# APPENDIX A

TECHNICAL SUPPORT DOCUMENTInternational Corporation 

### Air Sciences

Technical Support Document

CLARK COUNTY CARBON MONOXIDE MODELING AND SIP UPDATE

Prepared for

Clark County Department of Air Quality and Environmental Management 500 S. Grand Central Parkway PO Box 551776 Las Vegas, NV 89155-1776

Prepared by

Chris Emery Stella Shepard Michele Jimenez Gary Wilson Alison Pollack Sunja Rao Chris Lindhjem

ENVIRON International Corporation 101 Rowland Way, Suite 220 Novato, CA 94945

August 29, 2005

101 Rowland Way, Suite 220, Novato, CA 94945 415.899.0700August 2005



### i TABLE OF CONTENTS

Page

1. INTRODUCTION................................................................................................................ 1-1

1.1 Background................................................................................................................. ..... 1-1 1.1.1 CO Regulatory History ........................................................................................ 1-1 1.1.2 Previous CO Modeling ........................................................................................ 1-2 1.2 Modeling Updates........................................................................................................... . 1-2 1.2.1 On-Road Emission Estimates .............................................................................. 1-3 1.2.2 Other Emission Sources....................................................................................... 1-4 1.2.2.1 Airports ......................................................................................................... 1-4 1.2.2.2 Non-Road and Locomotive........................................................................... 1-4 1.2.2.3 Point Sources ................................................................................................ 1-5 1.2.3 Model Application ............................................................................................... 1-5

2. ON-ROAD MOBILE EMISSIONS.................................................................................... 2-1

2.1 Overview of Approach..................................................................................................... 2- 1 2.2 Base Year Estimates ........................................................................................................ 2-2 2.2.1 Base Year MOBILE6 Inputs................................................................................ 2-2 2.2.2 Base Year TRANPLAN Link Activity Adjustments........................................... 2-5 2.2.2.1 Month/Season, Day of Week ........................................................................ 2-5 2.2.2.2 Hourly Temporal Adjustments ..................................................................... 2-5 2.2.2.3 Speed Adjustments........................................................................................ 2-6 2.2.2.4 Transit Adjustments...................................................................................... 2-6 2.2.3 Base Year Link-Level Running Exhaust Emissions............................................ 2-6 2.2.4 Base Year Start Emissions................................................................................. 2-10 2.2.5 Base Year Intrazonal Activity............................................................................ 2-10 2.2.6 Base Year Total Emissions ................................................................................ 2-12 2.3 Future Year Estimates.................................................................................................... 2- 12 2.3.1 Future Year MOBILE6 Inputs........................................................................... 2-12 2.3.2 Future Year TransCAD Link Activity Adjustments.......................................... 2-16 2.3.2.1 Month/Season, Day of Week ...................................................................... 2-16 2.3.2.2 Link Volume Adjustments.......................................................................... 2-17 2.3.2.3 Hourly Temporal Adjustments ................................................................... 2-18 2.3.2.4 Speed Adjustments...................................................................................... 2-18 2.3.2.5 Transit Adjustments.................................................................................... 2-19 2.3.3 Future Year Link-Le vel Running Emissions ..................................................... 2-19 2.3.4 Future Year Start Emissions .............................................................................. 2-19 2.3.5 Future Year Intrazonal Activity......................................................................... 2-25 2.3.6 Future Year Total Emissions ............................................................................. 2-26

3. OTHER EMISSION CATEGORIES ................................................................................ 3-1

3.1 Non-Road Categories....................................................................................................... 3 -1 3.1.1 Airports ................................................................................................................ 3-1August 2005



### ii 3.1.1.1 Temporal and Spatial Allocation .................................................................. 3-1 3.1.2 Locomotive .......................................................................................................... 3-4 3.1.2.1 Locomotive Projections ................................................................................ 3-5 3.1.3 Other Non-Road Categories................................................................................. 3-7 3.1.3.1 NONROAD Model Equipment Estimates.................................................... 3-7 3.1.3.2 Base Year Gridding Surrogates .................................................................... 3-9 3.1.3.3 Future Year Gridding Surrogates.................................................................. 3-9 3.1.3.4 Temporal Allocation ................................................................................... 3-14 3.2 Point Sources .............................................................................................................. ... 3-14 3.3 Area Sources ............................................................................................................... ... 3-15 3.3.1 Area Source Gridding Surrogates ...................................................................... 3-16 3.4 Summary of Total Emissions......................................................................................... 3-16

4. URBAN AIRSHED MODELING ...................................................................................... 4-1

4.1 Base Case Simulation ...................................................................................................... 4 -2 4.1.1 UAM Results from Revised On-Road Emissions................................................ 4-2 4.1.2 UAM Results from Revised On-R oad and Non-Road Emissions ..................... 4-14 4.2 Future Year Simulations ................................................................................................ 4-16 4.3 Microscale Modeling ..................................................................................................... 4-2 9 4.3.1 CAL3QHC Intersection Modeling..................................................................... 4-29 4.3.2 EDMS Airport Modeling ................................................................................... 4-29 4.4 Estimating On-Road Emission Budgets......................................................................... 4-30 4.4.1 Impacts of Emissions from the Outer Domain .................................................. 4-30 4.4.2 Emission Budgets from Scaling On-Road Emissions........................................ 4-32

5. SUMMARY ..................................................................................................................... ..... 5-1

5.1 Emission Updates........................................................................................................... .. 5-1 5.2 Model Application .......................................................................................................... . 5-2 5.2.1 Base Case Simulations......................................................................................... 5-3 5.2.2 Future Year Simulations ...................................................................................... 5-4 5.2.2.1 Micro-scale Modeling................................................................................... 5-4 5.2.2.2 Estimating On-Road Emission Budgets........................................................ 5-5

REFERENCES..................................................................................................................... ..... R-1

TABLES

Table 2-1. 1996 Base Year Las Ve gas MOBILE6.2 input parameters ................................. 2-3 Table 2-2. MOBILE6 28 vehicle cl asses and their relative fraction of the overall fleet. ............................................................................................... 2-7 Table 2-3. Cross-reference between RTC and MOBILE6.2 facility types. .......................... 2-8 Table 2-4. 1996 VMT by facility type . Totals are shown as output by TRANPLAN, and after seas onal, day-of-week, and public transit adjustments ............................................................................................... 2-8 Table 2-5. Component and total on-road mobile source CO emissions (TPD) for the 1996 base year............................................................................. 2-12August 2005



### iii Table 2-6. MOBILE6.2 input parameters for future year Las Vegas runs.......................... 2-14 Table 2-7. Volume scaling factors by day of week............................................................. 2-17 Table 2-8. Adjustment factors to obse rved traffic counts by facility type.......................... 2-18 Table 2-9. Adjustment factor to scale link-level emissions to account for mass transit ..................................................................................... 2-19 Table 2-10. 2006 VMT by facility type. Totals are shown as output by TransCAD, and after seasonal, day-of-week, and public transit adjustments ............................................................................................. 2-20 Table 2-11. 2010 VMT by facility type. Totals are shown as output by TransCAD, and after seasonal, day-of-week, and public transit adjustments ............................................................................................. 2-21 Table 2-12. 2015 VMT by facility type. Totals are shown as output by TransCAD, and after seasonal, day-of-week, and public transit adjustments ............................................................................................. 2-22 Table 2-13. 2020 VMT by facility type. Totals are shown as output by TransCAD, and after seasonal, day-of-week, and public transit adjustments ............................................................................................. 2-23 Table 2-14. 2030 VMT by facility type. Totals are shown as output by TransCAD, and after seasonal, day-of-week, and public transit adjustments ............................................................................................. 2-24 Table 2-15. Component and total on-road mobile source CO emissions (TPD) for all future years................................................................................... 2-26 Table 3-1. Annual airport CO em ission estimates (tons per year) reported by Ricondo (1999) for the 1996 base year, and by Ricondo (2003) for future years 2010, 2015, and 2020 (2006 and 2030 estimated as described in the text). ............................................ 3-2 Table 3-2. Monthly factors used to disaggregate annual airport CO emissions to monthly totals. The factors for December were used in this study.................................................................................................. 3-2 Table 3-3. Locomotive emission reductions due to EPA regulations (EPA, 1997) 

### .............. 3-6 Table 3-4. Locomotive emissions relative to 1996 ............................................................... 3-7 Table 3-5. Summary of inputs us ed for NONROAD modeling for 1996 ............................. 3-8 Table 3-6. Summary of inputs used for NONROAD modeling future years........................ 3-8 Table 3-7. Clark County CO NONROAD gridded emission estimates (TPD)..................... 3-9 Table 3-8. Base year non-ro ad surrogate categories ........................................................... 3-10 Table 3-9. Land use category to surrogate code mapping................................................... 3-11 Table 3-10. Source category cross re ferences to gridded surrogates for NONROAD sources with county-to-modeling grid adjustment factors .............................................................................................. 3-11 Table 3-11. Land use categories ava ilable in the Clark County GIS data coverages for 2003 ..................................................................................... 3-12 Table 3-12. Landuse category aggr egation used for developing spatial allocation surroga tes for non-road categories......................................... 3-14 Table 3-13. Comparison of domain -wide land use percentages for future year spatial allocation.............................................................................. 3-14 Table 3-14. Clark County CO future year Potential To Emit (PTE) estimates + 70 TPY by facility .......................................................................... 3-15 Table 3-15. Modeling CO point source emission estimates (TPD) ...................................... 3-15 Table 3-16. Future year growth/proj ection factors for area sources. .................................... 3-16August 2005



### iv Table 3-17. Clark County CO area source gridded emission estimates (TPD)..................... 3-17 Table 3-18. Summary of total dail y CO emissions (TPD) in the UAM CO SIP revision....................................................................................... 3-18 Table 4-1. Summary performance st atistics for the December 8-9, 1996 Base Case with updated on-road m obile source emissions. Bold/colored metrics denote EPA criteria st atistics; green (red) indicates within (outside) acceptance criteria ................................................................................ 4-4 Table 4-2. Names and coordinates of all monitoring sites operating during the Phase II field study over the winter of 1996/97 (Egami et al., 1998). The first 14 sites are the standard Clark County sites................................................................................................ 4-6 Table 4-3. Summary performance statistics for the December 8-9, 1996 Base Case with updated on-road and non-road mobile source emissions. Bold/colored metrics denote EPA criteria statistics; green (red) indicates within (outside) acceptance criteria. ............................................................................. 4-16 Table 4-4. Peak UAM + CAL3QHC 8- hour average CO concentrations (ppm) predicted for each future year and for each intersection......................... 4-29 Table 4-5. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all fu ture years evaluated. Values shown for McCarran airport occur at th e peak publicly accessible receptor ................ 4-30 Table 4-6. Grid definition of the central urban sub-domain................................................ 4-30 Table 4-7. Change in peak 8-hour CO from doubling the total CO emissions inventory outside of th e central urban sub-domain............................................ 4-32 Table 4-8. Weekday domain-wide on-road emission increase, net on-road emission increase that includes an additional 70% increase outside the central urban sub-domai n, resulting UAM predicted peak CO, and resulting total and sub- domain on-road emission budgets for each future year.................................................................................................. 4-32 Table 4-9. Peak UAM + CAL3QHC 8-hour average CO concentrations (ppm) predicted for each future year and for each intersection. UAM results from the on-road sensitivity scaling tests. .............................................. 4-37 Table 4-10. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor. UAM results from the on-road sensitivity scaling tests..................................... 4-37 Table 5-1. Summary of total da ily CO emissions (TPD) in the UAM CO SIP revision......................................................................................... 5-3 Table 5-2. Peak UAM + CAL3QHC 8- hour average CO concentrations (ppm) predicted for each future year and for each intersection........................... 5-5 Table 5-3. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all three future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor ................................................................................. 5-5 Table 5-4. Change in peak 8-hour CO from doubli ng the total CO emissions inventory outside of the central urban sub-domain............................. 5-5August 2005



### v Table 5-5. Weekday domain-wide on-road emission increase, net on-road emission increase that includes an additional 70% increase outside the central urban s ub-domain, resulting UAM predicted peak CO, and resulting tota l and sub-domain on-road emission budgets for each future year................................................................................. 5-6 Table 5-6. Peak UAM + CAL3QHC 8- hour average CO concentrations (ppm) predicted for each future year and for each intersection. UAM results from the on-road sensitivity scaling tests....................................... 5-6 Table 5-7. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all three future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor. UAM results from the on-road sensitivity scaling tests......................................................................................... 5-7

FIGURES

Figure 2-1. Hourly weekend and wee kday start distributions (fraction) provided by Clark County, used to temporally allocate emissions derived from TRANPLAN and TransCAD ......................................................... 2-4 Figure 2-2. Fraction of original we ekday start distri bution and start distributions in all future years for the Las Vegas Boulevard area calculated from the TransCAD origin trips by TAZ.................................... 2-4 Figure 2-3. Weekday and Sunda y hourly VMT distribution.................................................. 2-5 Figure 2-4. Spatial distribution of on-road mobile source running exhaust CO emissions for the 1996 Base Case ................................................................. 2-9 Figure 2-5. Spatial distribution of on-road mobile source start exhaust CO emissions for the 1996 Base Case ............................................................... 2-11 Figure 2-6. Spatial distribution of total on-road mobile source CO emissions for the 1996 Base Case ............................................................... 2-13 Figure 2-7. Hourly start emission factors from the 2006 MOBILE6 run: “Sun EF” is the Sunday profile used for all start emissions; “Mon EF” is the Monday profile used for start emissions outside of the LVB area; and “LVB Mon EF” is the Monday profile used for start emissions within the LVB area .................................................... 2-17 Figure 2-8. 2006 hourly vehicle miles trav eled (VMT) for Sunday and Monday................ 2-25 Figure 2-9. Spatial distribution of total on-road mobile source CO emissions for the 2006 future year..................................................................... 2-27 Figure 2-10. Spatial distribution of total on-road mobile source CO emissions for the 2010 future year..................................................................... 2-28 Figure 2-11. Spatial distribution of total on-road mobile source CO emissions for the 2015 future year..................................................................... 2-29 Figure 2-12. Spatial distribution of total on-road mobile source CO emissions for the 2020 future year..................................................................... 2-30 Figure 2-13. Spatial distribution of total on-road mobile source CO emissions for the 2030 future year..................................................................... 2-31 Figure 3-1. Hourly activity at McCa rran airport used to temporally allocate daily emissions for all years modeled .................................................... 3-3August 2005



### vi Figure 3-2. Hourly activity at Hende rson and North Las Vegas airports used to temporally allocate da ily emissions for all years modeled...................... 3-3 Figure 3-3. Arial photograph of McCarran ai rport with UAM grid cells overlaid................. 3-4 Figure 3-4. Available locomotive fuel consumption trends. .................................................. 3-6 Figure 3-5. 2003 land use data for the Las Vegas area of Clark County.............................. 3-13 Figure 3-6. Hourly activity profil e used to temporally allocate non-road emissions ............................................................................................ 3-15 Figure 3-7. Spatial distributi on of airport and locomotive CO emissions for the 1996 Base Case. .............................................................. 3-19 Figure 3-8. Spatial distributi on of non-road and area source CO emissions for the 1996 Base Case. .............................................................. 3-20 Figure 3-9. Spatial distribution of total surface gridded CO emissions for the 1996 Base Case. ..................................................................................... 3-21 Figure 3-10. Spatial distribution of total surface gridded CO emissions for the 2006 future year...................................................................................... 3-22 Figure 3-11. Spatial distribution of total surface gridded CO emissions for the 2010 future year...................................................................................... 3-23 Figure 3-12. Spatial distribution of total surface gridded CO emissions for the 2015 future year...................................................................................... 3-24 Figure 3-13. Spatial distribution of total surface gridded CO emissions for the 2020 future year...................................................................................... 3-25 Figure 3-14. Spatial distribution of total surface gridded CO emissions for the 2030 future year...................................................................................... 3-26 Figure 4-1. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 Base Case with updated on-road mobile emissions ..................................................... 4-3 Figure 4-2. Locations of all Phase II monitoring sites operating during the Phase II field study over the winter of 1996/97 (Emery et al., 1998)............ 4-5 Figure 4-3. Time series of hourly CO measurements (dots) and UAM predictions (line) at Ph ase II field study monitoring sites. Plots cover the period 1500 LST December 8 to 1100 LST December 9, 1996. Gray shadi ng indicates the range of minimum to maximum predicted CO c oncentrations in the nine cells surrounding each site. .......................................................................................... 4-7 Figure 4-4. Scatter diag ram of UAM predictions vs . observations for the 1996 Base Case. The linear regression equation is given as the bold line................. 4-14 Figure 4-5. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 Base Case with updated on-road and non-road mobile emissions ............................. 4-15 Figure 4-6. Time series of hourly CO measurements (dots) and UAM predictions (black lin e = revised on-road emissions, red line = revised on-road and non-road emissions) at Phase II field study monitoring sites. Plots cover the period 1500 LST December 8 to 1100 LST December 9, 1996 ............................................ 4-17 Figure 4-7. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2006...................................................................... 4-24August 2005



### vii Figure 4-8. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2010...................................................................... 4-25 Figure 4-9. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2015...................................................................... 4-26 Figure 4-10. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2020...................................................................... 4-27 Figure 4-11. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2030...................................................................... 4-28 Figure 4-12. Weekday domain-wide on-road emission increase, net on-road emission increase that includes an addi tional 70% increase outside the central urban sub-domain, resulting UAM predicted peak CO, and resulting total and sub-domain on-road emission budgets for each future year. .............. 4-31 Figure 4-13. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2006 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. ....................... 4-33 Figure 4-14. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2010 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. ....................... 4-34 Figure 4-15. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2015 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. ....................... 4-35 Figure 4-16. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2020 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm ........................ 4-36 Figure 4-17. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2030 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm ........................ 4-37August 2005

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### 1-1 1. INTRODUCTION

1.1 BACKGROUND

The Las Vegas Valley is a large desert basi n at about 2000 feet el evation, surrounded by mountain ranges up to 11,900 feet, making it quite su sceptible to air pollu tion problems. This area includes the City of Las Vegas, the City of North Las Vegas, and the City of Henderson. The remainder constitutes unincorporated areas of Clark County. Clark County has been the fastest growing areas of the United States over the past 50 years, with a current population of about 1,750,000. During the winter m onths, cold air masses stagnate over the region , and nightly temperature inversions trap pollu tants within the valley. The ove rnight buildup of pollutants has historically caused violations of the national carbon monoxide standard in a limited area surrounding the East Charleston (Sunrise Acres) monitoring station. The East Charleston monitoring site in the vicinity of converging major transporta tion corridors named the “Five Points,” where three state highways intersect. Additionally, the site is located within a local depression where air pollution often collects.

The 1990 Clean Air Act Amendments (CAAA) esta blished two National Ambient Air Quality Standards (NAAQS) for carbon monoxide (CO). The first sets a maximum allowable concentration of 35 parts per million (ppm) av eraged over 1 hour, and the second sets a maximum concentration of 9 ppm averaged over 8 hour s. Areas that exceed one or both of the ambient standards more than two times in a tw o-year period are in vi olation and are thus classified as non-attainment areas for carbon monoxide.

