South Coast 

• Air Quality Management District 

21865 Copley Drive, Diamond Bar, CA 91765-4178 

(909) 396-2000 • www.aqmd.gov 

Ms. Elizabeth Adams 

Acting Director, Air Division 

U.S. Environmental Protection Agency- Region IX 

75 Hawthorne Street 

San Francisco, CA 94105 

Office of the Executive Officer 

Barry R. Wallerstein,D.Env 

909.396.2IOO,fax 909.396.3340 

July 28,2015 

Re: Request to U.S. EPA to Reclassify the South Coast Air Basin as Serious Nonattainment for 

the 24-hour PM2.5 National Ambient Air Quality Standard (NAAQS) 

In December 2012, the South Coast Air Quality Management District (SCAQMD) Governing 

Board adopted the 2012 Air Quality Management Plan (AQMP) demonstrating attainment of the 

24-hour PM2.5 NAAQS (35 Jlglm

3

) followed by a Supplement to the 24-hour PM2.5 State 

Implementation Plan (SIP) for the South Coast Air Basin (Basin), approved in February 2015, 

demonstrating attainment by 2015 under Clean Air Act (CAA), Title 1, Part D, Subpart 4. 

As discussed in previous correspondence with U.S. EPA, attainment ofthe NAAQS cannot be 

achieved without significant additional reductions in federal source emissions. Meeting the 8-

hour ozone standards, for example, requires up to 65-75 percent reduction in NOx emissions. 80 

percent ofthe NOx emissions are generated by mobile sources, many of which are preempted from 

state or local regulation ("federal sources"). In 2012, federal sources generated approximately 19 

percent ofthe total NOx emissions in the Basin and will constitute an estimated 29 percent of total 

NOx emissions by 2032. SCAQMD acknowledges the significant air quality benefits 

accomplished with NOx and fuel ·sulfur requirements imposed on ships operating in coastal 

Emission Control Areas, but it is critical that further emission reductions are achieved from other 

federal sources, such as railroads, aircraft, and interstate heavy-duty trucks. More specifically, 

new federal engine emission standards (0.02 g/bhp-hr NOx for heavy-duty on-road engines), 

additional authority provided to the states, and federal funding for faster deployment of new clean 

technologies are essential for attainment of the ozone and particulate standards in the South Coast 

Air Basin. Attainment will not be possible without federal actions in these areas. If sufficient 

federal actions are not taken, states should not be held accountable for emissions that they have no 

authority to control. Please view https://youtu.be/AFOpUSoUG9w from our July Governing Board 

meeting, where Board Members express great frustration regarding the lack of federal mobile 

source controls needed for compliance with the Clean Air Act in Southern California. 

The Mira Lorna air quality monitoring station is the only location in the Basin that exceeds the 24-

hour PM2.5 NAAQS, and preliminary ambient 24-hour PM2.5 measurements at that station for the 
Ms. Elizabeth Adams -2- July 28, 2015 

first quarter of 2015 (see Attachment 1) indicate that the Basin will not attain the NAAQS by the 

moderate area statutory deadline of 2015. Even considering only 1st quarter 2015 measurements, 

the 98th percentile ofthe 2015 24-hour PM2.5 mass at the Mira Lorna location is 41 Jlg/m3

, 

producing a 3-year design value at a minimum of39 Jlg/m3

, thus exceeding the NAAQS. The 

inability to attain the NAAQS is largely due to the lack ofrain days in January and February of 

2014 and 2015, which experienced 33 percent of the average rainfall. 

Under the CAA Subpart 4, Section 188(b)(l), the U.S. EPA may reclassify as a Serious 

nonattainment area any area that cannot practicably attain the NAAQS by the attainment date. 

This letter serves as the formal request to U.S. EPA to reclassify the South Coast Air Basin as a 

Serious nonattainment area for the 24-hour PM2.5 NAAQS based on the monitoring data 

indicating attainment is not practicable by the attainment date. Staff requests that EPA take this 

action at the same time as it acts on the 2012 PM2.5 SIP and 2015 Supplement. SCAQMD staff is 

also requesting that U.S. EPA approve any applicable elements in the Moderate SIP submitted 

previously and consider the data submitted herewith in conjunction with the 2012 and 2015 

submittals as a demonstration that the area cannot practicably attain by the Moderate area date. 

SCAQMD recognizes that more stringent Serious area requirements would apply, including 

requirements to implement Best Available Control Measures/ Best Available Control Technology, 

a lower major source threshold (from 100 tons per year to 70 tons per year), and an update to the 

Reasonable Further Progress (RFP) analysis. A full analysis for implementation of these 

requirements and a demonstration to ensure attainment as expeditiously as practicable, but not 

beyond December 31 , 2019, will be included in the 2016 AQMP, which is also addressing the 

annual PM2.5 NAAQS. 

SCAQMD is committed to meeting the NAAQS in our region and providing the public a healthy 

environment and economy in the process. However, without fair share reductions from federal 

sources, the burden is being unfairly placed on local sources. If you have any questions, please feel 

free to contact me at (909) 396-2100 or Dr. Philip Fine, Deputy Executive Officer, at (909) 396-2239. 

Attachment: Mira Lorna PM2.5 Data 

cc: Richard Corey, CARB 

Wienke Tax, U.S. EPA, Region IX 

Philip Fine, SCAQMD 

Barbara Baird, SCAQMD 

Barry R. Wal erstein, D.Env. 

Executive Officer 
ATTACHMENT 1 

Table Al: Days exceeding the 24-hour PM2.5 federal standard at the Mira Lorna air 

monitoring station in the first quarter of 2015 with Federal Reference Method (FRM) 

measurements 

Sample Mira Lorna 

24-Hour PM2.5 Mass Rank Date (J.tg/m3) * ,,, 

1/20/201 5 56.6 1 

1/1/2015 55.0 2 

1110/2015 50.0 3 

2/4/2015 49.9 4 

114/2015 47.5 5 

2119/2015 43.7 6 

1/19/2015 43 .2 7 

2/5/2015 41.0 8 

2/20/201 5 40.1 9 

118/2015 39.7 10 

1/14/2015 39.5 11 

1/2/2015 38.5 12 

2/17/2015 38.5 12 

2/6/2015 38.1 14 

1/9/2015 37.2 15 

1111 /201 5 37.2 15 

2/3/2015 36.2 17 

* Preliminary data, subject to change in the validation process 

Table A2: Mira Lorna annual 98th percentile PM2.5 concentrations and 3-year design 

values for 2010 through 2014 and for 2015* with first quarter data 

Mira Lorna Mira Lorna 

Year 98th Percentile 24-Hour PM2.5 

24-Hour PM2.5 Mass (pg!m

3

) 3-Year Design Value (pg!m

3

) 

2010 36.1 41 

2011 36.6 38 

2012 35.1 36 

2013 37.5 36 

2014 40.0 38 

2015 1 st Quarter * 41.0 39 

Preliminary data, subj ect to change in the validation process