San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Appendix F

Attainment	Demonstration	

(Provided	by	ARB)		

2015 Plan for the 1997 PM2.5 Standard

SJVUAPCD	

 

 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

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San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-1 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Appendix F: Attainment Demonstration (Provided by ARB) 

F.1 OVERVIEW 

The 2008 San Joaquin Valley (SJV or Valley) State Implementation Plan (SIP or Plan) 

reflected an attainment deadline of April 5, 2015 for the 15 μg/m3

 annual and 65 μg/m3

24-hour PM2.5 standards. Through ongoing implementation of the control strategy 

contained in the Plan, the Valley met the 65 μg/m3 24-hour standard in 2010, and only a 

few locations remained above the 15 μg/m3 annual standard as of 2012. However, 

meteorological conditions associated with the current drought resulted in unusually high 

PM2.5 levels during the winter of 2013/2014. Due to nearly two months without rainfall, 

a majority of days during December 2013 and January 2014 recorded PM2.5 

concentrations greater than 35 μg/m3, a nearly threefold increase over the prior winter. 

These elevated wintertime concentrations affected both 24-hour and annual average 

design values, especially in the central and southern Valley. As a result, the Valley will 

not meet the Moderate nonattainment area April 2015 attainment deadline. 

This updated attainment demonstration provides for expeditious attainment of the 

standards under the assumption that these adverse meteorological conditions occur 

again in the future. The new attainment demonstration uses the fundamental chemistry 

and associated response of different PM2.5 constituents to emission controls reflected in 

the approved modeling in the 2008 PM2.5 SIP. This modeling science is coupled with air 

quality data reflecting the drought impacts, 2013 design values and PM2.5 chemical 

composition, along with emission reductions expected through 2018 (24-hour standard) 

and 2020 (annual standard). 

The attainment demonstration includes the benefits of ARB and District control 

programs that provide ongoing emission reductions. Continued implementation of these 

control programs provides new emission reductions each year, resulting in a forecasted 

38 percent decrease in NOx emissions and an eight percent decrease in PM2.5 

emissions between 2012 and 2020. 

The NOx reductions result from ongoing implementation of both new vehicle standards 

for passenger and heavy-duty diesel vehicles and equipment, as well as rules 

accelerating the turnover of legacy diesel fleets. Implementation of stringent 

requirements for new off-road engines and in-use off road equipment lead to further 

NOx reductions, along with District rules addressing stationary source NOx emissions. 

PM2.5 emission reductions result from ongoing implementation of diesel on- and off-road 

equipment measures as well as the District’s recently strengthened rule for woodburning fireplaces and heaters. These measures, along with additional reductions from 

enhancements to the District’s commercial charbroiling rule slated for adoption in 2016 

provide the necessary control strategy to bring the entire Valley into attainment of the 

24-hour standard by 2018, and the annual standard by 2020 (Table 1 in Section D). 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-2 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

F.2 MODELING APPROACH 

The attainment demonstration approach for the current SIP is based on modeling 

conducted for the 2008 PM2.5 Plan, which addressed both the annual and 24-hour PM2.5

standards. The atmospheric dynamics and associated response to emission 

reductions represented in this modeling, coupled with 2013 design values (DV) and 

chemical composition, was used to project future (2020 for the annual standard and 

2018 for the 24-hour standard) design values. Photochemical modeling for the 2008 

PM2.5 SIP was conducted following the U.S. EPA guidance (2007 U.S. EPA)1 and was 

approved by U.S. EPA in 2011 (76 FR 69896, 76 FR 41338). While subsequent 

modeling was conducted for the attainment demonstration for the 2006 24-hour PM2.5 

standard of 35 μg/m3, this effort was based on modeling conducted only for the first and 

fourth quarters of the year. Thus it was not suitable for addressing the annual average 

standard as part of the current SIP update. 

The 2008 SIP modeling simulations used the Community Multiscale Air Quality (CMAQ) 

Modeling System, a “one-atmosphere” system that treats major atmospheric and land 

processes, plus a range of emissions species in a comprehensive framework. The 

version of CMAQ used in the 2008 Plan included California-specific updates as 

described in Liang and Kaduwela (2005)2. The meteorological inputs to CMAQ were 

generated using the Pennsylvania State University/National Center for Atmospheric 

Research Mesoscale Model (MM5). MM5 is designed to simulate or predict 

atmospheric motions at small scale. 