Although the Las Vegas Valley has never exceeded the 1 hour CO NAAQS, it has previously exceeded the 8 hour standard at l east once per year on a seasonal basi s. The last violation of the 8-hour standard occurred in January 1996 in the Five Points area and measured 10.2 ppm; this became the valley’s last CO Design Value. There have been no CO exceedances from 1999 through the most recent data year, 2004. Th is downtrend is the di rect result of the implementation of local CO control measures and the tighter federal motor vehicle emission standards.

1.1.1 CO Regulatory History

The number and severity of 8-hour CO violati ons caused the U.S. Environmental Protection Agency (EPA) to automatically designate th e Valley as a Moderate nonattainment area upon enactment of the 1990 CAAA on November 15, 1990. Moderate nonattainment areas were required to implement emission control measures as “expeditiously as pr acticable” in order to attain the CO NAAQS by December 31, 1995. Clar k County implemented the set of controls required by the Clean Air Act for CO nonattainme nt areas, and made great strides towards attaining the NAAQS for carbon mon oxide. However, due to phenomenal growth within the Las Vegas Valley, it fell short of m eeting the NAAQS by the applicable date of December 31, 1995.

Based upon improved CO levels, which were at tributed to the implementation of the aforementioned control measures, EPA grante d Clark County a one year extension to demonstrate compliance with the NAAQS. Howeve r, the Las Vegas Valley was not successful in achieving compliance by December 31, 1996. According to CAAA requirements, the EPAAugust 2005

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### 1-2 reclassified the Las Vegas Va lley as a “serious” nonattainment area for carbon monoxide on October 2, 1997. A deadline of May 1999 (18 mont hs from the notice pub lication date) was set for submission of a State Implementation Plan (S IP) that demonstrates attainment by December 31, 2000.

On September 21, 1999, the Clark County Board of Commissioners adopted the Las Vegas Valley Non-attainment Area Carbon M onoxide Air Quality Implementation Plan . However, EPA Region IX found that the Plan’s emissions budget was inadequate, and raised other issues that affected the Plan’s appr oval. On August 1, 2000, the Clark County Board of Commissioners adopted a revised plan, and submitted supplemen tal CO SIP materials on January 30, 2002, and June 4, 2002 that addressed recently adopted vehicl e inspection and wintertime fuel regulations. On January 28, 2003, EPA proposed to approve the CO SIP with the exception of two individual contingency measures. EPA gave final approval to the CO SIP revision on September 21, 2004, but did not take any action on the contingency measures. Finally, on June 1, 2005, EPA made a finding that the Las Vegas Valley had attained the CO NAAQS by the applicable date of December 31, 2000. This action removes the re quirement for contingency measures and obligation under 187(g) of the CAAA to submit a SIP revision to assure a 5% per year reduction of CO emissions until attainment of the NAAQS.

1.1.2 Previous CO Modeling

Between 1996-2000, the Clark County Department of Comprehensive Planning developed computer models for valley-wide carbon monoxide to provide technical support for the control measures being evaluated for their CO SIP. This modeling was developed and conducted according to CAAA requirements and followed EPA modeling guidance specific to 8-hour CO SIP demonstrations. Modeling was conducted for three historical CO episodes in 1995-96 using a combination of numerical models, each focusing upon a specific scale and issue. The Urban Airshed Model (UAM) was used to simulate epis odic urban-scale CO patterns on a grid with 1- km spacing over the entire de veloped portion of the Las Vegas Valley; the CAL3QHC intersection model was used to simulate mi cro-scale CO patterns at the “Five Points” intersections; and the EDMS air port model was used to simulate fine-scale emissions and CO concentration patterns at the three civil airpor ts in the area, including McCarran International Airport. At the time, CO emissions from on-road mobile sources (by far the largest contributor to the overall emission inventory for Las Vega s) were estimated us ing a combination of MOBILE5b, DTIM, and volume/roadway li nk information provided by the Regional Transportation Commission (RTC) via their TRANP LAN transportation dema nd model (TDM).

In August 2000, Clark County submitted their revise d CO SIP for Las Vegas to EPA Region IX. The CO plan was based on UAM/CAL3QHC/EDM S modeling for the single best performing episode of the three: the night of D ecember 8-9 (Sunday-Monday), 1996. Technical documentation for the models, application met hodologies, performance evaluation, and future year modeling assessments are provided in the 2000 CO SIP and its appendices.

1.2 MODELING UPDATES

The Clark County Department of Air Quality an d Environmental Management has updated their UAM CO modeling and conformity analysis us ing the latest tools, data resources, andAugust 2005

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### 1-3 methodologies available to estimate CO emissi ons. From the revised modeling results, Clark County is submitting a revised CO SIP document. This section outlines the approach to incorporate emission updates into the UAM datase t, and to perform revised UAM urban-scale and CAL3QHC intersection modeling. Details fo r each component are provided in the following Sections.

Clark County has based their revised mode ling upon the previous UAM/CAL3QHC/EDMS modeling datasets developed for the December 8-9, 1996 episode. Specific updates to the emission inventories are briefly li sted below; they include modifi cations to on-road mobile, nonroad mobile, civil airports, railroads and point sources. Emission estimates for all remaining categories (mainly stationary area sources and Nellis Air Force Base) were taken from the previous modeling detailed in the 2000 CO SI P submittal, although new spatial distributions were developed for area sources from updated land use projections. The future years modeled in this update include: 2006, 2010, 2015, 2020, and 2030.

1.2.1 On-Road Emission Estimates

The greatest effort in the CO modeling update has focused on the on-road mobile source inventory estimates. Section 2 details the sp ecific methodologies employed to update the onroad emissions for the base and all future years. The original EPA vehi cle emission factor model that was used in the previous SIP effort (MOB ILE5b) was replaced by the latest version of the model, MOBILE6.2.03. This version has update d CO emission rates for LEV and Tier 2 vehicles from the previous version of MOBI LE6.2. However, the Air Improvement Resource (AIR) version of this model was used because it provides the capability to create a condensed database of composite emission factors. This is important for applications such as this one where many MOBILE6 scenarios must be run to gene rate lookup factors for link-level emissions estimates.

For the 1996 base year, the RTC’s original TR ANPLAN output was used to define link-based volume (vehicle miles traveled, or VMT) and othe r traffic volume-related parameters. However, no trip tables were available, which allow for the separate es timation of start versus running emissions. Therefore, it was necessary to process base year start emissions differently than the future years by utilizing trip data from TransCAD TDM output from the year 2000 (as described in Section 2). All original ancillary information, including ve hicle fleet mix, seasonal/day-ofweek adjustment factors, and hourly activity pr ofiles remain the same as in the original modeling.

Since output data and formats for MOBILE6 are si gnificantly different from its predecessor, the original utility that was used to estimate link- level CO emissions (DTIM) was replaced by two new programs. The first processes the link- based emissions, and the other processes the emissions based on traffic analysis zones (TAZ). Both of the new programs produce inputs for the Emission Processing System, version 3 (EPS3). The EPS3 is the latest version of the EPS program suite used in the original CO SIP m odeling to generate gridded, time-resolved, UAMready CO emission input files.

For all future years modeled in this update, the RTC provided output fro m their new TransCAD TDM, which includes link volumes and trip tables for each year. For the link-based data, the same program written for the base year was used to produce the link-based emissions for EPS3.August 2005

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### 1-4 For the TAZ data, most of the same type of MOBILE6 output was used in the program developed for the base year; but start emissions were handled in a special way (see Section 2).

1.2.2 Other Emission Sources

Emission updates were also made to airports, railroad, non-road, and point source categories. Specific details are provided in Section 3.

1.2.2.1 Airports

In 1999, Clark County developed a detailed emissi ons inventory for the three county airports (McCarran, North Las Vegas, a nd Henderson), and performed air port-scale dispersion modeling, using the Federal Aviation Administration’s EDMS model. At the time, EDMS had Mobile5a embedded as the source of on-road mobile emi ssions generation, and used PAL2 and CALINE3 for dispersion calculations. EDMS was run for th e 1996 base year, along with the future years of 2000, 2010, and 2020. However, airport emission estim ates within the UAM were never updated to reflect the EDMS estimates, and instead re lied on much older airport estimates from a 1992 study.

In 2003, Clark County sponsored an updated EDMS project for the three county airports. The latest version of EDMS was used, which introduced the AE RMOD dispersion model. On-road mobile sources were estimated using Clark C ounty runs of Mobile6.2. EDMS was run for 2000, 2005, 2010, 2015 and 2020 (the 1996 base year was sk ipped). Again, UAM airport emissions were not updated.

In this CO modeling update, the latest 2003 EDMS airport em ission estimates have been included into the UAM emissions inventory. Deta ils of emissions by projection year, and their spatial/temporal allocation to the UAM grid, ar e described in Section 3. The issue of doublecounting airport emissions within the UAM a nd EDMS+UAM modeling results were carefully considered.

1.2.2.2 Non-Road and Locomotive

In the previous modeling, non-road emissions we re taken from NEVES estimates, and included only a few categories. Clark County has update d their railroad emissions estimates for 2001 based on a recent non-road study (Mactec, 2003), which include contributions from both line haul and switching. These have been incorpor ated into the updated UAM inventory.

EPA’s NONROAD2004 model, run with Clark County input data , estimates much higher nonroad emission than the NEVES-based estimates used in the 2000 CO SIP. In this modeling update, the NONROAD model was used to generate emission inputs to EPS3 for each simulated future year. New spatial and temporal allocati on factors were developed based on the latest land use projections from Clark County. Airport ground support equipment (GSE) were removed from the NONROAD estimates because they were included in the EDMS estimates; railroad maintenance emissions were left in since the Mactec emissions were estimated for locomotives only.August 2005

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### 1-5 1.2.2.3 Point Sources

Clark County incorporated an updated point s ource emission inventory, which included revised stack parameters, and which defined Potential To Em it (PTE) levels for seven specific facilities. The UAM future year inventor ies included the PTE levels pl us an additional 70 ton buffer (referred to as “PTE+70”) for these sources. The original point sour ce inventory was used, unchanged, for the 1996 base year simulation.

1.2.3 Model Application

UAM was provided the updated emission inventor ies for point, on-road mobile, and non-road mobile sources, and run for the December 8-9, 1996 historical CO event. All other environmental parameters were taken from the original modeling as documented in the 2000 CO SIP. A base-year model performance evaluati on was conducted similarly. The UAM was then used with the updated future year inve ntories for 2006, 2010, 2015, 2020 and 2030 to determine peak 8-hour CO levels in the basin for the same December 8-9, 1996 conditions. UAM results, without airport emissions included in the inventory, were added to EDMS receptor concentrations from the 2003 updated airport modeling.

For hotspot modeling, the CAL3QHC model wa s used to model th ree intersections: Charleston/Eastern, Charleston/ Fremont and Eastern/Fremont. EPA (1992, 1995) guidance for screening level modeling of these three intersecti ons was followed. The ambient temperature for each hour of the episode (needed to estimate em issions with the MOBILE6 model), and the wind direction and speed (needed for the CAL3QHC estimates) were taken from the original UAM/CAL3QHC modeling. The CAL3QHC model output was added to the background UAM levels to estimate 8-hour CO concentr ations for the duration of the episode.

All modeling results are detailed in Section 4.August 2005

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### 2-1 2. ON-ROAD MOBILE EMISSIONS

2.1 OVERVIEW OF APPROACH

The greatest effort of the update to the CO modeling system focused on the on-road mobile source inventory estimates. The original vehicl e emission factor model that was used in the previous SIP effort (MOBILE5b) was replaced by the EPA’s la test version of the model, MOBILE6.2.03. This version has updated CO emi ssion rates for LEV and Tier 2 vehicles from the previous version of MOBILE 6.2. In addition, since output data and formats for MOBILE6are significantly different from its predecessor, the original utility that was used to estimate linklevel CO emissions (DTIM) was replaced by new programs written by ENVIRON.

For the 1996 base year, the original TRANPL AN transportation demand model (TDM) output provided daily total link-based volumes (number of vehicles on each link), link lengths, and other link-related parameters by tr affic analysis zone (TAZ). Th e vehicle miles traveled (VMT) was calculated from the product of link volume a nd link length. The County provided the loaded network files, but no trip tables were available to process start emissions separately from running emissions. Therefore, trip data from the ne wer 2000 TransCAD TDM was used as a means to spatially allocate the 1996 start emissions fo r each period available in the daily TransCAD output. All other original anc illary information, including vehi cle fleet mix, seasonal/day-ofweek adjustment factors, and hour ly activity profiles were the same as in the original modeling.

For the future years (2006, 2010, 2015, 2020, and 2030) , the latest TransCAD TDM output was provided by the Regional Trans portation Commission of Southe rn Nevada (RTC). The TransCAD output included link level activity, intr azonal trips, and origin/ destination trips by TAZ for several periods of the day (note that the number and distribution of TAZs, and the periods for which TransCAD wa s run, differed substantially from the original TRANPLAN configuration). Three separate programs were written for each of these to generate inputs to the Emission Processing System, version 3 (EPS3) 1 

### . The EPS3 is the latest version of the EPS program suite used in the original CO SIP modeling.

For both the base and future year link-le vel emissions, VMT was calculated from the transportation model output (li nk volume times link length) for each period of the day, and allocated to each hour using an hourly distributio n for each day of the episode. VMT was then multiplied by hourly running exhaust emission factors (gram per mile) from MOBILE6.2. The total hourly emissions by link were spatially distributed according to the link end point coordinates using LBASE, a component of EPS3.

For both the base and future years, the star t emissions were calculated by multiplying hourly estimates of link-level VMT by hourly MOBILE6.2 start emission factors (gra m per mile). The link-level start emissions were then totaled over the entire network and spatially distributed using the period-specific transportation model trip orig in data by TAZ. Note that for the 1996 base year there were no TRANPLAN trip data by TAZ available. Instead, the 1996 start emissions were spatially allocated using 2000 TransCAD trip data.

1 Note that we used hourly emissi on factors from the MOBILE6 database output, and M6LINC was not applicable for this work because it does not handle hourly emission factors.August 2005

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### 2-2 The base year TRANPLAN intrazonal data were provided as volumes by TA Z with a trip length, from which VMT was calculated. The intrazonal running and start emissions were calculated as VMT times the MOBILE6.2 start and running emissi on factors, and then spatially allocated according to the centroid of each TAZ.

The future year TransCAD intrazonal data were provided as trips by TAZ only. The intrazonal trips were assumed to have a trip length of 1 mile, from which VMT was calculated. The VMT was then multiplied by the running emission factors, and then spatially distributed using gridded surrogates developed from the definiti on of the future year TransCAD TAZs.

2.2 BASE YEAR ESTIMATES

2.2.1 Base Year MOBILE6 Inputs

Base Year MOBILE6 inputs we re compiled based on sample MOBILE6 input files for 1996 provided by Clark County. External files were also provided, and th ese were used as detailed in the Table 2-1 below. Eight input files were crea ted, for each of the four roadway types (freeway, arterial, local, and ramp) and for weekday and weekend. For Freeway an d Arterial, the model was run for speeds between 5 and 65 mph for ever y 1 mph increment. The Local roadway type was set at 12.9 mph, and the Ramp roadway ty pe was set to 34.6 mph by MOBILE6 itself.

A first set of MOBILE6 runs was conducted us ing the start distribu tion contained in the

“ sdist.lv ” file shown in Figure 2-1. These emi ssion factors were ap plied to the whole domain except a small region around Las Vegas Boulevard.

A second set of MOBILE6 runs was conducted to better characterize the specific weekday start emission factors along the Las Vegas Boulevard (LVB ), where the start activity is not centered around residential areas, but rather parking lots near casinos (and thus are not characteristic of typical commute activity profiles). A more representative start di stribution was calculated as the fraction of 2000 TransCAD origin trips occurrin g over all the TAZs along the boulevard from all periods available in the 2000 Tran sCAD output. Figure 2-2 displays the original weekday start distributions (based on the distribution shown in Figure 2-1) against the LVB weekday start distributions for all future years. Given the sim ilarity of the future year start distributions, we elected to apply the 2000 modified start distribution to the base year and all future years for the region around the Las Vegas Boulevard.

Note that MOBILE6 I/M effectiveness was set to 100%. Clark County has developed a white paper to justify this value fo r Las Vegas (Clark County, 2005), a nd this is included in Appendix C to the 2005 CO SIP revision.August 2005

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### 2-3 Table 2-1. 1996 Base Year Las Vegas MOBILE6.2 input parameters. M6.2 Input Command Weekday Parameters Weekend Parameters

HOURLY TEMPERATURES 42.0 44.0 49.0 51.0 55.0 58.0 64.0 66.0 66.0 66.0 62.0 58.0 55.0 53.0 51.0 50.0 48.0 47.0 45.0 44.0 44.0 43.0 42.0 42.0 42.0 44.0 49.0 51.0 55.0 58.0 64.0 66.0 66.0 66.0 62.0 58.0 55.0 53.0 51.0 50.0 48.0 47.0 45.0 44.0 44.0 43.0 42.0 42.0

REG DIST LV_reg02.RDT LV_reg02.RDT

VMT FRACTIONS 0.5067 0.0770 0.2562 0.0790 0.0363 0.0111 0.0011 0.0009 0.0006 0.0024 0.0029 0.0032 0.0113 0.0028 0.0013 0.0072 0.5067 0.0770 0.2562 0.0790 0.0363 0.0111 0.0011 0.0009 0.0006 0.0024 0.0029 0.0032 0.0113 0.0028 0.0013 0.0072

VMT BY HOUR Hvmt_lv.wek Hvmt_lv.wnd START DIST sdist.lv sdist.lv OXYGENATED FUELS .240 .760 .027 .035 1 .240 .760 .027 .035 1

ANTI-TAMP PROG 83 81 50 22222 22222222 2 11 090. 22212112 83 81 50 22222 22222222 2 11 090. 22212112

Exhaust I/M program #1 same as weekday I/M PROGRAM 1 1983 2050 1 TRC 2500/IDLE I/M MODEL YEARS 1 1968 2050 I/M VEHICLES 1 22222 22222222 2 I/M STRINGENCY 1 22 I/M COMPLIANCE 1 90 I/M WAIVER RATES 1 0.1 0.1 I/M EFFECTIVENESS 1.00 1.00 1.00 I/M GRACE PERIOD 1 2 NO I/M TTC CREDITS 1

CALENDAR YEAR * 1997 1997 EVALUATION MONTH * 1 1 FUEL RVP 9 9 FUEL PROGRAM 1 1 * Since MOBILE6.2 models January and July periods, Ja nuary 1997 was chosen beca use it is closest to the December 1996 episode.August 2005

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### 2-4 Figure 2-1. Hourly weekend and weekday start distri butions (fraction) provided by Clark County, used to temporally allocate emi ssions derived from TRANPLAN and TransCAD.

Figure 2-2. Fraction of original weekday start distribution and start distributions in all future years for the Las Vegas Boulevard area calculat ed from the TransCAD origin trips by TAZ. 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

0 4 8 12 16 20 24 Hour beginningFraction of Daily Total Weekday

Weekend

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

HourFraction of Daily Total Original Starts

2000

2006

2010

2015

2020

2030August 2005

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### 2-5 2.2.2 Base Year TRANPLAN Link Activity Adjustments

The 1996 TRANPLAN activity data is representative of an average annual day. The following episode-specific adjustments were applied to th e data, where the two-day episode modeled was Sunday, December 8 through Monday, December 9, 1996.

