NEW_Volume II FUTURE-YEAR-CONVEYANCE-Draft 2008-06- 06.doc



# PHOTOCHEMICAL MODELING IN SUPPORT OF ATTAINING THE FEDERAL 8-HOUR OZONE AIR QUALITY STANDARD IN CENTRAL CALIFORNIA

Volume 2: 8-hour Ozone Future Year Design Value and Carrying Capacity Calculations

for the Sacramento Non-Attainment Area

California Air Resources Board Planning and Technical Support Division Sacramento, California 95814
Preliminary Draft Date 9/25/06 Revised Draft Date 6/6/08 (Provided for District Review and Comment)

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2 6/6/2008 TABLE OF CONTENTS
1 APPROACH

................................................... ................................................... ....... 5 1.1 Description of Methodology......................... ................................................... ................. 5
2 FUTURE YEAR RESULTS
................................................... ................................. 13 2.1 Base-Year Design Values............................ ................................................... ................. 13 2.2 Future Year Design Value and Carrying Capacity Esti mates.................................... 13
3 ANALYSIS OF MODEL-SIMULATED, UNMONITORED PEAKS..... .................... 18
4 REFERENCES.........................................
................................................... ........... 18
5 APPENDICES.........................................
................................................... ............ 19 5.1 Future Year 2018 ................................... ................................................... ...................... 19

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3 6/6/2008 For District review purposes, this document summari zes modeling-based calculation procedures to estimate future year design values in support of determining future year carrying capacity. Chapter 1 of this document desc ribes the approach utilized while Chapter 2 presents the associated results using the model simulations presented in the Volume 1 document, which describes model performanc e results for 8-hour ozone model simulations of the July 1999 and July-August, 2000, episodes. As indicated in the Volume 1 documentation and repe ated here, sub-regional model performance was conducted for 5 days per episode (1 0 days total) for each of the 15 sub-regions (Figure 1). Table 1 summarizes the num ber of modeled days that satisfied model performance criteria. With the exception of the North Coast (0 days), 2-9 days of the possible 10 days per sub-region are available f or consideration in calculating future year design values.

Table 1. Combined Number of Available Days Per Sub-region Under 8-hour Metrics

Region Name July 1999 July-Aug

2000 Total North Coast 1 0 1 BAAQMD 1 2 3 MBAQMD 1 2 3 Sacramento Valley North 4 4 8 Sacramento Region 5 3 8 SJVAPCD Central 3 5 8 SJVAPCD Kern 4 5 9 SJVAPCD North 3 2 5 Sierra Nevada Central 2 3 5 SJVAPCD Above 3000 ft 3 4 7 South Central Coast 3 1 4 Sierra Nevada North 3 5 8 Desert 1 5 6 Nevada 3 0 3 Total 37 41 78

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4 6/6/2008 Figure 1. Sub-regions used in the air quality mode l performance evaluation (3: Bay Area region, 6: Sacramento Metro region, 7: Cen tral San Joaquin Valley region , 8 Southern San Joaquin Valley region, 9: N orthern San Joaquin Valley region). 

## 1 2

3

4 5

6

7

8 9 10

11

12 13

14

15

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5 6/6/2008 

# 1 Approach This Chapter describes ARB’s proposed procedures, b ased on USEPA guidance, for calculating and applying RRFs for California’s 8-ho ur ozone State Implementation Plans. The information in this section was previou sly provided to the Sacramento Metropolitan Air Quality Management District for re view and comment. 

## 1.1 Description of Methodology While the emphasis of this discussion is on site-sp ecific RRFs, it is noted that the USEPA (2005) also requires an analysis to demonstra te that high ozone concentrations occurring away from monitors (e.g., unpaired in spa ce) will also be controlled in future years to meet air quality standards. This issue is addressed as well. The application of photochemical ozone models has a long history in California, for uses ranging from the preparation of State Implementatio n Plans to research activities to regulatory development. The modeling community has applied these tools in the State for over 30 years, and much has been learned about their proper uses and limitations. One of the fundamental understandings that has been learned about photochemical models is that they are best used to estimate the r elative difference between scenarios, rather than for absolute concentration estimates. That is, their strength is in estimating the relative change in concentration levels from a baseline condition (e.g., a current year) to an alternative scenario (e.g., a future ye ar), rather than predicting the exact concentration level that will result from the alter native scenario. The USEPA’s guidance on the use of models for attai nment demonstrations in support of 8-hour ozone planning (USEPA, 2005) is consisten t with the fundamental strength of models described above. USEPA’s recommended modele d attainment test is to utilize relative model response on a site-by-site basis, in the form of a relative response factor (RRF), to predict future-year 8-hour ozone design v alues. This methodology relies on the base year for the modeling for conducting model performance analyses, a reference year of 2002 for projecting forward site-specific d esign values, and a future year for the attainment test.

