1

Evan M. Shipp 

2088 Lester Avenue 

Fresno, CA 93720 

Jessica Hafer 

San Joaquin Valley APCD 

1990 E. Gettysburg Avenue 

Fresno, CA 93726 

April 7, 2008 

Subject: Comments on the Proposed 2008 PM2.5 Plan 

Dear Jessie: 

As in the past, thank you for the opportunity to submit comments on the 

proposed air quality plan. As you know, I have been involved in writing 

plans for some time, and I know how much work is involved. You and 

your colleagues should be commended for producing a plan that is based 

on innovative science. There are still some outstanding technical issues 

from my comments on the first and second draft of this plan that could 

affect the amount of reduction needed to achieve the NAAQS. Attached 

are my comments. 

Sincerely, 

________________________

Evan M. Shipp 
2

Comments on 2008 PM2.5 Plan – Proposed (March 13, 2008) 

Evan M. Shipp (April 97, 2008) 

I have reviewed the Proposed San Joaquin Valley 2008 PM2.5 plan and have 

the following comments. First, I would like to thank the technical staff of the 

ARB and SJVAPCD. They have done a good job in providing documentation 

of most of the technical milestones in the plan. 

In the recent past, I have commented extensively on the technical issues 

involved in the modeled attainment demonstration. For completenesss and 

reference those comments are attached. Outstanding issues that were not 

addressed adequately in the District’s response to comments in the new 

proposed plan include: 

• Missing data when meteorological conditions were strong enough to 

cause exceedances of the NAAQS 

• Failure to include intermediate year predictions of PM2.5 concentrations 

• Failure to recognize alternative methods of analysis under the weight of 

evidence provisions of the EPA modeling guidelines 

• Assessment of 2007 PM2.5 Data that shows numerous exceedances of 

the NAAQS have occurred and should be analyzed to protect near term 

public health 

• Assessment of meteorological representativeness of the 2004-2006 

period that sets the baseline design value to determine whether worst 

weather conditions could produce more exceedances of the NAAQS in 

the future 

• Inclusion of EPA model guidance required photochemical model 

evaluations 

• District contradiction of using meteorological indicators and then stating 

that they are invalid 

• Poor documentation of the relative reduction factors, and lack of 

documentation on how the photochemical was used to derive these 

These general comments are detailed below: 

1. Missing Reference Method Data During Periods When Meteorology 

and Non-Reference Monitors Show High PM2.5 Concentrations 

As stated in previous comments on the first and second draft of this plan, 

missing data during periods of weather stagnation that are conducive to high 

PM2.5 levels should be considered when calculating the design value. This 

should be done under the weight of evidence provisions of the PM2.5 modeling 

guidelines. Failure to address this issue will result in analyses that 

underestimate the amount and timing of reductions needed to achieve the 

NAAQS. 
3

As detailed in my comments on the second draft of the PM2.5 plan, (attached) 

BAM and meteorology show that there is good evidence from weather 

indicators that concentrations are much higher than characterized in the plan. 

Missing data during strong meteorological events that provide PM2.5 

concentrations have not been addressed in the plan. The District dismisses the 

correlation of PM2.5 to these weather parameters (stability index) as being 

poor; however, they use these indicators of meteorological potential to produce 

PM2.5 forecast. In addition, as referenced in the PM10 plan, the indicators 

were developed and presented by me in a peer-reviewed paper for AWMA 

(Shipp, 1995). The correlation of these stability parameters to PM2.5 and 

winter PM10 is about an r of 0.7, which is considered good for meteorology to 

air contaminant correlation. In addition, the SJVAPCD has provided numerous 

CRPAQS analyses that use these meteorological indicators. Therefore, the 

District should apply these to assess the meteorological potential of the days 

where the data is missing and make adjustments to the design values. Again, 

this would be allowed under the weight of evidence provisions of the EPA 

guidelines. The District owes it to the citizens of the San Joaquin Valley to do a 

thorough job assessing the baseline concentrations to start the emissions 

reductions, and follow the letter and spirit of the law to protect public health, by 

analyzing the days with missing data that would be unhealthy. 

2. Inclusion of Intermediate Year PM2.5 Predictions 

To demonstrate reasonable further progress the plan needs to show that progress 

toward attainment will be seen in PM2.5 concentrations in the intermediate 

years before attainment. The plan only shows the attainment year 

concentrations. Since the plan indicates that most emissions reductions occur 

close to the attainment year, the modeling needs to show steady progress toward 

attainment. 

3. Inclusion of 2007 PM2.5 Data 

The District dismisses the comment made regarding the 2007 PM2.5 season 

data by saying that the data is not available yet. Because the real-time data 

indicates that numerous exceedances of the NAAQS occurred in 2007, every 

effort to include the data in the plan should be done. As an experienced air 

quality analyst, I have been able to have ARB expedite filter data when 

necessary. If the District cannot produce reference method data, they need to 

address fully why BAMS data is not included. I have shown that the correlation 

of BAMS to FRM’s is very good and the analysis should be done under the 

weight of evidence provisions of the EPA modeling guidelines. The bottom line 

is that the 2007 data shows that the SJV has levels well above the NAAQS, and 

those emissions levels have not been brought down sufficiently to protect public 

health. The design values need to be adjusted up by inclusion of the 2007 data. 
4

4. Assessing the Representativeness of the 2004-2006 Period 

In accordance with EPA guidelines, and as outlined in my comments on the 2nd

draft of this plan, the meteorology for the time period that the design value was 

set needs to be assessed. My analysis for the 2nd Draft of the plan indicates that 

meteorological potential for PM2.5, during the assessment years 2004-2006, 

was lower than in past years, and a return to worst case conditions, such as 

occurred in 1999-2002 would bring PM2.5 concentrations to well over the 24 

hour and annual NAAQS. The response to comments that the District assessed 

100 years of data without providing any documentation on that analysis is 

completely inadequate. Again, the District owes it to the citizen’s of the SJV to 

do a thorough job on insuring that emissions reductions on worst-case 

meteorological days will still bring the valley into attainment of the 1997 

NAAQS. 

5. Inclusion of EPA Required Evaluation of the Photochemical Model 

Since the proposed plan does not include a full model photochemical model 

evaluation, it does not comply with EPA modeling guidelines and regulations. 

The model evaluation is meant to assess the uncertainty of the photochemical 

modeling and can result in designation of alternate controls strategies depending 

on that uncertainty. A full list of the photochemical model evaluation metrics is 

included in the plan, but there is no mention of the specific model evaluation for 

the plan. Uncertainty assessment and discussion is an integral part of specifying 

the amount and chemical species to control. 

