## Attachment I

Answers to the nine specific questions from the CEC Record of Conversation

1. Has the SJVAPCD provided the methodology used i n developing the interpollutant trading ratios to either U.S. EPA or the California Air Resources

Board for comment and/or review?

A. Yes. Projects triggering New Source Review tha t contain this analysis

method have been submitted to both US EPA and CARB for their review. The modeling methods used to prepare the basis for the analysis were submitted to both US EPA and CARB as part of prior State Impleme ntation Plan (SIP) submissions. Modeling protocols were submitted to both US EPA and CARB for this SIP modeling. The Chemical Mass Balance (CMB) modeling was performed by CARB in consultation with the District and the D istrict performed speciated rollback modeling based on the results of CMB outpu t that were submitted for review by both US EPA and CARB. The use of these m odeling results as the basis for the interpollutant assessment was selecte d due to the extensive review which this information has already received.

2. What is the role of the Chemical Mass Balance m odeling in developing the

ratios?

A. CMB receptor analysis provides evaluation which differentiates motor vehicle exhaust and vegetative burning from industrial emis sions. An interpollutant relationship requires identifying how much particul ate is observed per ton of

emissions released. A ratio determination would on ly be qualitative without the ability to separate industrial emissions from other sources. CMB does not provide the full analysis by itself. The analysis also uses speciated rollback, with consideration of spatial extent of contributing sou rces, and regional modeling, to provide the nonlinear relationship for secondary fo rmation of particulates from nitrogen oxides and sulfur oxides.

3. What years of ambient air quality data were use d and how do the interpollutant ratios vary over the years?

A. Much of the analysis was conducted using the ex tensive evaluation of special sampling collected in 1999-2001 for the California Regional PM10/PM2.5 Air Quality Study (CRPAQS). Extensive evaluation was u sed to identify contributing sources and spatial influence of sources. Addition ally, the speciation analysis projected the results to design value years for the SIP and future projected years. Recent reevaluation with new regional modeling cond ucted for the 2008 PM2.5 Plan answers the second part of the question by sho wing that there is very little change projected for the ratio between 2005 and 201 4 (summary of the evaluation is included as an attachment). This inf ormation was not available at the time of the evaluation of this project.4. Does the inventory of sulfate emissions (shown in the Avenal FDOC as 3.15

ton per day for Kings and Tulare County, with a typ o saying “NOx” on the SJVAPCD sulfate spreadsheet) include the inventory of banked sulfur dioxide credits for that area, and if not, should it?

A. No, banked emission reduction credits are not i ncluded in the inventory, and they do not need to be included. District SIP mode ling procedures include forecasting of growth for future years for all emis sion categories. Experience at the District has indicated that growth projections adequately represent the future

increases. It is not reasonable to assume that the use of emission credits would be larger than the maximum of trends of industrial growth. Therefore, the growth

estimate is considered as a reasonable estimate of emissions increase with or

without the use of emission credits.

5. In the February 13, 2009 “Draft Initial Comment s” on the PSA from Avenal Power Center to CEC, Avenal says that “the relevant emission inventory and ambient air quality data for purposes of evaluating interpollutant trading ratios should come from the general vicinity of the new so urce of emissions [...].” CEC staff asks, how is the wider geographical scope con sidered, given that the locations of the proposed SOx credits (mainly from Stockton or Kern County) are outside the boundaries of the Kings and Tulare Coun ty inventory?

A. The ratio analysis was conducted on a County sp ecific basis. The wider scope of particulate influence is accounted for in District SIP modeling, but not in terms pertinent to this question. Provisions withi n the District New Source Review Rule (Rule 2201, Section 4.8) adjust for the use of offsite reductions.

6. Given that the inventory of Kings and Tulare Co unty is used to develop the ratio, should Avenal be required to surrender only credits from Kings and Tulare County?

A. No. Only if the proposed project was, by itsel f, capable of producing a local exceedance of the ambient air quality standard woul d it be necessary to require

credits that are local. The creation or retirement of credits from areas with higher PM levels should be considered as highly desirable; therefore, the use of credits issued with Kern County should be especially favora ble, but no special weighting criteria has been established to encourage this use . The District New Source

Review Rule allows the use of credits issued in the San Joaquin Valley with appropriate consideration for distance from the pro posed emission source.