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6 6/6/2008 DV F 

### = (RRF) (DV R 

### ) where DV

R 

### = a reference year (2002) concentration (design va lue) measured at a monitoring site DV

F 

### = the estimated future year design value at the sa me site RRF = the relative response factor at the same sit e The RRF is calculated as the ratio of future year t o reference year modeled ozone concentrations at a site:

hr 8 hr 8 

### RY FY RRF

−

− 

### = 

### where RRF = the relative response factor for a moni tor FY

8-hr 

### = the modeled future year 8-hour daily maximum concentration predicted near the same monitor RY

8-hr 

### = the modeled reference year 8-hour daily maximum concentration predicted near the same monitor In principle, this concept is simple. Unfortunatel y, it can be confounded by a number of factors, including the limited number of modeled da ys available, the choice of year(s) to use for specification of the reference year design value, the uncertainties inherent in air quality modeling, and the presence of a non-zero ba ckground level of ozone. As a result of this, EPA technical staff have indicated that there is flexibility in the application of RRFs, as long as the methodology is technically sound and is properly documented.

1.1.1 

## Estimating Reference Year (2002) Design Values Specification of the reference year design value is a key consideration in the modeled attainment test, since this is the value that is pr ojected forward and used to test for attainment at each site. Since the reference desig n value is presumably reflective of conditions in the reference year, it should be repr esentative of the emissions used for that year. However, many areas experience fluctuat ions in their year-to-year meteorology, as well as emissions levels. In recog nition of this year-to-year variability, the reference design value should in some fashion a lso reflect this variability. A standard methodology for minimizing the influence o f year-to-year variations is to calculate an average value over multiple years. Th erefore, the following methodology is recommended for specification of the reference desi gn value at each monitoring site: The reference design value (DV R 

### ) will be calculated as the average of the three design values for the three years commenc ing with the reference year of the modeling. The reference year for modeling in support of the 8-hour ozone SIPs is 2002. Therefor e, the reference

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7 6/6/2008 design value will be calculated at each monitoring site as the average of the design values for 2002, 2003, and 20 04. 

### California design values are calculated as the thre e-year average of the 4 th 

### highest 8-hour ozone peak values, and are assigned to the l ast year. Thus, a design value for 2002 would be based on data for 2000-2002. The rec ommendation above implies that the reference design value at each monitoring site will be calculated as the average of nine design values over five years: the three years which make up the 2002 design value (2000-2002), the 2003 design value (2001-2003 ), and the 2004 design value (2002-2004). This gives the greatest weight to 200 2, since that year is included in the calculation of the design value for all three years

. The following table summarizes the recommended proc ess for calculating the reference design value at each monitoring site. Year Years Averaged for Design Value 2002 2000 2001 2002 2003 2001 2002 2003 2004 2002 2003 2004

Yearly Weighting for Average Design Value for Model ed Attainment Test 2002-2004 Average 9 Year ) 2)(Year ( ) 3)(Year ( ) (2)(Year Year DV 2004 2003 2002 2001 2000 R 

### + + + +
=



### 1.1.2 

## Relative Response Factors As discussed above, the relative response factor (R RF) is a monitor-specific value that is calculated based on daily peak 8-hour ozone conc entrations simulated in a future year, divided by daily peak concentrations simulate d in the reference year. To be consistent with the principle that the modeled atta inment test and design values should be robust and stable over a number of different typ es of meteorology, the RRF should be based on multiple simulated days. The following methodology will be used to calculate site-specific RRFs: Site-specific RRFs will be calculated as the ratio of the average daily peak 8-hour modeled ozone concentration in the future year, div ided by the average daily peak 8- hour modeled ozone concentration in the reference y ear. Only those days satisfying the model performance and threshold criteria described below shall be included in the RRF calculation.

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8 6/6/2008 

# ( ) ( ) AVG hr 8 AVG hr 8 AVG 

### RY FY RRF

−

− 

### =

where RRF

AVG 

### = the average relative response factor for a monit or (FY

8-hr 

### ) AVG 

### = the average future year 8-hour daily maximum concentration predicted near the same monitor, averaged over those days which satisfy model performance and threshold criteria (RY

8-hr 

### ) AVG 

### = the modeled reference year 8-hour daily maximum concentration predicted near the same monitor, averaged over those days which satisfy model performance and threshold criteria

1.1.3 

## Criteria for Use of Modeled Days in RRF Calculation s Adequate model performance is a requirement for use of modeled results. The lack of acceptable performance greatly increases uncertaint y in the use of the modeling results, and casts doubt on conclusions based on the modelin g. Although it is desirable to include as many days as possible in the RRF calcula tions, our experience has demonstrated that not all modeled days meet the min imum performance standards, and are thus not suitable for use. Therefore only thos e days which satisfy the following model performance criteria will be utilized in subs equent RRF calculations. The USEPA (1991) and ARB (1990) outline a number of procedures for analysis of base year, air quality model performance. These in clude spatial and time-series plots, and statistical analyses, comparing simulated and o bserved pollutant concentrations, as well as sensitivity analysis of selected input fiel ds. The purpose of the performance analysis is to provide some confidence that the air quality simulations – which are the basis of future-year ozone concentration estimates – are performing properly. The application of air quality modeling results to demonstrate attainment of the federal 1-hour ozone standard emphasized the simulated unpa ired peak ozone concentration. Three statistical measures were recommended to eval uate model performance: unpaired peak ratio (UPR), paired mean normalized b ias (NB), and paired gross error (GE). These statistical measures were calculated f or the modeling domain as a whole, and the NB and GE were calculated from all hourly c oncentrations in excess of 60 ppb (to avoid biasing the statistical measures with low concentrations). To meet performance guidelines, recommendations were that t he UPR should be within ± 20%, NB should be within ± 15%, and the GE less than 35%. However, Californi a’s geography is very complex and modeling domains have evolved to cover large geographic areas. Thus it is recommended that the domains be divided into subregions, and that the performance measures be calcu lated independently for each sub-