6. Documentation of the Relative Reduction Factors in the Plan and 

Demonstrating Reasonable Further Progress 

The process used to calculate the RRF’s and show attainment of the NAAQS is 

undocumented. It is unclear whether the RRF’s calculated from the 

photochemical model were the result of numerous runs at various percentage 

cuts in the inventory or just the 50% cuts as has been used in the past. Because 

photochemistry is non-linear, the RRF’s should be based on multiple cuts in the 

inventory. In addition, a run containing the attainment inventory should be 

documented. According to the ARB, the District was given RRF’s based on a 

future and base year model runs. This is not sufficient to demonstrate 

reasonable further progress toward attainment. A majority of the emissions 

reductions in the plan occurs at the end attainment year, and therefore the 

modeling system using the base and end year inventory is not sufficient 

The plan does not contain detailed documentation of the RRF’s that were used 

to scale the design values and show attainment. The District answered this 

concern in the proposed plan by stating that the files were too big to download 

and distribute. It is the District’s and/or ARB’s responsibility to condense this 

information into an easily understandable format showing the output of the 
5

photochemical model before and after control for each chemical species and 

how that affects the design value. If multiple cuts are run, the District should 

include nitrate, sulfate, and VOC isopleths. 

An evaluation of the result of control of individual NOx, VOC, EC, and SO2 

needs to be performed. In addition, the District should show alternative species 

strategies and give more detail on the way the model was used to show that a 

NOx only strategy is viable. As in the comment above on analyzing 

intermediate years, the plan needs to provide documentation on speciated RRF’s 

and predicted species concentrations for intermediate years. 

In addition to the more general comments above, I am providing specific 

comments (labeled S-number) on the text in the plan: 

S-1. Page 3-2 Paragraph 1 

The paragraph should state that PM2.5 emissions could be retained in the SJV 

air basin for up to one month. This was seen in the 2000-2001 CRPAQS 

episodes, and it is relevant to the assessment of the representativeness of 

episodes. Long-term episodes are more difficult to control than short term ones. 

In addition, assessment of representative meteorology should include how long 

episodes last. 

S-2. Page 3-2 Last Paragraph 

The description of subsidence does not account for the humidity increase at the 

surface as water vapor is trapped by the dry warm air above it. During major 

winter PM2.5 events, the descending air does not usually penetrate to the 

surface and a subsidence inversion is formed. 

S-3. Page 3-19 first paragraph in 3.3.3 

The District determined that the annual standard is more stringent than the 24-

hour NAAQS. This needs to be documented. 

S-4. Page 3-19 second paragraph in 3.3.3 

The statement in this paragraph supports the idea that the District does not have 

enough data to determine that the area is in compliance with the PM2.5 annual 

and 24 hour NAAQS. The plan states that the District is in compliance with the 

24 – hour NAAQS. 

S-5. Page 3-20 section 3.3.4 

The paragraph states that the District will perform the SMAT analyses. ARB 

did perform these analyses. 
6

S-6. Page 3-22 Section 3.4 first paragraph 

As stated above, without rigorous analysis and EPA approvals the text should 

not state that some sites already comply with the NAAQS. 

S-7. Page 3-23 Top 

As stated in previous comments, the 2004-2006 period had missing data and 

better dispersive meteorology and therefore is non-representative. Method 2 

projections may be misleading. 

S-8. Page 3-23 Regarding Lack of SMAT Documentation 

The District and ARB should provide detailed documentation on how the 

SMAT calculations were derived from the photochemical model. 

S-9. Page 3-27 Prior Accuracy of the PM10 Methodology 

The District is only in attainment of the PM10 NAAQS due to flagging of data 

that is over the NAAQS by the Natural Event Action Plans. These exceedances 

were not predicted by the PM10 plan. 

S-10. Page 3-30 Air Monitoring and Trends 

As stated above, the 2007 FRM data should be analyzed in the plan. My 

comments on the 2nd draft show that the 2007 data would change design values. 

ARB needs to expedite the processing of the 2007 FRM data and include it in 

the plan. It addition, the weight of evidence should include BAMS data which 

could be adjusted by the method portrayed in my comments on the 2nd Draft of 

this plan. 

S-11. Page 3-31 Weight of Evidence 

The total attainment demonstration approaches using CMB and PMF are not 

independent checks because they still depend on design value calculations that 

are flawed. 

S-12. Page 9-3 Last paragraph 

As stated above, PM10 is dependent on NEAP’s and non-representative years of 

2004-2006. 

S-13. Page A-1 
7

Because of the exceedances in 2007, the table should show 2005-2007 design 

values. 

S-14. Page A-2 

Quarter completion problems should be investigated. Is missing data due to 

aerosol loading during poor meteorological conditions? 

S-15. Table A-3 and A-8 

Missing data in 2004 at the highest sites during the highest quarters is shown in 

table A-3 and illustrates the point regarding the loss of high concentration data. 

Also, table A-8, shows the loss of data from 1999-2003 during the worst 

meteorological years. 

S-16. Page A-14 through A-24 Trends Charts 

As stated in previous comments, the trend charts need to reflect fluctuations in 

meteorology by using adjustment methods and/or analyzing meteorological 

parameters that correlate to PM2.5. 

S-17. Page F-61 Regional Modeling 

Here the protocol states that regional model evaluation will be included. As 

stated above, this evaluation is not included in the plan. 

S-18. Figure H-4 

Without a meteorological evaluation, this chart is not definitive. The 2001 

meteorology was much worst than it was in 2006. This may be the difference in 

the meteorological trend and not necessarily emissions. 

S-19. Bottom of page H-8 

Again, as stated above, these comparisons with 1999-2001 and 2004-2006 need 

a meteorological evaluation. 

S-20. Figure H-8 

The upward trend in 1998-2001 is caused by strong meteorology that has not 

returned in the 2004-2006 period the plan is based on. 

S-21. Figure H-14 Speciated Trends 

The species trends look pretty flat, and may not account for the entire PM2.5 

trend. This should be explained. 
8

S-22. Page H-18 

Again, the emissions trend looks pretty flat and would not account for the 

reduction in PM2.5 seen between 2001-2005. 

S-23. Page H-23 

The PMF and CMB model corroborate, but this is only a piece of the attainment 

process. More corroboration is needed for other characteristics of the 

attainment demonstration. These might include other photochemical modeling, 

meteorological adjusted trends, and alternate design value calculations. 

S-24. Figure H-23 

These plots are useful for worst-case scenarios, but may not reflect the 

chemistry involved that produces high annual averages. More documentation is 

needed on what data drives the annual average (e.g.-highest days, moderate 

episodes...). 

S-25. Page H-27 top 

As stated above, the 2005 design value may not be the best year to project into 

future years. This analysis is dependent on representative meteorology. 

S-26. Page H-27 3rd paragraph 

It is not clear from this how the RRF’s were derived (e.g. - photochemical 

model, rollback). 