7. Should a separate interpollutant ratio be appli ed to each credit considering the inventory and air quality of the vicinity of each o riginal credit, rather than use a single local ratio for all distant credits?A. No, District regulations call for the analysis to establish reasonable

requirements for the proposed facility location. T he atmospheric relationships where a credit was issued are not germane to the ev aluation of the proposed facility.

8. Should a single district-wide interpollutant tr ading ratio, or the worst-case of the vicinity interpollutant ratios, be applied to a ll new source transactions in the district, since new sources may use credits from pa rts of the district with different local inventories and air quality?

A. Not for this request. The District had not det ermined at the time of this project

what a District-wide ratio should be. The evaluati on was conducted at a local level in accordance with District regulations, as h as been done in past projects. Recent requests for a ratio evaluation in the North ern part of the San Joaquin Valley have led to a determination that a valley-wi de approach will be the best option for the District to address these requests i n the future. This constitutes a change from policy in effect when the Avenal reques t was processed.

9. What would be the interpollutant trading ratio considering a district-wide inventory and district-wide ambient air quality dat a?

A. A valley-wide ratio has recently been determine d, and the evaluation summary is included as an attachment. This was eva luated with new modeling

conducted for the 2008 PM2.5 Plan and establishes a ratio of 1:1 for SOx to

PM2.5 and PM10 and 2.63:1 for NOx to PM2.5 and PM10 , for projects received

in 2009 and thereafter to 2014. This information w as not available at the time of the original evaluation for Avenal.

## Attachment II

## Interpollutant Offset Ratio Explanation

The Air District’s Rule 2201, “New and Modified Sou rce Review”, requires facilities to supply “emissions offsets” when a permittee request s new or modified permits that

allow emissions of air contaminants above certain a nnual emission offset thresholds. In addition, Rule 2201 allows interpollutant tradin g of offsets amongst criteria pollutants and their precursors upon the appropriate scientifi c demonstration of an adequate trading ratio, herein referred to as the interpollu tant ratio. A technical analysis is required to determine the interpollutant offset rat io that is justified by evaluation of atmospheric chemistry. This evaluation has been co nducted using the most recent modeling analysis available for the San Joaquin Val ley. The results of the analysis are designed to be protective of health for the entire Valley for the entire year, by applying the most stringent interpollutant ratio throughout the Valley.

It is appropriate for District particulate offset r equirements to be achieved by either a reduction of directly emitted particulate or by red uction of the gases, called particulate precursors, which become particulates from chemical and physical processes in the atmosphere. The District interpollutant offset rel ationship quantifies precursor gas

reductions sufficient to serve as a substitute for a required direct particulate emissions reduction. Emission control measures that reduce g as precursor emissions at the facility may be used to provide the offset reductio ns. Alternatively, emission credits for precursor reductions may be used in accordance with District regulations.

The amount of particulate formed by the gaseous emi ssions must be evaluated to determine how much credit should be given for the g aseous reductions. Gases combine and merge with other material adding molecu lar weight when forming into particles. Some of the gases do not become particu late matter and remain a gas. Both the extent of conversion into particles and re sulting weight of the particles are considered to establish mass equivalency between di rect particulate emissions and particulate formed from gas precursors. The Interp ollutant offset ratio is expressed as a per-ton equivalency.

The District interpollutant analysis uses the most recent and comprehensive modeling of San Joaquin Valley particulate formation from su lfur oxides (SOx) and nitrogen oxides (NOx). Modeling compares industrial directl y emitted particulate to particulate matter from precursor emissions. The interpollutan t modeling procedure, assumptions

and uncertainties are documented in an extensive an alysis file. Additional documentation of the modeling procedure for the San Joaquin Valley is contained in the 2008 PM2.5 Plan and its appendices. The 2008 P M2.5 Plan provides evaluation of the atmospheric relationships for direct particulat e emissions and precursor gases when they are highest during the fourth quarter of the year. The southern portion of the Valley is evaluated by both receptor modeling a nd regional modeling of chemical relationships for precursor particulate formation. Regional modeling was conducted for the entire Valley through 2014. The two modeling a pproaches are combined to determine interpollutant offset ratios applicable t o, and protective of, the entire Valley (SOx for PM 1:1 and NOx for PM 2.629:1).

