## M A G 2013 CA RBON MONOXIDE MA INTENA NCE PLA N

FOR THE MA RICOPA

COUNTY A REA

MA RCH 2013

## M A G 2013 CA RBON MONOXIDE MA INTENA NCE PLA N

FOR THE MA RICOPA

COUNTY A REA

Pr epar ed by :

M ar ch 2013

T echni cal Assi stance Pr ov i ded By :
A r i z ona Departm ent of Env i r o nm ental Qual i ty A r i z ona Departm ent of T r ansportati on M ar i copa County A i r Qual i ty Departm ent U. S. Env i r onm ental Pr otecti on AgencyMAG 2013 CA RBON MONOXIDE MA INTENA N CE PLA N FOR THE MA RICOPA

COUNTY

A REA
TA B LE OF CONTENTS
CHA PTER PA GE

ONE INTRODUCTION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

OUT LINE OF T H E MAG 2013 CARBON M ONOXI DE MAINT ENANCE PLAN.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
TW O CO NT I N UED A T TA INMENT OF THE CA RBON MONOXIDE STA NDA RDS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
HIST ORICAL PERSPECT IVE.

. . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
CARBON MONOX IDE MONIT ORING NET W ORK.

. . . . . . . . . . 2-1
MONIT ORING RESULT S AND CONT INUED AT T AINMENT DEMONST RAT ION.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
QUALIT YASSURANCE PROGRAM.

. . . . . . . . . . . . . . . . . . . . . 2-2
THREE MA INTENA N CE PLA N

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

MAINT ENANCE PLAN CONT ROL MEASURES.

. . . . . . . . . . . . 3-1
EMISSIONS INVENT ORIES.

. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
MAINT ENANCE DEMONST RAT ION.

. . . . . . . . . . . . . . . . . . . . . 3-5
MONIT ORING NET W ORK AND VERIFICAT ION OF CONT INUED AT T AINMENT

. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
CONT INGENCY

PROVISIONS.

. . . . . . . . . . . . . . . . . . . . . . . . 3-19
T RANSPORT AT ION CONFORMIT YBUDGET

. . . . . . . . . . . . . 3-20
SUBSEQUENT MAINT ENANCE PLAN REVISIONS.

. . . . . . . . 3-22
REFERENCES.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23

iMAG 2013 CA RBON MONOXIDE MA INTENA N CE PLA N FOR THE MA RICOPA

COUNTY

A REA
LIST OF TA B LES
TA BLE PA GE
2-1 2008 Carbon Monox ide Monitoring Data Sum maryfor the Maricopa CountyMaintenance Area.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2-2 2009 Carbon Monox ide Monitoring Data Sum maryfor the Maricopa CountyMaintenance Area.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2-3 2010 Carbon Monox ide Monitoring Data Sum maryfor the Maricopa CountyMaintenance Area.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2-4 2011 Carbon Monox ide Monitoring Data Sum maryfor the Maricopa CountyMaintenance Area.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
3-1 Maintenance Measures in the 2013 Carbon Monox ide Maintenance Plan.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3-2 Av erag e W eekdayEm issions during the W inter Season in the Carbon Monox i de Modeling Dom ain.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3-3 Av erag e W eekdayEm issions during the W inter Season in the Carbon Monox i de Maintenance Area.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3-4 T otal Carbon Monox ide Em issions in the Carbon Monox i de Modeling Dom ain.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3-5 UAM/CAL3QHC Max im um Eig ht-Hour Carbon Monox ide Concentration Adjustm ents and Scaled Estim ates f or 2025..

. . . . . . . . . . . . . . . . . . . . . . . 3-10
3-6 Max im um CAL3QHC Eig ht-Hour Carbon Monox ide Concentrations in 2025.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3-7 Second Hig hest Eig ht-Hour Carbon Monox ide Concentrations at Monitors in Maricopa County for 1996-2011.

. . . . . . . . . . . . . . . . . . . . . . . . 3-13
3-8 Carbon Monox i de Monitoring Sites in Maricopa County

. . . . . . . . . . . . . . . . 3-18

i iMAG 2013 CA RBON MONOXIDE MA INTENA N CE PLA N FOR THE MA RICOPA

COUNTY

A REA
LIST OF FIGURES FIGURE PA GE
2-1. Carbon Monox i de Maintenance Area and Carbon Monox ide Monitoring Sites.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2-2. Carbon Monox i de T rends (2004-2011).

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
3-1. 2008 and 2025 Carbon Monox ide Em issions bySource Categ ory for the Carbon Monox i de Modeling Dom ain.

. . . . . . . . . . . . . . . . . . . . . . . . . 3-6
3-2. 2008 and 2025 Carbon Monox ide Em issions bySource Categ ory for the Carbon Monox i de Maintenance Area.

. . . . . . . . . . . . . . . . . . . . . . . . . 3-6
3-3. Carbon Monox i de Modeling Dom ain and Maintenance Area.

. . . . . . . . . . . . 3-8
3-4. Historical One-Hour and Eig ht-Hour Carbon Monox i de Monitoring Data and Projections f or the W est Phoenix Monitoring Site.

. . . . . . . . . . . . 3-14
3-5. Norm aliz ed Diurnal Cy cles of W i nd Speed, T em perature, Mix ing Heig ht and Max im um Eig ht-Hour Carbon Monox ide Concentrations.

. . . . . . . . . . . 3-16

iiiMAG 2013 CA RBON MONOXIDE MA INTENA NCE PLA N FOR THE MA RICOPA COUNTY

A R EA
A PPENDICES
A PPENDIX A
Ex hibit I: 2 0 0 8 P e r io d i c E m i s s ions Inv entory for Carbo n M o n o xi d e fo r t h e

M a ricopa County , Ariz ona Maintenance Area. Maricopa Count y A i r QualityDepartm ent. Nov em ber 2012.
Ex hibit 2: T e c h n i c a l S u p p o rt D o c u m ent in Support of the MAG 2013 Car b o n