S-27. Page H-27 Bottom of page 

As stated above, attainment is not the correct term. Only EPA can determine 

that. 

Appendix J Responses to my comments 

Verbal Comments, February 25-26 Workshop 

S-28. Comment 8 

The District needs produce this analysis of 100 years of meteorological data. I 

am requesting that this be included in the plan. 

S-29. Comment 16 
9

This response does not address whether the District or ARB knows what types 

of days drive the annual standard and whether those were analyzed for NOx 

limitation. There is still a question as to whether moderate days that affect the 

annual average are NOx limited. 

S-30. Comment 17 

Under weight of evidence, alternate approaches can be used. 

S-31. Comment 28 

The new rule should consider meteorology and not forecasted AQI. As stated in 

previous comments, declaration of no burn affects air quality to such a degree 

that forecasts do not verify. 

S-32. Comment 31 

This can be done under weight of evidence. The fact remains that missing data 

is occurring during stagnation periods when PM2.5 levels are high. Because of 

this phenomena, the District needs to fill in the missing gaps in the data. 

Written Comments, December 18-19, Public Workshop 

S-33. Comment 26 

As stated above the missing data should be addressed. This is allowed under the 

weight of evidence. Also, stated above, the statement regarding the weak 

correlation is incorrect. 

S-34. Comment 28 

As stated above, the 850mb temp – min temperature is used by the SJVAPCD, 

and has as good a correlation to PM2.5 as any met. parameter. 

S-35. Comment 32 

Response to comment noted that the plan is still missing the ARB model 

evaluation. 

S-36. Comment 34 

The District is saying here that they have not shown documentation of the RRF 

derived from the photochemical model. In addition, as stated above, 2007 data 

needs to be included. 
10

Verbal Comments, December 18-19, 2007 

S-37. Comment 6 

As stated above, ARB should expedite 2007 samples and get them into this 

plan. 

S-38. Comment 11 

Regarding the use of meteorological criteria instead of forecasted AQI, response 

to comment noted. 

Written Comments, December 18-19, 2007 Public Workshop on the Draft 

2008 Plan 

S-39. Comment 21 

Same as item 37. above. 

S-40. Comment 32 

Same as item 33, above. 

S-41. Comment 33 

2007 data needs to be included in the plan. 

S-42. Comment 35 

The District cannot make the statement that levels are not as high with the 

recent 2007 stagnation unless they have a meteorological analysis to prove that. 

Please include an analysis showing the stagnation events do not have as high a 

concentration as in the past. This analysis should include both strength and 

duration of these events. 

S-43. Comment 36 

It appears that the District did do a long-range trend analysis using dichot data. 

S-44. Comment 44 

Neither the 24-hour nor the annual NAAQS address the issue of the month long 

episodes the SJV experiences. 
11

Evan M. Shipp 

Comments on SJVAPCD 2008 PM2.5 Plan, 2nd Draft, February 14, 2008 

I have reviewed the 2008 PM2.5 Plan 2nd draft and have the following 

comments. I would like to commend the technical staff’s of the SJVAPCD and 

ARB for the good job they have done documenting the work that has been done 

so far. Since I have written parts of many air quality plans, I know this can be a 

daunting task. 

Overall, I find the plan much more complete and documented than that of the 

first draft; and many modeling and technical issues I have raised in my 

comments on the first draft have been addressed. However, there are still some 

remaining issues, and I have provided more detail below on my previous 

concerns than on the 1st Draft of this plan. Some of these issues may affect the 

amount of control needed to achieve the NAAQS. The plan in respect to 

modeling does not meet all EPA guidelines. Most of the issues below should be 

addressed to meet the weight of evidence sections of the EPA modeling 

guidelines. The main outstanding and unresolved issues are: 

• Recalculate design values accounting for missing federal reference filter 

data during events when meteorology and real-time data show 

exceedances of the PM2.5 NAAQS 

• Recalculate the design value using 2007 data, and show how the District 

would attain the NAAQS using data for 2005-2007 

• Reassess the 2004-2006 period for representative meteorology, average 

meteorological parameters that correlate to PM2.5 show that the period 

had less pollution potential than previous periods. 

• Provide, as required by EPA and addressed in the District’s protocol, a 

full photochemical model evaluation 

• Document whether the NOx limitation on PM2.5 is verified by the 

photochemical model for all days 

• As a corroborative attainment test, use the EPA method of applying 

Relative Reduction Factors (RRF) with direct photochemical model 

output 

Below are details of the bulleted concerns and additional comments: 

Design Value Recalculations 

Under EPA’s weight of evidence requirements, the District should reassess the 

24-hour and annual design values in the plan due to missing data when 

meteorological conditions are conducive to high PM buildup. EPA’s method of 

data substitution may not fully account for this biased loss of data during 

periods when BAMS concentrations are high. The design value for some sites, 

and especially the highest concentration site, Bakersfield-California is affected 

by missing data when meteorological conditions are conducive to PM2.5 
12

formation. Although, the data is missing, correlation to parallel real-time 

monitors is good, and this data can be used to calculate alternate design values. 

I have attached correlation plots and data in attachment 1. 

I have long suspected that when concentrations are high, flow controllers or 

other instrument components malfunction on the reference method samplers,

invalidating samples that would be high enough to affect design values. 

Analysis of the data supports this hypothesis. In years where meteorology 

produced high concentrations of PM2.5, filter based reference method data, is 

missing when BAMS data are high. For example, viewing a sort of BakersfieldCA, shows, that at Bakersfield-CA, a site with daily filter FRM data, in 2005, 

the 1st, 2nd,5th,6th, 7th, 10th, highest BAM values had no corresponding FRM’s 

(table 1). In addition, in 2003 the three highest BAM concentrations are 

missing reference data for those dates (table 2). Highest data in 2004 and 2006 

are not missing in Bakersfield, but BAMS concentrations for those years are 

relatively moderate and it would not be expected that the instruments would 

have filter loading problems. 