## DEVELOPMENT OF THE INTERPOLLUTANT RATIO

For the proposed substitution of reductions of sulf ur oxides (SOx) or nitrogen oxides (NOx) for directly emitted parti culate matter

March 2009

INTRODUCTION .......................................

................................................... ................................................... ..........2

ANALYSES INCLUDED IN INTERPOLLUTANT EVALUATION .....

................................................... ............3

F ACTORS C ONSIDERED

................................................... ................................................... ........................................3

E LEMENTS FROM 2008 PM 2.5 P LAN

................................................... ................................................... ...................3

E XTENSION BY ADDITIONAL ANALYSIS

................................................... ................................................... ................4

S TRENGTHS

................................................... ................................................... ................................................... ......4

L IMITATIONS

................................................... ................................................... ................................................... ....5

ANALYSES CONTAINED IN RECEPTOR MODELING............

................................................... ......................6

F ACTORS C ONSIDERED

................................................... ................................................... ........................................6

A NALYSES IN RECEPTOR MODELING THAT USE INPUT FROM RE GIONAL MODELING

................................................... 6

E XTENSION BY ADDITIONAL ANALYSIS

................................................... ................................................... ................6

S TRENGTHS

................................................... ................................................... ................................................... ......6

L IMITATIONS

................................................... ................................................... ................................................... ....7

ANALYSES CONTAINED IN REGIONAL MODELING ............

................................................... ......................8

F ACTORS C ONSIDERED

................................................... ................................................... ........................................8

E XTENSION BY ADDITIONAL ANALYSIS

................................................... ................................................... ................8

S TRENGTHS

................................................... ................................................... ................................................... ......9

L IMITATIONS

................................................... ................................................... ................................................... ....9

RESULTS AND DOCUMENTATION..........................

................................................... .......................................10DEVELOPMENT OF THE INTERPOLLUTANT RATIO

2 

## Introduction

Goal of Interpollutant Evaluation: Establish the at mospheric exchange relationship for substitution of alternative pollut ant or precursor reductions for required reductions of directly emitted particulate

Evaluation to establish the atmospheric relationshi p of different pollutants is required as a prerequisite for establishing procedures for allo wing a required reduction to be met by substitution of a reduction of a different pollutan t or pollutant precursor. Proposed new facility construction or facility modifications may result in increased emissions of a pollutant. The District establishes requirements f or reductions of the pollutant to “offset” the proposed increase. A facility may propose a re duction of an alternative pollutant or pollutant precursor where reductions of that materi al have already been achieved at the facility beyond the amount required by District reg ulations or where emission reductions credits for reductions achieved by other facilities are economically available; however,

for such a substitution to be allowed the District must establish equivalency standards for the substitution. The equivalency relationship used for offset requirements is referred to in this discussion as the interpollutan t ratio. The interpollutant ratio is a mathematical formula expressing the amount of alter native pollutant or precursor reduction required to be substituted for the requir ed regulatory reduction. This discussion is limited to the atmospheric relationsh ips and does not address other policy or regulatory requirements for offsets such as are contained in District Rule 2201.

The following description is provided to explain ke y elements of the analysis conducted to develop the atmospheric relationship between the commonly requested substitutions.

Emission reductions of sulfur oxide emissions or ni trogen oxide emissions are proposed by many facilities as a substitution for reduction of directly emitted particulates. Elemental and organic carbon emissions are the pred ominant case and dominant contribution to directly emitted particulate mass f rom industrial facilities, although other types of directly emitted particulates do occur. T herefore this atmospheric analysis examines directly emitted carbon particulates from industrial sources in comparison to the formation of particles from gaseous emissions o f sulfur oxides and nitrogen oxides.DEVELOPMENT OF THE INTERPOLLUTANT RATIO

3 

## Analyses included in Interpollutant evaluation

Factors Considered

The foundation for this analysis is provided by the atmospheric modeling conducted for the 2008 PM2.5 Plan. Modeling conducted for this S tate Implementation Plan was conducted by the District and the California Air Re sources Board using a variety of modeling approaches. Each separate model has techn ical limitations and uncertainties. To reduce the uncertainty of findings, a combined e valuation of results of all of the modeling methods is used to establish “weight of ev idence” support for technical analysis and conclusions. The modeling methods are supported by a modeling protocol which was sent to ARB and EPA Region IX for review and was included in the appendices to the Plan.