This work included two gridded modeling domains (Figure F-1). The first modeling 

domain (“CCAQS”) covers the Central Valley and its surroundings with 63 x 63 lateral 

12 km grid cells (CCAQS domain) for each vertical layer. This domain extends from the 

Pacific Ocean in the west to the Mojave Desert and Western Nevada in the East and 

runs from the northern Sacramento Valley to the Tehachapi Mountains in the south. 

The second domain (“SJV’) is nested within the CCAQS domain covers the SJV with 

80 x 89 lateral 4 km grid cells. Vertically, both domains include 15 layers of varying 

thicknesses up to the top of the meteorological domain (100 millibar (mb)). The CCAQS 

domain provided the initial and boundary conditions for the SJV domain. 

MM5 was set up for a 14-month simulation (December 1999 - January 2001) with three 

nested gridded domains. Vertically, the domains included 30 layers and extended up to 

100 mb. The two outer domains defined the atmospheric initial and boundary 

conditions for the area at large scale, while the innermost grid resolved the fine details 

of atmospheric motions within the SJV domain. 

Photochemical modeling was conducted for an entire year. Gridded, hourly, chemically 

speciated emissions of combined stationary, mobile, area, and biogenic sources were 

developed as inputs to CMAQ for the 2005 base year and the 2014 future year. The 

 

1

 U.S. EPA, 2007, Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality 

Goals for Ozone, PM2.5, and Regional Haze, EPA-454/B07-002. 

2

 Liang, J. and A. Kaduwela, 2005: Microdevelopment of CMAQ for California Regional Particulate-Matter Air Quality 

Study. Proceedings of the 4th Annual CMAS Models-3 Users’ Conference; September 26-28, 2005, Chapel-Hill, NC.
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-3 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

2014 inventory included expected emission reductions from the State and local controls 

proposed in the 2008 PM2.5 SIP. The resulting modeled relative response factors 

(RRFs) for each PM2.5 species between 2005 and 2014 were then used to project 2006 

design values and chemical composition to 2014 using U.S. EPA’s Speciated Modeled 

Attainment Test (SMAT). 

Further description of the photochemical modeling conducted for the 2008 PM2.5 SIP is 

provided in the “Regional Air Quality Modeling to the 2008 PM2.5 Plan” Appendix to the 

Plan: (http://www.arb.ca.gov/planning/sip/sjvpm25/Appendix%20ASJV%20Modeling.pdf), and ARB Modeling Documents posted at: 

http://www.arb.ca.gov/planning/sip/sjvpm25/sjvpm25.htm. 

Figure F-1 Modeling Domains 

CCAQS domain has 63x63 12 km grid cells and the SJV domain has 80x89 4 km grid cells. Both 

domains have telescopic vertical grid structure with 15 layers extending to 100 mb. 

F.3 MODELING METHODOLOGY 

To assess the representativeness of the 2008 SIP modeling for capturing the dynamics 

and response to emission reductions for the updated attainment demonstration, ARB 

staff evaluated both the meteorological characteristics, as well as the chemical 

composition used in the two modeling efforts. The types of meteorological conditions 

conducive to PM2.5 formation in 2013/2014 were similar to the 2000/2001 meteorological 

conditions simulated in the 2008 SIP. These factors include the presence of persistent 

ridges that result in warm air aloft and strong stability with limited mixing, cool morning 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-4 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

temperatures, and low wind speeds. Although the persistence of these meteorological 

conditions in 2013/2014 resulted in an increased number of days with high 

concentrations, the underlying meteorological factors driving elevated PM2.5 

concentrations were similar to 2000/2001. In addition, as described in Attachment A to 

this Appendix, the PM2.5 chemical composition used in the 2008 PM2.5 modeling was 

very similar to 2013, indicating common atmospheric chemistry regimes. Therefore, the 

2008 PM2.5 SIP modeling response to emission reduction, applied to 2013 DVs, 

provides a suitable basis for the updated attainment demonstration. 