Monox id e Maintenance Plan for the M aricopa County Area. March 2013.
A PPENDIX B
Ex hibit 1: Public Hearing Process Docum entation
Ex hibit 2: Certif i cation of Adoption

i vCHA PTER ONE
INTRODUCTION

T he Maricopa County nonattainm e n t a r e a has attained the National Am bient Air Quality Standards for carbon m onox ide and has been redesig nated as a m aintenance area by the Env ironm ental Protection Ag ency (EPA). In 1978, the Gov ernor of Ariz ona desig nated the Maricopa Association of Gov ernm ents (MAG) as the lead air q ualityplanning ag encyfor Maricopa County in accordance w ith the C lean Air Act Section 174(a). T og ether w ith the State, MAG is res p o n s i b l e for determ ining w hich elem ents of the State Im plem entation Plan w il l b e planned, im plem ented and enforced by State and local g ov ernm ents in Ariz ona. In 1992 , t h e A ri zo na Leg islature recertif ied MAG as the reg ional air q uality planning ag ency in accordance w ith Section 174 of the 1990 Clean Air Act Am endm ents (A.R.S. Section 49-406A.). MAG coordinates w ith the Ariz ona Departm ent of Env ironm ental Quality , Ariz ona Departm ent of T ransportation, and the M aricopa County Air Quality Departm ent in dev eloping the plans necessary to attain and m a i n t a i n t he national standards.
T here hav e been no v i olations of the one-hour c arbon m onox ide standard s ince 1984 and no v iolations of the eig ht-hour standard since 1996. T he Rev ised MAG 1999 Serious Area Carbon Monox ide Plan dem onstrated atta i n m e n t by 2000 and w as subm i tted to EPA in 2001. T he MAG Carbon Monox i de Redesi gn a t ion Req uest and Maintenance Plan dem onstrated m aintenance of the carbon monox ide s tandards throug h 2015 and w as subm itted to EPA in 2003. On M arch 9, 2005, EPA published f inal approv al of the Serious Area Plan, Maintenan c e P l a n , and redesig nation of the Maricopa County area to attainm ent status, effectiv e April 8, 2005.
Section 175A(b) of the Clean Air Ac t req uires that eig ht y ears af ter redesig nation of an area as an attainm ent area, a n a d d i t ional plan rev ision for maintaining the prim ary air q uality standard for ten y ears af ter the ex piration of the i nitial ten y e a r p e riod m ust be subm itted to EPA. In accordance w ith the Clean Air Act, the MAG 2013 Carbon M onox ide Maintenance Plan has been prepared. T he plan dem onstrates continued m aintenance of the carbon m on ox i de standards throug h 2025 w ith a m ax i m um eig ht-hour concentration o f 4.0 parts per m illion and establishes a 2025 m otor v ehicle em i ssions budg et o f 5 5 9

. 4 m etric tons per day for the carbon m onox ide m aintenance area.
OUT LINE OF T HE MAG 2013 CARBON MONOX IDE MAINT ENANCE PLAN
T he purpose of this docum ent is to present the M AG 2013 Carbon Monox ide Maintenance Plan for the Maricopa C ounty Area. T he plan w as prepared to address th e r elev ant portions of the Septem ber 4,1992 EPA m em orandum entitled, “ Procedures for Processing Req uests to Redesig nate Areas to Attainm ent” that are pertinent to m aintenance plans.

1-1T he MAG 2013 Carbon Monox ide Maintenance Plan is com posed of the follow ing m ajor

sections:
1. Introduction (T his Chapter) - Includes a g eneral discus s ion of the prior Serious Area Plan and Maintenance Plan appro va l s , redesig nation to attainm ent s tatus, and the outline of the M AG 2013 Carbon M onox ide Maintenance Plan.
2. Continued Attainm ent of the Carbon M on o xi d e S tandards - Includes the historical perspectiv e; carbon m onox ide monitoring netw ork; m onitoring results a n d c ontinued attainm ent dem onstration; and q uality assurance prog ram

. 3. Maintenance Plan - Includes the m aintenance plan control m easures; em issions i nv entories; m aintenance dem onstration; m onitoring netw ork and v erif ication of continued attainm ent; c onting en c y prov isions; transportation conform i tybudg et; and subseq uent m aintenance plan rev isions.

1-2CHA PTER TW O

CONTINUED A

T TA INMENT OF THE CA RBON MONOXIDE STA NDA RDS

Attainm ent of the National A m b ie n t A ir Quality Standards for carbon m onox ide (CO) is dem onstrated w hen tw o consecutiv e y ears of m onitoring data for each site s how no m ore than one ex ceedance per y ear of the eig ht-hour (9 ppm ) and one-hour (35 ppm ) standards. T he follow ing inform ation dem onstrates that the M aricopa County m aintenance area has continued to attain the national standards for c arbon m onox ide for the past 15 y ears. T his is based on q uality assured m onitoring data representing all carbon m onox ide m onitoring locations in the m aintenance area.
HIST ORICAL PERSPECT IVE
Data f rom the reg i onal m onitoring n e two r k i n d i c ates that the Maricopa County m aintenance area has not ex perienced a v i olation of the eig ht-hour standard for carbon m onox ide since 1996. The last v iolation of the one-hour standard w as recorded in 1984. In addition, both the f req uency of ex ceedance day s and the m ag nitude of o b s erv ed CO concentrations hav e declined dram aticallysince air q ualitym onitoring beg an in the late 1960's.
In contrast to the lack of eig ht-hour v iolations since 1996, eig hty -six ex ceedance day s w ere recorded in 1984. T here w as a noticeable decline in the num ber of ex ceedance day s f rom 1984 throug h 1990. In 1994 throug h 1996 period, there w ere a total of eig ht ex ceedance day s, three each i n 1 9 9 4 a n d 1995, and tw o in 1996. T here w ere tw o v iolation sites in 1994 (W est Indian School and W est Phoenix sites), and one each in 1995 and 1996 (both at the Phoenix Grand Av enue m icroscale m onitor). A sing le ex ceedance of the eig ht-hour standard occurred in 1999 at the Phoenix Grand Av enue site, but this one ex ceedance did not constitute a v iolation of the standard. T here hav e been no ex ceedances of the CO standard since 1999.
T he Maricopa C ounty m aintenance area has been i n attainm ent of the National Am bient Air Quality Standards for carbon m onox ide since 1997 a nd has had a c ontinuous dow nw ard trend in concentrations. In the past ten y ears, the annual eig ht-hour m ax im um concentrat i o n h a s d e c reased by approx im ately 57 percent, f rom 7.5 ppm in 2001 to 3.2 ppm in 2011. Since 2008, the m ax im um eig ht-hour concentrations reported at the CO m onitoring locations hav e been less than half o f t h e 9 p p m standard (9.4 ppm due to rounding ).
CARBON MONOX IDE MONIT ORING NET W ORK
T he am bie n t a ir monitoring netw ork for carbon m onox ide in the M aricopa County m aintenance area consists of 12 State and Local Air Monitoring Stations (SLAMS). T he Buckey e station is l o c ated w est of the maintenance area in Maricopa County and also m onitors c arbon m onox ide. T w elv e of these sites are operated by the M aricopa County
2-1Air Quality Departm ent and one m o n i t o r is operated by the Ariz ona Departm ent of