The analysis file prepared for the interpollutant r atio evaluation includes emissions inventories, regional model daily output files, che mical mass balance modeling and speciated rollback modeling as produced for the 200 8 PM2.5 Plan. This well examined and documented modeling information was used as a s tarting point for additional evaluation to determine interrelationships between directly emitted pollutants and particulates from precursors.

The interpollutant ratio analysis is limited to eva luation of directly emitted PM2.5 from industrial sources and formation of PM2.5 from prec ursor gases. While both directly emitted particulates and particulate from precursor gases also occur in the PM10 size range, there is much more uncertainty associated wi th deposition rates and particle formation rates for the larger size ranges. Additi onally, because PM2.5 is a subset of PM10; all reductions of PM2.5 are fully creditable as reductions towards PM10 requirements. This analysis concentrates on the qu arter of the year when both directly

emitted carbon from industrial sources and secondar y particulates are measured at the highest levels. Assessing atmospheric ratios at lo w concentrations is subject to much greater uncertainty and has limited value toward as sessment of actions to comply with the air quality standards.



### Elements from 2008 PM 2.5 Plan

• Regional modeling daily output for eleven location s

• Chemical Mass Balance (CMB) modeling for four loca tions – source analysis, speciation profile selection, event meteorology eva luation

• Receptor speciated rollback modeling with adjustme nt for nitrate nonlinearity for four locations, evaluation of spatial extent of contribu ting sources

• Emission inventories and projections to future yea rs as developed for the 2008 PM

2.5 PlanDEVELOPMENT OF THE INTERPOLLUTANT RATIO

4 • Modeling protocols for receptor modeling, regional modeling, and Positive matrix Factorization (PMF) analysis and evaluation of tech nical issues applicable to particulate formation in the San Joaquin Valley

• Model performance analysis as documented in append ices to the 2008 PM 2.5 Plan



### Extension by additional analysis

Additional evaluation was conducted to evaluate the receptor modeling relationship

between direct PM from industrial sources and sulfa te and nitrate particulate formed from SOx and NOx precursor gases. Area of influenc e adjustments were evaluated to ensure appropriate consideration of contributing so urce area for different types of pollutants for both directly emitted and secondary particulate. This evaluation was possible only for the southern four Valley counties and was conducted for both 2000

and 2009.

The regional model output was evaluated for the fou rth quarter to evaluate general atmospheric chemistry in 2005 and 2014 to determine the correlation between northern and southern areas of the Valley. This evaluation determined that the atmospheric chemistry observed and modeled in the north was wit hin the range of values observed

and modeled in the southern SJV. This establishes that a ratio protective of the southern Valley will also be protective in the nort h.

The District determined from the additional analyse s of both receptor and regional modeling that the most stringent ratio determined f or the southern portion of the Valley would also be protective of the northern portion of the Valley. Due to the regional nature of these pollutants, actions taken in other counties must be assumed to have at least some influence on other counties; therefore t o achieve attainment at the earliest practical date it is appropriate to require all cou nties to establish a consistent interpollutant ratio for the entire District.



### Strengths

The interpollutant ratio analysis uses established and heavily reviewed modeling and outputs as foundation data. Analysis of model perf ormance has already been completed for the models and for the emissions inve ntories used for this analysis. The modeling was performed in accordance with protocols developed by the District and ARB and in accordance with modeling guidelines esta blished by EPA. The combination of modeling approaches provides an analysis for the current year and provides projection to 2014. Weight of evidence comparison of various modeling approaches establishes the reliability of the foundation model ing, with all modeling approaches showing strong agreement in predicted results. Add itional analysis performed to develop the interpollutant ratio uses both regional and receptor evaluations which were the primary models used for the 2008 PM 2.5 Plan.DEVELOPMENT OF THE INTERPOLLUTANT RATIO