To ensure consistency with the approved 2008 PM2.5 SIP modeling, the current effort 

uses a single DV representing 2013 based on ambient measurements during 2011-

2013. The base emission year is the middle year of 2012, with future emission years of 

2020 for the annual standard attainment demonstration, and 2018 for the 24-hour 

standard demonstration. 

Due to the differences in base years (2005 vs. 2012) and future years (2014 vs. 2018 or 

2020), the RRFs calculated for the 2008 modeling cannot be used directly in the current 

Plan. Thus, the updated modeling uses scaled RRFs presented in the following 

equation. 

ܴܴܨଵଶିଶ଴ ൌ ൤1 െ ሺ1 െ ܴܴܨ଴ହିଵସሻ ൈ

%∆ܧଵଶିଶ଴

%∆ܧ଴ହିଵସ

൨

Here, 

%∆ܧଵଶିଶ଴ ൌ 	

ܧଵଶ െ ܧଶ଴

ଵଶܧ

ൈ 100%	ܽ݊݀	%∆ܧ଴ହିଵସ ൌ 	

ܧ଴ହ െ ܧଵସ

ହ଴ܧ

ൈ 100%,

where, Ej is the total emissions for a given emissions component for year j ( = 2005, 

2012, 2014, and 2020). That is, quantities in the above equation represent percent 

emissions changes for the current and 2008 Plans. Similarly, RRFi-k represents RRF 

values for the current (2012-2020) and 2008 Plans (2005-2014). 

In the 2008 PM2.5 SIP, 2004-2006 concentrations of ammonium ion, nitrate ion, sulfate 

ion, organic carbon, elemental carbon, and geologic material were calculated using the 

Sulfate, Adjusted Nitrate, Derived Water, Inferred Carbonaceous Material Balance 

Approach (SANDWICH) method. The current plan uses the same SANDWICH method 

to calculate these components for 2011-2013 speciation measurements made at 

Bakersfield (California Street), Visalia (North Church Street), Fresno (1st Street and 

Garland), and Modesto (14th Street). The particle bound water (PBW) was calculated 

using the e-AIM method that is more accurate than the parameterized equation for 

PBW. These components (except for PBW) were then projected to the future using the 

scaled RRFs. PBW is calculated again for the future concentrations. 

For those PM2.5 monitors that were not collocated with speciation monitors, the

composition measured at one of the four speciation sites was assigned (Table F-1). In 

the 2008 PM2.5 SIP, analysis of CRPAQS field study data was used to identifying which 

sites had similar chemical composition profiles. In the current study, proximity and 

similarity between sites were also considered. Based on these criteria, the composition 

at Bakersfield-California was used to represent Bakersfield-Planz. Similarly, Fresno-
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-5 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Garland composition was used to represent Fresno-Hamilton, Clovis, and Tranquility. 

Visalia composition was used for Hanford, and Modesto composition was used for sites 

at Stockton, Manteca, Turlock, and Merced. 

Planning inventories were used to calculate the scaling factors for RRFs (viz. %ΔE12-

20/%ΔE05-14). Nitrate and ammonium ion RRFs were scaled using NOx emission 

reductions, and sulfate ion RRFs were scaled using SOx emission reductions. The 

justification for using NOx for both the ammonium and nitrate ions relies on the fact that

sulfate ion concentrations are minor and therefore ammonium ion scales mainly with the 

nitrate ion. Source-level emissions profiles were applied to the PM2.5 planning 

inventory to calculate the PM2.5 chemical constituents of organic carbon, elemental 

carbon, and geologic material. 

F.4 MODELING RESULTS 

Eight of the fifteen sites in the SJV recorded 2013 DVs over the annual PM2.5 standard 

of 15 μg/m3 (Table F-1). The higher DVs occurred in the Valley’s southern region 

(including the Bakersfield and Visalia as well as Hanford) and the central region (around 

the Fresno urban area and Madera). Only one site in the northern region (Turlock) 

measured a 2013 DV over the standard. All sites in the SJV recorded 2013 DVs at or 

below the 24-hour standard of 65 μg/m3. 

Table F-1 lists the projected 2020 annual and 2018 24-hr DVs determined through the 

previously described modeling methodology. In 2020, all sites in the Valley are 

projected to attain the annual standard. For those sites that exceeded the standard, the 

projected 2020 DVs range from 12.5 μg/m3 to 15.0 μg/m3. 