Env ironm ental Quality

. T he CO m onitoring sites are identif ied, along w ith sum mary data f rom 2008 throug h 2011, in T ables 2-1 throug h 2-4. Fig ure 2-1 show s the g eog raphical distribution of

the reg ional m onitoring netw ork.
MONIT ORING RESULT S AND CONT INUED AT T AINMENT DEMONST RAT ION
T he m onitoring data presented in T ables 2-1 throug h 2-4 v erif y that the Maricopa County m aintenance area has rem ained in attainm ent of the nat ional standards for carbon m onox ide, in accordance w ith the federal req uirem ents of 40 C F R 5 0

. 8. Data recov ery rates for the m onitors ex ceed the 75 percent c om pleteness req uirem ents for all y ears and all state and federal q uality assurance procedures hav e been follow ed. Fig ure 2-2 illustrates the dow nw ard trend i n the second-hig hest carbon m onox ide concentrations at all m onitors in the m aintenance area.
QUALIT YASSURANCE PROGRAM
Carbon m o nox i de data for the M aricopa County area has been collected and q uality

assure d i n accordance w ith 40 CFR, Part 58, Appendix A “Quality Assurance Req uirem ents for SLAMS, SPMs, and PSD Air Monitoring ” and EPA’s “Quality Assurance Handbo o k for Air Pollution Measurem ent Sy stem s: Volum e II: Am bient Air Quality Monitoring Prog ram ”. T he data are recorded in the EPA Air Quali t y Sy stem and are av ailable for public rev iew throug h sources such as the EPA AirData w ebsite and air q uality m onitoring reports produced by the Maricopa C ounty A i r Q u a l i ty Departm ent and the Ariz ona Departm ent of Env ironm ental Quality

.

2-2TA B LE 2-1
2008 CA RBON MONOXIDE MONITORING DA TA SUMMA RY FOR THE MA RICOPA

COUNTY

MA INTENA NCE A R EA STA NDA R DS: 1-HOUR: 35 PPM; 8-HOUR: 9 PPM*

Site Name 1-Hour 8-Hour Max p pm 2 n d Max

ppm Max

p pm 2 n d Max

ppm Buckey e, 26449 W . 100 th Dr. s + 0.7 0.7 0.5 0.5 Central Phoenix , 1645 E. Roosev elt 3.6 3.5 2.6 2.2 Dy sart, 16825 N. Dy sart Rd. s 1.5 1.4 1.0 1.0 Glendale, 6001 W . Oliv e s 2.1 2.0 1.6 1.5 Greenw ood, 1128 N. 27 t h Av e. 3.0 3.0 2.7 2.4 JLG Supersite, 4530 N. 17 t h Av e. 3.1 3.1 2.5 2.4 Mesa, 310 S. Brooks s 1.7 1.7 1.4 1.3 North Phoenix , 601 E. Butler Dr. s 2.1 2.0 1.3 1.3 South Phoenix , 33 W . T am arisk Av e. s 3.7 3.2 2.2 2.0 South Scottsdale, 2857 N. Miller Rd. s 2.0 2.0 1.5 1.4 T em pe, 1525 S. Colleg e Av e. s 2.4 2.3 1.8 1.4 W est Chandler, 275 S. Ellis s 1.8 1.7 1.4 1.4 W est Indian School, 3315 W . Indian School Rd. 3.9 3.6 2.8 2.8

W est Phoenix , 3847 W . Earll 4.7 4.5 3.1 3.0

* Due to m athem atical rounding , v alues $ 35.5 and 9.5 ppm are necessary to ex ceed the standard. S Seasonal m onitor operating Septem ber 1st to April 1st.

+ T he Buckey e m onitor is located outside the carbon m onox ide m aintenance area. Sources: Env i ronm ental Protection Ag ency Air Quality Sy stem ; Maricopa C oun t y A ir

QualityDepartm ent 2008-2011 Air Monitoring Netw ork Rev i ew s.

2-3TA B LE 2-2
2009 CA RBON MONOXIDE MONITORING DA TA SUMMA RY FOR THE MA RICOPA

COUNTY

MA INTENA NCE A R EA STA NDA R DS: 1-HOUR: 35 PPM; 8-HOUR: 9 PPM*

Site Name 1-Hour 8-Hour Max p pm 2 n d Max

ppm Max

p pm 2 n d Max

ppm Buckey e, 26449 W . 100 th Dr. s + 1.2 1.1 0.6 0.5 Central Phoenix , 1645 E. Roosev elt 3.6 3.0 2.2 2.1 Dy sart, 16825 N. Dy sart Rd. s 1.0 0.9 0.9 0.8 Glendale, 6001 W . Oliv e s 2.0 1.9 1.3 1.2 Greenw ood, 1128 N. 27 t h Av e. 3.5 3.2 2.6 2.4 JLG Supersite, 4530 N. 17 t h Av e. 2.9 2.8 2.3 2.3 Mesa, 310 S. Brooks s 2.0 1.9 1.5 1.3 North Phoenix , 601 E. Butler Dr. s 5.9 2.1 1.3 1.3 South Phoenix , 33 W . T am arisk Av e. s 4.1 3.4 2.6 2.2 South Scottsdale, 2857 N. Miller Rd. s 2.9 1.9 1.4 1.4 T em pe, 1525 S. Colleg e Av e. s 4.0 3.6 2.9 2.1 W est Chandler, 275 S. Ellis s 2.1 2.1 1.7 1.5 W est Indian School, 3315 W . Indian School Rd. 5.6 5.0 4.2 3.3

W est Phoenix , 3847 W . Earll 4.9 4.8 4.6 3.3

* Due to m athem atical rounding , v alues $ 35.5 and 9.5 ppm are necessary to ex ceed the standard. S Seasonal m onitor operating Septem ber 1st to April 1st.

+ T he Buckey e m onitor is located outside the carbon m onox ide m aintenance area. Sources: Env i ronm ental Protection Ag ency Air Quality Sy stem ; Maricopa C oun t y A ir

QualityDepartm ent 2008-2011 Air Monitoring Netw ork Rev i ew s.

