Attachment B

Attain ment of Annual PM2.5 Standard by 2020 at Madera City Monitoring Site

Monitoring for PM2.5 began in Madera with deployment of a Federal Equivalence Method Beta Attenuation Monitor (FEM BAM) in July, 20 10. The monitor was installed at the Madera City monitoring site with operation and maintenance under the control of the San Joaquin Valley Air Pol lution Control District. Established north

- south PM2.5 concentration gradients within the San Joaquin Valley indicate that average PM2.5 concentrations in Madera are expected to be similar or slightly higher than measurements in Merced, but lower than those measured in Fresno. However,

c omparison of 2011 PM2.5 concentrations measured at Madera and Fresno revealed
tha t on an annual basis, M adera concentrations were 30 percent higher compared to

meas urements in Fresno

.

The weight of e vidence a nalysis for the 2015 PM2.5 Plan includes a comprehensive assessment of the representativeness of measu rements made with the FEM BAM at the
M adera moni toring site during 2011 ( s ee Appen dix A2 of the 2015 PM2.5 Plan ). Per
this assessment, the 2011 Madera FEM BAM data used in the attainment demonstration appear to be biased h igh. These anomalous PM2.5 results were likely
due to initial calibration issues associated with operation of the FEM BAM and are
therefore not considered representative of air quality in the surrounding region.

T he 2011 data were nevertheless included in the 2015 PM2.5 Plan attainment demonstration, and the site showed attainment by 2020 with a design value of
15.0 ug/m3

. However

, ARB staff recently identified a technical error in the annual

average and 24

- hour PM2.5 design value calculations. Correction of this error resulted
in a small increase in 24

- hour and annual average des ign values at most sites. All sites continue to have design values below the annual PM2.5 standard in 2020 with the exception of the Madera site with a corrected PM2 .5 design value in 2020 of
16.2 μ g/m 3

. ARB staff therefore conducted additional analysis that indicates development of a more representative design value supports a finding that Madera would demonstrate attainment by 2020.

PM2.5 Air Quality at Madera and Merced Monitoring Sites

Table 1 on t he next page shows the PM2.5 annual average s and design values for the
Madera monitor for 2011 through 2014 . D espite continued drought

- related conditions, recent data indicates that the annual average concentrations at Madera are improving.
I n 2014, the annual average decreased by 4.1 μ g/m 3 , resulting in a 2.3 μ g/m 3 decrease in the 2014 design value. Thus the most recent measured design value is already below what is predicted in the corrected attainment analysis for 2020.

Table 1. PM2.5 Annual Average and Design Values at Madera

Annual Average ( μ g/m 3 ) Annual DV ( μ g/m 3 )

2011 2012 2013 2014 2013 2014
20.4 16 17.6 13.5 18.1 15.8

1ARB staff also compared recent data from the Madera monitor to measurements collected in Merced, about 30 miles to the north. Given the regional nature of PM2.5 concentrations in the Valley

, the PM2.5 FEM BAM monitors at Madera and Merced

Coffee Road are expected to record similar values. They are located relatively close to
one another in cities with similar year

- round populations and surroun ding emission

sources . Review of the data from PM2.5 monitor ing conducted at the Madera and
Merced

- Coffee Road si tes from July 1, 2014, through June 30, 2015

, indicate that PM2.5 concentrations at both sites track each other closely

, with the Madera site recording values about three percent higher than the Merced

- Coffee site on average (Figure 1 & 2 ). This is consistent with the established concentration gradient in the Valley.

0 10 20 30 40 50 60 70

7/1/14 8/1/14 9/1/14 10/1/14 11/1/14 12/1/14 1/1/15 2/1/15 3/1/15 4/1/15 5/1/15 6/1/15PM2.5 Concentration (μg/m3) Figure 1. Comparison of PM2.5 Concentrations

at Madera and Merced

- Coffee Street Sites

Madera-28261 Avenue 14 Merced-S. Coffee Street

21 Based on data from Jul y 1, 2014 through June 30, 2015

Attainment Demonstration Using Alternative B ase Year Sce n arios

Based on the information discussed above, the annual average attainment
demonstration for 2020 at the Madera site was run using two alternative scenarios to develop a more representative base year design value. Each indicates attainment at the Madera site by 2020

.

Scenario 1:
T he Madera City 2014 design value of 15.8 μ g/m 3

- estimated using 2012 through 2014
BAM data was used as a replacement for the 2013 base year design value

. The

a ttainment demonstration analysis the n results in a 2020 PM2.5 design value of

14.1 μ g/m 3

.

Scenario 2 : The 2013 base year design value was estimated using 2011 through 2013 FEM BAM monitoring data, where 2011 Merced

- Coffee Road data replaced the 2011 Madera data

. Because the Madera PM2.5 monitoring values are slightly higher on average than
Merced , the 2011 Me rced data were adjusted upward to compensate for the observed
difference between the two sites. Quarterly average values for 2011 for Merced

- Coffee

were therefore multiplied by 1.03 to obtain 2011 substitute quarterly average values for
Madera. This substitution resulted in a 2013 design value at Madera of 16. 7 μg/m 3

. The attainment demonstration analysis then results in a 2020 design value of
14.9 μg/m 3

.

The results of the two scenarios are summarized in Table 2

. 0 5 10 15 20 25 30 35PM2.5 Concentrations (ug/m3) Figure 2. Comparison of Monthly Average PM2.5 Concentrations 1

at Madera and Merced

- Coffee Street Sites

Madera-28261 Avenue 14 Merced-S. Coffee Street

3Table 2. Alternative Attainment Demonstration Scenarios for Madera

Scenario Base Year Annual DV ( μ g/m 3 ) 2020 Annual DV ( μ g/m 3 ) Madera (using 2014 data) 15.8 14.1

Madera (using 2012, 2013, and
2011 Merced

- Coffee data) 16.7 14.9

Conclusion

As documented in the 2015 PM2.5 Plan weight of evidence analysis, ARB staff concluded that 2011 Madera data collected with a continuous federal equivalent method (FEM) monitor were not representative of PM2.5 air quality in the region due to
calibration issues . Inclusion of 2011 data i n the attainment demonstration analysis for Madera resulted in a design value that was substantially higher than other locations in the Valley. Procedures for operation and maintenance of the Madera monitor have since been improved, and PM2.5 measurements from the FEM are now consistent with
a new filter

- based federal reference method monitor installed at the site in mid

- 2014, as well as with similar sites in the central portion of the Valley.

T he analysis presented above to develop a more representative base year design value
for use in the attainment demonstration along with 2015 PM2.5 Plan weight of evidence supports the conclusion that the Madera monitoring site will reach attainment of the
annual PM2.5 standard of 15 μ g/m 3 by 2020.

4