Table 1 Sorted by BAMS Concentrations-2005 Missing FRM Data at 

Bakersfield - CA 

Date 

BAMS Real-time 

Data 24-Hour 

Concentration 

Filter Reference 

Method 

24-Hour 

Concentration 

12/11/2005 104.1 missing 

12/13/2005 98.5 missing 

11/23/2005 88.1 79.7 

12/9/2005 86.9 missing 

12/10/2005 86.5 missing 

12/12/2005 83.6 missing 

12/14/2005 83.5 80.5 

11/24/2005 82.7 85.7 

12/15/2005 81.7 80.1 

12/8/2005 76.2 missing 

11/22/2005 73.2 73 

10/23/2005 71.4 58.5 

3/10/2005 68.4 54.7 

10/22/2005 68.3 55.5 

10/21/2005 68.3 53.7 

11/21/2005 68.3 missing 

 
13

Table 2 Sorted by BAMS Concentrations 2003 Missing FRM at 

Bakersfield-CA 

Date 

AvgOfBakersfield5558 California 

Avenue 

5558 

CALIFORNIA 

AVE, 

BAKERSFIELD 

7/4/2003 86.4 missing 

12/5/2003 71.6 missing 

11/20/2003 69.9 missing 

12/6/2003 68.7 55.5 

1/4/2003 68.0 53.2 

12/4/2003 66.5 53.9 

12/18/2003 64.0 54.3 

1/31/2003 61.1 44.7 

1/8/2003 60.6 43.5 

1/6/2003 59.9 40 

1/15/2003 58.8 42.6 

11/6/2003 58.2 46.1 

1/3/2003 57.9 46.4 

1/30/2003 57.5 41.5 

11/30/2003 57.4 missing 

In 2005, the highest BAMS concentration at Bakersfield-CA was 104 ug/m3. 

My correlation analysis shows that at Bakersfield, BAMS are about 15% higher 

than FRM’s, so this might correspond to about 88 ug/m3 on the FRM’s which is 

well over the 65 ug/m3 with the health effects and mortality associated with 

such concentrations. EPA has indicated to me that this type of non-reference 

method analysis would be allowed under the weight of evidence provisions of 

the modeling and attainment test guidance. In addition, BAMS applications for 

Federal Equivalent Method have been submitted to EPA, the application shows 

that BAMS at Bakersfield – CA are very linear with correlation and slopes 

within EPA specifications (www.nescaum.org/documents/mac/mac-committeemeeting-1/bam-1020-2x-fem-gobeli.pdf). The SJVAPCD may indicate that the 

BAMS are not run in the same fashion, maintained similarly; however, in a 

weight of evidence analysis, these issues are not relevant, and the data should 

stand on its own, with the correlation shown in attachment 1 of these comments. 

Therefore, I am requesting that the APCD calculate BAMS-derived design 

values with possibility of applying correction factors to the data for differences 

in measurement methods. 

Because of the missing FRM’s, the 98% design values remain below the 

NAAQS; however, a look at the BAM’s, even adjusted for differences in 

measurement, would indicate that the District is over the NAAQS. A straight 

98% for Bakersfield-CA shows that concentrations for 2002, 2003, 2004, 2005 

and 2006, would be 71, 61, 64, 82, and 62 respectively. In addition, a review of 

BAMS data for 2007 at Bakersfield - CA, shows a 98% of 76. Scaling these for 

the correlation to the reference method and averaging them will still reveal 

concentrations greater than the 24-hour NAAQS. Contrary to the response to 
14

my comment pertaining to this in the plan, the District should assure that using 

this alternative method to calculate the design value, controls would reduce this 

level to under the NAAQS. 

Because of this missing data, an analysis of how this affects the annual average 

also needs to be done. Preliminarily, the BAMS at Bakersfield – CA for 2007 

shows an average of 19.4, much higher than the reported 2004-2006 period. A 

look at the 2007 data is needed before the weight of evidence analysis is 

complete. Not only should the District look at the BAMS, but should also 

expedient the processing of the filter (FRM’s) for 2007. The District needs to 

show that with these new data attainment can be reached by the attainment date. 

In addition, the District’s analysis is asserting that the District already meets the 

PM2.5 24 hour NAAQS, but given the severe air quality episodes that occurred 

in 2005 and again in 2007, the District should rethink this strategy. Foremost 

the District should not apply for attainment status until the most recent filter 

reference method data is analyzed. Furthermore, I am very concerned that the 

District will be granted attainment status, and use the Nature Event Action Plan 

to nullify any future exceedances of the PM2.5 NAAQS from consideration of 

future controls. Real-time instruments during 2004-2007 have caught numerous 

violations of the NAAQS, and the District owes it to the health and wellbeing of 

the residents of the San Joaquin Valley to mitigate this health risk. 
15

Assess the Meteorological Representativeness of the 2004-2006 Design 

Value Period 

EPA modeling guidance provides for an assessment of the meteorological 

representativeness of the design value period (2004-2006). As stated in several 

meetings, and reiterated in my comments on this plan and the previous PM10 

plan, the 2004-2006 period shows that meteorology, especially meteorology for 

the annual average, is less conducive to PM2.5 formation than previous years. 

In fact, that period shows the lowest annual average for stability factors 

conducive to PM formation during the time that official PM2.5 concentrations 

have been measured (1999-2007). As the District meteorologists know, and as 

the originator of the stability factor used in the plans, the average stability 

correlated to PM2.5 was less in the last few years than in other years. The 

District also contends that the correlation of PM2.5 to this factor is not high, but 

statistics show that the correlation or for the correlation is around 0.7; which is 

about as good as these factors get for correlation to meteorology. That is based 

on my experience with meteorological factors I have formulated for ozone and 

PM in Central and Southern California. Figure 1 shows an average value by 

year for this factor. It is apparent on the chart that the 2004-2006 had less 

stability on average than other years. In addition, in my comments on the PM10 

and 1st Draft of the PM2.5, I have provided more documentation on this subject. 

Responses to these comments were not adequate, and I am requesting a full 

investigation of this subject and a re-evaluation of how this affects the design 

value and control strategy. 
16

Figure 1 

October 01-January 31 Average T850 Stability Bakersfield

-2

-1

0

1

2

3

4

5

1999-20002000-20012001-20022002-20032003-20042004-20052005-20062006-2007*

Average T850 Stability

As Required By EPA Include a Full Photochemical Model Evaluation 

As stated in my verbal comments on the plan, the EPA requires a full model 

evaluation of the photochemical model. This evaluation has full bearing on the 

uncertainty of the estimation of reduction needed to achieve the NAAQS, and 

the conservatism of that estimate. According to ARB, this evaluation will be 

forthcoming, and needs to be included and then analyzed in the next version of 

the plan. Hopefully, this model evaluation will include analysis of individual 

chemical species and total PM. Once the model is evaluated, then the 

uncertainty of the application can be quantified. This evaluation is relevant to 

whether the model can be used to assess such issues as NOx, NH3, and VOC 

limitation. 

Document whether the NOx limitation on PM2.5 is verified by the 

photochemical model for all days 

Since this plan is mainly based on annual average calculations and the 

photochemical model was run for a full year, there should be some assessment 

on the daily change in NOx limitation in the plan. I believe that the NOx 

limitation statements made in the plan are based on severe episodes and those 

do not necessarily drive the magnitude of the annual standard. The plan should 
17

include an assessment of the individual days in the modeling effort and whether 

some days show major sensitivity to VOC and/or ammonia control. If these 

days exist, perform an analysis on theirre contribution to the annual average. 