The implementation of new reductions from California’s on-going emission control 

programs will provide the major portion of emission reductions needed to attain the 

annual PM2.5 standard by 2020. Further emission reductions from the District’s recently 

tightened residential wood combustion rule coupled with further control from commercial 

cooking operations slated for adoption in 2016, complement the PM2.5 emission 

reductions needed for the SJV to attain the annual standard in 2020. 

As shown on Table F-1, modeling results indicate these control programs will result in 

2018 24-hour design values ranging between 24 μg/m3

 and 52 μg/m3. For sites with 

2013 design values over 60 μg/m3

, the modeled 2018 design values range between 

46 μg/m3 and 52 μg/m3 (71-80 percent of the standard). 

F.5 CONSIDERATION OF 2014 AIR QUALITY 

The drought-related meteorological conditions that affected PM2.5 concentrations in the 

San Joaquin Valley during 2013 continued into 2014. Although complete data for 2014 

is not yet available, this section provides a preliminary assessment of 2014 air quality 

data in relation to the attainment demonstration. 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-6 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Despite the ongoing persistence of the drought, air quality conditions in 2014 generally 

improved at most locations, particularly in the northern and central portions of the 

Valley. This is an indication that although drought conditions are continuing, progress is 

resuming as a result of ongoing emission reductions. However, because 2014 design 

values will reflect the impact of multiple years of drought, a comparison to the 2013 

design values used in the attainment demonstration is expected to be mixed, with some 

locations recording design values that are slightly lower, and other locations recording 

design values that are slightly higher. Based on an assessment of the PM2.5 levels 

predicted for 2020 as well as ongoing trends and analyses, consideration of 2014 

design values is expected to remain consistent with the current attainment 

demonstration. However, ARB and the District will continue to monitor the impacts of 

the drought and its relationship to future PM2.5 attainment needs. 

F.6 UNMONITORED AREAS 

A screening analysis designed to assess the possibility of unmonitored violations of the 

annual PM2.5 NAAQS was presented in the 2008 PM2.5 Plan. An annual-averaged 

modeled PM2.5 field was generated for the entire modeling domain. This field was then 

scrutinized to see if there would be gradients in the field that would give rise to higher 

values away from monitors if this field were to be used to adjust the interpolated annualaveraged design value field. The analysis found there are no areas with steep 

gradients that would result in higher design values than those measured at monitors. 

This section intentionally blank. 

 
San Joaquin Valley Unified Air Pollution Control District 

F-7 Appendix F: Attainment Demonstr

2015 Plan for 

Table F-1 Projected 2020 Annual and 2018 24-hour Design Values

Monitoring Site AQS Site ID Type Speciation 2013 Ann. DV3 

2020 Ann. 

DV with 

Rules4 

2

Bakersfield - California Street 060290014 FRM Bakersfield- California 16.4 13.7 Bakersfield - 410 E Planz 060290016 FRM Bakersfield- California 17.03 14.3 Clovis - N Villa Avenue 060195001 FRM Fresno-1st 16.44 13.3 Fresno - 1st Street/Garland7 FRM Fresno-1st 15.45 12.5 Fresno - Hamilton and Winery 060195025 FRM Fresno-1st 14.7 12.0 Hanford-S Irwin Street 060311004 FEM-BAM Visalia - N Church 17.0 13.9 Madera 060392010 FEM-BAM Fresno-1st 18.1 15.0 Manteca-530 Fishback Rd 060772010 FEM-BAM Modesto 14th 10.2 8.7 Merced - 2334 M Street 060472510 FRM Modesto 14th 11.1 9.2 Merced – S Coffee Ave 060470003 FEM Modesto 14th 13.3 11.0 Modesto - 14th Street 060990005 FRM Modesto 14th 13.6 11.5 Stockton - Hazelton Street 060771002 FRM Modesto 14th 13.8 12.0 Tranquility 060192009 FEM-BAM Fresno-1st 7.9 6.6 Turlock-S Minaret Street 060990006 FEM-BAM Modesto 14th 15.7 13.2 Visalia - N Church Street 061072002 FRM Visalia - N Church 16.6 13.5 