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9 6/6/2008 region. The configuration of these sub-regions is somewhat arbitrary; however, they should be configured to isolate "common" regions of higher ozone. The USEPA (2005) recommends that the emphasis for 8 -hour model performance be based on concentrations occurring at, or in the vic inity of, individual monitoring sites. Specifically, modeled concentrations occurring with in 15 km of a site are considered to be in the vicinity of the site. The recommended st atistical measures to assess simulated versus observed maximum 8-hour ozone conc entrations include paired (in space, but not time) peak prediction accuracy (PPPA ), paired mean normalized bias (NB), and paired gross error (GE). Although limite d performance analysis has been completed for 8-hour ozone modeling in California, it seems prudent at this point to carry forward the 1-hour statistical goals and appl y them for the 8-hour standard (UPR within ± 20%, NB within ± 15%, and the GE less than 35%). However, these li mits may need to be revised as 8-hour SIP modeling progresse s and rigorous model performance evaluations are completed. While statistical measures for 1-hour model perform ance were typically calculated independently for each modeled day available, the U SEPA also recommends that PPPA, NB, and GE be calculated for each site over a ll modeled days. However, because the number of episode days available may be very limited, the statistical uncertainties in these latter calculations would be large and they are not recommended herein. In order to have confidence in future year estimate s from air quality models, there must be confidence in the air quality modeling for the b ase year. That is, days not meeting model acceptance criteria provide high uncertainty, and should not be used for the modeled attainment test. In addition to the issue of model performance, anal yses conducted by the USEPA (2005) suggest that air quality models respond more to emission reductions at higher predicted ozone values. Correspondingly, the model predicts less benefit at lower concentrations. This is consistent with preliminar y modeling in support of the 8-hour ozone standard conducted by the ARB and the distric ts. These results imply that RRF calculations should be restricted to days with pred icted high ozone concentrations. It is thus reasonable to establish a minimum threshold fo r predicted peak 8-hour ozone concentrations in the reference year. Days for whi ch the predicted daily peak 8-hour ozone concentration at a site is less than the thre shold, would not be used for calculating RRFs at that site. Consistent with USE PA’s recommendation, we propose to use a value of 85 ppb for the reference year thr eshold. Based on the above discussion, we propose the follo wing methodology for determining sites and modeled days to be used in the RRF calcul ations:

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10 6/6/2008 Only those modeled days meeting the following crite ria will be used to calculate site-specific RRFs: 1) The modeled daily 8-hour peak ozone concentratio n within 15 km of the site for the base year of the modeling must be within 

### ± 20% of the observed value at the site. 2) The modeled daily 8-hour peak ozone concentratio n within 15 km of the site in the reference year must be 85 ppb or greater. 3) The sub-regional 1-hour and 8-hour statistical m easures of NB and GE must fall within the thresholds of 

### ± 15% and 35%, respectively. 1.1.4 

## Estimating Future-Year Design Values As discussed above, the USEPA’s 8-hour modeling gui dance recommends utilizing relative model response on a site-by-site basis, in the form of an average relative response factor (RRF AVG 

### ), to predict future-year 8-hour design values for attainment planning. The average RRF is then multiplied by a site-specific design value to estimate the future-year design value. One of the confounding factors in this approach is consideration of the effects that background lev els have on the effectiveness of emission control programs. There is a large body of information that suggests that ambient concentrations consist of some (perhaps nonlinear) background value and a contribution due to anthropogenic emissions. That is, if all man-made emissions coul d be zeroed out, ozone concentrations would not go to zero but rather some finite value. The literature suggests that 40 ppb is a reasonable global backgro und ozone value, and it is quite likely that continental background is some other, s omewhat higher, value. One possibility for estimating background ozone values in a given modeling domain would be to exercise the model without anthropogenic emis sions, and to thus develop a gridded “background” ozone field. One concern with this approach is that at such low levels, the model’s boundary conditions exert a lar ge influence, and appropriate temporally- and spatially-resolved data to specify boundary conditions rarely exist. Thus boundary conditions can be subjective and unce rtain. Whether the background value is established at some finite value (e.g., 40 ppb) or is model-derived, it represents that portion of a site’s ozone problem that cannot be mitigated by anthropogenic emission controls. According to EPA’s 8-hour ozone modeling guidance, the modeled attainment test requires that a future year Design Value (DV F 

### ) be calculated at each site and compared to the standard to determine if the site is predict ed to be in attainment. To calculate the future year Design Value, the Design Value for the reference year (DV R 

### ) is multiplied by RRF AVG 

### . Although EPA’s guidance says nothing about backg round ozone, we propose to calculate the future year Design Value with cons ideration of background. The Table below illustrates calculation of the DV F 

### with and without background.

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11 6/6/2008 Calculation of the Average Relative Reduction Facto r with and without Consideration of Background Ozone 

### Without consideration of background With consideration of background 

# ( ) 

# ( ) AVG AVG AVG 

### RY FY RRF =



### DV F 

### = (RRF AVG 

### ) x (DV R 

### ) 

# ( ) 

# ( ) AVG

AVG AVG 

### BG

- RY BG

- FY RRF =



### DV F 

### = [(RRF AVG 

### ) x (DV R 

### – BG)] + BG

Definitions DV R 

### = Design Value for the reference year RY = reference year model prediction FY = future year model prediction BG = background ozone

Future year design values will be calculated with c onsideration of background ozone. Because the model’s boundary con ditions exert a large influence on modeled background ozone level s, 40 ppb will be used to represent background ozone concentration s.