Use Direct Photochemical Model Output to Calculate RRF’s 

As required by the EPA and included in the District’s own protocol, direct 

output of the photochemical model should be used to provide an alternative 

RRF. From discussions with ARB, direct RRF’s from the annual CMAQ 

modeling are available for many chemical species including nitrate, sulfate, 

elemental and organic carbon. These should be analyzed as an alternative to the 

rollback method. The protocol included in the plan describes independent 

modeling analysis using straight RRF’s as a check on the rollback modeling for 

use demonstrating attainment of the NAAQS. In EPA guidelines, they 

recommend using the output of the photochemical model straight to scale the 

DV by the RRF. Since the protocol and EPA guidelines recommend the use of 

straight photochemically derived RRF’s, the District should at least show these 

calculations as an alternative.
18

Attachment 1 

Bakersfield -CA PM2.5 FRM and BAMS Concentrations

y = 0.8558x - 2.1204

R2

 = 0.9081

-20

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140

BAMS concentration ug/m3

FRM concentrations ug/m3

Fresno-1st PM2.5 FRM and BAMS Concentrations

y = 0.9193x - 2.9268

R2

 = 0.9015

-20

0

20

40

60

80

100

0 10 20 30 40 50 60 70 80 90 100

BAMS Concentration (ug/m3)

FRM Concentrations (ug/m3)
19

Evan M. Shipp 

2088 Lester Avenue 

Fresno, CA 93720 

Jessica Hafer 

San Joaquin Valley APCD 

1990 E. Gettysburg Avenue 

Fresno, CA 93726 

January 8, 2008 

Subject: Comments on the Draft SJVAPCD Draft 2008 PM2.5 

Dear Jessie: 

Thank you for the opportunity to submit comments on the subject air quality plan. My 

comments pertain to the modeling and data analysis portion of this plan. Many of these 

comments I made verbally in the workshop in December. These comments have also 

been distributed widely to stakeholders. Attached are my comments. 

Sincerely, 

Evan M. Shipp 
20

Evan M. Shipp, 

Comments Regarding the 

San Joaquin Valley Air Pollution Control District 

2008 PM2.5 Plan and PM2.5 Modeling Protocol 

Acknowledgements 

First, I would like to thank the technical staff of the SJVAPCD and ARB that 

has done an excellent job documenting the analysis that has been performed, so 

far, by both agencies. The meteorological analysis section in appendix E has 

addressed some of my earlier questions regarding representativeness of recent 

PM2.5 data. I would especially like to thank the staff that provided the 

modeling protocol, which has detailed the steps toward modeling attainment in 

the SJV. I would also like to thank the San Joaquin Valley Technical and 

Policy committees for designing the field programs and providing the data that 

this plan is based upon. 

Summary and General Comments 

Attainment of the 65 ug/m3 PM2.5 NAAQS is a major health issue in the San 

Joaquin Valley in that concentrations above that standard, as documented in 

numerous papers and journals, result in major illnesses and premature death. 

These health effects have been documented by EPA as justification for the new 

35 ug/m3 PM2.5 NAAQS. Therefore, the plan should be rigorous, meet, and 

exceed the guidelines set down by EPA for this less stringent 65 ug/m3 

NAAQS. 

Because there are many components lacking in the plan, this first effort on the 

PM2.5 plan should not be considered a draft, but only a working draft. As 

stated in the protocol, crucial to demonstrating attainment is the use of state of 

the art photochemical modeling and application of that model’s relative 

reduction factors. Because this has not been done, the PM2.5 plan is 

incomplete. I had originally outlined my concerns regarding the modeling 

analysis to Scott Nester, SJVAPCD, and John DaMassa in an e-mail sent on 

August 30, 2007 (attached). Concerns over the meteorology were also 

documented in my comments to the SJVAPCD on the PM10 Attainment Plan 

dated August 10, 2007 (attached). The bullets below summarize my concerns 

with the Draft 2008 PM2.5 Air Quality Plan as written by the SJVAPCD. 
21

• As stated in the plan, the modeling is incomplete, the analyses lack 

several required elements including the current regional photochemical 

modeling and a rigorous weight of evidence approach 

• Because of the lack of current photochemical modeling, the amount of 

reduction needed to achieve the NAAQS is in flux, and the plan cannot 

be thoroughly evaluated 

• Since the plan lacks current photochemical modeling, there is no model 

evaluation as specified in the SJV protocol (appendix F) and EPA 

guidelines 

• Although numerous exceedances of the 65 ug/m3 24-Hour PM2.5 

NAAQS have occurred during the last five years, the plan dismisses 

these and does not adequately address that NAAQS 

• The plan does not address meteorological representativeness; the 

protocol states that this analysis will be done; the years the plan is based 

on (2004-2006) have had better meteorology than past years 

• In accordance with EPA guidelines, and repeated in the SJVAPCD 

protocol on page F-61, current regional modeling is required and is the 

mainstay of the demonstration of attainment, this analysis has not been 

performed in a manner conforming to the guidelines 

• As stated in the SJVAPCD protocol and EPA guidance, although some 

analysis has been performed the plan does not adequately address trends, 

and more importantly meteorologically adjusted trends for the 24 – hour 

NAAQS 

• As specified in EPA guidelines, the plan should address unmonitored 

peaks, but this has not been done because there is no current 

photochemical modeling 

• The plan does not adequately address the effect of controlling for the 

annual standard on the 24- hour NAAQS 

• Even though the plan states that attainment statistics show that the SJV 

is near attainment for the 24 – Hour NAAQS, recent real-time (Fall, 

2007) data show that meteorological can still drive PM2.5 well over the 

24 hour NAAQS and adversely affect public health 

• The plan should address the length of PM2.5 episodes in the SJV and 

their effect on public health 

• The District should change the residential wood combustion rule to 

make it more effective by using meteorological criteria rather than 

forecasted PM2.5 concentrations 

Detailed Comments 

Overall, I have major concerns that the plan in its present state does not address 

many of the requirements set down by EPA. Much of the information required 

by EPA modeling guidelines is missing and is referenced in the plan as 

forthcoming. Due to this lack of detail, the plan can only be considered 

preliminary and not a draft. 
22
23

Address the 24 – Hour PM2.5 NAAQS 

I have major concerns regarding, the failure of the plan to adequately address 

the 24-hour PM2.5 NAAQS. Although the District claims that it is attainment 

for that health standard, the SJVAPCD has not been officially designated by 

EPA that it is in attainment for the 65 ug/m3 NAAQS, nor has the District 

proven that major multi-day weather stagnation events will not cause more 

NAAQS violations. Attaining the 65 ug/m3 PM2.5 standard is literally vital to 

the health of persons living in the San Joaquin Valley. Health studies indicate 

that acute levels above this NAAQS cause premature death, and failure to attain 

this NAAQS will result in excess mortality among the population of the San 

Joaquin Valley. Because exceedances of the 24- hour NAAQS occur in multiday episodes, San Joaquin Valley, residents respiratory systems are insulted day 

after day. Many peer-reviewed papers supporting this view are available and 

many are referenced in the support documents for the new 35 ug/m3 NAAQS. 