3 Design values equal to or less than 15.0 μg/m3 attain the annual PM2.5 standard 4 Design values equal to or less than 65.4 μg/m3 attain the 24-hour PM2.5 standard 5 Does not include 167.3 μg/m3 measured on May 05, 2013 (supporting documentation provided in Attachment B) 6 Clovis 2013 DV is based on combined FRM/FEM BAM data 7 2013 DV is based on 2011 data for Fresno-1st (060190011) and 2012/2013 data for Fresno-Garland (060190008) 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-8 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Attachment A: Trends in PM2.5 Composition 

To assess the representativeness of the atmospheric chemistry regime included in the 

2008 SIP modeling for simulating conditions experienced in 2013, ARB staff compared 

the chemical composition of ambient PM2.5 collected during the periods represented by 

the two SIPs. The 2008 modeling reflected speciation for 2004-2006 while the current 

plan reflects 2011-2013. Speciation data is available for four sites in the Valley: 

Bakersfield, Fresno, Modesto, and Visalia. In this analysis, organic and elemental 

carbon are combined with “other” because the measurement technique for the organic 

and elemental carbon components have changed between the two three-year windows. 

The relative composition for each site during these two periods is shown in Figure F-2 

below. 

Figure F-2 Average PM2.5 Percent Composition During 2004-2006 Compared to 

2011-2013 

Ammoniu

m Nitrate

41%

Ammoniu

m Sulfate

13%

Geological

6%

Elements

2%

Other

38%

Bakersfield

2004-2006 Average Composition
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-9 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Ammonium 

Nitrate

37%

Ammonium 

Sulfate

Geological 12%

4%

Elements

2%

Other

45%

Fresno

2004-2006 Average Composition

Ammonium 

Nitrate

35%

Ammonium 

Sulfate

Geological 12%

5%

Elements

4%

Other

44%

Modesto

2004-2006 Average Composition
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-10 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

At all sites, ammonium nitrate and organic/elemental carbon as represented in the 

“other” category are the largest constituents in both periods. For Modesto and Visalia, 

the relative composition is nearly identical for the two three-year periods shown. At 

Bakersfield and Fresno, ammonium nitrate has decreased slightly, with a corresponding 

increase in other and geological. However, at both sites, the overall composition 

between the two three-year periods is very similar and therefore supports a conclusion 

that there have not been any major shifts in atmospheric chemistry regimes in SJV. 

This section intentionally blank. 

Ammonium 

Nitrate

44%

Ammonium 

Sulfate

12%

Geological

7%

Elements

3%

Other

34%

Visalia

2004-2006 Average Composition
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-11 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Attachment B: Assessment of the Representativeness of the PM2.5 Value 

Recorded at the Bakersfield-Planz Monitoring Site on May 5, 2013 

A. Overview 

On May 5, 2013, a PM2.5 concentration of 167.3 μg/m3 was measured at the 

Bakersfield-Planz monitoring site. A concentration of this magnitude is extremely 

unusual, especially during the spring/summer when PM2.5 concentrations are typically 

low. Further, all other Bakersfield PM2.5 monitors recorded concentrations that were 

substantially lower, consistent with levels typical for the Valley during this time of year. 

Meteorological analysis shows that high winds on May 5, 2013 may have resulted in 

microscale PM2.5 impacts at Bakersfield-Planz that are atypical from measured 

concentrations at the Bakersfield-Planz site and other nearby sites during similar events. 

Elemental analysis of particulates collected on the filter indicated an extraordinarily high 

concentration of elements associated with windblown dust. This unusual measured 

concentration indicates that the sample collected on May 5, 2013 was not representative 

of the broader spatial scale the Bakersfield-Planz monitor is intended to capture. 

Based on the following analysis, ARB staff is therefore excluding the value of 167.3 μg/m3

from use in the modeling analysis for the SJV 2015 PM2.5 Plan. ARB and the District are 

also pursuing further analysis of this event by engaging the Department of Public Health 

to conduct a more thorough examination of the filter media. The results of this analysis 

will be closely evaluated and aide in future planning efforts. 