1.1.5 

## Unpaired Peak Concentrations The USEPA (2005) recommends that maximum simulated and observed 8-hour ozone concentrations be investigated and combined to demo nstrate attainment for all areas in a region. This can be cause for concern because pe ak simulated ozone concentrations rarely occur at the exact location of a monitoring site. Conceptually, a design value for the location of the unpaired peak can be determined by extrapolation from existing monitoring sites. However, this could lead to desi gn value ozone concentrations that are greater than those that have been measured and may be the limiting factor in an attainment demonstration. California’s modeling domains include extreme varia tions in terrain and meteorology. Even during the most intense of field studies, the monitoring network is not sufficient to capture all of the gradients in the ozone concentra tion field. The modeling is subject to inaccuracies in the input data, and terrain gradien ts are smoothed over the spatial resolution of the model. However, the modeling doe s provide information on concentration gradients throughout the domain. To take advantage of the strengths of the modeling and the monitoring network, we propose the following approach for addressing unmonitored peak areas.

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12 6/6/2008 An unmonitored design value for the reference year and for each sub-region will be estimated by averaging the sub-r egional maximum 8-hour ozone concentrations for all days which sati sfy the model performance criteria described earlier. A sub-regi onal RRF will be calculated by averaging all site-specific RRFs in t he sub-region. The estimated unmonitored design value and sub-regional RRF will then be used in the attainment test. 

### This approach to the unpaired peak 8-hour ozone con centration differs from that described in the USEPA (2005) guideline document. However, we believe the approach described above is consistent with use of the modeled and monitoring data, and provides a reasonable alternative to EPA’s meth odology.

1.1.6 

## Other Potential Technical Issues The process outlined above for calculating site-spe cific RRFs seems straightforward. However, in practice, the process may turn out to b e tedious and cumbersome; especially if a large number of sites need to be ev aluated, and for different years. The greatest difficulty may be that the number of days used for the calculation of the RRF for each site may vary. The days used for each site in the future year must match those used in the reference year. Because the selection of these days is based, in part, on model performance statistical measures, it may be n ecessary to do much of this work by hand. Another problem that is almost certain to arise is that for some sites either the model performance or the observed and simulated concentra tions will fail to meet the recommended guidelines on all of the available epis ode days. This may result in situations wherein the day of the peak ozone concen tration is not used in the calculation of the RRF and days with lesser concentrations are. The risk is that if the episode and simulation results do not adequately represent high ozone concentrations at a site, the simulation results may overstate the emissions redu ctions necessary to reach attainment for the ozone air quality standards due to the model’s relatively limited response to controls at lower concentrations. In a ddition, the process of estimating a future year design value at an unmonitored peak loc ation will always be subject to great uncertainty. Some of the above difficulties may be avoided if a more simple and straightforward approach was used. For example, an RRF could be ca lculated from the reference- and future-year sub-regional maximum 8-hour daily maxim um ozone concentrations. The RRF could then be multiplied by the maximum design value within the control district or attainment area. This would deviate from the USEPA (2005) guidelines in a number if respects. But, it would greatly simplify the requi red calculations. A lot more study of this approach would be necessary to understand the implications of such an approximation. This would also have to be vetted w ith the USEPA.

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13 6/6/2008 

# 2 Future Year Results This chapter presents draft reference year design v alues and describes the future year design values and carrying capacity results contain ed in the Appendices. 

## 2.1 Base-Year Design Values Chapter 1 (Section 1.1.1) discusses a proposed appr oach for calculating future year design values. Based on this recommended approach, Table 2 presents the results of reference year design value calculations for the Sa cramento Non-Attainment Area. Table 2. Sacramento Non-Attainment Area Design Val ues for 2002-2004 (Non-Attainment Sites Only)

8-Hour Ozone Design Values Site 2002 2003 2004 2002-04 Avg. El Dorado County 

### Coo l -Highway 193 106 107 102 105 

### Placerville - Gold Nugget Way 94 95 94 94 

### Placer County 

### Auburn - Dewitt-C Avenue 101 99 95 98 

### Roseville - N Sunrise Blvd 92 90 87 90 

### Sacramento County 

### Folsom - Natoma Street 100 100 97 99 

### North Highlands - Blackfoot Way 92 91 85 89 

### Sacramento - Del Paso Manor 95 97 95 96 

### Sloughhouse 95 95 94 95


## 2.2 Future Year Design Value and Carrying Capacity Estimates Data processing programs are used to generate repor ts from modeling results to illustrate future year design values and carrying c apacities. These reports are generated for each 8-hour ozone non-attainment moni toring station following the methodology described in Chapter 1, sections 1.1.3 and 1.1.4. For illustration purposes, this section discusses the information co ntained on a sample report page (Figure 2). The Appendices contain future-year-spe cific results for specific years in the same form as the sample format. Report Header . At the top of the report, three header lines pro vide a variety of information, including the subject future year (201 2), the station (site) name, the associated sub-region (per Figure 1, Chapter 1), an d the 8-hour ozone design value for

