# Supplement to the Redesignation Demonstration

and
Maintenance Plan

for
The Rocky Mount, North Carolina 8-Hour Ozone Nonattainment Area

Prepared by North Carolina Department of Environment and Natural Resources Division of Air Quality

June 19, 2006 Revised February 7, 2011(This page intentionally left blank)Rocky Mount, NC 1 Supplement to the Redesignation Demonstration and Maintenance Plan February 7, 2011 

### INTRODUCTION
This document is intended to supplement th e Redesignation Demonstration and Maintenance Plan for the Rocky Mount, North Carolina 8- Hour Ozone Nonattainment Area that was submitted to the United States Environmental Protection Agency on June 19, 2006. This document revises the motor vehicle emission budgets to account for new emission models, vehicle miles traveled projection models and other emission model input data.



### REVISED SECTIONS

Attached are the revised sections to the Redesi gnation Demonstration an d Maintenance Plan for the Rocky Mount, North Carolina 8-Hour Ozone N onattainment Area. To appropriately revise the original package, replace the pages as outlined below:

Narrative Replacements

Replace June 19, 2006 pages 4-2 through 4-4 with the attached February 7, 2011 pages 4-2 through 4-4. (Note that June 19, 2006 page 4- 1 has been included for ease of substitution.)

Appendix B Replacements

Add February 7, 2011 Appendix B pages 14 through 18 to the end of June 19, 2006 Appendix B.

Appendix C Replacements

Replace June 19, 2006 Appendix C.3 pages 4-28 through 4-30 with the attached February 7, 2011 pages 4-28 through 4-30. (Note that June 19, 2006 Appendix C.3 page 4-31 has been included for ease of substitution.).Rocky Mount, NC 2 Supplement to the Redesignation Demonstration and Maintenance Plan February 7, 2011 (This page intentionally left blank)Rocky Mount, NC 4-1 Redesignation Demonstration and Maintenance Plan June 19, 2006 

### 4.0 MOTOR VEHICLE EMISSION S BUDGET FOR CONFORMITY

4.1 TRANSPORTATION CONFORMITY

The purpose of transportation conformity is to ensure that Federal transportation actions occurring in nonattainment areas do not hinder th e area from attaining and maintaining the 8- hour ozone standard. This means that the leve l of emissions estimated by the NCDOT or the metropolitan planning organizations for the Tran sportation Implementation Plan (TIP) and Long Range Transportation Plan must not exceed the motor vehicle emission budget (MVEB) as defined in this maintenance plan.

4.2 HIGHWAY MOBILE SOURCE VOC INSIGNIFICANCE

Section 93.109(k) in the Transpor tation Conformity Rule Amendments for the new 8-hour ozone and fine particulate matter NAAQS addresses areas with insignifi cant motor vehicle emissions. The rule suggests that such a finding would be based on a number of factors, including the percentage of motor vehicle emi ssions in the context of the tota l SIP inventory, the current state of air quality as determined by monitoring data for that NAAQS, the absence of SIP motor vehicle control measures, and historical trends and future projections of the growth of motor vehicle emissions.

The NCDAQ has examined the sources of VOC emissions and their contribution to ozone formation in North Carolina. Because of the generally warm and moist climate of North Carolina, vegetation abounds in many forms, a nd forested lands naturally cover much of the state. The biogenic sector is the most abunda nt source of VOCs in North Carolina and accounts for approximately 90% of the total VOCs statew ide. The overwhelming abundance of biogenic VOCs makes the majority of North Carolina a NO x limited environment for the formation of ozone. This holds true in Edgecombe and Nash Counties.

Also noteworthy are the projecte d decreases in highway mobile VOC emissions through the year 2017 despite projected VMT increases. These redu ctions are due mainly to the retirement of older vehicles and the growing fl eet of Tier 2 vehicles on the ro ads in future years. Some additional reductions are attribut able to North Carolina’s inspection and maintenance program in Edgecombe and Nash Counties.