The plan should address the health impacts of contiguous multi-day NAAQS 

exceedance episodes. 

Use More Rigorous Weight of Evidence 

According to EPA, attainment of the PM2.5 NAAQS (24 hour NAAQS) is more 

than just modeling and analyzing the last three years of PM2.5 data. It is a 

rigorous process of corroborating the modeling system including analyzing 

meteorology for representative or typical conditions. As specified in the EPA 

modeling guidelines, areas with PM2.5 24-hour design values concentrations 

between 62-67 ug/m3 need to provide a weight of evidence approach to 

determining attainment. For the last 3 years, design values in this range have 

been recorded in the SJV. Because the District has not done a complete analysis 

of predicting the future 24 – hour design value the determination as to whether 

weight of evidence is needed cannot be made. 

Weight of evidence using rigorous trends and data analysis for both the 24 – 

hour and annual standard needs to be addressed in the plan. Although the plan 

stated that there is not enough data to do trends analyses, fine particulate data 

does exist back many years, and this analysis needs to be incorporated into the 

plan. There is enough data at the Fresno-1st Street site to look at trends for 

several years of nitrate and carbon data. In addition, several years of 

IMPROVE data at the national parks above the valley can give an idea of what 

is being transported from the SJV into the parks. Any trend analyses should 

also address the issue of missing data. During the early 2000’s, data was lost 

during meteorological conditions that were conducive to forming high 

concentrations of PM2.5. 

The District and/or ARB should also do meteorologically adjusted trends 

analyses to determine whether there is statistical significance to the better 

PM2.5 values of recent years. More elaboration is needed on the claim that 
24

recent strong stability events have resulted in lower PM2.5 concentrations. 

These analysis should include a look at the 24 – hour average trend, and 

whether historically strong poor dispersion events would still cause exceedances 

of the 24-hour NAAQS. 

In addition, complete metrics of PM2.5 trends need to be included in the plan. 

There is a great deal of variation in measuring improvement of PM2.5 

concentrations depending on what trend statistics is selected. At the least, the 

District should provide meteorologically adjusted averages for both annual and 

winter PM2.5 season and the number of exceedances of the 24-hour NAAQS 

per year. Because the exceedances are a key factor in the health effects seen in 

the SJV, the later statistic should be provided even though the design value is 

below the NAAQS. Because of the statistical nature of the 98% design value, 

many exceedances can occur that effect public health even when the District 

demonstrates attainment. 

The plan only provides corroboration of modeling using another source 

apportionment model (PMF). There is no corroboration of the attainment test. 

As stated above, the attainment test involves photochemical modeled relative 

reduction factors (RRF), and other statistical analyses. The plan rebuffs EPA 

methodology of using RRF and photochemically modeled chemical species to 

test for attainment. This EPA approved methodology should be used and 

compared to the plan’s methodology for corroboration. 

Although there is some analysis in the plan, the District has not done a rigorous 

study of meteorology to determine whether the cleaner concentrations in recent 

years have been due to weather. Preliminary analyses indicate that 

meteorological parameters that are correlated to PM2.5 have shown less PM2.5 

forming potential in the last three years than in previous periods. The plan 

should look at the strength and duration of historical episodes. Specifically, as 

indicated in my written public comments of August 10, 2007 (attached) on the 

PM10 Maintenance Plan and Request for Redesignation, I believe that if periods 

of stagnation occur for as long as the period in the CRPAQS episodes of 2001, 

PM2.5 concentrations would exceed the NAAQS with such frequency as to 

affect the PM2.5 design values. Furthermore, the SJVAPCD protocol states that 

when design values, are between, 62-67 ug/m3 as occurs in the SJV, the weight 

of evidence analysis is crucial. This should warrant a more rigorous analysis of 

the weight of evidence than included in the plan as specified by the protocol. 

This issue is also addressed below by the paragraph regarding recent 

exceedances of the NAAQS. The Distict should do this analysis and submit to 

EPA for redesignation before they claim to be in attainment of the 24-hour 

NAAQS. 

The Plan Should Analyze the Most Recent Data 
25

Although the SJVAPCD claims they are in attainment of the 24-hour NAAQS, 

analysis of recent PM2.5 episodes that occurred in November and December 

2007, indicate that poor meteorology can still drive PM2.5 well over the 

NAAQS. Recent BAMS real-time PM2.5 measurements show that for the 

period from 11/2/2007 through 11/8/2007, 11/15/2007 through 11/16/2007, 

11/28/2007 through 11/29/2007, and 12/12/2007 through 12/16/2007 there were 

numerous exceedances of the 24 hour NAAQS. Preliminary ARB and 

SJVAPCD data shows that real-time instruments recorded the following number 

of violations of the 65 ug/m3 NAAQS so far this season. The District needs to 

do a very rigorous analysis of these recent events to determine the cause and the 

emissions control implications for these episodes. Of note was the episode that 

occurred outside of the traditional PM2.5 season, usually starting in midNovember, in early November. The cause of this unusual event needs to be 

determined. The number of exceedances of the PM2.5 65 ug/m3 this PM2.5 

season are provide below. 

Site Number of Exceedances 

 2007-08 PM2.5 Season to Date 

Bakersfield-Calif 9

Bakersfield-Gold 7

Clovis 9

Corcoran 4

Fresno-First 8

Modesto-14th 1

Turlock 1

Visalia, Church 4

The maximum 24 hour average measured during these events was 92 ug/m3 or 

almost 1.5 times the 24- hour NAAQS. In Bakersfield, there was a PM2.5 event 

that lasted 7 days. Since levels greater than 65 ug/m3 are considered unhealthy 

for everyone, this has tremendous health effects on the general population. 