2.2.2.1 Month/Season, Day of Week

A factor of 1.021 was applied to adjust from aver age annual day to a typical December day. This adjustment factor was applied to all the running, start, and intraz onal emissions for both days of the episode. This value is the same as wa s used in the previous SIP modeling effort.

A factor of 0.774 and 1.022 were applied to adju st from a typical day to Sunday and Monday, respectively. These are the same factors as used in the 2000 SIP.

2.2.2.2 Hourly Temporal Adjustments

The same day-specific hourly VMT distributi on factors used to generate hourly MOBILE6 emission factors were used to scale daily VM T from TRANPLAN to each hour of the episode, presented in Figure 2-3.

On-Road Hourly VMT Distribution

0 1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

HourPercent

Dec. 8 Dec. 9

Figure 2-3. Weekday and Sunday hourly VMT distribution.August 2005

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### 2-6 2.2.2.3 Speed Adjustments

After the link data were temporally allocate d to hourly values, the TRANPLAN hourly speed was calculated using the following Bureau of Pub lic Roads (BPR) curve, where the volume to capacity ratio was capped at 1.25:



# ( ) ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + = B ff

a 

### C V A S S

* 1

where:

S a = adjusted link speed (mph)

S ff

= reported link free flow speed (mph)

V

= total link volume (vehicles OR vehicles per hour)
C = total link capacity (vehicles OR vehicles per hour)
For freeways, interstates, syst em ramps, and expressways,

A = 0.66 B = 7.2
For major arterials, minor arterial s, collectors, ramps, and other,

A = 0.76 B = 5.9 

### However, the resulting adjustment to the speed s using the BPR curve had no impact on the total base year emissions.

2.2.2.4 Transit Adjustments

The link-level emissions were adjusted upward by a factor of 1.00295 to in clude the contribution from public transit activity, which were not included in the TRANPLAN calculations.

2.2.3 Base Year Link-Level Running Exhaust Emissions

Emission factors were generated using the Air Improvement Resource, Inc. (AIR) version of MOBILE6, outputting hourly emission factors for 28 vehicle classes. A vehicle composite emission factor was calculated acr oss all 28 classes using the vehi cle class distribution shown in Table 2-2.

The TRANPLAN link activity data consisted of th e annual daily average volume for each link in the network. The links were classified by the RTC facility type code. The cross-reference between the RTC facility type code and the MOBILE6.2 roadway types used is displayed in Table 2-3.

In summary, the link-level running exhaust em issions processing steps were as follows: 1) Adjust the daily volumes to hourly volumes (using profiles shown Figure 2-3); 2) Adjust the link speeds usi ng the hourly volume to capacity ratio in the BPR curve; 3) Calculate the hourly link VMT as th e hourly volume times the link length;August 2005

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### 2-7 Table 2-2. MOBILE6 28 vehicle classes and their relative fraction of the overall fleet.
Class Number Class Description Fraction
1 LDGV Light-Duty Gasoline Vehicles (Passenger Cars) 0.504287 2 LDGT1 Light-Duty Gasoline Trucks 1 (0-6,000 lbs. GVWR, 0-3750 lbs. LVW) 0.076726

3 LDGT2 Light-Duty Gasoline Trucks 2 (0-6,000 lbs. GVWR, 3751-5750 lbs. LVW) 0.25529

4 LDGT3 Light-Duty Gasoline Trucks 3 (6,001-8,500 lbs. GVWR, 0-5750 lbs. ALVW) 0.077912

5 LDGT4 Light-Duty Gasoline Trucks 4 (6,001-8,500 lbs. GVWR, 5751 lbs. and greater ALVW) 0.0358
6 HDGV2B Class 2b Heavy-Duty Gasoline Vehicles (8501-10,000 lbs. GVWR) 0.008055 7 HDGV3 Class 3 Heavy-Duty Gasoline Vehi cles (10,001-14,000 lbs. GVWR) 0.000261 8 HDGV4 Class 4 Heavy-Duty Gasoline Vehi cles (14,001-16,000 lbs. GVWR) 0.000197 9 HDGV5 Class 5 Heavy-Duty Gasoline Vehi cles (16,001-19,500 lbs. GVWR) 0.000348 10 HDGV6 Class 6 Heavy-Duty Gasoline Vehi cles (19,501-26,000 lbs. GVWR) 0.000773 11 HDGV7 Class 7 Heavy-Duty Gasoline Vehi cles (26,001-33,000 lbs. GVWR) 0.000373 12 HDGV8A Class 8a Heavy-Duty Gasoline V ehicles (33,001-60,000 lbs. GVWR) 0.000002 13 HDGV8B Class 8b Heavy-Duty Gaso line Vehicles (>60,000 lbs. GVWR) 0 14 LDDV Light-Duty Diesel Vehi cles (Passenger Cars) 0.002413 15 LDDT12 Light-Duty Diesel Trucks 1 and 2 (0-6,000 lbs. GVWR) 0.001184 16 HDDV2B Class 2b Heavy-Duty Diesel Vehicles (8501-10,000 lbs. GVWR) 0.003045 17 HDDV3 Class 3 Heavy-Duty Diesel V ehicles (10,001-14,000 lbs. GVWR) 0.000839 18 HDDV4 Class 4 Heavy-Duty Diesel V ehicles (14,001-16,000 lbs. GVWR) 0.000703 19 HDDV5 Class 5 Heavy-Duty Diesel V ehicles (16,001-19,500 lbs. GVWR) 0.000252 20 HDDV6 Class 6 Heavy-Duty Diesel V ehicles (19,501-26,000 lbs. GVWR) 0.001627 21 HDDV7 Class 7 Heavy-Duty Diesel V ehicles (26,001-33,000 lbs. GVWR) 0.002527 22 HDDV8A Class 8a Heavy-Duty Diesel Vehicles (33,001-60,000 lbs. GVWR) 0.003198 23 HDDV8B Class 8b Heavy-Duty Dies el Vehicles (>60,000 lbs. GVWR) 0.0113 24 MC Motorcycles (Gasoline) 0.0072 25 HDGB Gasoline Buses (School, Transit and Urban) 0.000832 26 HDDBT Diesel Transit and Urban Buses 0.0013 27 HDDBS Diesel School Buses 0.001968 28 LDDT34 Light-Duty Diesel Trucks 3 and 4 (6,001-8,500 lbs. GVWR) 0.001588



### 4) Calculate the link emissions as the li nk VMT times the MOBILE6.2 composite emission factor for the link roadway type, hour, and adjusted link speed; 5) Spatially allocate the link emissions using LBASE; and 6) Adjust the emissions to average Dece mber day, Sunday or Monday, and for transit activity, in EPS3.

Table 2-4 presents tabulations of 1996 VMT by f acility type, directly reported by TRANPLAN, and after various adjustments described above.

Figure 2-4 shows the spatial di stribution of link-level runnin g exhaust emissions for the 1996 base case.August 2005

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### 2-8 Table 2-3. Cross-reference between RTC and MOBILE6.2 facility types.
RTC Facility Code Description MOBILE6.2 Roadway Type 0 Externals Freeway 1 System Ramps Ramp 2 Minor Arterials Arterial 3 Major Arterials Arterial 4 Freeway Ramps Ramp 5 Interstates Freeway 6 Freeways Freeway 7 Expressways Freeway 8 Collectors Arterial 9 Centroid Connectors Local 10 Intrazonal Local

Table 2-4. 1996 VMT by facility type. Totals are shown as output by TRANPLAN, and after seasonal, day-of-week, and public transit adjustments.
Group Code Facility Type Modeled 1996 DVMT DVMT A djusted to

December DVMT Adjusted for Transit Sunday DVMT Monday DVMT
0 External Connctor 640,605 654,058 655,988 507,734 670,419 1 System Ramp 69,247 70,701 70,910 54,884 72,470 2 Minor Arterial 7,469,952 7,626,821 7,649,320 5,920,574 7,817,605 3 Major Arterial 3,655,890 3,732,664 3,743,675 2,897,605 3,826,036

4 Freeway on- or off-ramp 267,725 273,348 274,154 212,195 280,185 5 Interstate 3,825,715 3,906,055 3,917,578 3,032,205 4,003,764 6 Freeway 1,202,253 1,227,501 1,231,122 952,888 1,258,207 7 Expressway 214,096 218,592 219,237 169,690 224,060 8 Collector 2,776,772 2,835,084 2,843,448 2,200,828 2,906,003

9 Centroid Connector 2,185,691 2,231,591 2,238,174 1,732,347 2,287,414 Intrazonal 87,303 89,136 89,399 69,195 91,366 Daily Total 22,395,251 22,776,414 22,843,605 17,680,950 23,346,164 Transit adjustment 1.00295 December adjustment 1.021 Sunday adjustment 0.774 Monday adjustment 1.022August 2005

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### 2-9 Figure 2-4. Spatial distribution of on-road mobile source running exhaust CO emissions for the 1996 Base Case. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.00 0.30 0.60 0.90 1.20 1.50 1.80 2.10 2.40 2.70



### Onroad Running Emissions Base Year - Dec 9, 1996 CO (tons per day)August 2005

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### 2-10 2.2.4 Base Year Start Emissions

The daily link-level VMT from TRANPLAN was allocated to hourly values using the dayspecific hourly VMT profiles shown in Figure 2- 3. The base year start emissions were calculated from the product of hourly link VMT and the hourly MOBILE6.2 start emission factors. To remain consistent with how the futu re year start emissions were to be developed, the base year start emissions were translated from link-level to TAZ level. Note that for the 1996 base year there were no TRANPLAN trip data by TAZ available. Instead, the 1996 start emissions were spatially allocated to TAZs using 2000 TransCAD trip data. For Monday, the hourly link start emissions were totaled over th e entire network and redistributed to 2000 TransCAD TAZs based on the fraction of period-sp ecific trip origins for each TAZ over the total number of trip origins over all TAZs. For Sunday, the Tr ansCAD start activity is not representative of a typical wee kday profile, so the start emissions for all hours were spatially distributed to each TAZ using a single ratio of the daily total TAZ trip origin s to the daily total of all trip origins over the domain.

A month/season adjustment factor of 1.021 was app lied to the start emissions. This adjustment is from average annual day to average December day. This adjustment factor was applied to all the running, start, and in trazonal emissions for both days of th e episode. It is the same as was used in the previous SIP modeling effort.

The day of week adjustments are from averag e annual day to Sunday and Monday. The factors used were 0.774 for Sunday and 1.022 for Monday. These are the same factors as used in the 2000 SIP.

The hourly TAZ start emissions were spatially allocated to the grid cell containing the TAZ centroid and the 24 surrounding cells in a “weddi ng cake” fashion: the grid cell containing a TAZ centroid receives 25% of the start emission s from that TAZ, the surrounding 8 grid cells receive 60% of the start emissions (7.5% per cell), and the outsid e 16 grid cells receive 15% of the start emissions (0.9375% per cell). The we dding cake approach is based on the duration of start emissions as defined from EPA’s vehicle te sting cycle, which reports emissions during the first 505 seconds (Bag 1) of operation after a cold engine start. Emissions are highest during the first few minutes after a vehicle is started. As the vehicle travels from the start location, its catalytic converter warms and the emissions decrease. With the wedding cake approach, all engine starts occur within a given TAZ, so the grid cell containing that TAZ receives the highest fraction of those start emissions. Grid cells surrounding that TAZ receive progressively smaller fractions of emissions as engines warm and vehicles travel from the TAZ. Clark County believes that this is a very conservative method for allo cating start emissions. Given the lack of any research data to improve upon this methodology, Clark County requested EPA Region IX and the Office of Transportation and Air Quality to review the wedding cake approach; both verbally agreed to allow its use for this modeling anal ysis (EPA Region IX, personal communication).

Figure 2-5 shows the spatial di stribution of start exhaust em issions for the 1996 base case.

2.2.5 Base Year Intrazonal Activity

Intrazonal VMT was included in the previous modeling by locating their contribution at the centroid coordinates of each TAZ. The TAZ boundary information for the 1996 base year wasAugust 2005

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### 2-11 Figure 2-5. Spatial distribution of on-road mobile source start exhaust CO emissions for the 1996 Base Case. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.00 0.08 0.16 0.24 0.32 0.40 0.48 0.56 0.64 0.72



### Onroad START Emissions Base Year - Dec 9, 1996 CO (tons per day)August 2005

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### 2-12 not available, so these were allocated to the gr id cells corresponding to each centroid coordinate as was performed in the previous modeling for the 2000 SIP submittal.

2.2.6 Base Year Total Emissions

Table 2-5 lists the component a nd total on-road mobile source em issions for the 1996 base year. Figure 2-6 presents the spatial distribution of the total on-road mobile source emissions for December 9, 1996.

Table 2-5. Component and total on-road mobile source CO emissions (TPD) for the 1996 base year. Links - Running Starts Intrazonals Total Sunday 12/8 202.75 126.42 0.78 329.95
Monday 12/9 269.31 241.09 1.03 511.43



### 2.3 FUTURE YEAR ESTIMATES

The RTC provided TransCAD model output fo r each of the future years: 2006, 2010, 2015, 2020, and 2030. The TransCAD model output provided link-level volumes (number of vehicles) and trip origins and destinations for the follo wing seven diurnal periods: midnight – 7 AM, 7 AM – 9 AM, 9 AM – 2 PM, 2 PM – 4 PM, 4 PM – 6 PM, 6 PM – 8 PM, 8 PM – midnight. When modeling Sunday, the period data were firs t summed together over all seven periods and then redistributed to hourly va lues using a weekend temporal distribution. When modeling Monday, the period totals were maintained as output by TransCAD. They were further disaggregated into hourly values by applying th e fraction of each hour within each period from the weekday distribution.

2.3.1 Future Year MOBILE6 Inputs

Future year MOBILE6 inputs were compiled based on sample MOBILE6 input files for 2010 provided by Clark County. External files were also provided, and th ese were used (as detailed in Table 2-6). For each future year (2006, 2010, 2015, 2020, 2030), eight input files were created, for each of the four roadway types (freeway, ar terial, local, and ramp) both for weekday and weekend. For Freeway and Arterial, the model was run for speeds between 5 and 65 mph for every 1 mph increment. The Local roadway t ype was set at 12.9 mph, and the Ramp roadway type was set to 34.6 mph by MOBILE6 itself.

For the Natural Gas Vehicles Fractions external files, the following assumptions were made (by Clark County) in creating the f iles. CNG vehicles start with model year 1998, and are assumed to be a very small fraction of the fleet and comprised of governme nt vehicles only. It is also assumed that the vehicles last seven years, a nd then are removed from service or sold to a consumer, who fuels them with gasoline.August 2005

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### 2-13 Figure 2-6. Spatial distribution of total on-road mobile source CO emissions for the 1996 Base Case. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.00 0.30 0.60 0.90 1.20 1.50 1.80 2.10 2.40 2.70



### ONROAD Emissions Base Year - Dec 9, 1996 CO (tons per day)August 2005

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### 2-14 Table 2-6. MOBILE6.2 input parameters for future year Las Vegas runs. M6 Input Parameter Weekday Parameters Weekend Parameters Source

HOURLY TEMPERATURES 42.0 44.0 49.0 51.0 55.0 58.0 64.0 66.0 66.0 66.0 62.0 58.0 55.0 53.0 51.0 50.0 48.0 47.0 45.0 44.0 44.0 43.0 42.0 42.0 42.0 44.0 49.0 51.0 55.0 58.0 64.0 66.0 66.0 66.0 62.0 58.0 55.0 53.0 51.0 50.0 48.0 47.0 45.0 44.0 44.0 43.0 42.0 42.0 same temperatures used as in previous work

REG DIST LV_reg02.RDT LV_reg02.RDT provided by Clark County

VMT FRACTIONS 0.5067 0.0770 0.2562 0.0790 0.0363 0.0111 0.0011 0.0009 0.0006 0.0024 0.0029 0.0032 0.0113 0.0028 0.0013 0.0072 0.5067 0.0770 0.2562 0.0790 0.0363 0.0111 0.0011 0.0009 0.0006 0.0024 0.0029 0.0032 0.0113 0.0028 0.0013 0.0072 provided by Clark County

VMT BY HOUR Hvmt_lv.wek Hvmt_lv.wnd provided by Clark County

START DIST sdist.lv sdist.lv provided by Clark County

NGV FRACTION ngvfr06.lv, ngvfr10.lv, ngvfr15.lv, ngvfr20.lv, ngvfr30.lv ngvfr06.lv, ngvfr10.lv, ngvfr15.lv, ngvfr20.lv, ngvfr30.lv provided by Clark County

OXYGENATED FUELS .001 .999 0.027 0.035 1 .001 .999 0.027 0.035 1 provided by Clark County

ANTI-TAMP PROG 83 81 50 22222 22222222 2 11 090. 22212112 83 81 50 22222 22222222 2 11 090. 22212112 provided by Clark County

> Exhaust I/M program #1 provided by Clark County

I/M PROGRAM 1 1983 2050 1 TRC 2500/IDLE 1 1983 2050 1 TRC 2500/IDLE I/M MODEL YEARS 1 1968 1995 1 1968 1995 I/M VEHICLES 1 22222 22222222 2 1 22222 22222222 2 I/M STRINGENCY 1 22 1 22 I/M COMPLIANCE 1 90 1 90 I/M WAIVER RATES 1 0.1 0.1 1 0.1 0.1 I/M EFFECTIVENESS 1.00 1.00 1.00 1.00 1.00 1.00 I/M GRACE PERIOD 1 2 1 2 I/M CREDIT FILE tech12.d tech12.dAugust 2005

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### 2-15 Table 2-6 (continued). M6 Input Parameter Weekday Parameters Weekend Parameters Source > Exhaust I/M program #2

I/M PROGRAM 2 1983 2050 1 TRC OBD I/M 2 1983 2050 1 TRC OBD I/M I/M MODEL YEARS 2 1996 2050 2 1996 2050 I/M VEHICLES 2 22222 22222222 2 2 22222 22222222 2 I/M STRINGENCY 2 22 2 22 I/M COMPLIANCE 2 90 2 90 I/M WAIVER RATES 2 0.1 0.1 2 0.1 0.1 I/M GRACE PERIOD 2 2 2 2

> Evap I/M program #3

I/M PROGRAM 3 1983 2050 1 TRC EVAP OBD 3 1983 2050 1 TRC EVAP OBD I/M MODEL YEARS 3 1996 2050 3 1996 2050 I/M VEHICLES 3 22222 11111111 1 3 22222 11111111 1 I/M COMPLIANCE 3 90 3 90 I/M WAIVER RATES 3 0.1 0.1 3 0.1 0.1 I/M GRACE PERIOD 3 2 3 2

CALENDAR YEAR 2007, 2011, 2016, 2021, 2031 2007, 2011, 2016, 2021, 2031 EVALUATION MONTH 1 1 WE VEH US no yes

FUEL RVP 9 9 provided by Clark County

FUEL PROGRAM 4 4 provided by Clark County Average Gasoline Fuel Sulfur Content = 30 ppm Average Gasoline Fuel Sulfur Content = 30 ppm Maximum Gasoline Fuel Sulfur Content = 80 ppm Maximum Gasoline Fuel Sulfur Content = 80 ppm

DIESEL SULFUR 250,15,15,15,15 250,15,15,15,15 provided by Clark CountyAugust 2005

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### 2-16 Note that MOBILE6 I/M effectiveness was set to 100%. Clark County has developed a white paper to justify this value fo r Las Vegas (Clark County, 2005), a nd this is included in Appendix C to the 2005 CO SIP revision.