Additionally, the NCDAQ has performed a number of modeling sensitivities to determine the impact of highway mobile source VOCs on ozone formation in the Rocky Mount area. The results of these sensitivities i ndicate no change in future ozon e concentrations in the RockyRocky Mount, NC 4-2 Supplement to the Redesignation Demonstration and Maintenance Plan February 7, 2011 Mount area when highway mobile VOCs are si gnificantly changed. Th ese sensitivities are discussed in more deta il in Appendix C.3.

The NCDAQ believes highway mobile VOCs are in significant contributors to ozone formation in the Rocky Mount nonattainment area. Emissi on estimates indicate highway mobile VOC is a small percentage of the total VOC emissions inventory. Highway mobile VOC emissions are projected to decrease into the future notwithstan ding VMT increases. The area is currently well below the NAAQS and emission sensitivity modeli ng indicates no change in future ozone concentrations when VOC emissions are signific antly changed. Further, the NCDAQ considers it unreasonable to expect that Edgecombe a nd Nash Counties will experience enough motor vehicle emissions growth for a future ozone viol ation to occur. For these reasons, the NCDAQ will not be setting MVEB for VOC for the Rocky Mount area.

4.3 SAFETY MARGIN

As stated in Section 3.3.4, a safe ty margin is the difference be tween the attainment level of emissions from all source categories (i.e., point, area, and mobile) and the projected level of emissions from all source categories. The safety margins for the Rocky M ount area are listed in Table 3-7 above. The State may choose to allocate some of the safety margin to the MVEB, for transportation conformity purposes, so long as th e total level of emissions from all source categories remains equal to or less than the attainment level of emissions.

The NCDAQ has decided to allocate safety marg in to the MVEB to account for new emissions models, VMT projections models, as well as change s to future vehicle mix assumptions, etc. that influence the emission estimations. Since 2008 is a historic year, the NCDAQ decided to allocate the entire safety ma rgin available to the MVEBs. For 2017, the NCDAQ estimated the amount needed to account for the current emission model and VMT projections model and then added an additional 21% to account for any future changes to the emission model, projection model and other input data.

Motor Vehicle Emission Budgets The NCDAQ did not receive any comments regardi ng the geographic extent of the MVEB from any of the Rocky Mount transportation partne rs during the maintenance plan interagency consultation process. However, there was di scussion through the in teragency consultation process on the years to set MVEB for the Rocky Mount maintenance plan. According to Section 93.118 of the transportation conformity rule, a main tenance plan must establish a MVEB for the last year of the maintenance plan (in this ca se, 2017). Through the interagency consultationRocky Mount, NC 4-3 Supplement to the Redesignation Demonstration and Maintenance Plan February 7, 2011 process, it was decided that another MVEB woul d be set for the year 2008 in the Rocky Mount maintenance plan.

The NCDAQ will set MVEB, for tr ansportation conformity purposes, as county budgets within the Rocky Mount maintenance area for 2008 and 2017. Tables 4-1 and 4-2 below list out the NOx MVEB, for transportation conformity pur poses, by county for the years 2008 and 2017. Upon the USEPA’s approval of these county- by-county sub-area MVEB, these MVEB will become the applicable MVEB for each county.

Table 4-1 Edgecombe County MVEB in kilograms per day 2008 2017

NOx Emissions (kg/day) Base Emissions 2,483 1,143 Safety Margin Allocated to MVEB 1,674 1,108 NOx Conformity MVEB 4,157 2,251

Table 4-2 Nash County MVEB in kilograms per day 2008 2017

NOx Emissions (kg/day) Base Emissions 8,790 3,767 Safety Margin Allocated to MVEB 1,655 2,374 NOx Conformity MVEB 10,444 6,141