The District has historically claimed that these are not official exceedances 

because BAMS are only an equivalent monitoring method; however, the 

District’s own analysis shows that the correlation between the BAMS and 

Federal Reference Monitors is very good and within the measurement error of 

each monitor. Because the correlation between the BAMS and FRM’s is high, 

the District should investigate and include in the plan episodes where BAMS 

remain high and above the NAAQS. Once available, the District should also 

analyze the recent preliminary data from the filter based FRM’s before making 

attainment claims. I am very concerned that the District will attempt to 

designate itself attainment for the 24 – hour PM2.5 NAAQS, and once in 

official attainment use the Natural Events Action Plan (NEAP) to exempt any 

future violations of the NAAQS from consideration of control. That policy 

which was used for PM10 is detrimental to health of the citizens of the SJV. 
26

Analyze the Effects of the Annual Strategy on 24-Hour Concentrations 

In addition, the SJVAPCD has not analyzed the effects of the annual PM2.5 

control strategy on the shorter-term 24- hour concentrations. As described in 

EPA’s modeling guidelines, there may be control strategies that reduce ambient 

controls on an annual basis, but may have little effect, no effect, or exacerbate 

episodic PM2.5 problems. Also, at issue is whether chemical speciation used 

for the annual assessment is representative of the species involved in the 24-

hour standard problem. The guidelines describe the recommended procedure 

for the modeled attainment test. This procedure also addresses non-monitored 

peaks using interpolation and RRFs. The software is called MATS (modeled 

attainment test software). 
27

Change the Residential Wood Combustion Forecast Criteria 

Finally, although the District has excellent forecasting staff, the current 

residential wood combustion rule by using forecasted concentration criteria has 

made it less effective than if had been based strictly on meteorological criteria. 

Because the declaration of a prohibited day many times results in reduction of 

concentrations levels below the 65 ug/m3, forecasters are reluctant to forecast 

greater or equal to that 65 ug/m3 NAAQS. The criteria results in difficulty for 

the forecasters, where if they call the prohibited when conditions are near the 

NAAQS they will be under-predicting the NAAQS violation, and overpredicting if they do not call the prohibited. This reluctance to call the 

prohibited is driven by public scrutiny of the forecast. Instead, to protect public 

health, the prohibited should be based on meteorological criteria that would 

cause an exceedance of the NAAQS if residential wood combustion were 

allowed. The prohibited declaration is the largest single action the District can 

take to protect the NAAQS and public health. 
28

Attachement 1 

E-Mail to Scott Nester and John DaMassa Send August 30, 2007, 

Regarding Concerns on PM2.5 Modeling 

As promised in phone conversations to both of you at the end of last week, I am 

documenting my concerns regarding the modeling for the PM2.5 attainment 

plan. To summarize, I am concerned that the modeling for the plan should 

follow, as closely as possible, the latest EPA guidelines, and that the protocol 

for the modeling be done in time for public review. EPA guidelines follow an 

approach of using speciated relative reduction factors (RRF). The reason for 

my concern is that the latest PM10 plan relies on procedures that were 

customized for SJVAPCD, essentially speciated rollback, and somewhat 

difficult to follow. For PM2.5, any deviation from the EPA guidelines needs to 

be well justified. In some instances, there may be SJV specific issues that will 

require modifying EPA procedures, but this should only be done with a detailed

justification for the change. Because of the extreme technical nature of the 

protocol, a review period of 30 days should be provided. In my reading of the 

modeling guidelines, EPA requires the following key elements: 

• A modeling protocol for public review that describes the procedures and 

models used to demonstrate attainment 

• Evaluation of the period used to calculate the design value for 

meteorological representativeness 

• Application of speciated RRF derived from an EPA approved 

photochemical model (e.g.-CAMx, CMAQ, UAM-V) 

• Application of primary Gaussian modeling to apply RRF 

• Use of a variety of modeling episodes, and a full year of modeling for 

the annual NAAQS 

• Use of EPA approved meteorological models (MM5, WRF, RAMS) 

• Adjustments for retained NO3, SO4, OC, EC mass 

• Elimination of doubled counting for use of combination of 

photochemical and Gaussian models. 

In my conversions with ARB, it appears that there is not a plan to use Gaussian 

or dispersion models for investigating hotspots. If this procedure not used, there 

should be some very good documentation on why PM2.5 hotspots were not 

addressed. 
29

Justification for the calculation of the design value, and the procedure used to 

deal with missing data needs to be included in the plan. This procedure should 

consider that in the early years of PM2.5 monitoring instrument problems 

caused deletion of data during weather conditions that produced very high 

PM2.5 values. Data substitution that ignores this fact should not be used. One 

way to deal with this would be to construct data based on the correlation of 

meteorology to PM2.5. Because of the nature of that correlation analysis, the 

reconstruction of data would be biased low, but would be better than not 

including data for those PM2.5 values where we know the data was very high. 

A very rigorous analysis of the periods where data deletion occurred needs to be 

performed. 

As I have stated in comments on the PM10 plan, in general, the meteorological 

representativeness of the last 3 years of meteorology compared to historical 

episodes needs to be analyzed for both the strength and duration of PM2.5 

episodes. 

EPA guidelines call for correction of speciated mass to account for sampling 

characteristics of these chemicals and allow for comparison of the sum of the 

species to the total PM2.5 concentration on RFM filters. The procedure 

outlined by EPA, for this should be followed. 

The District and/or ARB should perform speciated trends, and if possible 

correct those for meteorology. If correlation between PM2.5 chemical species 

and meteorology are found, those corrected trends can give an indication of 

what source sectors have been influenced by control strategies. Before I left the 

District, I had looked at what species we available in the EPA’s AQS system, 

but most of the data was from IMPROVE sites in remote locations. 

Preliminarily, it did not look like key species from these sites had declined as 

fast as the design values. A much more rigorous look at those trends needs to 

be done. 

These are my concerns for now, but I am sure as we get further into the SIP 

process, I will have more comments. I appreciate the chance to get these 

comments in before the PM2.5 process is more solidified. Since new evidence 

shows even more links of PM2.5 to mortality, it is imperative that this SIP be 

done with most scientifically creditable evidence. 

I appreciate the chance to comment on the PM2.5 plan in the early stages of 

development. 

If you have questions regarding my comments, please call me at (559) 903-2290 

or e-mail me at troutshp@comcast.net. 
30

Attachment 2 

Comments on PM10 Plan Including Analysis of the Meteorological 

Representativeness of Recent Particulate Episodes Sent to David Nunes on 

8/10/2007 

Evan M. Shipp 

2088 Lester Avenue 

Fresno, CA 93720 

David Nunes 

Atmospheric Modeler 

1990 E. Gettysburg Avenue 

Fresno, CA 93726 

August 10, 2007 

Subject: Comments on the Draft PM10 Maintenance Plan and Request for Redesignation 

Dear David: 

Thank you for the opportunity to submit comments on the subject plan. Attached are 

those comments. My statements pertain to subjects within my predominate expertise; 

however, given more time, I would provide other comments regarding modeling. 