B. Representativeness of Bakersfield-Planz PM2.5 Data 

Air quality planning begins with evaluating pollutant concentrations measured at air 

monitoring stations and comparing those measurements to established air quality 

standards. In practice, monitors are only capable of sampling a relatively small portion 

of the atmosphere in the immediate vicinity around the inlet. However, the samples are 

intended to be representative of concentrations over a larger area as defined by the 

spatial scale of the monitoring site. 

The Bakersfield-Planz monitoring site is identified as neighborhood scale, meaning that 

PM2.5 measurements are expected to be representative of air quality within an area that 

has relatively homogenous land use ranging from 0.5 to 4.0 kilometers around the 

monitor. If measurements at the site are overwhelmed by local dust sources and driven 

by unusual meteorological events atypical of the area, the measurements may no 

longer be considered representative of air quality within the broader area around the 

monitor. 

San Joaquin Valley Seasonal PM2.5 Concentrations 

PM2.5 concentrations throughout the Valley follow the same seasonal pattern. During 

the low concentration season (primarily April through September), concentrations are 

generally below 25 to 30 μg/m3 Valley-wide. A measured concentration of 167.3 μg/m3
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-12 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

in May is therefore extraordinarily unusual. Evaluating days where wind speeds were 

similar in magnitude shows that PM2.5 values measured during those days were much 

lower than the 167.3 μg/m3 measured on May 5, 2013. 

Data presented in Table 1 illustrates the typical observed pattern and shows the highest 

PM2.5 concentrations recorded between April and September in the Valley over the last 

14 years. Apart from the May 5, 2013 value, flagged data, and an anomalous reading in 

April 2010, other recorded PM2.5 values are consistently low during the April to 

September time period. 

Table F-2 Highest SJV PM2.5 Concentrations - April thru September 2000-2013 (μg/m3)

Year April May June July August September 

2000 31.4 20 27.1 28.1 23 33

2001 27.3 21.6 19.3 43 17.3 18.5

2002 40 20.7 25.4 25.5 49 19.6

2003 15 18 20.3 25.3 23.2 31.5

2004 28 18.6 15.4 63.1 19 20.7

2005 30.6 18 21.7 31 24 19.4

2006 23 23.7 23.7 32 22.6 42.5

2007 28 30.5 21.3 103.8 20.5 52

2008 32.3 36 99.3 60.8 28.3 36.5

2009 31.3 24.4 26.5 25.8 31.9 28

2010 107.8* 21 23.2 92.2 25.8 37.8

2011 33.2 23.6 38.4 33.2 20 29.3

2012 29.7 21.9 23.4 31 19.7 29.4

2013 24.9 167.3 28.3 40.1 39.1 26.8

On May 5, 2013 all other monitoring sites in the Valley measured PM2.5 typical of the low 

concentration season. Measurements ranged from 9.9 μg/m3

 to 24 μg/m3 (Table 2). 

The Bakersfield-California monitoring site recorded 24, 23, and 26 μg/m3 on the PM2.5 

Federal Reference Method monitor, and primary and collocated Beta Attenuation 

Monitors, respectively. As seen in Table 2, the Bakersfield-Planz site recorded the 

highest 24-hour average PM2.5 concentration in the Valley on May 5, 2013, with levels 

an order of magnitude higher than any other site. 

 

   Fireworks (Data flagged in AQS)

   Fires (Data flagged in AQS)

   Highest Concentrations at Planz  

*Bakersfield-California BAM recorded a 26.9 μg/m3 daily average; FRM value not available 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-13 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Table F-3 PM2.5 FRM and FEM Concentrations in the San Joaquin Valley on May 5, 2013

Site Name 

Avg. 24-Hr PM2.5 Concentration 

(μg/m3) 

Fresno-Garland 10.3 

Tranquility-32650 West Adams Avenue 10.3 

Clovis-North Villa Avenue 10.8 

Bakersfield-410 E Planz Road 167.3 

Bakersfield-5558 California Avenue 24 

Hanford-South Irwin Street 9.9 

Madera-28261 Avenue 14 16.2 

Merced-South Coffee Avenue 10 

Manteca-530 Fishback Road 12.7 

Stockton-Hazelton Street 15.9 

Turlock-South Minaret Street 10.4 

Modesto-14th Street 11.4 

Elemental Species Composition 

To further evaluate the representativeness of the May 5, 2013 sample, ARB’s 

Monitoring and Laboratory Division analyzed the FRM filter using X-Ray Fluorescent 