2-4TA B LE 2-3
2010 CA RBON MONOXIDE MONITORING DA TA SUMMA RY FOR THE MA RICOPA

COUNTY

MA INTENA NCE A R EA STA NDA R DS: 1-HOUR: 35 PPM; 8-HOUR: 9 PPM*

Site Name 1-Hour 8-Hour Max p pm 2 n d Max

ppm Max

p pm 2 n d Max

ppm Buckey e, 26449 W . 100 th Dr. s + 1.9 1.3 0.6 0.6 Central Phoenix , 1645 E. Roosev elt 3.2 3.2 2.4 2.2 Dy sart, 16825 N. Dy sart Rd. s 2.0 1.8 0.9 0.6 Glendale, 6001 W . Oliv e s 9.0 8.9 3.0 1.5 Greenw ood, 1128 N. 27 t h Av e. 4.3 3.9 3.0 2.3 JLG Supersite, 4530 N. 17 t h Av e. 2.9 2.7 2.1 2.1 Mesa, 310 S. Brooks s 2.0 2.0 1.4 1.4 North Phoenix , 601 E. Butler Dr. s 2.9 2.4 1.7 1.6 South Phoenix , 33 W . T am arisk Av e. s 4.4 4.3 3.1 3.1 South Scottsdale, 2857 N. Miller Rd. s 2.1 2.0 1.6 1.6 T em pe, 1525 S. Colleg e Av e. s 3.4 2.4 1.9 1.6 W est Chandler, 275 S. Ellis s 2.0 2.0 1.9 1.6 W est Indian School, 3315 W . Indian School Rd. (Closed June 30, 2010) # 3.7 3.3 2.3 2.3

W est Phoenix , 3847 W . Earll 4.3 4.2 3.3 3.2

* Due to m athem atical rounding , v alues $ 35.5 and 9.5 ppm are necessary to ex ceed the standard. S Seasonal m onitor operating Septem ber 1st to April 1st. # Less than 75 percent data av ailable.

+ T he Buckey e m onitor is located outside the carbon m onox ide m aintenance area. Sources: Env i ronm ental Protection Ag ency Air Qu a l i t y Sy stem ; Maricopa County Air

QualityDepartm ent 2008-2011 Air Monitoring Netw ork Rev i ew s.

2-5TA B LE 2-4
2011 CA RBON MONOXIDE MONITORING DA TA SUMMA RY FOR THE MA RICOPA

COUNTY

MA INTENA NCE A R EA STA NDA R DS: 1-HOUR: 35 PPM; 8-HOUR: 9 PPM*

Site Name 1-Hour 8-Hour Max p pm 2 n d Max

ppm Max

p pm 2 n d Max

ppm Buckey e, 26449 W . 100 th Dr. s + 1.8 1.2 0.9 0.8 Central Phoenix , 1645 E. Roosev elt 3.8 3.5 2.1 2.1 Dy sart, 16825 N. Dy sart Rd. s 1.0 0.9 0.5 0.5 Glendale, 6001 W . Oliv e s 1.9 1.8 1.3 1.2 Greenw ood, 1128 N. 27 t h Av e. 3.0 2.9 2.5 2.5 JLG Supersite, 4530 N. 17 t h Av e. # 2.5 2.5 2.3 2.1 Mesa, 310 S. Brooks s 1.9 1.8 1.5 1.3 North Phoenix , 601 E. Butler Dr. s 2.9 2.7 1.6 1.5 South Phoenix , 33 W . T am arisk Av e. s 3.0 2.9 2.6 2.0 South Scottsdale, 2857 N. Miller Rd. s 1.8 1.7 1.4 1.3 T em pe, 1525 S. Colleg e Av e. s 3.6 3.4 3.2 2.9 W est Chandler, 275 S. Ellis s 1.8 1.7 1.4 1.3 W est Phoenix , 3847 W . Earll 4.4 3.9 3.0 2.9

* Due to m athem atical rounding , v alues $ 35.5 and 9.5 ppm are necessary to ex ceed the standard. S Seasonal m onitor operating Septem ber 1st to April 1st. # Less than 75 percent data av ailable.

+ T he Buckey e m onitor is located outside the carbon m onox ide m aintenance area. Sources: Env i ronm ental Prot e c t i on Ag ency Air Quality Sy stem ; Maricopa County Air

QualityDepartm ent 2008-2011 Air Monitoring Netw ork Rev i ew s.

2-62-7 ARICOPA ASSOCIATION of

GOVERNMENTS Prepared b y the Maricopa Associa t ion of Go v ernments , December 2012 

### FIGURE 2-1 CARBON MONOXIDE MAINTENANCE AREA AND CARBON MONOXIDE MONITORING SITES

Legend Carbon Monoxide Maintenance Area
• Carbon Monoxide Monitoring Site Freeway Planned Freeway Major Roads N Monitoring Site Name BE Buc k e y e CP C e n tra l Phoen ix D Y D ys art GL Glenda le GR G r een w oo d JLG JLG S u pe rs i t e M E M esa NP No rt h Phoen ix SP So u t h P h oeni x ss Sout h S c o tt sdale 1E Tempe

MAP AREA

While every effort has been made to ensure the accuracy of this information , the Maricopa Association of Governments makes no warranty , expressed or implied , as to its accuracy and expressly disclaims liability for the accuracy thereof.

I : \ Projects\ air_quality \ Maps \ 85x11 \ co _mntrs_201 1

. mxd* D ue t o m at hem at ical rounding , v alues $ 9. 5 ppm ar e necessaryt o ex ceed the st andar d. S econd- Hig hest Concent r at ion 8- Hour Av er ag e Values

T E, W P W P W P W P W P W P W I 8- hour st andar d = 9. 4 ppm *

W P FIGURE 2-2

CA RBON MONOXIDE TRENDS

(2004-2011)

Monitors W here the Second-Hig hest Reading Occurred (T E) T em pe (W I) W est Indian School Road (W P) W est Phoenix
Source: Env i ronm ental Protection Ag encyAir QualitySy stem

.