Sincerely, 

Evan M. Shipp 
31

Comments on the PM10 Maintenance Plan and Attainment 

Designation 

Evan M. Shipp 

2088 E. Lester Avenue 

Fresno, CA 93720 

troutshp@comcast.net

(559) 903-2290 

As stated at the August 8, 2007, workshop regarding the PM10 maintenance 

plan, I am providing written comments detailing my concerns on the 

meteorological and modeling analyses for the plan. Aside from those technical 

comments, as I and others stated at the meeting, the timeline for submitting 

these comments was unreasonably short and should not be repeated for future 

plans. Considering the complicated technical issues involved in these plans, a 

comment period of 30 days would be much more appropriate. In additional, I 

am very concerned that the analysis will set a precedent for the PM2.5 plans. 

Due do the very serious health consequences of PM2.5 the analyses for that plan 

need to be much more rigorous than this document, and use state of the science 

methods for both the modeling and attainment demonstration. Specific 

technical comments follow: 

1. The plan states that guidelines and regulations for the PM10 

maintenance plans require a demonstration that meteorology was not 

unusual during the period that was used for the attainment 

demonstration. As I stated at the meeting, the District showed that the 

average meteorology for 2004-2006 has some of lowest potential for 

forming PM10 than in recent history; therefore, without further analyses 

the period of time the attainment declaration is based on the plan does 

not pass the EPA test. More detailed work on how representative the 

meteorology has been during the past three years needs to be done. I 

would as least recommend that the District look at the persistence of the 

meteorological factors during the 2004-2006 and compare that to other 

periods. Several CRPAQS and IMS95 reports have indicated that the 

duration of an episode from weather system cleanout to the next 

cleanout has a significant effect on the magnitude of PM10 

concentrations. As an expert in this type of analysis, I originated the use 

of this analysis in 1995 in an AWMA paper, my review of that period 

compared to historical records indicates that both average stability and 

episodic stability during the 2004-2006 period were less conducive to 

forming PM10 than many previous periods. I have attached plots of 

stability for the 2004-2006 for Fresno, and for comparison show years 

where the stability parameter remained high for a long period. In 

reviewing plots since the 1970’s it appears that occurrences of persistent 

stability of much more magnitude than the 2004-2006 years have 

occurred with some frequency The District needs to review these plots 
32

and determine the representativeness of the last 3 years. The plots below 

show stable periods in the 1999-2000 and 2000-2001 winter seasons that 

are much stronger and persistent than the 2003-2004 and 2005-2006 

winter period. Also, note that data is missing at Fresno – First Street 

sites because instruments malfunctioned during high aerosol loading. 

This may be driving the change the District sees in the correlation 

between the stability parameter and PM2.5 in recent years. In addition, 

there are three plots, showing the 2004-2006 winter PM seasons. Note 

that due to trough and frontal weather systems the atmosphere was less 

conducive to PM formation during 2003-2004 and 2005-2006 seasons. 

2004-2005 winter does show some persistent strong stability, but not 

quite the strength and duration of other poor dispersion years. The 

stability parameter does not stay as high or persist as it did during other 

years. This is especially true of 2006. The District has diurnal stability 

plots dating back to the 1970’s and these should be analyzed for 

comparison with the 2004-2006 period. For historical purpose, I have 

included the 1989-1990 winter stability plot that shows poor dispersion 

conditions for nearly one month. In an episode like this, even at today’s 

emission levels, PM10 could be driven over the NAAQS for many days 

in a row. 
Fresno-1st PM2.5 VRS. T850 MB Stability

0

1020304050607080

11/15/99

11/22/99

11/29/99

12/6/99

12/13/99

12/20/99

12/27/99

1/3/00

1/10/00

1/17/00

1/24/00

1/31/00

2/7/00

2/14/00

2/21/00

Fresno 1st PM2.5 (micrograms / m3)

PM2.5T850MB Sta
Fresno-1st PM2.5 VRS. T850 MB Stability

0

1020304050607080

11/15/00

11/22/00

11/29/00

12/6/00

12/13/00

12/20/00

12/27/00

1/3/01

1/10/01

1/17/01

1/24/01

1/31/01

2/7/01

2/14/01

2/21/01

Fresno 1st PM2.5 (micrograms / m3)

PM2.5T850MB Sta
Fresno-1st PM2.5 VRS. T850 MB Stability

0

1020304050607080

11/15/03

11/22/03

11/29/03

12/6/03

12/13/03

12/20/03

12/27/03

1/3/04

1/10/04

1/17/04

1/24/04

1/31/04

2/7/04

2/14/04

2/21/04

Fresno 1st PM2.5 (micrograms / m3)

PM2.5T850MB Sta
Fresno-1st PM2.5 VRS. T850 MB Stability

0

1020304050607080

11/15/05

11/22/05

11/29/05

12/6/05

12/13/05

12/20/05

12/27/05

1/3/06

1/10/06

1/17/06

1/24/06

1/31/06

2/7/06

2/14/06

Fresno 1st PM2.5 (micrograms / m3)

PMT85
October 1, 1989-February 28, 1990 Stability Parameter and Precipitation

-10

-5

05

1015

11/15/89

11/22/89

11/29/89

12/6/89

12/13/89

12/20/89

12/27/89

1/3/90

1/10/90

1/17/90

1/24/90

1/31/90

2/7/90

2/14/90

PPTT850 St

39

2. PM10 Trends 

As stated by several meeting participants, the Figure 2 graphic needs to be caveated by 

indicating the amount of PM10 exceedances or the NAAQS that have been removed from 

the analyses, but were flagged under the Natural Events Action Plan (NEAP’s). A list of 

pending and approved NEAP’s should be included in the plan. In addition, as stated at 

the meeting, a look at the trends in individual chemical species needs to be done to assess 

the control program. 

3. PM10 Hotspots 

The District needs to ensure that no non-monitored PM10 hotspots occur or will occur in 

the District due to local sources. This is true of both directly emitted PM10 and 

secondary PM10 from ammonia or NOx sources. Placement of locally high NOx sources 

may result in increased PM10 from ammonium nitrate. 

4. Chemical Speciation Trends 

The District needs to look at chemical speciation to determine whether controls, such as, 

the residential wood combustion rule have been effective, and that secondary PM 

concentrations are declining. Preliminary analysis that I have done is not conclusive. A 

graphic of trends follows for Fresno-First Street and shows little improvement for EC and 

nitrate. 

5. Future modeling endeavors 

Although, the speciated rollback, my be adequate for this plan, in the future for PM2.5 

modeling, speciated Relative Reduction Factors are specified in the EPA PM2.5 

guidelines. This will require regional modeling of nitrate, sulfate, EC, and OC, to use in 

the RRF calculations. The PM2.5 plan should follow all modeling guidelines, including 

the required corroborative analysis. This is a complex process, and needs to be done with 

public and stakeholder scrutiny. The first step to this process is the EPA required 

modeling protocol that needs to have a significant review period for comments of at least 

30 days.