ambient air quality standards for the last two years. Therefore, for developing LSTs, the attainment pollutant approach is applicable.

³Ambient air quality information is based on the pollutant concentrations measured at the AQMD’s monitoring stations in or near the specified SRA.

Construction PM10 LSTs are developed using a dispersion model to back-calculate the emissions necessary to exceed a concentration equivalent to 50 micrograms per cubic meter (µg/m3) averaged over five hours, which is the control requirement in Rule 403. The equivalent concentration for developing PM10 LSTs is 10.4 µg/m3, which is a 24-hour average.

Operation PM10 LSTs are derived using an air quality dispersion model to back-calculate the emissions necessary to make an existing violation in the specific SRA worse, using the allowable change in concentration thresholds in Table A-2 in Rule 1303. For PM10 the allowable change in concentration thresholds is 2.5 µg/m3. These levels represent measurable impacts taking into account modeling sensitivity.

The staff proposal recommends using the LST look-up tables only for projects that are less than or equal to five acres. It should be noted that lead agencies are not precluded from performing project-specific modeling if they prefer more precise results. It is recommended that lead agencies perform project-specific air quality modeling for larger projects.

The concepts inherent in the above staff recommendations are generally consistent with the modeling requirement in AQMD Rule 1303(b)(1), which states that the Executive Officer shall deny a Permit to Construct for any new or modified source with an emission increase unless, "The applicant substantiates with modeling that the new facility or modification will not cause a violation, or make significantly worse an existing violation… of any AAQS at any receptor in the district." The actual methodology used to derive the LSTs is described in more detail in the attached Draft Localized Significance Threshold Methodology document.

Legal Authority

CEQA Guidelines §15022(a) states that a public agency shall adopt objectives, criteria, and specific procedures consistent with CEQA and these [State] Guidelines for administering its responsibilities under CEQA. CEQA Guidelines 15022(d) states further, "In adopting procedures to implement CEQA, a public agency may adopt the State CEQA Guidelines through incorporation by reference. The agency may then adopt only those specific procedures or provisions described in subsection [15022] (a) which are necessary to tailor the general provisions of the guidelines to the specific operations of the agency." At the December 11, 1998 Public Hearing the AQMD’s Governing Board formally incorporated by reference the State CEQA Guidelines as the implementing guidelines for the AQMD’s CEQA program. Adopting LSTs would be consistent with CEQA Guidelines §15022 provision to tailor a public agency’s implementing guidelines by adopting criteria relative to the specific operations of the AQMD.

Specifically with regard to thresholds of significance, CEQA Guidelines §15064.7(a) states, "Each public agency is encouraged to develop and publish thresholds of significance that the agency uses in the determination of the significance of environmental effects." Subsection (b) of the same section states further, "Thresholds of significance to be adopted for general use as part of the lead agency’s environmental review process must be adopted by ordinance, resolution, rule or regulation, and developed through a public review process and be supported by substantial evidence." The methodology for developing LSTs and the resulting LSTs developed by the AQMD staff have undergone a public review process as part of stakeholder working group meetings that were open to the public and a public consultation meeting. The attached methodology document provides the substantial evidence relative to the methodology for developing LSTs. The LST proposal is also being heard by the AQMD’s Governing Board at a public meeting, where it will be considered for adoption by resolution, consistent with CEQA Guidelines §15064.7(b). Upon Board adoption, LSTs serve as guidance, not a mandatory requirement, to other lead agencies for their air quality impact analyses.

Key Issues/Comments

The following summarizes the key issues raised during the development of the staff proposal and received by the AQMD staff either in writing or during the public consultation meeting held on June 19, 2003. A more complete discussion of public comments and staff responses can be found in Attachment C to this Board letter.

• LSTs should be delayed until the CEQA Handbook is revised, including identification of new mitigation measures.

LSTs have been under development for almost five years and no inconsistencies with other areas of the existing Handbook or the updates contemplated for the Handbook have been identified. Identifying mitigation measures and associated control efficiencies is an ongoing effort by AQMD staff. The AQMD has hired a consultant to assist with this effort. The Handbook currently contains a substantial list of mitigation measures and associated control efficiencies. Lead agencies are not constrained to use only those mitigation measures in the Handbook. If the lead agencies identify feasible mitigation measures not identified in the Handbook, it is recommended that they be implemented as part of the CEQA analysis.

• LSTs may be inconsistent with local government policies such as infill projects.

Infill projects that meet certain criteria are exempt from CEQA pursuant to CEQA Guidelines §15332. Otherwise, staff has not identified policies related to the LSTs that may be inconsistent with locally adopted policies. CEQA currently requires public agencies to examine adverse impacts from proposed projects to determine whether or not they may exceed significance criteria. LSTs simply provide another indicator of significance. Staff is willing to work with other lead agencies to assist them with implementing the LSTs.

• Implementing LSTs may cause disparities in siting projects.

The same federal and state AAQSs and risk values are uniformly applied to all areas in the district; except for Class I protected areas which are more stringent. These values, set by federal and state law, are the basis for evaluating adverse localized air quality impacts. Similarly for PM10, the construction LSTs are based on Rule 403 and the operational LSTs are based on the detectable change in concentration threshold in Table A-2 in Rule 1303. Both rules are applicable district-wide. Differences in LSTs between SRAs are caused primarily by differences in background concentrations and meteorology. The differences between neighboring areas and regions are already present in any analysis of adverse localized air quality impacts.

• LSTs may increase project costs and delay projects.

It is possible that costs could increase if more mitigation measures are required to be implemented. However, an evaluation by staff on the effects of adopting LSTs indicated that in the majority of cases it was construction emissions that exceeded the PM10 LSTs. However, project proponents would have to perform more realistic emission calculations to avoid overestimation. Furthermore, mitigation measures to reduce PM10 emissions during construction would have to be cost effective to be available and in many cases would likely be relatively inexpensive. It is possible that projects that now qualify for a negative declaration will need to be classified as mitigated negative declarations, but this is not expected to appreciably increase the time or cost burdens on project proponents or the lead agencies.

Implementation of the Localized Significance Thresholds

Because environmental analyses typically take months or longer to prepare, it is recommended that voluntary use of the LSTs begin on the date of adoption for new projects undergoing the environmental analysis process after the date of adoption. Projects that have already begun the environmental analysis process may continue using only the existing regional significance thresholds.

Resource Impacts

It is expected that implementation of EJ Enhancement I-4 will begin in July 2003. Existing AQMD resources will be sufficient to implement this policy.

Attachments (1,913 KB)

1. LST Development Process
2. Resolution
3. Localized Significance Thresholds – Key Issues/Comments
4. Draft Localized Significance Threshold Methodology Document

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