New Safety Margins A total of 3,329 kg (3.67 tons) and 3,482 kg (3.84 tons) of 2008 and 2017 NOx safety margin, respectively, were added to the MVEB for the Ro cky Mount area. Taking into consideration the portion of the safety margin applied to th e MVEB the resulting difference between the attainment level of emissions from all sources and the projected level of emissions from all sources in the maintenance area, i.e., the new sa fety margins, for each projected year is listed below in Table 4-3.Rocky Mount, NC 4-4 Supplement to the Redesignation Demonstration and Maintenance Plan February 7, 2011 Table 4-3 New Safety Margins for the Rocky Mount Area
Year VOC TPD NOx TPD
2005 N/A N/A 2008 -0.59 0.0 2011 -0.51 -6.93 2014 -0.07 -9.77 2017 -0.07 -7.79Mobile Source Inventory Appendix C.3 4-28 Supplement to the Rocky Mount 8-hour Ozone Maintenance Plan February 7, 2011 Based on the information discussed above, the NCDAQ steadfastly believes highway mobile VOCs are insignificant contributo rs to ozone formation in Edgecombe and Nash Counties. Emission estimates indicate highway mobile VOC is a small percentage of the total VOC emissions inventory. Highway mobile VOC emissions are projected to decrease into the future notwithstanding VMT increases. The area is currently well below the NAAQS and emission sensitivity modeling performed by ASIP and the NCDAQ indicates no change in future ozone concentrations when VOC emissions are signific antly changed. Further, the NCDAQ considers it unreasonable to expect that Edgecombe a nd Nash Counties will experience enough motor vehicle emissions growth for a future ozone viol ation to occur. For these reasons, the NCDAQ will not be setting MVEB for VOC for the Rocky Mount area.

Safety Margin A safety margin is the difference between the attainment level of emissions from all source categories (i.e., point, area, and mobile) and the projected level of emissions from all source categories. The State may choose to allocate some of the safety margin to the MVEB, for transportation conformity purposes, so long as th e total level of emissions from all source categories remains equal to or less than the attainment level of emissions.

The NCDAQ has decided to allocate safety marg in to the MVEB to account for new emissions models, VMT projections models, as well as change s to future vehicle mix assumptions, etc. that influence the emission estimations. Since 2008 is a historic year, the NCDAQ decided to allocate the entire safety ma rgin available to the MVEBs. For 2017, the NCDAQ estimated the amount needed to account for the current emission model and VMT projections model and then added an additional 21% to account for any future changes to the emission model, projection model and other input data.

Motor Vehicle Emission Budgets The NCDAQ did not receive any comments regardi ng the geographic extent of the MVEB from any of the Rocky Mount transportation partne rs during the maintenance plan interagency consultation process. However, there was di scussion through the in teragency consultation process on the years to set MVEB for the Rocky Mount maintenance plan. According to Section 93.118 of the transportation conformity rule, a main tenance plan must establish a MVEB for the last year of the maintenance plan (in this ca se, 2017). Through the interagency consultation process, it was decided that another MVEB woul d be set for the year 2008 in the Rocky Mount maintenance plan.Mobile Source Inventory Appendix C.3 4-29 Supplement to the Rocky Mount 8-hour Ozone Maintenance Plan February 7, 2011 The NCDAQ will set MVEB, for tr ansportation conformity purposes, as county budgets within the Rocky Mount nonattainment area for 2008 and 2017. Tables 4.1.6-1 and 4.1.6-2 below list out the NOx MVEB, for transportation conform ity purposes, by county for the years 2008 and 2017. Upon the USEPA’s approval of these coun ty-by-county sub-area MVEB, these MVEB will become the applicable MVEB for each county.

Table 4.1.6-1 Edgecombe County MVEB in kilograms per day 2008 2017

NOx Emissions (kg/day) Base Emissions 2,483 1,143 Safety Margin Allocated to MVEB 1,674 1,108 NOx Conformity MVEB 4,157 2,251

Table 4.1.6-2 Nash County MVEB in kilograms per day 2008 2017

NOx Emissions (kg/day) Base Emissions 8,790 3,767 Safety Margin Allocated to MVEB 1,655 2,374 NOx Conformity MVEB 10,444 6,141Mobile Source Inventory Appendix C.3 4-30 Supplement to the Rocky Mount 8-hour Ozone Maintenance Plan February 7, 2011 (This page intentionally left blank)Mobile Source Inventory Appendix C.3 4-31 Rocky Mount 8-hour Ozone Maintenance Plan June 19, 2006 4.1.7 Speed and VMT provided in January 11, 2006 email from NCDOT