Spectroscopy (XRF). The analysis revealed that the PM2.5 mass was heavily dominated 

by fugitive dust. In order to estimate the fugitive dust contribution to the total PM2.5 

mass, ARB staff used the IMPROVE formula: 

(2.2 x Al) + (2.49 x Si) + (1.63 x Ca) + (2.42 x Fe) + (1.94 x Ti) 

The fugitive dust concentration, estimated at 107.7 μg/m3

, far exceeded the values 

typically seen in the PM2.5 size fraction. The recorded value of 107.7 μg/m3 was over four 

times higher than the next highest value of 26.2 μg/m3 observed in the entire California 

network based on 14 years of available data. The PM2.5 fraction of fugitive dust is 

generally low, and PM2.5 concentrations during high wind events are thus typically not 

nearly as high as the May 5, 2013 reading. 

Concentrations of total elemental species were also unusually high, about 6.6 μg/m3

. 

Some of these species, such as cobalt, manganese, phosphorus, and rubidium, 

reached levels not previously measured in the State. These unusual concentration 

levels suggest that, along with fugitive dust, elemental species in the soil, combined with 

other chemical species, were deposited onto the filter. Figure 1 below compares 

average and maximum concentrations for select species historically measured at 

Bakersfield-California to what was measured at Bakersfield-Planz on May 5, 2013. 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-14 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Figure F-3 Comparison of Concentrations of Select Soil Elements: BakersfieldCalifornia & Bakersfield-Planz 

C. Potential Fugitive Dust Sources Impacting the Bakersfield-Planz Site 

To evaluate the potential influence of local fugitive dust sources on the Bakersfield-Planz 

monitor on May 5, 2013, the location of open soil areas, stationary sources, and known 

dust-generating activities were reviewed relative to the monitoring site. This information, 

coupled with observations of potential dust sources made by District enforcement staff on 

December 18, 2014, is summarized below. 

The Bakersfield-Planz monitor is located on the grounds of the Bakersfield Municipal 

Airport, a city-owned airport used for private, civil aviation. The airport also includes a 

helicopter landing area near the monitor and helicopters are known to periodically use 

the airport. As shown in Figures 2 and 3 below, the monitor is closely surrounded on 

several sides by open areas with the potential of emitting dust during high wind events. 

These open parcels of land are located to the east, west, and south of the monitor and 

include the airport infield areas between taxiways and runways. Dust sources located 

nearest to the monitor have the greatest potential impact because dust particles do not 

remain suspended and deposit quickly. Additionally, as discussed above, the PM2.5 

fraction of fugitive dust is generally low; therefore, the abnormally high value of 167.3 

μg/m3

 measured on May 5, 2013 is unusual. ARB and the District are pursuing further 

analysis of this value through a more thorough examination of the filter media. 

 

0.0000

0.0500

0.1000

0.1500

0.2000

0.2500

0.3000

0.3500

0.4000

Avg Max 5/5/2013

Concentrations (μg/m3)

Comparison of Concentrations of Select Soil Elements:

Bakersfield‐California & Bakersfield‐Planz

Phosphorus (P)

Manganese (Mn)

Cobalt (Co)

Rubidium (Rb)

Bakersfield‐California Bakersfield‐Planz
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-15 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Figure F-4 Bakersfield-Planz PM2.5 FRM Monitor8

Figure F-5 Aerial Photo of Bakersfield Municipal Airport9

 

 

8

 Photo taken looking west 

9

 Red marker indicates monitor location 

N

Open areas 

(dust, silt) 

Infield areas 

(open soil, 

partial 

vegetation) 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-16 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

Additional potential sources of fugitive dust in the broader area surrounding the airport 

were also evaluated through field investigation by District enforcement staff. A review of 

aerial photos, combined with field investigations, indicate that additional potential dustemitting sources in the area are present to the east and southeast of the Bakersfield 

Municipal Airport (Figure 4). These sources are subject to District rules for controlling 

fugitive dust from construction and demolition activities; handling, storage and transport 

of storage of bulk materials; disturbed open areas; paved and unpaved roads; and offfield agricultural sources. 