2-8CHA PTER THREE
MA INTENA NCE PLA N

No v iolation of

the one-hour National Am bient Air Quality Standard f or carbon m onox ide has occurred in M aricopa County since 1984 and no v iolation o f t h e e i gh t-hour carbon m onox ide standard has been recorded at any m onitor sin c e 1 9 9 6

. The Rev ised MAG 1999 Serious Area Carbon Monox ide Plan f or the Maricopa County Nonattainm ent Area w as subm itted to the Env i ronm ental Protection Ag ency (EPA) in 2001 ( MAG, 2001). T he Carbon Monox ide Redesig nation Req uest and Maintenance Plan for the M aricopa County Nonattainm ent Area w as subm itted to EPA in 2003 (MAG, 2003).
T he Rev i s ed 1999 Serious Area Carbon Monox ide Plan dem onstrated attainm ent of the carbon monox ide standards by 2000. The 2003 C arbon Monox ide M ai n t e n ance Plan dem onstrated continued m aintena n c e of the carbon m onox ide standards throug h 2015. EPA approv ed the Rev ised 19 9 9 Serious Area Carbon Monox ide Plan and the 2003 Carbon Monox ide Maintena n c e P l a n and redesig nated the Maricopa County area to attainm ent, effectiv e April 8, 2005 (EPA, 2005).
Section 175A(b) of the Clean Air Act Am endm ents states that “8 years after redesignation of any area as an attainm ent area under section 107(d), the Stat e s hall s ubm it to the Adm inistrator an additional revision of the applicable S ta te i m plem entation plan for m ai ntaining the national prim ary am bient air quality standard for 10 years after the expiration of the initial 10-year period”

. T hus, a second c arbon m onox ide m aintenance plan for the y ears 2016 throug h 2025 for the Maricopa county area is req uired for subm ittal to EPA by April 8, 2013.
T his s econd c arbon m o n ox ide m aintenance plan (hereafter referred to as the 2013 CO Maintenance Plan) dem onstrates m aintenance o f t h e National Am bient Air Quality Standards for carbon m onox ide in the Maricopa County area throug h 2025 and establishes a 2025 conform ity budg et for onroad m obile source em issions using the latest v ersion of the EPA Motor Vehicle Em i ssion Sim ulator (MOVES) model, MOVES20 1 0 b

. T he 2008 Per i o d i c Em issions Inv entory for Carbon Monox ide for the Maricopa County , Ariz ona Maintenance Area is also included in Appendix A, Ex hibit 1.
MAINT ENANCE PLAN CONT ROL MEASURES
T he Maricopa County area w ill continu e t o im plem ent the m aintenance m easures in the 2003 Carbon Monox ide Maintenance Plan. T he f i rs t n i n e m easures in T able 3-1 w ere used for num eric c redit i n dem onstrating m aintenance of the carbon m onox ide standards throug h 2015. T hese m easures are descri b e d i n Chapter T w o of the 2003 CO Maintenance Plan. T he tenth m easure, Ex pansion of Area A Boundaries, w as one of three conting ency m eas u r e s in the 2003 Carbon Monox ide Maintenance Plan. T his m easure is described in Section VII-2-2 of the T echnical Support Docum ent in Appendix A, Ex hibit

3-1TA B LE 3-1

MA INTENA NCE MEASURES IN THE 2013 CA RBON MONOXIDE MA INTENA NCE PLA N

1. California Phase 2 Ref orm ulated Gasoline w ith 3.5% Ox y g en Content From Nov em ber 1 T hroug h March 31
2. Of

f-Road Vehicle and Eng ine Standards
3. Phased-In Em ission T est Cutpoints
4. One-tim e W aiv er f rom Vehicle Em issions T est
5. Defer Em issions Associated w ith Gov ernm ent Activ ities
6. Coordinate T raf

f ic Sig nal Sy stem s
7. Dev elop Intellig ent T ransportation Sy stem s
8. T oug her Enf orcem ent of Vehicle Reg istration and Em i ssions T est Com pliance
9. Clean Burning Fireplace Ordinances
10. Ex pansion ofArea A Boundaries

3-22 of the 2003 Carbon Monox ide M aintenance Plan (MAG, 2003). T he reason for conv erting

this m easure f rom conting ency to m aintenance in the 2013 Carbon Monox ide Maintenance Plan is discussed below

. In Nov em ber 2012, EPA proposed t o a p p rov e the 110(l) SIP rev ision subm itted by the Ariz ona Departm ent of Env ironm ental Quality (ADEQ, 2009; ADEQ, 2011) that w ill elim inate the req uirem ent for m otorcy cles to participate in the Ariz ona v ehicle em issions inspection and m aintenance (VEI) prog ram (EPA, 2012a). EPA has indicated that the benef its of the conting ency m easure, Ex pansion of Area A Boundaries, i n t h e 2003 Carbon Monox ide Maintenance Plan m ay be used to of fset the increase in em issi o n s a t t r i butable to the ex em ption of m otorcy cles f rom the VEI prog ram . Like other conting encym easures in the 2013 CO Maintenance Plan, this m easure w as i m plem ented early , in accordance w ith EPA g uidance (EPA, 1993).
T herefore, the Ex pansion ofArea A Boundaries is included as a m aintenance m easure in the 2013 Carbon Monox ide Maintenance Plan. As discussed i n the Conting ency Prov isions section of this c hapter, ADEQ has m ade a com m itm ent to re-insti t ute the VEI prog ram req uirem ent for m otorcy cles, i f there is a f uture v i olation of the carbon monox ide standard.
EMISSIONS INVENT ORIES
T he em issions i n v e n t o r i e s u s e d i n p e r fo r ming the m aintenance dem onstration are presented in T able 3-2, for 2006, 2008, 2015 and 2025 in the carbon monox ide m odeling dom ain, and T a b l e 3-3, for 2008 and 2025 in the CO m aintenance area. T he 2008 em ission s i n b o t h tables are based on the l atest periodic em issions inv entory (PEI) for carbon monox ide (CO) contained in Appendix A, Ex hibit 1 (MCAQD, 2012). T he PEI estim ates CO em issions for a ty pical w eekdayduring the w inter m onths, Nov em ber - January

. Em ission reduction credit for tw o m easures in T able 3-1, California Phase 2 Reform ulated Gasoline and O f

f-R o a d Vehicle and Eng ine Standards, is ref lected in the em issions inv entories show n in T ables 3-2 and 3-3. T he E P A MOVES2010b m odel estim ates that California Phase 2 Ref orm ulated Gasoline w ill reduce CO em issions by128.9 m etric tons per day in 2025, a reduction in C O m aintenance area em issions of about 17 percent. T he EPA NONROAD2008a m odel estim ates that Off-Road Vehicle and Eng ine Standards w ill reduce C O em issions by 15.0 m etric tons per day in 2025, w hich represents a tw o percent reduction in CO m aintenance area em issions.
W hile o t her m aintenance m easures in T able 3-1 w ill c ontinue to be im plem ented, their collectiv e carbon m onox ide reduction i m pact in 2025 i s anticipated to be l e s s t han one percent. T h e r e fo re , no num eric credit has been taken for these m easures in the m aintenance dem onstration. I n addition to R eform ulated Gasoline and Of f

- Road Vehicle and Eng ine Standards, the m aintenance dem onstration in this plan is dependent upon the em ission reduction benef its of tig hter federal em ission standards for new on r oad and nonroad eng ines, f uel req uirem ents, and continuing f l eet turnov er to low er em issions f rom onroad and nonroad v ehicles. T hese em ission reduction benef its are ref lected in the onroad and nonroad em issions show n in T ables 3-2 and 3-3.