For the VMT mix, values generated from a 2002 traffic study conducted by RTC in Las Vegas (Orth-Rodgers and Associates, 2003) were used, which yielded VMT for 5 vehicle types that were further broken down into 16 vehicle type s based on MOBILE6 default VMT mix for 2002. Clark County does not have future year foreca sts for vehicle VMT mix, seasonal/day-of-week adjustments, or hourly activity profiles, so the 2002 vehicle VMT mix and other information from the base year were used for all future years.

A first set of MOBILE6 runs was conducted using the star t distribution containe d in the sdist.lv file (shown in Figure 2-1). These emission fact ors were applied to the whole domain except for a small region around Las Vegas Boulevard.

A second set of MOBILE6 runs was conducted to better estimate the specific weekday start emission factors along the Las Vegas Boulevard (LVB ), where the start activity is not centered around residential areas, but rather parking lots near casinos (and thus are not characteristic of typical commute activity profiles). A more representative start di stribution was calculated as the fraction of TransCAD origin trips occurring over all TAZs along the boulevard from all periods available in the TransCAD output. Figure 2-2 above shows the w eekday start distributions for all future years along the Las Vega s Boulevard. Given the similarity of the future year start distributions, we elected to appl y the 2000 modified start distribu tion to the base year and all future years for the region around the Las Vega s Boulevard. Figure 2- 7 compares the hourly 2006 MOBILE6 start emission factor profiles fo r Sunday (entire domain), Monday (LVB area), and Monday (remainder of the domain).

2.3.2 Future Year TransCAD Link Activity Adjustments

2.3.2.1 Month/Season, Day of Week

The link-level activity was adjusted from annua l average to December by a factor of 1.021, as was done for the base year.

The TransCAD volume data is representative of an average weekday. The data were scaled to Sunday estimates by weighting the Sunday day-of-w eek factor by the average weekday factor. The day of week factors are shown in Table 2-7.

The Sunday adjustment was therefore calculated as:

Sunday Adjustment = 0.774/[(1.022 + 1.047 + 1.060 + 1.062 + 1.109)/5] = 0.73

Monday was not adjusted.August 2005

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### 2-17 Table 2-7. Volume scaling factors by day of week.

Day of Week Day of Week Factors Sunday 0.774 Monday 1.022 Tuesday 1.047 Wednesday 1.060 Thursday 1.062 Friday 1.109 Saturday 0.925

Figure 2-7. Hourly start emission factors from t he 2006 MOBILE6 run: “Sun EF” is the Sunday profile used for all start emissions; “Mon EF” is the Monday profile used for start emissions outside of the LVB area; and “LVB Mon EF” is the Monday profile used for start emissions within the LVB area.



### 2.3.2.2 Link Volume Adjustments

Prior to calculating the link-based emissions, the link volumes were first adjusted to observed traffic counts by facility type. Then, the adjusted link volumes we re adjusted to bring the total volume into agreement with the VMT reporte d through the Highway Performance Monitoring System (HPMS). Table 2-8 shows the adjustment factors to observed traffic counts by facility type.

The overall HPMS adjustment was a single factor multiplied uniformly to the volumes to bring the total into agreement w ith HPMS. The HPMS adjustment factor used was 1.0145. 0 0.002 0.004 0.006 0.008

0.01 0.012123456789101112131415161718192021222324

Hourg/mile

Mon EF Sun EF LVB Mon EFAugust 2005

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### 2-18 Table 2-8. Adjustment factors to observed traffic counts by facility type. Facility Type Count Correction Factor external connector 0.9880 system ramp 0.9880 minor arterial 1.0917 major arterial 1.0917 service ramp 0.9880 interstate 0.9880 freeway 0.9880 beltway 0.9880 collector 1.0917 centroid 1.0917



### 2.3.2.3 Hourly Temporal Adjustments

The TransCAD volume data is representative of an average weekday. Within each of the seven periods, the data were further di saggregated using the default w eekday (Dec. 9) distribution for Monday. For Sunday, the data were summed to obtai n the daily total before re-distributing into the hours using the default weekend (Dec. 8) distribution. The same VMT distributions that were used for the 1996 base year were used for the future years, as illustrated in Figure 2-3.

2.3.2.4 Speed Adjustments

After the link data were temporally allocated to hourly values, the hourly speeds were adjusted using the following Bureau of Public Roads (BPR ) curve, where the volume to capacity ratio was capped at 1.25:



# ( ) ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ + = B ff

a 

### C V A S S

* 1

where:

S a = adjusted link speed (mph)

S ff

= reported link free flow speed (mph)

V

= total link volume (vehicles OR vehicles per hour)
C = total link capacity (vehicles OR vehicles per hour)
For freeways, interstates, syst em ramps, and expressways,

A = 0.66 B = 7.2
For major arterials, minor arterial s, collectors, ramps, and other,

A = 0.76 B = 5.9August 2005

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### 2-19 2.3.2.5 Transit Adjustments

The link-level emissions were adjusted upward by the factors shown in Table 2-9 to capture transit activity (interpolated to the model years from transit fractions from the RTP-TIP). The link-level emissions were also adjusted slight ly downward as shown in Table 2-9 to capture impacts from TCMs.

Table 2-9. Adjustment factor to scale link-level emissions to account for mass transit. Year Transit Adjustment Factor TCM Adjustment Factor 2006 1.004962 

### 0.9996 2010 1.003913 

### 0.9996 2015 1.003553 

### 0.9995 2020 1.003192 

### 0.9995 2030 1.002471 

### 0.9995

2.3.3 Future Year Link-Level Running Emissions

The TransCAD link level volumes were first adju sted by the count corr ection factor and the HPMS adjustment. Then, they were disaggregat ed to hourly volumes. The speed was adjusted using the hourly volume to capacity ratio in th e BPR curve. The MOBILE6 emission factor for that hour and adjusted speed was multiplied by th e hourly link volume to get hourly emissions. The hourly emissions were further adjusted to December, day of week, transit activity, and TCM’s in CNTLEM within the EPS3 processing . Figure 2-8 shows the resulting hourly 2006 VMT.

Tables 2-10 through 2-14 present tabulations of VMT by facility type for each future year, as directly reported by Tran sCAD, and after the adjust ments described above.

2.3.4 Future Year Start Emissions

The start emissions were calculated in the same manner as was done for the base year. For Monday, the hourly VMT was estimated by disaggregating the period VMT to hourly VMT using the weekday VMT distributi on show in Figure 2-3. The star t emissions were calculated by multiplying the hourly VMT by the hourly MOBILE6 start emission factors. The hourly link start emissions were then totaled over the entire network and redistributed to TAZ, based on the fraction of period-specific trip origins for each TAZ over the total number of trip origins over all TAZs. For Sunday, the TransCAD data is not repres entative of a typical weekend profile, so the hourly VMT was estimated by first totaling all th e period VMT to a daily value, then it was distributed to hourly values using the weekend pr ofile in Figure 2-3. The Sunday start emissions were then calculated by multiplying the hourly VMT by the MOBILE6 hourly emission factors for all hours. The emissions were totaled over the entire network and then spatially distributed to each TAZ using a single ratio of the daily total TAZ trip origins to the daily total of all trip origins over the domain.August 2005Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_2_Onroad.doc2-20Table 2-10.2006 VMT by facility type. Totals are shown as outputby TransCAD, and after seasonal, day-of-week, and publictransit adjustments.Group CodeFacility TypeModeled2006DVMTDVMTCorrected toCountDVMTCorrected toHPMSDVMTAdjusted toDecemberDVMTAdjusted forTransitSundayDVMTMondayDVMT0 External Connector 621,151 613,697 622,596 635,671 637,546 465,408 637,5461 System Ramp 288,128 284,671 288,798 294,863 295,733 215,885 295,7332 Minor Arterial 2,777,828 3,032,555 3,076,527 3,141,134 3,150,401 2,299,793 3,150,4013 Major Arterial 16,612,275 18,135,621 18,398,587 18,784,958 18,840,373 13,753,473 18,840,3734Freeway on- or offramp962,346 950,798 964,585 984,841 987,746 721,055 987,7465 Interstate 8,341,200 8,241,106 8,360,602 8,536,174 8,561,356 6,249,790 8,561,3566 Freeway 3,088,561 3,051,499 3,095,745 3,160,756 3,170,080 2,314,159 3,170,0807 Expressway 142,816 141,103 143,149 146,155 146,586 107,008 146,5868 Collector 1,416,105 1,545,961 1,568,378 1,601,314 1,606,038 1,172,407 1,606,0389 Centroid Connector 2,738,699 2,989,838 3,033,191 3,096,888 3,106,024 2,267,397 3,106,024Intrazonal 87,303 87,303 88,569 90,429 90,696 66,208 90,696Daily Total 37,076,414 39,074,152 39,640,727 40,382,753 40,501,883 29,566,374 40,501,883Transit adjustment 1.004962HPMS adjustment 1.0145December adjustment 1.021Sunday adjustment 0.73Monday adjustment 1August 2005Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_2_Onroad.doc2-21Table 2-11.2010 VMT by facility type. Totals are shown as outputby TransCAD, and after seasonal, day-of-week, and publictransit adjustments.Group CodeFacility TypeModeled2010DVMTDVMTCorrected toCountDVMTCorrected toHPMSDVMTAdjusted toDecemberDVMTAdjusted forTransitSundayDVMTMondayDVMT0 External Connector 611,100 603,767 612,521 625,384 627,229 457,877 627,2291 System Ramp 427,211 422,084 428,204 437,197 438,486 320,095 438,4862 Minor Arterial 3,472,785 3,791,239 3,846,212 3,926,982 3,938,567 2,875,154 3,938,5673 Major Arterial 19,347,711 21,121,896 21,428,164 21,878,155 21,942,696 16,018,168 21,942,6964 Freeway on- or off-ramp 1,264,307 1,249,136 1,267,248 1,293,860 1,297,677 947,304 1,297,6775 Interstate 10,176,081 10,053,968 10,199,750 10,413,945 10,444,666 7,624,606 10,444,6666 Freeway 5,650,830 5,583,020 5,663,974 5,782,917 5,799,977 4,233,983 5,799,9777 Expressway 525,996 519,684 527,219 538,291 539,879 394,111 539,8798 Collector 2,013,021 2,197,615 2,229,481 2,276,300 2,283,015 1,666,601 2,283,0159 Centroid Connector 3,525,078 3,848,327 3,904,128 3,986,115 3,997,874 2,918,448 3,997,874Intrazonal 156,061 156,061 158,324 161,649 162,126 118,352 162,126Daily Total 47,170,180 49,546,797 50,265,226 51,159,147 51,310,066 37,456,348 51,310,066Transit adjustment 1.003913HPMS adjustment 1.0145December adjustment 1.021Sunday adjustment 0.73Monday adjustment 1August 2005Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_2_Onroad.doc2-22Table 2-12.2015 VMT by facility type. Totals are shown as outputby TransCAD, and after seasonal, day-of-week, and publictransit adjustments.Group CodeFacility TypeModeled2015DVMTDVMTCorrected toCountDVMTCorrected toHPMSDVMTAdjusted toDecemberDVMTAdjusted forTransitSundayDVMTMondayDVMT0 External Connector 621,151 613,697 622,596 635,671 637,546 465,408 637,5461 System Ramp 476,926 471,203 478,035 488,074 489,514 357,345 489,5142 Minor Arterial 3,964,841 4,328,417 4,391,179 4,483,394 4,496,620 3,282,532 4,496,6203 Major Arterial 21,843,415 23,846,456 24,192,229 24,700,266 24,773,132 18,084,386 24,773,1324 Freeway on- or off-ramp 1,313,314 1,297,554 1,316,369 1,344,013 1,347,978 984,024 1,347,9785 Interstate 11,023,875 10,891,588 11,049,516 11,281,556 11,314,837 8,259,831 11,314,8376 Freeway 6,542,175 6,463,669 6,557,392 6,695,097 6,714,848 4,901,839 6,714,8487 Expressway 1,599,742 1,580,545 1,603,463 1,637,136 1,641,966 1,198,635 1,641,9668 Collector 2,354,214 2,570,095 2,607,361 2,662,116 2,669,969 1,949,077 2,669,9699 Centroid Connector 4,088,071 4,462,947 4,527,660 4,622,740 4,636,377 3,384,556 4,636,377Intrazonal 145,409 145,409 147,517 150,615 151,060 110,274 151,060Daily Total 53,973,132 56,671,581 57,493,319 58,550,063 58,722,786 42,867,634 58,722,786Transit adjustment 1.003553HPMS adjustment 1.0145December adjustment 1.021Sunday adjustment 0.73Monday adjustment 1August 2005Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_2_Onroad.doc2-23Table 2-13.2020 VMT by facility type. Totals are shown as outputby TransCAD, and after seasonal, day-of-week, and publictransit adjustments.Group CodeFacility TypeModeled2020DVMTDVMTCorrected toCountDVMTCorrected toHPMSDVMTAdjusted toDecemberDVMTAdjusted forTransitSundayDVMTMondayDVMT0 External Connector 641,546 633,848 643,039 656,542 658,479 480,690 658,4791 System Ramp 491,767 485,866 492,911 503,262 504,747 368,465 504,7472 Minor Arterial 4,433,933 4,840,525 4,910,712 5,013,837 5,028,628 3,670,899 5,028,6283 Major Arterial 23,282,398 25,417,394 25,785,946 26,327,451 26,405,117 19,275,735 26,405,1174 Freeway on- or off-ramp 1,403,726 1,386,881 1,406,991 1,436,538 1,440,776 1,051,766 1,440,7765 Interstate 12,148,354 12,002,574 12,176,611 12,432,320 12,468,996 9,102,367 12,468,9966 Freeway 7,019,517 6,935,283 7,035,844 7,183,597 7,204,789 5,259,496 7,204,7897 Expressway 1,612,455 1,593,105 1,616,205 1,650,146 1,655,014 1,208,160 1,655,0148 Collector 2,596,741 2,834,862 2,875,968 2,936,363 2,945,025 2,149,869 2,945,0259 Centroid Connector 4,383,208 4,785,148 4,854,533 4,956,478 4,971,100 3,628,903 4,971,100Intrazonal 167,472 167,472 169,900 173,468 173,980 127,005 173,980Daily Total 58,181,118 61,082,958 61,968,661 63,096,535 63,282,670 46,196,349 63,282,670Transit adjustment 1.003192HPMS adjustment 1.0145December adjustment 1.021Sunday adjustment 0.73Monday adjustment 1August 2005Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_2_Onroad.doc2-24Table 2-14.2030 VMT by facility type. Totals are shown as outputby TransCAD, and after seasonal, day-of-week, and publictransit adjustments.Group CodeFacility TypeModeled2030DVMTDVMTCorrected toCountDVMTCorrected toHPMSDVMTAdjusted toDecemberDVMTAdjusted forTransitSundayDVMTMondayDVMT0 External Connector 678,697 670,552 680,275 694,561 696,610 508,525 696,6101 System Ramp 548,440 541,859 549,716 561,260 562,915 410,928 562,9152 Minor Arterial 5,394,312 5,888,971 5,974,361 6,099,822 6,117,817 4,466,006 6,117,8173 Major Arterial 26,825,037 29,284,892 29,709,523 30,333,423 30,422,907 22,208,722 30,422,9074 Freeway on- or off-ramp 1,580,942 1,561,971 1,584,619 1,617,896 1,622,669 1,184,548 1,622,6695 Interstate 13,368,302 13,207,882 13,399,396 13,680,784 13,721,142 10,016,434 13,721,1426 Freeway 8,306,442 8,206,765 8,325,763 8,500,604 8,525,681 6,223,747 8,525,6817 Expressway 598,066 590,889 599,457 612,046 613,852 448,112 613,8528 Collector 3,079,919 3,362,348 3,411,102 3,482,735 3,493,009 2,549,897 3,493,0099 Centroid Connector 5,034,875 5,496,573 5,576,273 5,693,375 5,710,170 4,168,424 5,710,170Intrazonal 171,308 171,308 173,792 177,442 177,965 129,914 177,965Daily Total 65,586,340 68,984,010 69,984,278 71,276,506 71,486,772 52,185,344 71,486,772Transit adjustment 1.002471HPMS adjustment 1.0145December adjustment 1.021Sunday adjustment 0.73Monday adjustment 1August 2005

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### 2-25 Figure 2-8. 2006 hourly vehicle miles trav eled (VMT) for Sunday and Monday.



### The future year start emissions were calculate d twice; once using the MOBILE6 emission factors generated using the sdist.lv hourly start distri bution (Figure 2-1), and once using the MOBILE6 emission factors generated using the modified start distribution discussed above to reflect the activity along the Las Vegas Boulevard.

The hourly TAZ start emissions were spatially allocated to the grid cell containing the TAZ centroid and the 24 surrounding cells in a “weddi ng cake” fashion: the grid cell containing a TAZ centroid receives 25% of the start emission s from that TAZ, the surrounding 8 grid cells receive 60% of the start emissions (7.5% per cell), and the outsid e 16 grid cells receive 15% of the start emissions (0.9375% per cell). This approach was reviewed by EPA Region IX and the Office of Transportation and Air Quality (EPA Region IX, pers onal communication).

2.3.5 Future Year Intrazonal Activity

The intrazonal VMT was calculated assuming a defau lt length of 1 mile for each intrazonal trip (as is described in the 2004-2005 Regional Tr ansportation Plan documentation [FY 2004-2025 RTP and FY 2004-2006 TIP, Chapter 5, page 5-16]). 0 500 1000 1500 2000 2500 3000 3500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hourmiles/1000

Mon VMT Sun VMTAugust 2005

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### 2-26 2.3.6 Future Year Total Emissions

Table 2-15 lists the component and total on-road mobile source emi ssions for all future years. Figures 2-9 through 2-13 present th e future year spatial distributi on of the total on-road mobile source emissions for December 9, 1996.