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14 6/6/2008 the USEPA-defined reference year of 2002 (98 ppb) f rom Table 2, shown previously in Section 2.1). Report Table . The mid-section of the report contains a table w ith 8 rows: a header row, plus 7 rows of information. For specific episode d ays (columns), this table contains a pass/fail summary of sub-regional model performance results for the site (row 2), a variety of concentration data (rows 3-7), and a yes /no assessment as to whether the station data are useable in the RRF analysis (row 8 ). A “-99” value in rows 3-7 indicates that acceptable data are not available. The purpos e of each row is described below:

• Row 1 

### : Header

. Columns represent episode days via two digit yea r followed by three digit day-of-year, or Julian day.
• Row 2 

### : Performance Status : This line lists the model performance status for each of the episode days. The model performance st atus is a pass/fail designation as to whether the model performance for the sub-region within which the monitoring station is located meets both the 1-hour and the 8-hour statistical model performance criteria, per Section 1.1.3 and t he Volume 1 report. Per the Figure 2 report header, Auburn is located in Region 6.
• Row 3 

### : Peak Observed 8-hour Ozone . These data represent the peak, measured 8-hour ozone concentrations at the Auburn station for each specific day. These 8-hour ozone concentrations need to be above 70 ppb to be used in the RRF calculation (U.S. EPA guidance recommends e xcluding days with concentrations less than 70 ppb from RRF calculatio ns to avoid a strong RRF dependence on the predicted baseline maximum concen trations).
• Row 4 

### : Peak Simulated 8-hour Ozone . These are the model-simulated, peak 8-hour ozone concentrations occurring in the modeli ng grid cell within which the station (Auburn in this case) is geographically loc ated. Per Section 1.1.3, simulated concentrations must be 85ppb or greater t o be used in the RRF calculation.

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15 6/6/2008 Figure 2. 

### Sample Report Page for the Auburn monitoring site

.

Year: 2018 Model: CAMX/MM5/SAPRC99 Site: AUBD - Auburn-Dewitt-C Avenue Subregion: 6 Reference Year Design Value: 98 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 105 103 107 102 91 -99 8 0 82 95 107 Peak Simulated 8-hour Ozone 87 80 86 77 73 71 78 74 93 104 Peak Simulated 8-hour Ozone within 15 km 106 84 101 84 77 79 86 83 106 106 Reference Year 15-km, 8-hour Average Ozone 105 Future Year 15-km, 8-hour Average Ozone 89 73 83 71 67 70 75 74 91 90 Use in RRF Analysis? Yes No Yes No No No No No Yes Yes

85

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx AUBD Average 15-km Concentration (ppb)

Without RRFs

82 83 85 86 87

82

83 85 86 88

82

84 85 86 88

82

84 85 87 88

82

84 85 87 88

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx AUBD FY Design Value(ppb) With RRFs Offset = 0 ppb

76 78 79 80 81

76

78 79 80 82

77

78 79 81 82

77

78 79 81 82

77

78 80 81 82

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx AUBD FY Design Value(ppb)

With RRFs Offset = 40 ppb

77 78 80 81 82

77

79 80 81 82

77

79 80 81 82

78

79 80 81 83

78

79 80 82 83

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16 6/6/2008 • Row 5 

### : Peak Simulated 8-hour Ozone within 15km . These values represent the model-simulated, daily 8-hour peak ozone concentrat ion within 15 km of the site for the base year of the modeling. Per Section 1.1 .3, these concentrations must be 85 ppb or greater and within ± 20% of the observed value at the site.
• Row 6 

### : Reference Year, 15km, 8-hour Average Ozone . This represents the average of the Row 4 values for which the data are useable in RRF analyses (per row 8). For Auburn, since row 8 indicates tha t only days 99190, 99192, 00214, and 00215 are usable, 105 ppb is calculated from the average of 106, 101, 106, and 106 ppb.
• Row 7 

### : Future Year, 15km, 8-hour Average Ozone . This represents the average, future-year simulated concentrations withi n 15 km of the site.
• Row 8 

### : Use in RRF Analysis? This YES/NO field represents whether data for the days can be used in calculating the RRF. As in dicated in Section 1.1.3 and in the row descriptions above, the criteria for sel ecting which days will be used in the RRF calculation include an assessment of sub-re gional model performance as well as concentration thresholds for observed an d simulated 8-hour ozone concentrations. That is, in addition to meeting mo del performance criteria, the observed base-year ozone concentration must be 70 p pb or greater and the maximum simulated ozone concentration for the year 2002 must be 85 ppb or greater. RRF Calculation Example . Of the 10 available episode days reported in Fig ure 2 for Auburn, six of the days fail to meet the 1-hour and /or the 8-hour model performance criteria ('99191', '99193', '99194', '00211', ‘0021 2’, and '00213'). The simulation results from the remaining four days are used in the RRF ca lculation: days '99190', ‘99192’, ‘00214’, and '0215' (per row 8). Per Section 1.1.4 the sample RRF for Auburn, without a background offset, is calculated as follows:



# ( ) 

# ( ) AVG AVG AVG 

### RY FY RRF = 

### = ((89+83+91+90)/4) / ((106+101+106+106)/4) = (88/ 105) = 0.84

Also per Section 1.1.4, with a 40 ppb background of fset, the RRF is calculated as:



# ( ) 

# ( ) AVG

AVG AVG 

### BG

- RY BG

- FY RRF = 

### = (88-40)/(105-40) = 0.74
Reported Design-Value-Based Carrying Capacity Diagr ams . The lower half of the page for each report contains four design-value-based ca rrying capacity diagrams. These diagrams are intended to characterize the effect of domain-wide emission changes on a design value, based upon multiple model simulations . The diagrams are based on model response to 25 future year emission scenarios for which baseline, domain-wide NO x 

### and ROG emissions for the 2018 future year are sca led by factors ranging from 0.80 to 1.00 in increments of 0.05 (i.e. 5% NO x 

### and/or ROG reductions at a time).

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17 6/6/2008 The diagram on the left side of the report is based on the average of the “Future Year 15-km, 8-hour Average Ozone” values reflected in ro w 6 of the report table, for those days that meet all the criteria for RRF application . However, no RRF is applied. Thus the future year design value indicated at the top r ight of each diagram is calculated as follows: DV F 

### = (89+83+91+90) / 4 = 88 ppb The two diagrams on the right incorporate RRFs, wit hout consideration of background ozone (top diagram) and with consideration of backg round (bottom diagram). The future year design value indicated at the top right of the top diagram on the right is calculated as follows, using the RRFs discussed abo ve: DV F 

### = (RRF AVG 

### ) x (DV R 

### ) = 0.84 x 98 ppb = 82 ppb Similarly, the future year design value indicated a t the top right for the bottom right diagram is calculated as follows, using the backgro und-adjusted RRFs discussed previously and equations in section 1.1.4: DV F 

### = [(RRF AVG 

### ) x (DV R 

### – BG)] + BG = [ 0.74 x ( 98 – 40 ) ] + 40 = 83 p pb

### 18 6/6/2008



## 3 Analysis of Model-Simulated, Unmonitored Peaks This work will be reported separately. 

# 4 References Air Resources Board, 1990. “TECHNICAL GUIDANCE DOC UMENT: Photochemical Modeling”. USEPA, 1991. "Guideline for Regulatory Application of the Urban Airshed Model". EPA-450/4-91-013. USEPA, OAQPS. Research Tr iangle Park, NC 27711. July, 1991. USEPA, 2005. "Guidance on the Use of Models and Oth er Analysis in the Attainment Demonstration for the 8-Hour Ozone NAAQS ". Final Draft. USEPA, OAR/OAQPS, Research Triangle Park, NC 2771. Februa ry, 2005.

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

19 6/6/2008 

# 5 Appendices 5.1 Future Year 2018

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

20 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: AUBD - Auburn-Dewitt-C Avenue Subregion: 6 Reference Year Design Value: 98 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 105 103 107 102 91 -99 8 0 82 95 107 Peak Simulated 8-hour Ozone 87 80 86 77 73 71 78 74 93 104 Peak Simulated 8-hour Ozone within 15 km 106 84 101 84 77 79 86 83 106 106 Reference Year 15-km, 8-hour Average Ozone 105 Future Year 15-km, 8-hour Average Ozone 89 73 83 71 67 70 75 74 91 90 Use in RRF Analysis? Yes No Yes No No No No No Yes Yes

85

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx AUBD Average 15-km Concentration (ppb)

Without RRFs

82 83 85 86 87

82

83 85 86 88

82

84 85 86 88

82

84 85 87 88

82

84 85 87 88

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx AUBD FY Design Value(ppb) With RRFs Offset = 0 ppb

76 78 79 80 81

76

78 79 80 82

77

78 79 81 82

77

78 79 81 82

77

78 80 81 82

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx AUBD FY Design Value(ppb)

With RRFs Offset = 40 ppb

77 78 80 81 82

77

79 80 81 82

77

79 80 81 82

78

79 80 81 83

78

79 80 82 83

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

21 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: 3002 - Colfax-City Hall Subregion: 6 Reference Year Design Value: 85 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 89 86 87 82 69 -99 -99 - 99 -99 -99 Peak Simulated 8-hour Ozone 81 75 83 75 69 75 78 74 85 100 Peak Simulated 8-hour Ozone within 15 km 92 80 91 8 2 74 78 83 79 92 105 Reference Year 15-km, 8-hour Average Ozone 91 Future Year 15-km, 8-hour Average Ozone 76 70 75 69 65 70 73 69 79 89 Use in RRF Analysis? Yes No Yes No No No No No No N o

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx 3002 Average 15-km Concentration (ppb)

Without RRFs

70 71 72 74 75

70

71 72 74 75

70

71 73 74 75

70

71 73 74 75

70

71 73 74 75

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx 3002 FY Design Value(ppb) With RRFs Offset = 0 ppb

64 65 67 68 69

64

66 67 68 69

64

66 67 68 69

64

66 67 68 69

65

66 67 68 69

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx 3002 FY Design Value(ppb)