3-3TA BLE 3-2 A VERAGE W EEKDA

Y EMISSIONS DURING THE W INTER SEASON IN THE CA RBON MONOXIDE MODELING DOMA IN

Source Category CO Emissions (metric tons/day )

2006 2008 2015 2025 Point 0.4 0.7 18.0 18.0 Area 26.4 25.8 29.6 33.1 Nonroad 227.1 187.0 133.1 129.4 Onroad 549.1 410.0 297.9 223.4 Total 803.0 623.5 478.6 403.9

TA BLE 3-3 A VERAGE W EEKDA

Y EMISSIONS DURING THE W INTER SEASON IN THE CA RBON MONOXIDE MA INTENA NCE A REA

Source Category CO Emissions

(metric tons/day ) 2008 2025 Point 0.7 19.8 Area 37.8 47.3 Nonroad 281.5 213.1 Onroad 581.6 359.4 Total 901.6 639.6

3-4T he data used to deriv e g rowth factors for estim ating point and area s ource em issions w ere

deriv ed f rom the MAG Socioeconom ic Projections of Population, Housing and Em ploy ment by Municipal Planning Area and Reg ional Analy sis Zone in Maricopa County ( MAG, 2007). T h e s e projections, w hich cov er the period 2010 throug h 2030, are based on the 200 5 Special U.S. Census conducted in Maricopa C ounty and w ere ap p r o ve d b y the MAG Reg ional Council in May2007.
Onroad mobile source em i ssions for the 2013 Carbon Monox ide Maintenance Pl a n w ere e s t im ated using the MOVES2010b m odel and traf f ic assig nm ent data output by the MAG T ransCAD trav el dem and m odel. The soc i o e conom ic projections adopted by the MAG Reg ional Council in 2007 w ere also used as input to the trav el dem and m odel.
N o n ro a d e q u i p me n t e mi s s i o n s w e re dev eloped w ith the EPA NONROAD2008a m odel, using default N ONROAD2008a activ ity g rowth rates for Mar i c opa C ounty , w ith one ex ception. Eq uipm ent population and activ ity lev els for com m ercial law n and g arden eq uipm ent w ere based on a surv e y perform ed as part of Cap and T rade Ov ersig ht C om m ittee w ork (ENVIRON, 2003).
T he Em issions and Dispersion Modeling Sy stem (EDMS) and Federal Av iation Adm inistration T erm i nal Area Foreca s t sy stem database w ere used to estim ate f uture em issions for all airports, ex c ept Luke Air Force Base (AFB). Luke A FB em issions w ere deriv ed f rom the 2008 M obile Source Em issions Inv entory for Luke AFB (W eston, 2010) and the F-35A T raining Basing Env i ronm ental Im pact Statem ent (USAF, 2012).
Details reg a r d i n g the technical inputs and assum ptions used in preparing the em issions inv entories are prov ided in Chapter II of the T SD (Appendix A, Ex hibit 2). T he percentag e contributions of CO em issions by source categ ory are illustrated in Fig ures 3-1 and 3-2 for the CO m odeling dom ain and m aintenance area, respectiv ely

. MAINT ENANCE DEMONST RAT ION
T he 2013 Carbo n M o n o xi d e Maintenance Plan relies on a s eries of technical analy ses to dem onstrate m a i n t e n a nce of the National Am bient Air Quality Standards for carbon m onox ide throug h 2025. T he m aintenance dem onstration assum es that the m easures in T able 3-1 w ill continue to be im plem ented throug h 2025.
T hree dif

ferent m o d e ling analy ses w ere perform ed to estim ate the ef fects of g rowth and em ission reduction strateg ies on f uture carbo n m onox ide concentrations in the Maricopa County area. In addition, tw o w eig ht of ev idence ev aluations w ere conducted using actual trends i n air q uality and m eteorolog ical data to reinforce the m odeling analy ses. T he results of these f iv e q uantitativ e assessm ents prov ide assurance that the r e w i ll c ontinue to be com pliance w ith the f ederal carbon m onox i de standards throug h 2025.
A m odeling protocol w as dev eloped to detail the technical approaches and assum ptions to be used in dem onstrating m aintenance of the federal s tandards for carbon m onox ide. T he m odeling protocol i s c o n t a in e d in Appendix I of the Technical Support Docum ent for the 2013 CO Maintenance Plan (T SD), contained in Appendix A, Ex hibit 2.
3-5FIGURE 3-1

2008 A ND 2025 CA R BON MONOXIDE EMISSIONS BYSOURCE CA TEGORY

FOR THE CA RBON MONOXIDE MODELING DOMA IN

FIGURE 3-2 2008 A ND 2025 CA R BON MONOXIDE EMISSIONS BYSOURCE CA TEGORY

FOR THE CA RBON MONOXIDE MA INTENA NCE A REA

3-6For the m aintenance dem onstration, t w o sets of carbon m onox ide em issions inv entories

we r e d e veloped representing : (1) the carbon m onox ide m odeling dom ain in 2006, 200 8 , 2015, and 2025 and (2) the carbon m onox ide maint e n a n c e area in 2008 and 2025. T he carbon monox ide m odeling dom ain and maintenance area are illustrated in Fig ure 3-3. T he m odeling dom ain cov ers 792 s q uare m iles, w hile the m aintenance area repres e n t s 1,814 sq uare m iles. Both ofthese areas are located w ithin Maricopa County