Table 2-15. Component and total on-road mobile source CO emissions (TPD) for all future years. 2006 2010 2015 2020 2030 Sunday 12/8/2005 Links - Running 149.64 150.26 137.32 133.15 142.66 Starts 125.10 135.93 138.46 139.23 152.54 Intrazonals 0.57 0.82 0.66 0.71 0.70
Total 275.30 287.01 276.44 273.09 295.90 Monday 12/9/2005 Links - Running 204.62 205.29 187.70 182.00 194.67 Starts 235.73 257.33 262.53 264.10 289.81 Intrazonals 0.88 1.33 1.07 1.14 1.13
Total 441.23 463.95 451.30 447.24 485.61August 2005

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### 2-27 Figure 2-9. Spatial distribution of total on-road mobile source CO emissions for the 2006 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7



### ONROAD Emissions Future Year - Dec 9, 2006 CO (tons per day)August 2005

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### 2-28 Figure 2-10. Spatial distribution of total on-road mobile source CO emissions for the 2010 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7



### ONROAD Emissions Future Year - Dec 9, 2010 CO (tons per day)August 2005

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### 2-29 Figure 2-11. Spatial distribution of total on-road mobile source CO emissions for the 2015 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7



### ONROAD Emissions Future Year - Dec 9, 2015 CO (tons per day)August 2005

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### 2-30 Figure 2-12. Spatial distribution of total on-road mobile source CO emissions for the 2020 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7



### ONROAD Emissions Future Year - Dec 9, 2020 CO (tons per day)August 2005

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### 2-31 Figure 2-13. Spatial distribution of total on-road mobile source CO emissions for the 2030 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7



### ONROAD Emissions Future Year - Dec 9, 2030 CO (tons per day)August 2005

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### 3-1 3. OTHER EMISSION CATEGORIES

3.1 NON-ROAD CATEGORIES

3.1.1 Airports

In 1999, Clark County and their contractor Rico ndo and Associates de veloped a detailed emissions inventory at the three county civ il airports (McCarran, North Las Vegas, and Henderson), and performed dispersion modeling using the Federal Aviation Administration’s (FAA) EDMS model. At the time, EDMS ha d MOBILE5a embedded as the source of on-road mobile emissions generation, and used PAL2 and CALINE3 for dispersion calculations. EDMS was run for the 1996 base year, along with the future years of 2000, 2010, and 2020. UAM results were used to provide the larger scal e "background" CO levels. The combination of UAM-predicted grid cell concentrations from the 2000 SIP submittal, plus EMDS-predicted receptor concentrations, were used for the airp ort microscale analyses. The UAM+EDMS results showed no 8-hour CO exceedances at any EDMS receptor (Ricondo, 1999).

In 2003, Clark County sponsored an updated EDMS project for the three county airports. The latest version of EDMS was used, which introduced the AE RMOD dispersion model. On-road mobile sources were estimated using Clark County runs of MOBILE 6.2. EDMS was run for 2000, 2005, 2010, 2015 and 2020 (the 1996 base year wa s skipped). UAM results were not added to the EDMS receptor results. The revi sed modeling resulted in predictions above the 8- hour CO standard at several receptors in all years (Ricondo, 2003); however, these were located in "non-public access" areas (pri marily aircraft docking areas, apron, etc.), as documented by Ricondo (2005). EPA has indicated that it will accept the removal of receptors in non-public access areas from consideration.

To properly account for the contribu tions of airports toward the valley-wide dist ribution of CO during the December 8-9 episode, UAM needs to include the updated EDMS airport emissions within the gridded inventory. Airport emissi ons for 1996 were taken from the Ricondo (1999) estimates, while emissions for the 2010, 2015, and 2020 future years were taken from the updated Ricondo (2003) estimates. Emission es timates for 2006 were derived by linearly interpolating total airport emissions from 2005 and 2010, while emission estimates for 2030 were derived by linearly extrapolat ing total airport emissions from 2015 and 2020. Annual airport emissions are shown in Table 3-1. Note that original 2000 SIP emission estimates for Nellis AFB were retained in the UAM modeling.

3.1.1.1 Temporal and Spatial Allocation

The EDMS CO emission estimates are reported as t ons per year. Therefore it was necessary to disaggregate these estimates to December, Sunday and Monday, and to each hour of the day. Clark County provided activity data for these airports on which to base the disaggregation from annual to hourly emission rates.August 2005

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### 3-2 Table 3-1. Annual airport CO emission estimates (tons per year) reported by Ricondo (1999) for the 1996 base year, and by Ricondo (2003) for future years 2010, 2015, and 2020 (2006 and 2030 estimated as described in the text). Year McCarran Henderson North Las Vegas 1996 10,022 536 2,727 2006 11,600 646 1,848 2010 13,494 762 1,880 2015 15,482 949 1,924 2020 17,553 1,220 1,971 2030 21,695 1,762 2,063



### Factors to translate from annual to December em issions are provided in Table 3-2. The same day-of-week activity factors were given for Hende rson and North Las Vegas airports to translate from monthly estimates to specific days: 3.2% for Sunday, and 2.5% for Monday. No dayspecific factors were given for McCarran airport, so a constant day-of-week profile was applied. Figure 3-1 shows the hourly distri bution applied to McCa rran airport, while Figure 3-2 shows the hourly distribution applied for both He nderson and North Las Vegas airports.

Table 3-2. Monthly factors used to disaggregate annual airport CO emissions to monthly totals. The factors for December were used in this study. Month McCarran Henderson North Las Vegas January 7.75% 8.46% 6.25% February 7.61% 9.13% 7.27% March 8.86% 10.26% 7.20% April 8.47% 9.00% 7.13% May 8.70% 10.16% 9.35% June 8.40% 8.37% 7.82% July 8.43% 7.11% 8.32% August 8.67% 7.18% 8.53% September 8.47% 7.84% 9.49% October 9.01% 8.71% 10.40% November 8.10% 7.38% 9.76% December 7.54% 6.40% 8.48%



### Airport emissions were placed evenly across the grid cells in which the airpor ts reside. Note that in this project we expanded the definition of Mc Carran airport from two cells (as treated in the 2000 SIP modeling) to twelve cells, based on grid overlays upon aerial photogr aphs of the airport layout (Figure 3-3). The single hos t cell for North Las Vegas airpor t was shifted one cell east to better locate that property relative to the near by roadways. The location of Henderson was not changed from the original location.August 2005

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### 3-3 Figure 3-1. Hourly activity at McCarran airport used to temporally allocate daily emissions for all years modeled.

Figure 3-2. Hourly activity at Henderson and North Las Vegas airports used to temporally allocate daily emissions for all years modeled. 0% 1% 2% 3% 4% 5% 6% 7% 8% 9%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
HourFraction

0% 2% 4% 6% 8% 10% 12%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
HourFractionAugust 2005

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### 3-4 Figure 3-3. Arial photograph of McCarran airport with UAM grid cells overlaid.



### Airport grid cells are defined as follows:

McCarran (i,j) (24,21) (24,22) (24,23),(24,24) (25,21) (25,22) (25,23),(25,24) (26,21) (26,22) (27,21) (27,22)

North Las Vegas (i,j) (21,36)

Henderson (i,j) (27,10)

3.1.2 Locomotives

Clark County has updated railroad emissions for 2001 based on a Mactec non-road study (Mactec, 2003). These updated emission estimates we re incorporated into this work. The base year emissions estimates were taken from Table 3-33 of the Mact ec report. Locomotive emissions from the Mactec report include both lin e haul and switching. For switching, emissions are placed at the same two facilitie s as modeled previously. The grid cells for these facilities are:

Civic Center Yard (i,j) (24,29) (24,30) ( 25,30) (25,31) (25,32)

Boulder Junction Wye (i,j) (21,20) (21,21) (21,22) (21,23)August 2005

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### 3-5 These locations are modeled as zero length link sources. For the line haul, the locomotive emissions were put into grid ce lls using coordinates defined fro m the rail map provided by Clark County. Each segment is defined by two node endpoints with the emissions of each segment distributed equally along the line between each node.

3.1.2.1 Locomotive Projections

Projecting locomotive emissions requires two estima tes: activity growth a nd effects of emissions control through fleet tur nover with EPA engines. Only Union Pacific operates locomotives in Clark County, so Union Pacific may have more accura te figures of historic usage for the specific rail segments in Clark County. However, conduc ting a survey of this historic usage was beyond the scope of this project.

The locomotive activity unit most useful for emis sion evaluation is fuel consumption. Projected fuel consumption from locomotive use is difficu lt to estimate especially for a given track segment such as through Clark County. The fuel consumption depends on factors not exclusively restricted to the num ber of trains, tons of freight, or business indicators because of efficiency improvements to the trains or operations.

To project the locomotive activity increases due to the growth in business, a time series plot of the available fuel consumption data was used. Three sources of fuel consumption data were available: online data purchased from the Amer ican Association of Railroads (AAR) for the years 1999 and 2002 (AAR, 2004), the AAR ten y ears trends report for 1990 through 1999 (AAR, 2000), and estimates from the Energy Information Administration (EIA) of the Department of Energy that track fuels consump tion by end use (EIA, 2005). As shown in Figure 3-4, the EIA data does not match at all the AAR figures so these were ignored. The AAR online data provides fuel consumption estimates for i ndividual railroads and has a total of the largest railroads called Class 1 railroads, of which Union Pacific is the largest. The most recent trend between 1999 and 2001 for Union Pacific indica tes a 1.9% per year increase in fuel consumption. While basing a growth estimate with only two years of data is suspect, the 1.9% per year growth rate mirrors the US total growth rate of 2.0% for 1990 through 1999 and 1.5% for the period of 1990 through 2002.

The emissions were projected using the EPA’s estimat es of the effect of fleet turnover. Table 3- 3 shows the percent reduc tion in emissions for Class 1 line-haul and switching engines due to the Federal standard (EPA, 1997). Combining the projected growth from fuel consumption estimates with the expected emission reductions fro m engine controls, the emissions relative to 1996 were calculated and shown in Table 3-4.

The 1996 railroad maintenance emissions were estimated with EPA’s NONROAD Model, which is discussed in detail in the fo llowing subsection. These estima tes were processed and reported separately. The 1996 base case railroad mainte nance emissions were projected based on the locomotive projections presented in Table 3-4.August 2005

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### 3-6 Figure 3-4. Available locomotive fuel consumption trends.

Table 3-3. Locomotive emission reductions due to EPA regulations (EPA, 1997). Year HC CO NOx PM Class 1 Line-Haul 1996 0.0% 0.0% 0.0% 0.0% 2002 0.1% 0.0% 11.8% 0.0% 2006 7.5% 0.0% 37.6% 7.7% 2010 17.8% 0.0% 46.1% 18.7% 2015 24.1% 0.0% 49.7% 25.4% 2020 30.0% 0.0% 53.1% 31.8% 2025 35.4% 0.0% 56.2% 37.6% Switching Engines 1996 0.0% 0.0% 0.0% 0.0% 2002 0.0% 0.0% 1.7% 0.0% 2006 1.1% 0.0% 8.9% 1.3% 2010 3.6% 0.0% 16.7% 4.2% 2015 7.3% 0.0% 27.1% 8.3% 2020 11.4% 0.0% 33.3% 13.1% 2025 16.2% 0.0% 38.1% 18.5% 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

1988 1990 1992 1994 1996 1998 2000 2002 2004

YearMillions of Gallon per Year

AAR Online
AAR 10-Year Trend
DOE - EIA
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### 3-7 Table 3-4. Locomotive emissions relative to 1996. Year HC CO NOx PM Class 1 Line-Haul 1996 1 1 1 1 2002 1.12 1.12 0.99 1.12 2006 1.12 1.21 0.75 1.12 2010 1.07 1.30 0.70 1.06 2015 1.09 1.43 0.72 1.07 2020 1.10 1.57 0.74 1.07 2025 1.12 1.73 0.76 1.08 Switching Engines 1996 1 1 1 1 2002 1.12 1.12 1.10 1.12 2006 1.19 1.21 1.10 1.19 2010 1.26 1.30 1.08 1.25 2015 1.33 1.43 1.04 1.31 2020 1.39 1.57 1.05 1.37 2025 1.45 1.73 1.07 1.41



### 3.1.3 Other Non-Road Categories

3.1.3.1 NONROAD Model Equipment Estimates

Weekday and weekend emissions were estima ted using EPA’s NONROAD Model (Core Model Ver. 2.3c, Apr 2004). For the Clark County base year inventory, the period type was set to Winter Season, and emissions we re reported as tons per day.

Table 3-5 summarizes the input parameters sp ecified for the 1996 Clark County base year NONROAD Model runs. The temperatures used for the NONROAD modeling were the same as the modeling temperatures used for the previ ous Clark County SIP modeling work. Gasoline fuel RVP, oxygen weight %, gasoline sulfur leve l, and CNG/LPG sulfur levels were those used in 1996 modeling for Clark County in work pe rformed by ENVIRON for the Western Regional Air Partnership (Pollack et al., 2004). From discussions with Clark County, the non-road diesel sulfur level for 1996 was set at 250 ppm for this m odeling. In addition, it was agreed that Clark County would be modeled as a “Southwest” regi on instead of the EPA default “Central West” region and the NONROAD model seasonality file (containing temporal adjustment data), SEASON.DAT, was modified to reflect this decision.

Similar NONROAD Model (Core Model Ver. 2.3c , Apr 2004) weekday and weekend runs were performed for the five future years ( 2006, 2010, 2015, 2020, 2030) for Clark County. Table 3-6 summarizes the NONROAD Model input parameters for each future year. Temperature and CNG/LPG sulfur level inputs were not changed from the base year. From discussions with Clark County, the oxygen weight % was set to 3.5% for all the future years based on local regulations. The gasoline sulfur level was set to 30 ppm for a ll future years and the n on-road diesel sulfur level was set to 250 ppm for 2006 and 15 ppm fo r subsequent future years, per federal regulation. Similar to the base year, Clark County was modeled as a “Southwest” region instead of the default “Central West” region.August 2005

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### 3-8 Table 3-5. Summary of inputs used for NONROAD modeling for 1996. 1996 Weekday (tons/day) Weekend (tons/day) Period Type Seasonal Seasonal Summation Type Typical Day Typical Day Year of Episode 1996 1996 Season of Year Winter Winter Weekend or Weekday Weekday Weekend Fuel RVP for gas 9 9 Oxygen Weight % 3.31 3.31 Gas sulfur % 0.009 0.009 Diesel sulfur % 0.025 0.025 CNG/LPG sulfur % 0.003 0.003 Minimum temper. (F) 42 42 Maximum temper. (F) 66 66 Average temper. (F) 51.875 51.875 Altitude of region low Low

Table 3-6. Summary of inputs used for NONROAD modeling future years.

2006 2010 2015 2020 2030
Weekday

(tpd) Weekend (tpd) Weekday (tpd) Weekend (tpd) Weekday (tpd) Weekend (tpd) Weekday (tpd) Weekend (tpd) Weekday (tpd) Weekend (tpd) Period Type Monthly Monthly Monthly Monthly Monthly Monthly Monthly Monthly Monthly Monthly

Summation Type Typical Day Typical Day Typical Day Typical Day Typical Day Typical Day Typical Day Typical Day Typical Day Typical Day Year of Episode 2006 2006 2010 2010 2015 2015 2020 2020 2030 2030
Month of Year Dec. Dec. Dec. Dec. Dec. Dec. Dec. Dec. Dec. Dec. Weekend or weekday Weekday Weekend Weekday W eekend Weekday Weekend Weekda y Weekend Weekday Weekend Fuel RVP for gas 9 9 9 9 9 9 9 9 9 9 Oxygen Weight % 3.50 3.50 3.50 3.50 3.50 3.50 3.50 3.50 3.50 3.50
Gas sulfur % 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003
Diesel sulfur % 0.025 0.025 0.0015 0.0015 0.0015 0.0015 0.0015 0.0015 0.0015 0.0015
CNG/LPG sulfur % 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 Minimum temper. (F) 42 42 42 42 42 42 42 42 42 42 Maximum temper. (F) 66 66 66 66 66 66 66 66 66 66 Average temper. (F) 51.9 51.9 51.9 51.9 51.9 51.9 51.9 51.9 51.9 51.9 Altitude of region low low low low low low low low low low



### Airport ground support equipment (GSE) wa s removed from the NONROAD emissions estimates because they were handled separa tely, as described above in Section 3.1.1. Recreational marine estimates were also removed since the major water ar eas in Clark County lie outside of the modeling domain. Railroad main tenance emissions for the 1996 base case were extracted from the non-road output and processed with locomotive emissions.

Table 3-7 presents a summary of NONROAD model CO emissions estimates for the base year and all future years evaluated in this modeling. The NONROAD model estimates emissions for the entirety of Clark County; the emissions shown in Table 3-7 are those for the modeling domain only. The gridding approach is described in the next subsection.August 2005

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### 3-9 Table 3-7. Clark County CO NONROAD gridded emission estimates (TPD). Base 2006 2010 2015 2020 2030 Sunday 12/8/2005 Recreational 2.47 2.40 2.44 2.52 2.58 2.72 Construction and Mining 17.47 1.28 0.99 0.80 0.68 0.59 Industrial 1.80 1.34 0.95 0.41 0.25 0.24 Lawn & Garden 33.56 32.61 36.28 39.97 43.58 50.70 Agriculture 0.00 0.00 0.00 0.00 0.00 0.00 Commercial 10.82 12.91 14.86 16.98 19.12 23.23 Total 66.13 50.53 55.52 60.68 66.22 77.48 Monday 12/9/2005 Recreational 1.24 1.20 1.22 1.26 1.29 1.36 Construction and Mining 34.94 2.56 1.98 1.60 1.36 1.18 Industrial 3.36 2.54 1.74 0.69 0.46 0.43 Lawn & Garden 42.22 42.24 46.32 51.03 55.66 64.78 Agriculture 0.00 0.00 0.00 0.00 0.00 0.00 Commercial 21.64 25.82 29.72 33.97 38.24 46.45
Total 103.40 74.36 80.98 88.55 97.02 114.20



### 3.1.3.2 Base Year Gridding Surrogates

Base year emission estimates were allocated to the modeling grid cells using spatial surrogates developed from land use acreage obt ained from the Clark County RTC. These surrogate data were the same that were used in the 2000 SI P submittal. However, since the NONROAD Model generates more source categories than were orig inally used in the 2000 SIP, additional surrogates were developed for this base inventory. Tables 3-8 and 3-9 indicate the categories provided by Clark County and the surrogate category mapping used for the base inventory.

The original Clark County land use data set cove rs the UAM modeling domain for the Las Vegas urban growth area while the NONROAD emissions estim ates are county totals. Therefore, an additional set of county-wide landuse data provide d by RTC was used to estimate the fraction of each category that was allocated to the modeling gr id. Table 3-10 lists the surrogates that were used to spatially allocate each of the NONRO AD source categories to the UAM grid, and the fraction of county surrogate within the modeling domain.