With RRFs Offset = 40 ppb

65 67 68 69 70

66

67 68 69 70

66

67 68 69 70

66

67 68 69 70

66

67 68 69 70

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

22 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: CUS - Cool Stn (1400 American Subregion: 6 Reference Year Design Value: 105 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 116 114 118 100 94 94 87 90 99 104 Peak Simulated 8-hour Ozone 95 82 93 83 76 75 83 78 92 100 Peak Simulated 8-hour Ozone within 15 km 111 86 106 85 79 81 88 85 98 105 Reference Year 15-km, 8-hour Average Ozone 98 Future Year 15-km, 8-hour Average Ozone 93 75 87 72 69 72 76 72 85 89 Use in RRF Analysis? Yes Yes Yes Yes No No No No Ye s Yes

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx CUS Average 15-km Concentration (ppb)

Without RRFs

78 79 80 82 83

78

79 81 82 83

78

79 81 82 83

78

80 81 82 83

78

80 81 82 84

8 5

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx CUS FY Design Value(ppb)

With RRFs Offset = 0 ppb

83 84 85 87 88

83

84 86 87 88

83

84 86 87 88

83

84 86 87 88

83

85 86 87 89

85

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx CUS FY Design Value(ppb)

With RRFs Offset = 40 ppb

82 83 85 86 87

82

83 85 86 87

82

83 85 86 88

82

84 85 86 88

82

84 85 87 88

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

23 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: ELK - Elk Grove Stn (Brucevil Subregion: 6 Reference Year Design Value: 77 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 75 93 97 95 78 64 50 64 66 63 Peak Simulated 8-hour Ozone 76 89 83 91 86 81 85 99 96 86 Peak Simulated 8-hour Ozone within 15 km 80 99 95 1 02 88 91 91 110 100 87 Reference Year 15-km, 8-hour Average Ozone 96 Future Year 15-km, 8-hour Average Ozone 76 84 80 84 79 83 83 97 88 80 Use in RRF Analysis? No Yes Yes Yes Yes No No No No No

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx ELK Average 15-km Concentration (ppb)

Without RRFs

76 77 79 80 81

76

77 79 80 81

76

78 79 80 81

76

78 79 80 82

76

78 79 81 82

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx ELK FY Design Value(ppb) With RRFs Offset = 0 ppb

60 61 63 64 64

60

62 63 64 65

61

62 63 64 65

61

62 63 64 65

61

62 63 64 65

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx ELK FY Design Value(ppb)

With RRFs Offset = 40 ppb

63 64 65 66 67

63

64 65 66 67

63

64 65 66 67

63

64 65 66 67

64

65 65 66 67

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

24 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: FLN - Folsom Stn (Natoma St.) Subregion: 6 Reference Year Design Value: 99 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 109 129 124 102 86 70 66 43 -99 95 Peak Simulated 8-hour Ozone 109 96 121 87 87 88 97 84 105 88 Peak Simulated 8-hour Ozone within 15 km 115 114 12 5 98 98 101 107 92 116 104 Reference Year 15-km, 8-hour Average Ozone 108 Future Year 15-km, 8-hour Average Ozone 102 96 101 80 87 88 96 82 98 90 Use in RRF Analysis? Yes Yes Yes Yes Yes Yes No No No Yes

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx FLN Average 15-km Concentration (ppb)

Without RRFs

86 87 88 90 91

86

87 89 90 91

86

88 89 90 91

86

88 89 91 92

87

88 90 91 92

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx FLN FY Design Value(ppb) With RRFs Offset = 0 ppb

78 79 81 82 83

78

80 81 82 83

79

80 81 82 83

79

80 81 83 84

79

80 82 83 84

8 5

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx FLN FY Design Value(ppb)

With RRFs Offset = 40 ppb

79 80 82 83 84

79

81 82 83 84

80

81 82 83 84

80

81 82 83 85

80

81 83 84 85

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

25 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: PGN - Placerville Stn (Gold N Subregion: 6 Reference Year Design Value: 94 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 110 119 111 98 92 97 93 82 89 88 Peak Simulated 8-hour Ozone 107 88 94 89 74 80 85 8 3 85 79 Peak Simulated 8-hour Ozone within 15 km 115 106 10 6 95 92 97 94 86 93 91 Reference Year 15-km, 8-hour Average Ozone 99 Future Year 15-km, 8-hour Average Ozone 98 89 87 78 78 83 82 75 81 78 Use in RRF Analysis? Yes Yes Yes Yes Yes Yes No No Yes Yes

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx PGN Average 15-km Concentration (ppb)

Without RRFs

78 80 81 82 83

78

80 81 82 83

79

80 81 82 84

79

80 81 83 84

79

80 82 83 84

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx PGN FY Design Value(ppb) With RRFs Offset = 0 ppb

74 75 76 77 78

74

75 76 77 78

74

75 76 77 79

74

75 76 78 79

74

75 77 78 79

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx PGN FY Design Value(ppb)