. T he 2008 Periodic E m i s s i o n s Inv entory for Carbon Monox ide in the Maricopa County Maintenance Area is prov ided in Appendix A, Ex hibit 1 (MCAQD, 2012). T his inv entory w as used to establish the 2008 base case em issions, back-cast the 2006 em issions, and project the 2015 and 2025 f uture em issions w ith control m easures in place.
T he m odeling for the 2013 CO Maintenance Plan w as conducted using three approaches: (1) an em issions inv entory com parison, (2) a s caling of the Urban Airshed Model/CAL3QHC m ax i m um concentration, and (3) a C AL3QHC intersection hotspot analy sis. T he f irst approach dem onstrates m aintenance of the standard by show ing a c ontinuing decrease in em issions lev els in 2015 and 2025 com pared w ith em issions lev els in 2006 and 2008. T he second approach scales the UAM/CAL3QHC m ax im um eig ht-hour concentrations for 2006 and 2015 deriv ed f rom the 2003 CO Maintenance Plan based on the ratio of f uture y ear to base y ear total anthropog enic carbon m o n o x i d e e m issions. T he scaled UAM/CAL3QHC m ax i m um concentration in 2025 w as used to dem onstrate m aintenance of the eig ht-hour carbon m onox ide standard.
In the third approach, C AL3QH C m odeling w as perform ed for six intersections w hich are ex pected to ex perience the heav iest traf f ic v olum es and c ong estion in 2025. T he CAL3QHC m ax i m um eig ht-hour CO concentration projected for eac h i ntersection w as added to the estim ated backg round concentration for 2025. T he com bined backg round and CAL3QHC m ax i m um eig ht-hour concentration at each intersection wa s also used to dem onstrate m aintenance ofthe eig ht-hour carbon m onox ide standard in 2025.
In addition to the three m odeling approa c h e s described abov e, tw o w eig ht of ev idence analy ses w ere perform e d t o dem onstrate m aintenance throug h 2025. T hese include an ev aluation of historical one-hour and eig ht-ho u r carbon m onox ide concentration trends at m onitoring sites and a reg ional meteorolog ical an a l ys i s

. For the f i rst w eig ht of ev idence analy sis, historical CO c oncentration trends for each m onitoring s ite w ere dev eloped and the trend w as extended to 2015 and 2025 using reg ression analy sis. For the second w eig ht of ev idence approach, a m e t e o r olog ical analy sis w as perform ed to dem onstrate that the historical im prov em ents in CO concentrations in the Maricopa County area are not due to unusuallyfav orable m eteorolog ical conditions.
Sum m aries of the f iv e technical analy ses c o n d u c t e d as part of the m aintenance dem onstration are described in the subsection s t h a t follow

. Details reg arding these analy ses and underly ing technical assum ptions are docum ented in Section IV of the T SD (AppendixA, Ex hibit 2).

3-7FIGURE 3-3 CARBON MONOXIDE MODELING DOMAIN AND MAINTENANCE AREA

3-8 

## .·

;ii Palo Ver d e**Me iteRedhawk** **on**. .V

alley Energy

0 2

. 25 4

. 5 

# • BE



### ·. 

# • ;ii Powe r Plant

_ 

### c::J CO Mod eli ng Domain 

### CJ CO M a in te n ance Ar ea 

## c:::::J M a r i copa Co u nt yEmissions Inv entory Comparison
T he em i ssions in the carbon m onox ide m odeling dom ain show n in T able 3-2 w ere estim ated using the latest em issions m odels and planning assum ptions. T able 3-4 com pares the total 2 0 0 6 and 2015 CO em issions i n T able 3-2 w ith em issions deriv ed w ith older m od e ls a n d assum ptions as part of the 2003 CO Maintenance Plan. In order to estim ate the m ax im um eig ht-hour CO concentration in 2025, the m ax im um concentration in 2006 of 5.3 ppm at the W est Indian School m onitor w as m ultiplied by the ratio of 403.9 m etric tons per day in 2025 div ided by 803.0 tons per day in 2006. T h i s r e s u l t s in an estim ated m ax im um eig ht-hour concentration in the CO m odeling dom ain of 2.7 parts per m illion (ppm ) in 2025.
T able 3-3 indicates that total em issions in the CO m aintenance area are 639.6 m etric tons per day in 2025 and 901.6 m etric tons per day in 2008. Apply ing this ratio to the m ax im um eig ht-hour CO concentration of 3.1 ppm at the W est Phoenix m onitor in 2008, results in an estim ated m ax im um eig ht-hour CO concentration of 2.2 ppm In 2025. T hese tw o em issions inv entory com parisons rev eal that the m ax im um c oncentration w ill rem ain w ell below the eig ht-hour standard o f 9 p p m i n both the C O m odeling dom ain and the C O m aintenance area throug h 2025.
Scaled UA M/CA L3QHC Maximum Eight-Hour Concentrations
In the MAG 2003 CO Maintenance Plan, the eig ht-hour carbon m onox ide concentrations in the m odeling dom ain w ere estim ated for the y ears 2006 and 2015 using the EPA-approv ed Urban Airshed Model (UAM) and intersection hotsp o t m odel ( CAL3QHC). Since the UAM/CAL3QHC predictions w ere deriv ed f rom the e m is s i ons inv entories based on older v ersions of

m odels (e.g ., MOBILE6) av ailable at the tim e the MAG 2003 CO Maintenance Plan w as dev eloped, em i ssions inv entories fo r the y ears 2006 and 2015, as w ell as the m aintenance y ear 2025, w ere new ly dev elo p e d , as show n in T able 3-4, using the latest v ersions of m odels and updated input data. T he UAM/CAL3QHC projections for the y ears 2006 and 2015 w ere adjusted by the ratio of the new to old em issions inv entory totals. T he adjusted 2006 and 2015 UAM/CAL3QHC estim ates f rom the M AG 2003 CO Maintenance Plan w ere scaled f or the m aintenance y ear 2025. Althoug h the Phoenix Grand Av enue and W est Indian School monitors w ere deactiv ated in 1993 and 2010, respectiv ely , modeling conducted for the Rev ised MAG 1999 Serious Area CO Plan (MAG, 2001) and the MAG 200 3 C O M a i n t e nance Plan (MAG, 2003) projected that these m onitored intersections w ould hav e s o m e o f the hig hest lev els of traf f ic cong estion and CO concentrations in f uture y ears. In a d d i t i o n , the W est Indian School m onitor recorded the peak CO c oncentration of 10.5 ppm during the 1994 episode that w as m o deled in both plans. T he adjusted and scaled m ax im um concentrations for t h e s e two intersections, as w ell as the hig hest eig ht-hour CO conce ntrations predicted by UAM/CAL3QHC in the modeling dom ain, are show n in T able 3-5. T he s caled m ax im um U AM/CAL3QHC eig ht-hour CO concentration for 2025 is 4.0 ppm , w hich is l ess than half the eig ht-hour CO standard of9 ppm

.