3.1.3.3 Future Year Gridding Surrogates

Future-year emissions estimates were allocated to the modeling grid cells using a different set of spatial surrogates that were de veloped from an updated land us e database obtained from the Clark County RTC. The updated land use data were developed for the year 2003 and characterized the land use in th e entire county based on the desc riptions given in Table 3-11. Figure 3-5 displays a subset of these data for the Las Vegas area as aggregated land use categories for clarity.August 2005

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### 3-10 Table 3-8. Base year non-road surrogate categories. Category Description Rural 1-2 units per acre Low Density 3-5 units per acre Medium 6-8 units per acre Medium High 9-18 u/ac, single level apts., some trailer, multi-family low High Density 7-18 u/ac, multi-level apartments, some trailer parks Neighborhood Retail grocery, convenience, restaurants, service station, etc. Community Retail large shopping centers Regional Retail small shopping malls, factory outlet Resort Casino casinos with table gaming Office office complexes, government, medical, banking, etc. Light Industrial small manufacturing, repair, warehousing, etc. Heavy Industrial cement plants, steel, BMI complex, larger manufacturing Government non-office building government (fire, police, bus yard) Education schools and attached parks Hospitals hospitals only Parks and Golf Courses free standing parks (incl. buildings) Public Facilities limited trip generators (landfill, utility facilities) Open Space drainages and other un-developable land Mining gravel pits, excavation projects Religion churches, etc. Special Generators UNLV, McCarran Airport, Nellis AFB, etc. Vacant land that can be developed Agriculture farmingAugust 2005

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### 3-11 Table 3-9. Land use category to surrogate code mapping. Surrogate Code Surrogate Description Based on 1995 LULC categories 1 Housing rural + low density + medium + medium high + high density 2 Industrial light industrial + heavy industrial 3 Commercial neighborhood retail + community retail + regional retail

4 Buildings above Housing + above Commercial + above Industrial + casinos + office + government + education + hospitals + public facilities + religion
5 Land area land area 6 Casinos resort and casinos

7 Recreational Space open space + mining + vacant

8 Commercial Lawn & Garden neighborhood retail + community retail + regional retail + parks and golf courses 9 Golf Courses parks and golf courses 10 Agriculture agriculture
11 Vacant Land vacant land 12 Population density weighted housing

Table 3-10. Source category cross references to gridded surrogates for NONROAD sources with county-to-modeling grid adjustment factors. Surrogate Code SCC Adjustment Factor Description Surrogate Description 1 22xx004xxx 0.950 Lawn & Ga rden Equipment Housing 2 22xx003xxx 0.786 Industrial Equipment Industrial 3 22xx006xxx 0.786 Light Commercial Commercial
7 22xx001xxx 0.244 Recreational Vehicles Recreational Space 8 22xx004yyy 0.802 Lawn and Garden Equipment (Commercial) Comm ercial Lawn & Garden 9 22xx001050 0.802 Recreational Vehicles, Golf Carts Golf Courses 10 22xx005xxx 0.113 Farm Equipment Agriculture 11 22xx002xxx 0.958 Construction Equipment Vacant LandAugust 2005

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### 3-12

Table 3-11. Land use categories available in the Clark County GIS data coverages for 2003.
# LU_TDFM NOTE DENSITY AVG
1 RRes Residential - Rural < 2 2.0
2 LDRes Residential - Low Density >= 2, < 6 5.0 3 MDRes Residential - Mid Density >= 6, < 8 6.0
4 MHDRes Residential - Mid-High Density >= 8, < 13.5 12.0
5 HDRes Residential - High Density >= 13.5 16.0 6 Hotel_R Hotel&Resort
7 Hotel_H Hotel 8 Casino Casino 9 RRet Retail - Regional 10 CRet Retail - Community
11 NRet Retail - Neighborhood
12 CarSale Retail - Auto Dealership 13 ORet Retail - Race Track, etc
14 Office Office 15 Hospital Hospital and Medical Center 16 School School
17 Religiou Religious 18 P_F Police and Fire Station
19 Trans_1 Transportation - Terminal, Depot, etc 20 Warehous Warehouse
21 REC_O Recreational - out door (golf course, race track)
22 REC_I Recreational - indoor 23 REC_RP Recreational - RV Park
24 Parking Parking lot, garage 25 OS Open Space
26 LInd Light Industrial
27 HInd Heavy Industrial 28 AgMining Agriculture, Ranching, Mining 29 ROW Right-Of-Way 30 PHeld Public Land Management Area\Public Held
31 NAFB Nellis AFB 32 MIA MaCarran Int'l Airport
33 UNLV UNLV 34 Vac VacantAugust 2005

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### 3-13 Figure 3-5. 2003 land use data for the Las Vegas area of Clark County.



### For future-year land use, Clark County provided GIS databases that specify which vacant land parcels in the 2003 dataset are to be devel oped for each of the planning years 2005, 2010, 2015, 2020, 2025 and 2030, as well as the planned land us e for that parcel. The land use planning databases included separate GIS coverages for Las Vegas, North Las Vegas, Henderson and the rest of Clark County. Land use coverages for eac h of the future years modeled were developed by replacing those vacant land parcels in the land use base-year datasets with the future year planned land use category. Each of the future year GIS databases was developed incrementally from the previous planning year starting fr om the 2003 land use base year database.

The Arc/INFO GIS was used to generate the requ ired spatial surrogate ratios for the development of gridding surrogates. Within the GIS, each futu re year land use coverage was overlayed with the modeling grid and the fraction of each land us e type in each grid cell was calculated. Because the land use categories available in the databases (Table 3-11) are more detailed than required for spatial allocation of emission estim ates, they were aggregated prior to the development of the surrogate ratios. Table 3-12 presents the aggregation scheme used for the project.

Table 3-13 provides a comparison of the domain-wi de percentage of primary land use categories used for allocation of non-road mobile source em issions for each of the future years modeled.August 2005

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### 3-14 Table 3-12. Landuse category aggregation used for developing spatial allocation surrogates for non-road categories. Surrogate Code Surrogate Description Based on 1995 LULC categories

1 Housing residential: rural + low + mid + mid-high + high density + single family + multi family 2 Industrial light industrial + heavy industrial + industrial

3 Commercial neighborhood retail + community retail + regional retail + racetrack retail + car sale retail

4 Buildings above Housing + above Industrial + above Commercial + hotels + casinos + office + government + education + hospitals + public facilities + religion 5 Land area land area 6 Casinos hotels + hotels&resort + casinos

7 Recreational Space recreational outdoor + open space + vacant land

8 Commercial Lawn & Garden neighborhood retail + community retail + regional retail + recreational_outdoor + hotel&resort + school + hospital 9 Golf Courses Recreational – outdoor 10 Agriculture Agriculture, Ranching and Mining 11 Vacant Land vacant land

Table 3-13. Comparison of domain-wide land use percentages for future year spatial allocation.

Year Housing Industrial Commercial Buildings Land Area Casinos Rec Space Comm L&G GolfCrses Agriculture Vacant 2005 0.812 0.611 0.741 0.775 0.120 0.845 0.091 0.793 0.794 0.140 0.086 2010 0.886 0.672 0.772 0.844 0.120 0.857 0.075 0.816 0.794 0.140 0.069 2015 0.895 0.702 0.788 0.853 0.120 0.870 0.071 0.826 0.794 0.140 0.064 2020 0.898 0.726 0.801 0.860 0.120 0.877 0.068 0.833 0.794 0.140 0.061 2025 0.901 0.736 0.806 0.864 0.120 0.881 0.066 0.837 0.794 0.140 0.059 2030 0.903 0.748 0.811 0.867 0.120 0.885 0.065 0.840 0.794 0.140 0.058 % of county total within modeling domain



### 3.1.3.4 Temporal Allocation

Figure 3-6 shows the hourly distribution used to temporally allocate non-road sources.

3.2 POINT SOURCES

The 1996 base year point source inventory from the original 2000 SIP modeling was used for this update. Clark County provided an updated po int source emission inventory for future years that included updated stack parameters and emissi ons based on “Potential To Emit” (PTE) levels for seven specific facilities. The UAM future ye ar inventories included PTE levels plus a 70 ton/year buffer for these sources. All future y ear modeling used the same future year point source data. Table 3-14 indicates the future year tons per year estimates by facility provided by Clark County. Table 3-15 shows a breakdown by elevated and low-level point sources.August 2005

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### 3-15 Figure 3-6. Hourly activity profile used to temporally allocate non-road emissions.

Table 3-14 . Clark County CO future year Potential To Emit (PTE) estimates + 70 TPY by facility.

Facility Name PTE + 70 (tons/Year) Nevada Power- Clark Station (NDEP) 620.9 Nevada Power- Clark Station (DAQM) 2106.9 Nevada Power - Sunrise Station (NDEP) 392.9 Nevada Power - Sunrise Station (DAQM) 463.5 Titanium Metals 1707.8 USAF - 99 CES/CEV 295.7 James Hardie Gypsum/BPB Gypsum, Inc 184.4 Total 5772.1

Table 3-15. Modeling CO point source emission estimates (TPD).
Base Future Years Elevated 2.07 15.53
Low Level 1.06 0.28
Total 3.13 15.82



### 3.3 AREA SOURCES

The 1996 base year area source estimates were taken from the 2000 SIP modeling with no changes. The base year emi ssions were projected by the fact ors shown in Table 3-16 to the future modeling years. These factors were de veloped by the Clark County Department of Air Quality and Environmental Management. Values were interpolated for those modeling years in between reported years. 0 0.02 0.04 0.06 0.08

0.1 0.121357911131517192123

HourAugust 2005

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### 3-16 Table 3-16. Future year growth/projection factors for area sources. Adjustment Factors Applied to Base Year Category Description 2006 2010 2015 2020 2030 Electric Utility Generati on 1.2312 1.3154 1.4101 1.5048 1.6942 Small Stationary 1.2632 1.3623 1.4738 1.5853 1.8083
Boiler Emissions 1.2632 1.3623 1.4738 1.5853 1.8083
Industrial Natural Gas 1.2636 1.3627 1.4743 1.5858 1.8089
Commercial Natural Gas 1.2291 1.3429 1.4331 1.5233 1.7037
Residential Natural Gas 1.1686 1.2329 1.2917 1.3504 1.4679 Fireplaces 1.5022 1.7254 2.0221 2.3187 2.9121 Railroad Equipment 0. 9479 0.9341 0.9186 0.9031 0.8722
Brush Fires 1.5022 1.7254 2.0221 2.3187 2.9121 Cigarette Smoking 1.5022 1.7254 2.0221 2.3187 2.9121
Structural Fires 1.5022 1.7254 2.0221 2.3187 2.9121
Vehicular Fires 1.5022 1.7254 2.0221 2.3187 2.9121



### 3.3.1 Area Source Gridding Surrogates

The 1996 base year area source emissions were spa tially allocated to the modeling domain using the same gridding surrogates that were develope d for the 2000 SIP. The future year gridding surrogates were based upon those developed for the non-road emission categories, as described in Section 3.1.3.3. The only change needed for area source categories was to normalize them relative to the modeling domain (i nstead of county total), since th e original area source emission estimates were wholly contained within the UAM domain.

A summary of area source emissions by category is provided in Table 3-17 for each future year.

3.4 SUMMARY OF TOTAL EMISSIONS

Table 3-18 presents a summary of total daily CO emissions by source category, including onroad emissions, for 1996 base and all future y ears. Figures 3-7 through 3-9 show the spatial distribution of component and to tal CO emissions for the 1996 ba se case. Figures 3-10 through 3-14 show the spatial distribution of to tal CO emissions for all future years.August 2005

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### 3-17 Table 3-17. Clark County CO area source gridded emission estimates (TPD) after season, and day-of-week adjustments.
Source Category Base 2006 2010 2015 2020 2030 Sunday 12/8 Electric Utility Generation 0.558 0.687 0.734 0.787 0.840 0.946 Small Stationary 2.701 3.412 3.680 3.981 4.283 4.885
Boiler Emissions 0.385 0.486 0.524 0.567 0.610 0.696
Industrial Natural Gas 0.148 0.186 0.201 0.218 0.234 0.267
Commercial Natural Gas 0.041 0.051 0.055 0.059 0.063 0.070
Residential Natural Gas 0.308 0.360 0.380 0.398 0.416 0.452 Fireplaces 3.033 4.556 5.233 6.133 7.033 8.832
Brush Fires 1.262 1. 896 2.178 2.552 2.927 3.675 Cigarette Smoking 0.044 0.066 0.076 0.089 0.102 0.128
Structural Fires 0.646 0.971 1.115 1.307 1.499 1.882
Vehicular Fires 0.054 0.081 0.093 0.110 0.126 0.158
Total 9.181 12.753 14.270 16.200 18.131 21.991 Monday 12/9 Electric Utility Generation 0.558 0.687 0.734 0.787 0.840 0.946 Small Stationary 2.701 3.412 3.680 3.981 4.283 4.885
Boiler Emissions 0.385 0.486 0.524 0.567 0.610 0.696
Industrial Natural Gas 0.369 0.466 0.503 0.544 0.585 0.667
Commercial Natural Gas 0.103 0.127 0.138 0.148 0.157 0.176
Residential Natural Gas 0.308 0.360 0.380 0.398 0.416 0.452 Fireplaces 3.033 4.556 5.233 6.133 7.033 8.832
Brush Fires 1.262 1. 896 2.178 2.552 2.927 3.675 Cigarette Smoking 0.044 0.066 0.076 0.089 0.102 0.128
Structural Fires 0.646 0.971 1.115 1.307 1.499 1.882
Vehicular Fires 0.054 0.081 0.093 0.110 0.126 0.158

Total 9.464 13.109 14.654 16.615 18.576 22.497August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-18 Table 3-18. Summary of total daily CO emissions (TPD) in the UAM CO SIP revision.
Base 2006 2010 2015 2020 2030 Sunday 12/8 On-Road Running (Links) 202.75 149.40 150.18 137.31 133.18 142.80 On-Road Starts 126.42 125.10 135.93 138.46 139.23 152.54 On-Road Intrazonals 0.78 0.57 0.82 0.66 0.71 0.70 Henderson Airport 1.12 1.35 1.59 1.99 2.55 3.69 McCarran Airport 24.69 28.57 33.24 38.14 43.24 53.44 Nellis AFB 2.86 2.86 2.86 2.86 2.86 2.86 North LV Airport 7.58 5.13 5.22 5.35 5.48 5.73 Area Sources 9.18 12.75 14.27 16.20 18.13 21.99 Non-road - NONROAD 66.13 50.49 55.50 60.66 66.21 77.44 Point Sources 3.13 15.82 15.82 15.82 15.82 15.82 Railway - Line Haul 0.14 0.17 0.19 0.20 0.22 0.27 Railway - Maintenance 0.03 0.04 0.04 0.04 0.05 0.06
Total 444.81 392.49 415.73 417.71 427.65 477.19 Monday 12/9 On-Road Running (Links) 269.31 204.62 205.29 187.70 182.00 194.67 On-Road Starts 241.09 235.73 257.33 262.53 264.10 289.81 On-Road Intrazonals 1.03 0.88 1.33 1.07 1.14 1.13 Henderson Airport 0.88 1.07 1.26 1.57 2.01 2.91 McCarran Airport 24.69 28.57 33.24 38.14 43.24 53.44 Nellis AFB 2.86 2.86 2.86 2.86 2.86 2.86 North LV Airport 5.98 4.05 4.12 4.22 4.32 4.52 Area Sources 9.46 13.11 14.65 16.62 18.58 22.50 Non-road - NONROAD 103.40 74.30 80.94 88.52 96.99 114.17 Point Sources 3.13 15.82 15.82 15.82 15.82 15.82 Railway - Line Haul 0.14 0.17 0.19 0.20 0.22 0.27 Railway - Maintenance 0.11 0.14 0.15 0.16 0.18 0.21
Total 662.08 581.31 617.17 619.41 631.46 702.31August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-19 Figure 3-7. Spatial distribution of airport and locomotive CO emissions for the 1996 Base Case. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5



### Airports and Rail Emissions Base Year - Dec 8, 1996 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-20 Figure 3-8. Spatial distribution of non-road and area source CO emissions for the 1996 Base Case. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.00 0.08 0.16 0.24 0.32 0.40 0.48 0.56 0.64 0.72



### Area and NONROAD Emissions Base Year - Dec 9, 1996 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-21

Figure 3-9. Spatial distribution of total surface gridded CO emissions for the 1996 Base Case. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4



### Total Surface Emissions Base Year - Dec 9, 1996 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-22 Figure 3-10. Spatial distribution of total surface gridded CO emissions for the 2006 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4



### Total Surface Emissions Future Year - Dec 9, 2006 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-23 Figure 3-11. Spatial distribution of total surface gridded CO emissions for the 2010 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4



### Total Surface Emissions Future Year - Dec 9, 2010 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-24 Figure 3-12. Spatial distribution of total surface gridded CO emissions for the 2015 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4



### Total Surface Emissions Future Year - Dec 9, 2015 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-25 Figure 3-13. Spatial distribution of total surface gridded CO emissions for the 2020 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4



### Total Surface Emissions Future Year - Dec 9, 2020 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_3_Other.doc 

### 3-26 Figure 3-14. Spatial distribution of total surface gridded CO emissions for the 2030 future year. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4



### Total Surface Emissions Future Year - Dec 9, 2030 CO (tons per day)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-1 4. URBAN AIRSHED MODELING

The Urban Airshed Model (UAM) was provided w ith the updated emission inventories for onroad mobile, non-road mobile, point and ar ea sources, and run for the December 8-9, 1996 historical CO event. All other environmental pa rameters were taken from the original modeling as documented in the 2000 CO SIP. A base -year CO model perfor mance evaluation was similarly conducted. The UAM was then used wi th the updated future year inventories for 2006, 2010, 2015, 2020 and 2030 to determine peak 8-hour CO levels in the basin for the same December 8-9, 1996 conditions.

For the future year assessments, we addresse d UAM valley-wide CO di stributions, intersection “hot spot” modeling with CAL3QHC, and the upd ated EDMS micro-scale results reported by Ricondo (2003). With regard to the airports, it was necessary to run UAM twice using two different inventories per future year:

1. Valley-wide CO and micro-scale inte rsection modeling – including updated EDMS emissions in the UAM; 2. Micro-scale airport CO m odeling – removing EDMS airport emissions from the UAM inventory in order to avoid double-counting.

EDMS results from the Ricondo (2003) analyses were combined with the revised UAM model predictions for the future years of 2006, 2010, 2015, 2020 to estimate 8-hour CO concentrations for the duration of the episode on and around the ai rport properties. This was not done for the 1996 base case since the EDMS dispersion results fo r that year are consid ered out-dated. Note that the 2005 EDMS results were added to the 2006 UAM results , and that 2030 was disregarded since it was not considered in the EDMS analysis.

For hotspot modeling, the CAL3QHC model wa s used to model th ree intersections: Charleston/Eastern, Charleston/Fr emont and Eastern/Fremont, whic h are referred to collectively as the “Five Points” area. EPA (1992, 1995) gui dance for screening level modeling of these three intersections was followed. The ambient te mperature for each hour of the episode (needed to estimate emissions with the MOBILE6 model) , and the wind direction and speed (needed for the CAL3QHC dispersion estimates) were take n from the original UAM/CAL3QHC modeling documented in the 2000 SIP. The same MOBILE6 inputs documented for the on-road emissions calculations in Section 2 were used to estimate emission input s for CAL3QHC. The CAL3QHC model output was added to the background UAM leve ls to estimate 8-hour CO concentrations for the duration of the episode.

Following the micro-scale analyses, additional an cillary simulations were run with UAM to develop on-road mobile emission budgets, both fo r the entire modeling domain and just the central urban portion, that demonstrate co mpliance with the 8-hour CO standard.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-2 4.1 BASE CASE SIMULATION

The UAM was used to simulate the emissions and transport of carbon monoxide throughout the Las Vegas Valley during the night of December 8-9, 1996 (Sunday-Monday). Specifically, the UAM was run from 1500 LST December 8 to 1100 LST December 9 to cover the most cold, stagnant and stable portion of the episode duri ng which CO was observed to build up. Two base case simulations were run:

A. With revised on-road emission estimates, keeping all point, area, and non-road emissions the same as the 2000 SIP modeling (see Section 4.1.1);

B. With both revised on-road and non-road emission estimates, keeping all point and area emission the same as the 2000 SIP modeling (see Section 4.1.2).