5 

### Limitations

Both industrial direct emissions and secondary form ed particulate may be both PM2.5 and PM10. The majority of secondary particulates f ormed from precursor gases are in the PM2.5 range as are most combustion emissions fr om industrial stacks, however both secondary and stack emissions do contain parti cles larger than PM2.5. Regional modeling is more reliable for the smaller fraction due to travel distances and deposition rates. Large particles have much higher deposition and are much more difficult to replicate with a regional model. This leads to a s trong technical preference for evaluating both emission types in terms of PM2.5 be cause the integration of receptor analysis and regional modeling for coarse particle size range up to PM10 has a much greater associated uncertainty.DEVELOPMENT OF THE INTERPOLLUTANT RATIO

6 

## Analyses contained in Receptor modeling

Factors Considered

This modeling approach uses speciated linear modeli ng based on chemical mass balance evaluation of contributing sources with San Joaquin Valley specific identification of contributing source profiles, adj ustments from regional modeling for the nonlinearity of nitrate formation, adjustments for area of influence impacts of contributing sources developed from back trajectory analysis of high concentration particulate episodes and projections of future emis sion inventories as developed for the

2008 PM2.5 Plan.



### Analyses in receptor modeling that use input from r egional modeling

The receptor modeling analysis uses a modified proj ection of nitrate particulate formation from nitrogen oxides based upon results o f regional modeling. The atmospheric chemistry associated with nitrate parti culate formation has been determined to be nonlinear; while the default proce dures for speciated rollback modeling assume a linear relationship. This adjust ment has been demonstrated as effective in producing reliable atmospheric project ions for the prior PM10 Plans.



### Extension by additional analysis

Additional evaluations were added to results of the receptor modeling performed for the

2008 PM2.5 Plan. Calculations determine the observ ed micrograms per ton of emission for each contributing source category that can be r esolved by chemical mass balance modeling methods. These ten categories allow diffe rentiation of industrial direct emissions of organic and elemental carbon from othe r sources that emit elemental and organic carbon. The interpollutant calculation is developed as an addition to the receptor analysis by calculating the ratio of emiss ions per ton of directly emitted industrial PM2.5 to the per ton ratio of secondary particulate formed from NOx and SOx emissions. Summary tables and issue and documentat ion discussion was added to the analysis.



### Strengths

Receptor modeling provides the ability to separatel y project the effect of different key sources contributing to carbon and organic carbon. This is critical for establishing the atmospheric relationship between industrial emissio ns and the observed concentrations due to industrial emissions. Regional modeling met hods at this time do not support differentiation of vegetative and motor vehicle car bon contribution from the emissions

form industrial sources. The area of influence of contributing sources was also considered as a factor with the methods developed b y the District to incorporate the gridded footprint of contributing sources into the receptor analysis. While regionalDEVELOPMENT OF THE INTERPOLLUTANT RATIO

7 models use gridded emissions, current regional mode ling methods do not reveal the resulting area of influence of contributing sources

.



### Limitations

Receptor modeling uses linear projections for futur e years and cannot account for equilibrium limitations that would occur if a key r eaction became limited by reduced availability of a critical precursor due to emissio n reductions. The regional model was used to investigate this concern and did not projec t any unexpected changes due to precursor limitations.DEVELOPMENT OF THE INTERPOLLUTANT RATIO

8 

## Analyses contained in Regional modeling

Factors Considered

The analysis file includes the daily modeling outpu t representing modeled values for the base year 2005 and predicted values for 2014 for ea ch of the eleven Valley sites that have monitoring data for evaluation of the models p erformance in predicting observed

conditions. These sites are located in seven of th e eight Valley counties. Madera County does not have monitoring site data for this comparison.