With RRFs Offset = 40 ppb

74 76 77 78 79

74

76 77 78 79

75

76 77 78 79

75

76 77 78 79

75

76 77 78 79

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

26 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: ROS - Roseville Stn (151 N Su Subregion: 6 Reference Year Design Value: 89 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 86 107 113 88 86 90 85 7 0 93 97 Peak Simulated 8-hour Ozone 92 83 86 71 73 75 83 80 107 102 Peak Simulated 8-hour Ozone within 15 km 111 101 12 5 89 90 92 107 85 113 106 Reference Year 15-km, 8-hour Average Ozone 103 Future Year 15-km, 8-hour Average Ozone 102 86 101 74 80 81 94 76 97 92 Use in RRF Analysis? Yes Yes Yes Yes Yes Yes No No Yes Yes

85

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx ROS Average 15-km Concentration (ppb)

Without RRFs

83 85 86 87 88

83

85 86 87 88

84

85 86 88 89

84

85 87 88 89

84

85 87 88 89

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx ROS FY Design Value(ppb) With RRFs Offset = 0 ppb

71 72 73 74 75

71

73 74 75 76

72

73 74 75 76

72

73 74 75 76

72

73 74 75 76

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx ROS FY Design Value(ppb)

With RRFs Offset = 40 ppb

73 74 75 76 77

73

74 75 76 77

73

74 75 76 77

73

75 76 76 77

74

75 76 77 78

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

27 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: SDP - Sacramento Stn (Del Pas Subregion: 6 Reference Year Design Value: 95 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 78 111 107 95 77 92 93 7 4 101 80 Peak Simulated 8-hour Ozone 81 100 100 78 85 84 107 84 105 90 Peak Simulated 8-hour Ozone within 15 km 103 113 12 4 102 95 99 110 99 115 102 Reference Year 15-km, 8-hour Average Ozone 107 Future Year 15-km, 8-hour Average Ozone 100 97 101 84 88 89 100 92 98 92 Use in RRF Analysis? Yes Yes Yes Yes Yes Yes No No Yes Yes

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SDP Average 15-km Concentration (ppb)

Without RRFs

87 89 90 91 92

88

89 90 92 93

88

89 91 92 93

88

90 91 92 93

88

90 91 93 94

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SDP FY Design Value(ppb) With RRFs Offset = 0 ppb

77 79 80 81 82

78

79 80 81 82

78

79 80 81 83

78

79 81 82 83

78

80 81 82 83

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SDP FY Design Value(ppb)

With RRFs Offset = 40 ppb

79 80 81 82 83

79

80 81 82 83

79

80 81 82 83

79

81 82 83 84

80

81 82 83 84

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

28 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: SLU - Sloughouse Rd. Stn Subregion: 6 Reference Year Design Value: 94 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone -99 -99 -99 -99 -99 96 9 1 83 109 91 Peak Simulated 8-hour Ozone 85 111 106 102 94 98 87 99 110 87 Peak Simulated 8-hour Ozone within 15 km 99 116 125 107 99 102 110 110 116 91 Reference Year 15-km, 8-hour Average Ozone 103 Future Year 15-km, 8-hour Average Ozone 94 98 101 8 7 88 90 100 97 98 85 Use in RRF Analysis? No No No No No Yes No No Yes Y es

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SLU Average 15-km Concentration (ppb)

Without RRFs

85 87 88 89 90

86

87 88 89 90

86

87 88 90 91

86

87 89 90 91

86

88 89 90 91

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SLU FY Design Value(ppb) With RRFs Offset = 0 ppb

77 78 79 80 81

77

79 80 81 82

78

79 80 81 82

78

79 80 81 82

78

79 80 82 82

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SLU FY Design Value(ppb)

With RRFs Offset = 40 ppb

78 79 80 81 82

78

80 81 81 82

79

80 81 82 83

79

80 81 82 83

79

80 81 82 83

### DRAFT FUTURE YEAR RESULTS – FOR DISTRICT REVIEW ONL Y Please do not cite, quote, or distribute

29 6/6/2008 Year: 2018 Model: CAMX/MM5/SAPRC99 Site: SNH - Sacramento-North Highla Subregion: 6 Reference Year Design Value: 89 ppb Episode Days 99190 99191 99192 99193 99194 00211 00212 00213 00214 00215 Performance Status Pass Pass Pass Pass Pass Pass Fa il Fail Pass Pass Peak Observed 8-hour Ozone 53 79 69 64 80 89 81 77 100 87 Peak Simulated 8-hour Ozone 90 88 79 72 78 78 85 79 103 102 Peak Simulated 8-hour Ozone within 15 km 103 105 12 4 85 90 94 110 87 113 105 Reference Year 15-km, 8-hour Average Ozone 101 Future Year 15-km, 8-hour Average Ozone 100 91 101 72 84 84 99 78 98 92 Use in RRF Analysis? No Yes No No Yes Yes No No Yes Yes

8 5

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SNH Average 15-km Concentration (ppb)

Without RRFs

84 85 87 88 89

84

86 87 88 89

85

86 87 88 89

85

86 87 88 90

85

86 88 89 90

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SNH FY Design Value(ppb) With RRFs Offset = 0 ppb

73 74 75 76 77

74

75 76 77 78

74

75 76 77 78

74

75 76 77 78

74

75 76 77 78

0.80 0.85 0.90 0.95 1.000.80 0.85 0.90 0.95 1.00

ROGNOx SNH FY Design Value(ppb)

With RRFs Offset = 40 ppb

75 76 77 77 78

75

76 77 78 79

75

76 77 78 79

75

76 77 78 79

75

76 77 78 79