1 STATE OF CALIFORNIA

CALIFORNIA AIR RESOURCES BOARD

STAFF REPORT

**ANALYSIS OF THE 2012**  **PM 2.5**  **EMISSION INVENTORY SUBMITTAL**  **TO THE STATE IMPLEMENTATION PLAN FOR**  **THE CHICO PLANNING AREA** 

I. BACKGROUND

The federal Clean Air Act establishes planning requirements for those areas that
exceed the health

- based National Ambient Air Quality Standards ( NAAQS ). Areas are designated as nonattainment based on monitored exceedances of the NAAQS . These nonattainment areas must develop and implement a State Impl ementation Plan (SIP) that demonstrates how they will attain the NAAQS by specified dates.

In December 2006, the United States Environmental Protection Agency (U.S. EPA)
lowered the 24

- hour NAAQS for fine particulate matter (PM 2.5 ) from 65 μ g/m 3 to
35 μ g/m 3 . Effective December 14, 2009, U.S. EPA designated the Chico, CA/Butte County (partial) Planning Area ( Chico Planning Area) in the Butte County Air Quality Management District ( Butte District) as nonattainment for this more stringent 24

- hour
PM 2.5 NAA QS . The subsequent SIP submittal deadline is December 14, 2012.

II. CLEAN DATA POLICY REQUIREMENTS

Under the U.S. EPA’s Clean Data Policy for the Fine Particulate National Ambient Air Quality Standards (Clean Data Policy), areas designated nonattainment that subsequently attain the NAAQS prior to the SIP submittal deadline are eligible for reduced regulatory requirements. Based on quality

- assured federal reference method monitoring data for 2008

- 2010, the Chico Planning Area has demonstrated attainment of the 24

- hour PM 2.5 NAAQS (Table 1) . The Chico Planning Area also continues to attain based on the most recent air quality data for 2009

- 2011

.

Table 1

98 th Percentile ( μ g/m 3 ) 3

- year Average ( μ g/m 3 ) 2008 2009 2010 2011 2008

- 2010 Design Value 2009

- 2011 Design Value 35.7 30.0 29.0 46.2 32 352 On June 2, 2011, ARB submitted a request to U.S. EPA to find the Chico Planning Area
in attainment of the 35 μ g/m 3 24

- hour PM 2.5 NAAQS . This clean data finding under the Clean Data Policy, suspend s the majority of the planning elements under the Clean Air Act, including the attainment demonstration, reasonably available control measures, and contingency elements of a SIP. The only planning element required under the C lean D ata Policy is an emission inventory. Other requirements under the Clean Air
Act , specifically transportation conformity and new source review, are still applicable and are discussed in Section IV of this document.

III. EVALUATION OF THE BUTTE COUNTY AQMD EMISSION INVENTORY

The But te District developed the 2012 PM 2.5 Emission Inventory Submittal to the State Implementation Plan for the Chico, CA/Butte County (partial) Planning Area (Emission Inventory SIP Submittal ) to address the emission inventory requirements under the Clean Data Policy . The Governing Board of the Butte District adopted the Emission Inventory SIP Submittal at a public hearing on September 27, 2012.

An essential tool to support the evaluation, control, and mitigation of air pollutants, an
emi ssion inventory is a systematic listing of air pollutant sources, along with an accounting of the amount of pollutants emitted by each source or category over a given period of time. This accounting is an estimate of emissions, not direct ambient
concentr ation measurements. U.S. EPA requires states to submit an attainment year inventory that includes directly emitted PM 2.5 emissions, as well as emissions of precursors that contribute to the formation of particles formed through chemical
reactions in the a tmosphere, in particular, oxides of nitrogen (NOx), oxides of sulfur (SOx), reactive organic gases (ROG), and ammonia (NH 3 ).

In addition, U.S. EPA allows the use of a seasonal inventory, rather than an annual inventory, when it has been demonstrated that the seasonal emissions have significantly led to the original nonattainment status

. Analysis of daily air quality data, as well as source apportionment analysis detailed in the Emission Inventory SIP Submittal

, has demonstrated that high PM 2.5 concentrations occur primarily during the winter season. Exceedances during other seasons have been demonstrated to have been influenced by exceptional events, such as wildfires, but are outside of regulatory
control.

The Butte District’s Emission Invent ory SIP Submittal is the most up

- to

- date emission inventory for the Chico Planning Area. Based on the daily winter season PM 2.5 emissions for 2011, it is typical of both the 2008

- 2010 and 2009

- 2011 attainment demonstration years . The winter

- time 2011 bas eline inventory includes PM 2.5 , NOx, SOx, ROG, and NH 3 emissions. Residential wood heating comprises almost half of3 winter directly emitted PM 2.5 emissio ns, while mobile sources are the largest contributors to NOx and ROG emissions.

IV. OTHER CLEAN AIR ACT REQUIREMENTS

a. Conformity

The Clean Air Act requires that p rocedures be in place to ensure that there is conformity of federal actions and federally funded transportation projects efforts to attain the NAAQS . The Butte District has two rules in place to ensure both general conformity (Rule 1103) and federal transportation conformity (Rule 1102). Under the Clean Data Policy, the Butte District had a choice to either set transportation conformity budgets or allow the existing transportation conformity process to continue. The Butte District chose to allow the existing process to continue. Under this process, the Butte District works closely with the Butte County Association of Governments to ensure that emissions from new transportation projects are less than the baseline (or attainment year) emissions.

b. New Source Review

U.S. EPA’s New Source Review (NSR) requirements specify that t here must be a method to identify and quantify allowable emissions of pollutants from construction and operation of major new or modified stationary sources in the Butte District . Permits for new or modified stationary sources are required. This r equirement is met with a new
Butte District rule (Rule 432) implementing NSR requirements; it will be submitted separately to ARB and U.S. EPA as a revision to the California SIP

.

V. STAFF RECOMMENDATION

ARB staff has reviewed the Emission Inventory SIP Su bmittal to the State Implementation Plan for the Chico, CA/Butte County (partial) Planning Area and
consulted with Butte District staff during this review. ARB staff finds that the Emission Inventory SIP Submittal meets all applicable Clean Air Act and Cl ean Data Policy requirements. Therefore, staff recommend s that the Board adopt the Emission Inventory SIP Submittal as a revision to the California SIP for submittal to U.S. EPA.