EDGECOMBE COUNTY Modeled Area

Functional Class>Code 2002 2010 2020 2030

U-Inter>11 0 0 0 0 Frwy/Exway>12 96,183 132,442 145,217 181,269 U-OtherPrincipal>13 18,434 21,299 23,253 26,477 U-MinorArterial>14 95,164 112,033 150,093 178,359 Collector>15 14,935 17,097 18,254 19,974 U-Local>18 50,229 63,048 72,449 84,957

R-Inter>21 - - - - R-OtherPrincipal>23 130,368 195,824 249,218 321,288 R-MinorArterial>24 8,061 8,455 9,395 10,339 MajorCollector>26 106,438 85,241 106,833 137,766 MinorCollector>27 60,680 66,977 75,900 100,975 R-Local>28 71,333 87,077 97,925 111,287

Total from Model 651,825 789,495 948,535 1,172,690 Rural spreadsheet Portion 851,465 1,042,781 1,249,659 1,456,538 County total 1,503,290 1,832,275 2,198,194 2,629,229
County total from Universe file 1,548,100 1,895,942 2,272,058 2,648,173

2002 2010 2020 2030 Rural VMT(Outside MPO)

Urban Interstate 0.0 0.0 0.0 0.0 Urban Other Freewa y 44,399.5 67,744 81,184 94,624 Urban Other P A 53,540.0 65,312 78,270 91,227 Urban Minor Arterial 72,580.5 101,020 121,062 141,103 Urban Collector 8,768.0 11,533 13,822 16,110 Urban Local 40,677.5 50,167 60,120 70,072

Rural Functional Classes Rural Interstate 0.0 0.0 - - Rural Other PA 196,647.0 235,449 282,160 328,871 Rural Minor Arterial 73,139.0 90,089 107,962 125,834 Rural Major Collector 197,092.5 217,920 261,154 304,387 Rural Minor Collector 104,681.5 131,202 157,232 183,261 Rural Local 59,939.0 72,343 86,695 101,048

Total 851,464.50 1,042,781 1,249,659 1,456,538Hearing Record Appendix B 14 Supplement to the Rocky Mount 8-Hour Ozone Maintenance Plan February 7, 2011 

### Public Notice Report

For the Supplement to the Redesignation Demonstration and Maintenance Plan for the Ro cky Mount, North Carolina 8-Hour Ozone Nonattainment Area

On December 3, 2010, a draft version of the Nort h Carolina supplement to the redesignation demonstration and maintenance plan for th e Rocky Mount, North Carolina 8-hour ozone nonattainment area was submitted to the U. S. Environmental Protection Agency (USEPA). A request for public hearing, in accordance with 40 CFR 51.102, and the public comment period were noticed in the local newspapers on Wednesday, December 8, 2010. The public comment period was open from December 8, 2010, through January 10, 2011. No request for public hearing was received and no pub lic comments were received.

In March 2010, the USEPA announced in the Federal Register (FR) that the new mobile model, Motor Vehicle Emission Simulator (MOVES), will be required for transportation conformity purposes starting March 2012 (40 FR 9411). Th e NCDAQ committed to the transportation partners to review and revise the motor vehicle emission budgets if necessary to account for changes to the emission models, to the vehicl e miles traveled projec tion models and other emission model input data. This supplement revises the motor vehicle emission budgets through the allocation of a portio n of the safety margin. These re vised motor vehicle emission budgets will be used for transportation conformity purposes once approved by the USEPA.

The North Carolina Division of Air Quality will be moving forward with the final submittal to the USEPA of the North Carolina supplement to the redesignation demonstration and maintenance plan for the Rocky Mount, Nort h Carolina 8-hour ozone nonattainment area.