In both cases, revised 1996 airport emissions from Ricondo (1999) were included in the emissions inventory. Model performance was eval uated graphically and statistically relative to the observational data that were available duri ng this period. EPA (1992) provides the following criteria that must be met in order to consid er UAM performance acceptable for CO attainment demonstrations:

1. The unpaired peak prediction accuracy (UPPA; a comparison between the peak measurement and the peak prediction anywhe re in the domain at any time) must be within ±30-35%;

2. The average gross error among all paired m easured and predicted peaks (matched in space and time) above 5 ppm must be within 20-25%;

3. The average gross error in the timing of the predicted peaks among all sites above 5 ppm must be within 2 hours.

4.1.1 UAM Results From Revised On-Road Emissions

Figure 4-1 shows the UAM predicted episode-maxim um 8-hour CO concen trations (ppm) from the base case simulation using the revised on-ro ad emissions documented in Section 2. Two distinct areas of CO maxima occur in the simulati on: (1) near the “elbow” of U.S. 95 in northeast Las Vegas, and (2) along the Las Vegas Boulev ard “strip” near the intersection with Spring Mountain Road. The peak in the domain is 10.7 ppm along Las Vegas Boulevard. The secondary maximum reaches above 9 ppm along U. S. 95, and this occurs during the morning commute hours on Monday, December 9. Overall, the spatial pattern of predicted 8-hour maximum CO agrees with the previous modeli ng performed for the 2000 CO SIP, and with the distribution of observed CO for this period.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-3 Figure 4-1. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 Base Case with updated on-road mobile emissions. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 1996 Base Case (96B07)

Peak = 10.7 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-4 Standard and EPA criteria model performance statistics are shown in Table 4-1 for this simulation. These statistics are based upon pairin gs of 8-hour CO predictions and observations across all available monitoring sites for the period, which include standard EPA-method monitoring conducted by Clark C ounty, as well as special saturation monitoring performed for the Las Vegas Phase II field monitoring study (Ega mi et al., 1998; Emery et al., 1998). Figure 4-2 shows the locations of all monitoring site s operating during the Phase II field study, while Table 4-2 lists the site names with their c oordinates. Based upon these statistics, UAM performance is quite good and should be considered acceptable.

Table 4-1. Summary performance statistics for the December 8-9, 1996 Base Case, with updated on-road mobile source emissions. Bold/colored metrics denote EPA criteria statistics; green (red) indicates within (outside) acceptance criteria. Peak 8-hour Observation 9.6 ppm, Marnell Field Unpaired Peak 10.7 ppm Paired Peak 8.1 ppm Statistical Measures Unpaired Peak Accuracy 12 % Paired Peak Accuracy -15 % Peak Timing Error 1 hr Average Peak Bias > 5 ppm -5 % Average Peak Error > 5 ppm 12 % Average Peak Timing Bias > 5 ppm 1 hr Average Peak Timing Error > 5 ppm 2 hr Overall Bias > 5 ppm -7 % Overall Error > 5 ppm 14 %



### Figure 4-3 presents hourly time series of observed and predicted CO concentrations at each of these monitoring sites. The dots represent the observations at each site, while the solid line shows the UAM prediction at that location. Th e gray shaded area delineates the minimum to maximum predicted CO concentratio ns within the surround ing nine grid cells around each site to indicate the extent of predicted spatial gradients. Overall, the trends are reproduced adequately. Some notable exceptions include City Center, Shadow Lane, Winterwood, MGM, and Eastern and Owens. The MGM site was new in 1995 and measured micro-scale influences near the busiest intersections on Las Vegas Boulevard. The general under pr ediction there is likely due to the inability of UAM to resolv e the small scale conditions. Th e Eastern and Owens special study site is located about 2.5 km north of U.S. 95 in northeastern Las Vegas; according to Egami et al. (1998), this site is situated in a local depression, and a pooling of locally-derived CO may be occurring there. The other iden tified sites are located within or very near high emission density grid cells (freeways) and over pred ictions at these sites might be the result from a “smearing” of high CO emissions over the entire 1 km grid ce lls. In most cases the range of predicted CO within one grid cell of each site is suff icient to contain the observed CO each hour.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-5 Figure 4-2. Locations of all Phase II monitoring si tes operating during the Phase II field study over the winter of 1996/97 (Emery et al., 1998). 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-6 Table 4-2. Names and coordinates of all monitoring sites operating during the Phase II field study over the winter of 1996/97 (Egami et al., 1998). The first 14 sites are the standard Clark County sites.

Symbol Site Name UTM Easting (km) UTM Northing (km) BS Craig Road/Bemis 671.439 4012.654 CC City Center 667.440 4004.817 CW Crestwood 668.500 4002.500 EC East Charleston 670.028 4003.124 FL East Flamingo 665.386 3998.034 GV Green Valley 675.025 3991.294 MC Maycliff 672.246 4001.458 MG MGM 664.600 3996.700 PL Powerline 680.431 3989.445 PM Paul Meyer 657.191 3997.118 PT Pittman 680.390 3991.640 SA Sunrise Acres 669.675 4003.630 SL Shadow Lane 665.304 4003.473 WW Winterwood 675.025 4001.446 ECB East Charleston DRI 670.028 4003.124 MAF Marnel Field 669.804 4003.776 EAB Eastern & Bonanza 669.720 4004.636 EAO Eastern and Owens 669.722 4006.290 BAG Bruce and Grayson 668.604 4005.709 CAR Carson and 17 th 668.510 4003.407 EAT Eastern and Tioga 669.226 3998.931 SLA St. Louis & Atlantic 669.836 4001.811 CAP Charleston and Pecos 671.152 4003.252 CAS Charleston & Sacrame 672.130 4003.142 PVP Paradise Valley Park 670.171 3996.693 DRS Del Robison School 673.511 4005.104 SIL Silver Bowl 679.238 3995.384 ALC Alhambra & Cordova 667.151 4001.601August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-7 Figure 4-3. Time series of hourly CO measurements (dots) and UAM predictions (line) at Phase II field study monitoring sites. Plots cover the period 1500 LST December 8 to 1100 LST December 9, 1996. Gray shading indicates the range of minimum to maximum predicted CO concentrations in the nine cells surrounding each site. 

### BS: Craig Road/Bemis 671.439 4012.654

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### CC: City Center 667.440 4004.817

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### CW: Crestwood 668.500 4002.500

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### EC: East Charleston 670.028 4003.124

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-8 Figure 4-3. (continued). 

### FL: East Flamingo 665.386 3998.034

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### GV: Green Valley 675.025 3991.294

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### MC: Maycliff 672.246 4001.458

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### MG: MGM 664.600 3996.700

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-9 Figure 4-3. (continued). 

### PL: Powerline 680.431 3989.445

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### PM: Paul Meyer 657.191 3997.118

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### PT: Pittman 680.390 3991.640

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### SA: Sunrise Acres 669.675 4003.630

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-10 Figure 4-3. (continued). 

### SL: Shadow Lane 665.304 4003.473

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### WW: Winterwood 675.025 4001.446

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### ECB: East Charleston DRI 670.028 4003.124

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### MAF: Marnel Field 669.804 4003.776

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-11 Figure 4-3. (continued). 

### EAB: Eastern & Bonanza 669.720 4004.636

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### EAO: Eastern and Owens 669.722 4006.290

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### BAG: Bruce and Grayson 668.604 4005.709

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### CAR: Carson and 17th 668.510 4003.407

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-12 Figure 4-3. (continued). 

### EAT: Eastern and Tioga 669.226 3998.931

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### SLA: St. Louis & Atlant ic 669.836 4001.811

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### CAP: Charleston and Pecos 671.152 4003.252

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### CAS: Charleston & Sacrame 672.130 4003.142

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-13 Figure 4-3. (concluded). 

### PVP: Paradise Valley Park 670.171 3996.693

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### DRS: Del Robison School 673.511 4005.104

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### SIL: Silver Bowl 679.238 3995.384

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed Predicted



### ALC: Alhambra & Cordova 667.151 4001.601

0 5 10 15

12/8/1996



### DateCO [ppm] Minimum to Maximum Range Observed PredictedAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-14 A scatter diagram of all observations and predic tions combined from all monitoring sites is provided in Figure 4-4. The slope of the regression line is near 1:1, which indicates that the UAM develops only a minor negati ve bias tendency towards in creasing CO concentrations. Model performance in this regard is quite good and encouraging. The R 2 

### value (fraction of variation explained) provides a quantitative measure that indicates a large degree of scatter (as seen in the spread of the observation-pred iction pairings). At first glance an R 2 

### value of 0.62 would appear to be low; however this is a common trait of dispersion modeling and so UAM performance in this regard is not particularly problematic when considered in that context.

Figure 4-4. Scatter diagram of UAM predictions vs. observations for the 1996 Base Case. The linear regression equation is given as the bold line.



### 4.1.2 UAM Results From Revised On -Road and Non-Road Emissions

Figure 4-5 shows the UAM predicted episode-maxim um 8-hour CO concen trations (ppm) from the base case simulation using the revised on- road and non-road emissions documented in Sections 2 and 3. Overall the pattern is quite similar to the results described in Section 4.1.1, with a slight increase in CO of a few tenths of a ppm. The peak in the domain is 11.4 ppm along Las Vegas Boulevard. Scatter Plot of Predicted vs. Observed Concentrations LV Dec 8-9

y = 0.7946x + 1.301
R 2 = 0.6211

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Observed [ppm]Predicted [ppm]August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-15 Figure 4-5. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 Base Case with updated on-road and non-road mobile emissions. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 1996 Base Case (96B08)

Peak = 11.4 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-16 Standard and EPA criteria model performance statistics are shown in Table 4-3 for this simulation. UAM performance is quite similar to the previous run, and should be considered acceptable.

Figure 4-6 presents hourly time series of observed and predicted CO concentrations at each of the monitoring sites. The dots represent the observ ations at each site, while the black solid line shows the UAM predictions from Section 4.1.1, and the red solid line shows the UAM predictions with the addition of updated non-road emissions. Differences in the model predictions only appear in the morning hours, when non-road emissions begin to build up. However, these differences are insignificant as they are certainly within model uncertainty, and they do not overtly impact model performance.

Table 4-3. Summary performance statistics for the December 8-9, 1996 Base Case with updated on-road and non-road mobile source emissions. Bold/colored metrics denote EPA criteria statistics; green (red) indicates within (outside) acceptance criteria. Peak 8-hour Observation 9.6 ppm, Marnell Field Unpaired Peak 11.4 ppm Paired Peak 8.1 ppm Statistical Measures Unpaired Peak Accuracy 19 % Paired Peak Accuracy -15 % Peak Timing Error 1 hr Average Peak Bias > 5 ppm -3 % Average Peak Error > 5 ppm 13 % Average Peak Timing Bias > 5 ppm 2 hr Average Peak Timing Error > 5 ppm 2 hr Overall Bias > 5 ppm -6 % Overall Error > 5 ppm 15 %



### 4.2 FUTURE YEAR SIMULATIONS

Figures 4-7 through 4-11 display predicted 8-hour maximum CO c oncentrations in the modeling domain for the years 2006, 2010, 2015, 2020, and 2030, respectively. UAM predictions show that the 8-hour CO standard of 9 ppm will not be violated anywhere within the domain. Peak 8- hour CO decreases in each year to 2015, then begins to increase out to 2030:

Year Peak 8-hour CO 2006 7.4 2010 7.2 2015 6.5 2020 6.7 2030 8.0

Note that the contribution of Mc Carran airport to local CO concentrations in that area steadily increases over this period. This is due to the projected growth in airpor t activities as reported by Ricondo (2003). In each successive year thr ough 2020, however, the contribution from on-road mobile sources diminishes, while the peak move s from the U.S. 95 “elbow” in northeast Las Vegas to the northern boundary of McCarran ai rport along Tropicana Boulevard. Like the 1996 Base Case, a lower secondary peak occurs in the Las Vegas Boulevard area near SpringAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-17 Figure 4-6. Time series of hourly CO measurements (dots) and UAM predictions (black line = revised on-road emissions, red line = revised on-road and non-road emissions) at Phase II field study monitoring sites. Plots cover the period 1500 LST December 8 to 1100 LST December 9, 1996. 

### BS: Craig Road/Bemis 671.439 4012.654

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### CC: City Center 667.440 4004.817

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### CW: Crestwood 668.500 4002.500

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### EC: East Charleston 670.028 4003.124

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-18 Figure 4-6. (continued). 

### FL: East Flamingo 665.386 3998.034

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### GV: Green Valley 675.025 3991.294

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### MC: Maycliff 672.246 4001.458

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### MG: MGM 664.600 3996.700

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-19 Figure 4-6. (continued). 

### PL: Powerline 680.431 3989.445

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### PM: Paul Meyer 657.191 3997.118

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### PT: Pittman 680.390 3991.640

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### SA: Sunrise Acres 669.675 4003.630

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-20 Figure 4-6. (continued). 

### SL: Shadow Lane 665.304 4003.473

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### WW: Winterwood 675.025 4001.446

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### ECB: East Charleston DRI 670.028 4003.124

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### MAF: Marnel Field 669.804 4003.776

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-21 Figure 4-6. (continued). 

### EAB: Eastern & Bonanza 669.720 4004.636

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### EAO: Eastern and Owens 669.722 4006.290

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### BAG: Bruce and Grayson 668.604 4005.709

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### CAR: Carson and 17th 668.510 4003.407

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-22 Figure 4-6. (continued). 

### EAT: Eastern and Tioga 669.226 3998.931

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### SLA: St. Louis & Atlant ic 669.836 4001.811

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### CAP: Charleston and Pecos 671.152 4003.252

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### CAS: Charleston & Sacrame 672.130 4003.142

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-23 Figure 4-6. (concluded). 

### PVP: Paradise Valley Park 670.171 3996.693

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### DRS: Del Robison School 673.511 4005.104

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### SIL: Silver Bowl 679.238 3995.384

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NR



### ALC: Alhambra & Cordova 667.151 4001.601

0 5 10 15

12/8/1996



### DateCO [ppm] Observed New _NR Orig_NRAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-24 Figure 4-7. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2006. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 2006 Future Year

Peak = 7.37 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-25 Figure 4-8. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2010. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 2010 Future Year

Peak = 7.17 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-26 Figure 4-9. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2015. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 2015 Future Year

Peak = 6.47 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-27 Figure 4-10. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2020. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 2020 Future Year

Peak = 6.74 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-28 Figure 4-11. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2030. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

## UAM Max 8-hour CO Concentrations 2030 Future Year

Peak = 7.96 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-29 Mountain Road. The Las Vegas Boulevard – Spring Mountain road area possesses a high concentration of parking structures, which leads to a local maximum in trip starts in the RTC TransCAD transportation demand model, and th erefore a local maximum in vehicle “start” emissions in the modeling emission inventory. This poses a potential for an actual local emissions “hot spot” in this area. However, Clark County recently und ertook a saturation study in 2002 (T&B Systems and Parsons Engineering Science, 2002 1 

### ) to address this possibility. Although the TransCAD, EPS, and UAM modeling show a potential emissions hot spot at Spring Mountain Road and Las Vegas Boulevard, the 2002 saturation study showed no hot spot at all in that location.

4.3 MICROSCALE MODELING

Future year UAM simulation results were used to provide estimates of background ambient CO levels for micro-scale modeling performed for the “Five Points” hot spot intersection and for the three civil airports in the modeling domain (McCarran, Henderson Executive, and North Las Vegas). UAM concentrations from the appropr iate grid cells were simply added to the concentrations predicted at each micro-scale receptor to ob tain a total (background + microscale) CO concentration. Results are presented in the following sub-sections.

4.3.1 CAL3QHC Intersection Modeling

Table 4-4 presents the peak UAM + CAL3QHC 8- hour average CO concentrations predicted in each of the future years for each of the three inte rsections in the “Five Points” area. All values are well below the 9 ppm standard.

Table 4-4. Peak UAM + CAL3QHC 8-hour average CO concentrations (ppm) predicted for each future year and for each intersection. Year Eastern/Charleston Eastern/Fremont Fremont/Charleston 2006 6.14 5.66 5.09 2010 5.61 5.32 4.81 2015 4.97 4.76 4.31 2020 4.67 4.48 4.07 2030 4.83 4.58 4.20



### 4.3.2 EDMS Airport Modeling

In consideration of micro-scal e airport modeling, the UAM was run for all future years with exactly the same inputs as described in Section 4. 2; however, airport emissions for the three civil airports in the domain were removed from the UAM inventory to avoid double counting. Clark County provided EDMS simulations for 2005, 2010, 2015 and 2020, based on the work of Ricondo (2003). In each of thes e years, several receptors at Mc Carran airport re ported total 8- hour CO concentrations (sum of EDMS and UAM components) above the 8-hour CO standard of 9 ppm. Note, however, that all receptors above the 9 ppm standard in all future years evaluated

1 Information regarding the 2002 Las Vegas Boulevard Saturation Study can be found at http://www.co.clark.nv.us/air_ quality/Studies/COSat1-7.pdf

.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-30 occur within areas that are not publicly accessible, as defined by Ricondo (2005). Disregarding any receptors in publicly restricted areas removes all exceedance estimates.

Table 4-5 presents the peak total 8-hour CO concentration at all three airports for each future year evaluated. Values for McCarran are taken from the peak publicly accessible receptor. All peak CO concentrations are below the 9 ppm standard in all years.

Table 4-5. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor. Airport 2005 2010 2015 2020 McCarran 7.47 7.14 7.60 8.45 Henderson Executive 1.12 1.36 1.99 3.05 North Las Vegas 5.01 5.04 4.46 4.19



### 4.4 ESTIMATING ON-ROAD EMISSION BUDGETS

The UAM was used to undertake several sensitivity tests to refine the estimation of future year on-road mobile CO emission budgets for the centr al, most urbanized portion of the modeling domain. The definition of the central urban sub-domain is given in Table 4-6 and shown in Figure 4-12. The first analysis tested the assert ion that the emissions in ventory outside of the central urban sub-domain has no significant im pact on CO concentrations downtown, along the Las Vegas Boulevard “strip”, and in traditional “hot spot ” areas. Emissions in the outer grid area were doubled for each future year, and the UAM wa s run to show the incremental impact on the peak CO concentration.

In the second analysis, on-road mobile source em issions were scaled up over the entire domain to the point at which the peak 8-hour CO concentrati on reached 8.9 ppm in each of the future years. Hence, the resulting daily on-road emission tota ls for December 9 can be used to establish future-year emission budgets for both the entire domain and the centr al urban sub-domain.

Table 4-6. Grid definition of the central urban sub-domain. Column Row UTM East UTM North Low-left 11 19 652.000 3991.000 Upper-Right 36 45 678.000 4018.000



### 4.4.1 Impacts of Emissions from the Outer Domain

The total CO emissions inventory in the out er area of the modeling domain was doubled to investigate the sensitivity of peak predicted CO in central Las Vegas to outlying emission sources. As shown in Table 4-7, peak 8-hour CO concentrations changed by a maximum of only 0.07 ppm. There was no change in the location of the predicted peak.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-31 Figure 4-12. Location of the central urban sub-domain used in the UAM sensitivity tests (heavy red line). 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-32 Table 4-7. Change in peak 8-hour CO from doubling the total CO emissions inventory outside of the central urban sub-domain. Peak 8-hour CO (ppm) Year From Section 4.2 Doubled Outer Emissions 2006 7.37 7.41 2010 7.17 7.24 2015 6.47 6.54 2020 6.74 6.80 2030 7.96 8.03



### This demonstrates that the model-predicted peak CO is driven by local emission sources in the central urban sub-domain, and is therefore insensitive to large changes in emissions in outer

areas.