Figure F-6 Aerial Photo of Bakersfield Municipal Airport - Potential nearby Fugitive 

Dust 

 Sources* (Red marker indicates monitor location)

No violations of District fugitive dust rules were documented at any nearby dust emitting 

facilities in Figure 4 on May 5, 2013. Based on this assessment of fugitive dust sources 

surrounding the monitor, the likely source of total particulate mass is from the open 

areas immediately adjacent to the monitor, reflecting a localized microscale impact. 

However, due to the significance difference in readings from nearby monitors, other 

factors may have contributed to the unusually high reading at Planz. 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-17 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

D. Meteorology at the Bakersfield-Planz Monitoring Site 

An evaluation of Bakersfield area meteorology indicates that high winds measured at 

the airport are the expected cause of the localized dust impact on May 5. Wind speed 

data for the Bakersfield-Municipal Airport monitoring site was used to assess winds at 

Bakersfield-Planz. The Bakersfield-Municipal Airport meteorological site is located on 

the northern edge of the airport property, approximately one-half mile from the 

Bakersfield-Planz monitor. Strong winds on May 5, 2013 included 9 hours (including 

eight consecutive hours) exceeding 25 miles per hour (mph), in excess of U.S. EPA’s 

Interim Exceptional Events Guidelines threshold of 25 mph,10 and far in excess of the 

San Joaquin Valley’s Exceptional Event threshold of 17 mph as established in prior 

EPA-approved Exceptional Event submissions. Figure 5 illustrates the difference 

between wind speeds on May 5, 2013 and a typical day in May of 2013. 

By contrast, wind speeds were notably lower at the Bakersfield-California monitoring 

station, located about 4 miles from Bakersfield-Planz. 

Figure F-7 May 2013 Wind Speeds at Bakersfield-Planz by Hour 

To evaluate wind speeds on May 5, 2013, relative to other significant wind event days at 

Bakersfield-Planz, wind speed data were reviewed from the first day meteorological 

 

10 Page, Stephen D. (May 10, 2013). Interim Guidance to Implement Requirements for the Treatment of Air Quality 

Monitoring Data Influenced by Exceptional Events [Memorandum]. Research Triangle Park, North Carolina: U.S. 

Environmental Protection Agency. 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-18 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

data were collected at the Bakersfield-Municipal Airport site on September 11, 2012, 

through December 31, 2014. During that 2 year and 3 month period, there were 3 days 

that included sustained winds over 25 mph (Figure 7). Among these high wind days, 

May 5, 2013, had over 8 hours with winds in excess of 25 mph, a significantly greater 

amount of time than the next highest day of December 11, 2014, with about 4 hours of 

sustained winds over 25 mph. 

It should be noted that May 5, 2013 was the only high wind day during the dry season in 

the San Joaquin Valley. The other high wind days occurred during winter months, when 

moisture in the ground would minimize the potential for fugitive dust to become 

airborne. PM2.5 concentrations were measured only on one of these winter days, 

January 23, 2014, and reached 49.7 μg/m3, which is fairly typical for PM2.5 

concentrations during winter in the Valley. 

Figure F-8 Days with High Wind Speeds at Bakersfield-Planz by Hour 

The available meteorological data indicate that May 5, 2013 was highly unusual in terms 

of wind speed and the duration of high winds as compared with other days in which 

wind speed was measured at the airport. 

E. Conclusion 

In summary, comparison of the 167.3 μg/m3

 concentration measured on May 5, 2013, to 

values typical for this season as well as comparison to values measured throughout the 

Valley on the same day, combined with the record high fugitive dust and elemental 

species concentrations, indicate that the monitor was impacted by microscale sources 

High Winds Threshold = 25 mph
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-19 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

that are not representative of the neighborhood spatial scale the monitor is intended to 

represent. Therefore, this value is not included in modeling analysis for the San Joaquin 

Valley 2015 PM2.5 Plan. ARB and the District are pursuing further analysis of this event in 

order to conduct a more thorough examination of the filter media. The results of this 

analysis will be closely evaluated and aide in future planning efforts. 

 
San Joaquin Valley Unified Air Pollution Control District April 16, 2015 

F-20 Appendix F: Attainment Demonstration (Provided by ARB) 

2015 Plan for the 1997 PM2.5 Standard 

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