Modeling data for all quarters of the year was prov ided. Due to the higher values that occur due to stagnation events in the fourth quarte r, both industrial carbon concentrations and secondary particulates forming f rom gases are highest in the fourth quarter. Evaluating the interpollutant ratio for o ther quarters would be less reliable and of less significance to assisting in the reduction of high particulate concentrations. Modeling for lower values has higher uncertainty. Modeling atmospheric ratios when the air quality standard is being met are axiomatic ally not of value to determining offset requirements intended to assist in achieving compli ance with the air quality standard. However, for consistency of analysis between sites, days when the standard was being met during the fourth quarter were not excluded fro m the interpollutant ratio analysis. Bakersfield fourth quarter modeled data included on ly eight days that were at or below the standard. Fresno and Visalia sites averaged tw elve days; northern sites 24 days and the County of Kings 38 days.

Modeling output provided data for both 2005 and 201 4. While there is substantial emissions change projected for this period, the reg ional modeling evaluation does not project much change in the atmospheric ratios of di rectly emitted pollutants and secondary pollutants from precursor gases. This in dicates that the equilibrium processes are not expected to encounter dramatic ch ange due to limitation of reactions by scarcity of one of the reactants. This further justifies using the receptor evaluation determining the interpollutant ratio for 2009 throu gh the year 2014 without further adjustment. If observed air quality data demonstra tes a radical shift in chemistry or components during the next few years, such a change could indicate that a limiting reaction has been reached that was not projected by the model and such radical changes might require reassessment of the conclusio n that the ratio should remain unchanged through 2014.



### Extension by additional analysis

Regional modeling results prepared for the 2008 PM2 .5 Plan were analyzed to extract fourth quarter data for all sites. The atmospheric chemistry for all counties was analyzed for consistency and variation. This analy sis provided a determination that the secondary formation chemistry and component sources contributing to concentrations observed in the north fell within the range of valu es similarly determined for the southern four counties. Based upon examination of the components and chemistry, the northern counties would be expected to have an inte rpollutant ratio value less than theDEVELOPMENT OF THE INTERPOLLUTANT RATIO

9 ratio determined for Kern County but greater than t he one for Tulare County. This establishes that the interpollutant ratio determine d by receptor analysis of the southern four counties provides a value that is also suffici ently protective for the north.



### Strengths

Regional models provide equilibrium based evaluatio ns of particulate formed from precursor gases and provide a regional assessment t hat covers the entire Valley. The projection of particulate formed in future years is more reliable than linear methods used for receptor modeling projections.



### Limitations

The regional model does not provide an ability to f ocus on industrial organic carbon emissions separate from other carbon sources such a s motor vehicles, residential wood smoke, cooking and vegetative burning. Regional mo deling does not provide an

assessment method for determination of sources cont ributing at each site or the area of influence of contributing emissions. Receptor anal ysis provides a more focused tool for this aspect of the evaluation.DEVELOPMENT OF THE INTERPOLLUTANT RATIO

10 

## Results and Documentation

SJVAPCD Interpollutant Ratio Results

SOx for PM ratio: 1.000 ton of SOx per ton of PM

NOx for PM ratio: 2.629 tons of NOx per ton of PM

These ratios do not include adjustments for other r egulatory requirements specified in provisions of District Ru le 2201.

The results of the modeling analysis developed an a tmospheric interpollutant ratio for NOx to PM of 2.629 tons of NOx per ton of PM. This result was the most stringent ratio

from the assessment industrial carbon emissions to secondary particulates at Kern County; with Fresno, Tulare and Kings counties havi ng a lower ratio. The assessment of chemistry from the regional model required compa rison of total carbon to secondary particulates and is therefore not directly useful t o establish a ratio. However, the regional model does provide an ability to compare t he general atmospheric similarity and compare changes in chemistry due to Plan reduct ions. Evaluation revealed that the atmospheric chemistry of San Joaquin, Stanislaus an d Merced counties falls within the range of urban characteristics evaluated for the so uthern four counties; therefore the ratio established should be sufficiently protective of the northern four counties. Additionally, comparison of future year chemistry s howed minimal change in pollutant ratio due to the projected changes in the emission inventory from implementation of the

Plan. The SOx ratio as modeled indicates a value o f less than one to one due to the increase in mass for conversion of SOx to a particu late by combination with other atmospheric compounds; however, the District has se t guidelines that require at least one ton of an alternative pollutant for each requir ed ton of reduction in accordance with

District Rule 2201 Section 4.13.3. Therefore the S Ox interpollutant ratio is established as 1.000 ton of SOx per ton of PM. These ratios do not include adjustments for other regulatory considerations, such as other provisions of District Rule 2201.