4.4.2 Emission Budgets from Scaling On-Road Emissions

Future year on-road mobile source emissions we re scaled up across the entire modeling domain to the point at which the peak 8-hour CO c oncentration reached 8.9 ppm. Additionally, the onroad mobile source emissions outside the centr al urban sub-domain we re increased by an additional 70% in each year to reach a maximu m peak 8-hour CO concentration of just under 9.0ppm. Results from this analysis are presente d in Table 4-8. Plots of daily maximum CO concentrations for each future year are shown in Figures 4-13 through 4-17. There was no change in the location of the pr edicted peak. No additional hot spots were generated anywhere in the domain by increasing the on-road mobile source emissions in the outer portion of the domain by 70%.

Table 4-8. Weekday domain-wide on-road emission increase, net on-road emission increase that includes an additional 70% increase outside the central urban sub-domain, resulting UAM predicted peak CO, and resulting total and sub-domain on-road emission budgets for each future year.

Year Domain-Wide On-Road Emissions

Increase Net On-Road Emissions

Increase Peak 8-hr CO (ppm) Total Domain On-Road Emissions (TPD) Sub-Domain On-Road Emissions (TPD) 2006 23% 41% 8.96 623 427 2010 26.5% 49% 8.98 690 438 2015 41.5% 70% 8.98 768 453 2020 50% 83% 8.97 817 463 2030 46% 81% 8.97 881 464



### Table 4-9 presents the peak UAM + CAL3QHC 8- hour average CO concentrations predicted in each of the future year sensitivity runs shown in Table 4-8 and for each of the three intersections in the “Five Points” area. All values remain well below the 9 ppm standard.

Table 4-10 presents the peak total UAM + EDMS 8-hour CO concentration from the UAM sensitivity runs shown in Table 4- 8 (without airports incl uded) at all three air ports for each future year evaluated. Values for McCarran are taken from the peak publicly accessible receptor. All peak CO concentrations are below the 9 ppm standard in all years.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-33 Figure 4-13. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2006 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

### UAM Max 8-hour CO Concentrations 2006 Future Year

Peak = 8.96 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-34 Figure 4-14. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2010 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

### UAM Max 8-hour CO Concentrations 2010 Future Year

Peak = 8.98 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-35 Figure 4-15. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2015 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

### UAM Max 8-hour CO Concentrations 2015 Future Year

Peak = 8.98 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-36 Figure 4-16. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2020 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

### UAM Max 8-hour CO Concentrations 2020 Future Year

Peak = 8.97 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-37 Figure 4-17. Spatial distribution of UAM predicted 8-hour maximum CO concentrations (ppm) for the December 8-9, 1996 episode using emission forecasts for 2030 with increased on-road mobile source emissions to reach peak CO just under 9.0 ppm. 642 652 662 672 682 692 UTM Easting (km) 3973 3983 3993 4003 4013 4023UTM Northing (km)

5 6 7 8 9 10 11 12



### ppm 

### UAM Max 8-hour CO Concentrations 2030 Future Year

Peak = 8.97 ppmAugust 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_4_Modeling.doc 

### 4-38 Table 4-9. Peak UAM + CAL3QHC 8-hour average CO concentrations (ppm) predicted for each future year and for each intersection. UAM results from the on-road sensitivity scaling tests. Year Eastern/Charleston Eastern/Fremont Fremont/Charleston 2006 7.14 6.65 6.12 2010 6.70 6.43 5.94 2015 6.53 6.30 5.88 2020 6.43 6.23 5.83 2030 6.49 6.22 5.85

Table 4-10. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor. UAM results from the on-road sensitivity scaling tests. Airport 2005 2010 2015 2020 McCarran 7.76 7.47 8.09 8.98 Henderson Executive 1.28 1.61 2.74 3.96 North Las Vegas 6.07 6.28 6.14 6.08August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_5_Conclusion.doc 

### 5-1 5. SUMMARY

The Clark County Department of Air Quality an d Environmental Management has updated their UAM CO modeling and conformity analysis us ing the latest tools, data resources, and methodologies available to estimate CO emissi ons. From the revised modeling results, Clark County is submitting a revised CO SIP document. The revised modeling is based upon the previous UAM/CAL3QHC/EDMS modeling data sets developed for the December 8-9, 1996 episode and reported in the 2000 CO SIP for Cl ark County. Specific updates to the emission inventories include modifications to on-road mobile, non-road m obile, civil airports, railroads and point sources. Emission estimates for all remaining categories (mainly stationary area sources and Nellis Air Force Base) were taken fr om the previous modeling detailed in the 2000 CO SIP submittal, although new spatial distribu tions were developed for area sources from updated land use projections. The future ye ars modeled in this update include: 2006, 2010, 2015, 2020, and 2030.

5.1 EMISSION UPDATES

The greatest effort in the CO modeling update has focused on the on-road mobile source inventory estimates. The original EPA vehicle emission factor model that was used in the previous SIP effort (MOBILE5b) was replac ed by the latest version of the model, MOBILE6.2.03. However, the Air Improvement Res ource (AIR) version of this model was used because it provides the capability to create a condensed database of composite emission factors. This is important for applications such as this one where many MOBILE6 scenarios must be run to generate lookup factors for link- level emissions estimates.

Since output data and formats for MOBILE6 are si gnificantly different from its predecessor, the original utility that was used to estimate link- level CO emissions (DTIM) was replaced by two new programs. The first processes the link- based emissions, and the other processes the emissions based on traffic analysis zones (TAZ). Both of the new programs produce inputs for the Emission Processing System, version 3 (EPS3). The EPS3 is the latest version of the EPS program suite used in the original CO SIP m odeling to generate gridded, time-resolved, UAMready CO emission input files.

For the 1996 base year, the RTC’s original TRANPLAN transportati on demand model (TDM) output was used to define link-based volume (vehic le miles traveled, or VMT) and other traffic volume-related parameters. However, no trip tables were available, which allow for the separate processing of start versus running emissions. Therefore, trip data from the newer 2000 TransCAD TDM was used as a means to spatia lly allocate the 1996 start emissions for each period available in the daily TransCAD output. All other original ancillary information, including vehicle fleet mix, seas onal/day-of-week adjustment fact ors, and hourly activity profiles remain the same as in the original modeling.

For all future years modeled in this update, the RTC provided output fro m their new TransCAD, which includes link volumes and trip tables fo r each year. For the link-based data, the same program written for the base year was used to produce the link-based emissions for EPS3. For the TAZ data, most of the same type of MOBILE 6 output was used in the program developed for the base year; but start emissions were handled in a special way.August 2005

Y:\Las_Vegas_MSEI\CO SIP Update\Tech Support Doc\Final TSD\Sec_5_Conclusion.doc 

### 5-2 In this CO modeling update, the latest EDMS airport emission estimates developed in 2003 have been included into the UAM emissions invent ory. The issue of double-counting airport emissions within the UAM and EDMS+UAM mo deling results were carefully considered.

Clark County has updated their railroad emissions estimates for 2001 based on a recent non-road study, which include contributi ons from both line haul and switching. These have been incorporated into the updat ed UAM inventory.

The EPA’s NONROAD model was used to generate emission inputs to EPS3 for each simulated future year. New spatial and temporal allocati on factors were developed based on the latest land use projections from Clark County. Airport ground support equipment (GSE) were removed from the NONROAD estimates because they were included in the EDMS estimates; railroad maintenance emissions were left in since the Mactec emissions were estimated for locomotives only.

Clark County incorporated an updated point s ource emission inventory, which included revised stack parameters, and which defined Potential To Em it (PTE) levels for seven specific facilities. The UAM future year inventor ies included the PTE levels pl us an additional 70 ton buffer (referred to as “PTE+70”) for these sources. Th e original point source inventory was used, unchanged, for the 1996 base year simulation.

Table 5-1 presents a summary of total daily CO emissions by source category for 1996 base and all future years.

5.2 MODEL APPLICATION

UAM was provided the updated emission inventor ies for point, on-road mobile, and non-road mobile sources, and run for the December 8-9, 1996 historical CO event. All other environmental parameters were taken from the original modeling as documented in the 2000 CO SIP. A base-year model performance evaluation was conducted for two base cases: (1) using the original NEVES-based non-road emission estimates reported in the 2000 CO SIP; and (2) with revised non-road emission estimates develope d using EPA’s NONROAD model. The UAM was then used with the updated future year inventories for 2006, 2010, 2015, 2020 and 2030 to determine peak 8-hour CO levels in the basin for the same December 8-9, 1996 conditions. UAM results, without airport emi ssions included in the inventory, were added to EDMS receptor concentrations from the 2003 updated airport modeling.

For hotspot modeling, the CAL3QHC model wa s used to model th ree intersections: Charleston/Eastern, Charleston/ Fremont and Eastern/Fremont. EPA (1992, 1995) guidance for screening level modeling of these three intersecti ons was followed. The ambient temperature for each hour of the episode (needed to estimate em issions with the MOBILE6 model), and the wind direction and speed (needed for the CAL3QHC estimates) were taken from the original UAM/CAL3QHC modeling. The CAL3QHC model output was added to the background UAM levels to estimate 8-hour CO concentr ations for the duration of the episode.August 2005

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### 5-3 Table 5-1. Summary of total daily CO emissions (TPD) in the UAM CO SIP revision.
Base 2006 2010 2015 2020 2030 Sunday 12/8/2005 On-Road Mobile 329.95 275.30 287.01 276.44 273.09 295.90 Henderson Airport 1.12 1.35 1.59 1.99 2.55 3.69 McCarran Airport 24.69 28.57 33.24 38.14 43.24 53.44 Nellis AFB 2.86 2.86 2.86 2.86 2.86 2.86 North LV Airport 7.58 5.13 5.22 5.35 5.48 5.73 Area Sources 9.18 12.75 14.27 16.20 18.13 21.99 Non-road - NONROAD 66.13 50.49 55.50 60.66 66.21 77.44 Point Sources 3.13 15.82 15.82 15.82 15.82 15.82 Railway 0.17 0.21 0.23 0.24 0.27 0.33
Total 447.81 395.81 419.81 422.51 433.24 484.39 Monday 12/9/2005 On-Road Mobile 511.43 441.23 463.95 451.30 447.24 485.61 Henderson Airport 0.88 1.07 1.26 1.57 2.01 2.91 McCarran Airport 24.69 28.57 33.24 38.14 43.24 53.44 Nellis AFB 2.86 2.86 2.86 2.86 2.86 2.86 North LV Airport 5.98 4.05 4.12 4.22 4.32 4.52 Area Sources 9.46 13.11 14.65 16.62 18.58 22.50 Non-road - NONROAD 103.40 74.30 80.94 88.52 96.99 114.17 Point Sources 3.13 15.82 15.82 15.82 15.82 15.82 Railway 0.25 0.31 0.34 0.36 0.40 0.48
Total 669.15 591.60 627.67 630.36 643.13 715.87



### 5.2.1 Base Case Simulations

The UAM base case results show two distinct areas of CO maxima occur in the simulation: (1) near the “elbow” of U.S. 95 in northeast La s Vegas, and (2) along the Las Vegas Boulevard “strip” near the intersection w ith Spring Mountain Road. Both base case simulations show a domain peak of 10.7 ppm and 11.4 ppm along Las Vegas Boulevard, respectively. This is primarily caused by a large contribution from au tomobile start emissions during the morning of December 9, which is in turn due to the large co ncentration of parking structures in that area, according to TransCAD. The secondary maximu m reaches above 9 ppm along U.S. 95, and this occurs during the morning commute hours on Monday, December 9. Overall, the spatial pattern of predicted 8-hour maximum CO agrees with the previous m odeling performed for the 2000 CO SIP, and with the distribution of observed CO for this period.

Performance statistics were calculated base d upon pairings of 8-hour CO predictions and observations across all available monitoring site s for the period, which include standard EPAmethod monitoring conducted by Clark County, as well as sp ecial saturation monitoring performed for the Las Vegas Phase II field m onitoring study (Egami et al., 1998; Emery et al., 1998). Statistics were compared to EPA crite ria for acceptable model performance, and all criteria were met. Based upon th e statistics calculated for both base cases, UAM performance is quite good and should be considered acceptable. Analysis of time-series of predicted and observed hourly CO concentrations at each m onitoring sites showed that the diurnal and neighborhood CO trends are reproduced adequately.August 2005

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### 5-4 5.2.2 Future Year Simulations

UAM predictions show that the 8-hour CO standard of 9 ppm will not be violated anywhere within the domain. Peak 8-hour CO decreases in each year to 2015, then begins to increase out to 2030:

Year Peak 8-hour CO 2006 7.4 2010 7.2 2015 6.5 2020 6.7 2030 8.0

In each successive year through 2020, the contribu tion from on-road mobile sources diminishes, while the peak moves from the U.S. 95 “elbow” in northeast Las Vegas to the northern boundary of McCarran airport along Tropican a Boulevard. Like the 1996 Base Case, a lower secondary peak occurs in the Las Vegas Boulevard area ne ar Spring Mountain Road. Again, the Las Vegas Boulevard – Spring Mountain road area possesses a high concentration of parking structures, which leads to a local maximum in trip starts in TransCAD, and therefore a local maximum in vehicle “start” emissions in the modeling emissi on inventory. This pos es a potential for an actual local emissions “hot spot” in this ar ea. However, Clark County recently undertook a saturation study in 2002 (T&B Systems and Parsons Engineering Science, 2002) to address this possibility. Although the TransCAD, EPS, and UAM modeling show a potential emissions hot spot at Spring Mountain Road and Las Vega s Boulevard, the 2002 sa turation study showed no hot spot at all in that location.

5.2.2.1 Micro-scale Modeling

Future year UAM simulation results were used to provide estimates of background ambient CO levels for micro-scale modeling performed for the “Five Points” hot spot intersection and for the three civil airports in the modeling domain (McCarran, Henderson Executive, and North Las Vegas). UAM concentrations from the appropr iate grid cells were simply added to the concentrations predicted at each micro-scale receptor to ob tain a total (background + microscale) CO concentration.

Table 5-2 presents the peak UAM + CAL3QHC 8- hour average CO concentrations predicted in each of the future years for each of the three inte rsections in the “Five Points” area. All values are well below the 9 ppm standard.August 2005

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### 5-5 Table 5-2. Peak UAM + CAL3QHC 8-hour average CO concentrations (ppm) predicted for each future year and for each intersection. Year Eastern/Charleston Eastern/Fremont Fremont/Charleston 2006 6.14 5.66 5.09 2010 5.61 5.32 4.81 2015 4.97 4.76 4.31 2020 4.67 4.48 4.07 2030 4.83 4.58 4.20



### In consideration of micro-scal e airport modeling, the UAM was re-run for all future years, but airport emissions for the three civil airports in the domain were removed from the UAM inventory to avoid double coun ting. Clark County provided ED MS simulations for 2005, 2010, 2015 and 2020, based on the work of Ricondo (20 03). At McCarran airport, all receptors reporting peak 8-hour CO above the 9 ppm standard in all future years evaluated occur within areas that are not publicly accessible, as define d by Ricondo (2005). Disregarding any receptors in publicly restricted areas removes all exceedance estimates.

Table 5-3 presents the peak total 8-hour CO concentration at all three airports for each future year evaluated. Values for McCarran are taken from the peak publicly accessible receptor. All peak CO concentrations are below the 9 ppm standard in all years.

Table 5-3. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all three future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor. Airport 2005 2010 2015 2020 McCarran 7.47 7.14 7.60 8.45 Henderson Executive 1.12 1.36 1.99 3.05 North Las Vegas 5.01 5.04 4.46 4.19



### 5.2.2.2 Estimating On-Road Emission Budgets

The UAM was used to undertake several sensitivity tests to refine the estimation of future year on-road mobile CO emission budgets for the centr al, most urbanized portion of the modeling domain. The first analysis tested the assertion th at the emissions inventor y outside of the central urban sub-domain has no significant impact on CO concentrations downtown, along the Las Vegas Boulevard “strip”, and in traditional “hot spot” areas. Emissions in the outer grid area were doubled for each future year, and the UAM wa s run to show the incremental impact on the peak CO concentration. As shown in Table 5- 4, peak 8-hour CO concentrations changed by a maximum of only 0.07 ppm. There was no change in the location of the predicted peak.

Table 5-4. Change in peak 8-hour CO from doubling the total CO emissions inventory outside of the central urban sub-domain. Peak 8-hour CO (ppm) Year Future Year Peak Doubled Outer Emissions 2006 7.37 7.41 2010 7.17 7.24 2015 6.47 6.54 2020 6.74 6.80 2030 7.96 8.03August 2005

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### 5-6 This demonstrates that the model-predicted peak CO is driven by local emission sources in the central urban sub-domain, and is therefore insensitive to large changes in emissions in outer

areas

In the second analysis, future year on-road m obile source emissions we re scaled up across the entire modeling domain to the point at which the peak 8-hour CO concentration reached 8.9 ppm. Additionally, the on-road mobile source emissions outside the central urban sub-domain were increased by an additional 70% in each year to reach a maximum peak 8-hour CO concentration of just under 9.0 ppm. Hence, th e resulting daily on-road emission totals for December 9 can be used to establish future-year emission budgets. Results from this analysis are presented in Table 5-5. There was no change in the location of the predicted peak. No additional hot spots were generated anywhere in the domain by increasing the on-road mobile source emissions in the outer portion of the domain by 70%.

Table 5-5. Weekday domain-wide on-road emission increase, net on-road emission increase that includes an additional 70% increase outside the central urban sub-domain, resulting UAM predicted peak CO, and resulting total and sub-domain on-road emission budgets for each future year.

Year Domain-Wide On-Road Emissions

Increase Net On-Road Emissions

Increase Peak 8-hr CO (ppm) Total Domain On-Road Emissions (TPD) Sub-Domain On-Road Emissions (TPD) 2006 23% 41% 8.96 623 427 2010 26.5% 49% 8.98 690 438 2015 41.5% 70% 8.98 768 453 2020 50% 83% 8.97 817 463 2030 46% 81% 8.97 881 464



### Table 5-6 presents the peak UAM + CAL3QHC 8- hour average CO concentrations predicted in each of the future year sensitivity runs above and for each of the three inte rsections in the “Five Points” area. All values remain well below the 9 ppm standard.

Table 5-6. Peak UAM + CAL3QHC 8-hour average CO concentrations (ppm) predicted for each future year and for each intersection. UAM results from the on-road sensitivity scaling tests. Year Eastern/Charleston Eastern/Fremont Fremont/Charleston 2006 7.14 6.65 6.12 2010 6.70 6.43 5.94 2015 6.53 6.30 5.88 2020 6.43 6.23 5.83 2030 6.49 6.22 5.85



### Table 5-7 presents the peak total UAM + ED MS 8-hour CO concentration from the UAM sensitivity runs (without airports included) at all three airports for each future year evaluated. Values for McCarran are taken from the peak publicly accessible receptor. All peak CO concentrations are below the 9 ppm standard in all years.August 2005

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### 5-7 Table 5-7. Peak total UAM + EDMS 8-hour CO concentrations (ppm) at all three airports and for all future years evaluated. Values shown for McCarran airport occur at the peak publicly accessible receptor. UAM results from the on-road sensitivity scaling tests. Airport 2005 2010 2015 2020 McCarran 7.76 7.47 8.09 8.98 Henderson Executive 1.28 1.61 2.74 3.96 North Las Vegas 6.07 6.28 6.14 6.08August 2005

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### R-1 REFERENCES

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