A guide to the key technical topics and the referen ce material relevant to that topic is found on the next page. References from the 2008 P M2.5 Plan may be obtained by requesting a copy of that document and its appendic es or by downloading the document

from http://www.valleyair.org/Air_Quality_Plans/AQ_Final _Adopted_PM25_2008.htm

. References in Italics are spreadsheets included in the interpollutant analysis file “ 09 Interpollutant Ratio Final 032909.xls ” which includes 36 worksheets of receptor modeling information from the 2008 PM2.5 Plan, 11 m odified and additional spreadsheets for this analysis and two spreadsheets of regional model daily output. This file is generally formatted for printing with the exception of the two spreadsheets containing the regional model output “ Model-Daily Annual ” and “ Model-Daily Q4 ” which are over 300 pages of raw unformatted model output files. The remainder of the file is formatted to print at approximately 100 pages. Thi s file will be made available on request but is not currently posted for download.DEVELOPMENT OF THE INTERPOLLUTANT RATIO

11 

## Interpollutant Ratio Issues & Documentation

TOPIC Reference

1 Reason for using PM2.5 for establishing the substit ution relationship between direct emitted carbon PM and secondary nitr ate and sulfate

PM: consistency of relationship between secondary part iculates and

industrial direct carbon combustion emissions. 2008 PM2.5 Plan,

Sections 3.3.2 through 3.4.2
2 Reason for using 4th Quarter analysis: Highest PM2.5 for all sites. DV Qtrs
3 Reason for using analysis of southern SJV sites to apply to regional interpollutant ratio: Northern site chemistry ratios are within the range of southern SJV ratios. Peak ratio will be protective for all SJV counties. Q4 Model Pivot, Model-site chem, Model-Daily Q4

4 Reason for using combined results of receptor and r egional model: Receptor model provides breakdown of different carb on sources to isolate

connection between industrial emissions and seconda ry PM. 2008 PM2.5 Plan, Appendix F Regional model provides atmospheric information con cerning the northern SJV not available from receptor analysis. 2008 PM2.5 Plan, Appendix G
5 Most significant contributions of receptor evaluati on: Separation of industrial emissions from other source types. Area of influence evaluation for contributing sources. 2008 PM2.5 Plan, Appendix F
6 Most significant contributions of regional model: Scientific equilibrium methods for atmospheric chemistry projections for 2 014. Receptor technique

is limited to linear methods. 2008 PM2.5 Plan, Appendix G
7 Common area of influence adjustments used for all r eceptor

evaluations: Geologic & Construction, Tire and Brake Wear, Vege tative Burning - contribution extends from more than just the urban area (L2)

Mobile exhaust (primary), Organic Carbon (Industria l) primary, Unassigned - contribution extends from more than larger area, su bregional (L3)

Secondary particulates from carbon sources are domi nated by the local area with some contribution from the surrounding area (a verage of L1 and L2)

Marine emissions not found present in CMB modeling for this analysis. Modeling evaluation by

J. W. Sweet February 2009

Reflected in IPR County 2000-2009

worksheets

8 Variations to reflect secondary area of influence s pecific to location:

Fresno: Evaluation shows extremely strong urban sig nature (L1) for secondary sources Kern: Evaluation shows a strong urban signature mix ed with emissions from the surrounding industrial areas (average L1 and L2 ) for both carbon and secondary sources Kings and Tulare: Prior evaluation has show a share d metropolitan contribution area (L2) Modeling evaluation by

J. W. Sweet February 2009

Reflected in IPR County 2000-2009

worksheets 9 Reasons for using 2009 Interpollutant Ratio Project ion:

2009 Interpollutant ratio is consistent with curren t emissions inventories 2008 PM2.5 Plan Regional modeling does not show a significant chang e in chemical relationships through 2014. Q4 Model Pivot

10 Reason for using SOx Interpollutant Ratio at 1.000: A minimum offset

ratio is established as 1.000 to 1.000 consistent w ith prior District policy and procedure for interpollutant offsets. District Rule 2201

Section 4.13.3