3-9TA BLE 3-4

TOTA L CA RBON MONOXIDE EMISSIONS IN THE CA RBON MONOXIDE MODELING DOMA IN

Source T otal CO Emissions (metric tons/day ) 2 006 2015 2025 2003 CO Mai ntenanc e Pl a n 912.3 901.2 N/A 2013 CO Mai ntenanc e Pl a n 803.0 478.6 403.9

TA BLE 3-5 UA M/CA L3QHC MA

XIMUM EIGHT-HOUR CA RBON MONOXIDE CONCENTRA TION A DJUSTMENTS A N D SCA LED ESTIMATES FOR 2025

(units = ppm) 2006 2015 2025
UA M / CA L3Q HC Adjusted UA M / CA L3Q HC Adjusted Based on 2 006 Based on

2015 W I Monitor* 7.28 6.41 6.59 3.50 3.22 2.95 W I Receptor #9 8.25 7.26 8.08 4.29 3.65 3.62 W I Receptor #8 8.08 7.11 7.84 4.16 3.58 3.51 W I Receptor #20 7.85 6.91 7.44 3.95 3.48 3.33 PHGA Monitor** N/A N/A N/A N/A N/A N/A PHGA Receptor #30 8.24 7.25 7.81 4.15 3.65 3.50 PHGA Receptor #46 8.08 7.11 7.45 3.96 3.58 3.34 PHGA Receptor #29 8.03 7.07 7.39 3.92 3.56 3.31 UAM/CAL3QHC Max im um 8.92 7.85 8.06 4.28 3.95 ( rounded t o 4. 0) 3.61

W I = W est I ndian S chool PHG A = P hoenix G r and Av enue

* T he W I M onit or w as deact iv at ed on June 30, 2010 **T he PHG A mon i t o r v alues w er e not av ailable (N/A) for t he 1994 episode modeled w it h UAM / CAL3Q HC ( M AG , 2001; M AG , 2003) , b e c ause t he monit or w as deact iv at ed on M ar ch 31, 1993, due t o im pending r econst ruct ion of t he adj acent int er sect ion. *** T he UAM / CAL3Q HC m ax im um w as rounded t o one decim al place.

3-10Intersection Hotspot A nalysis

T he three intersections projected to hav e the hig hest traf f ic v olum es and the three intersections projected to hav e the w orst traf f ic c ong estion w ere identif ied using the MAG T ransCAD traf

f ic assig nm ent for the y ear 2025. Detailed data sets w ere collected for each of the six intersections and they w ere m odeled using CAL3QHC to determ ine the m ax im um eig ht-hour CO concentration i n 2025. The m odeling input a s s u m p t io n s and results are detailed in Section III of the T SD (AppendixA, Ex hibit 2). T he backg round eig ht-hour CO concentration used for all intersections w as determ ined to be 1.3 ppm

. T he m ax im um eig hthour CO concentration in 2025, w hich is the sum of the i ntersection m ax im um im pact and the backg round concentration, w as projected to be 1.7 ppm at tw o intersections: 16 t h Street and Cam elback Road and Priest Driv e and Southern Av enue, as s how n i n T able 3-6. T he results f rom the C AL3QHC intersection hotspot analy sis support the con c l u s io n t hat hig h traf f ic v olum es and cong estion w ill not contribute to ex c eedances of the eig ht-hour carbon m onox ide standard in 2025.
Continued Monitored A ttainment
In addition to the three m odeling analy s es described abov e, MAG conducted tw o w eig ht of ev idence ev aluations to support the m aintenance de m onstration. T he f irst of these a s s e s s ed the historical trends in one-hour and eig ht-hour concentrations m easured a t c a r b o n m onox ide m onitors in the Maricopa County area. T o dem onstrate attainm en t , carbon m onox ide concentrations at each monitor should not ex ceed the one-hour standard of 35 ppm m ore than once per y ear for tw o consecutiv e y ears. In addition, the eig ht-hour standard of 9 ppm can not be ex ceeded m ore than once per y ear for tw o c onsecutiv e y ears.
T h e trends in the s econd-hig hest eig ht-hour c arbon m onox ide concentrations at eig htee n m onitors for the y ears 1996

- 2 0 1 1 a r e s h o w n in T able 3-7. Sim ilar tables show ing the hig hest and second-hig hest o n e - hour CO concentrations and hig hest eig ht-hour CO concentrations recorded at these eig hteen m onitors are show n in Section IV-3-1 of the T SD (Appendix A, Ex hibit 2). T he one-hour carbon m onox ide standard has not been v iolated at any m onitor since 1984. T he hig hest and second hig hest one-hour CO concentrations at all m onitors in 2011 w ere 4.4 ppm and 3.9 ppm , respectiv ely

. T he second-hig hest eig ht-hour carbon m onox i de c oncentration of 10.0 ppm w as recorded at the Grand Av enue monitor in 1996. Since then, no m onitor has v iolated the eig ht-hour CO s tandard. Eig ht-hour CO concentra t io n s hav e continued to decline ov er the past decade. T he hig hest and second hig hest eig ht-hour C O concentrations in 2011 w ere 3.2 ppm and 2.9 ppm , respectiv ely

. T o predict f uture c oncentrations based on the historical m onitored c arbon m onox ide conc e n t r ations, a reg ression analy sis w as perform ed using data recorded at fourteen CO m onitors for the period 1980 to 2011. T he reg ression eq uations w ere used to project carbon m onox ide concentrations to 2015 and 2025. Fig ure 3-4 show s the historical and projected

3-11TA BLE 3-6

MA XIMUM CA L3QHC EIGHT-HOUR CA RBON MONOXIDE CONCENTRA TIONS IN 2025 (units = ppm)

Intersection CA L3Q HC M aximum O ne-Hour CO Concentration M aximum

Eight-Hour CO Concentration Background CO Concentration T otal

M aximum Eight-Hour CO C oncentration
16 th St & Cam el bac k Rd 0.5 0.4

1.3 1.7
107 th Av e & G rand Av e 0.4 0.3 1.6
Pri es t Dr & Southern Av e 0.5 0.4 1.7
7 th Av e & Van Buren St 0.4 0.3 1.6 G erm ann Rd & G i l bert Rd 0.4 0.3 1.6
T hom as Rd & 27 th Av e 0.4 0.3 1.6

3-12TA BLE 3-7

SECOND HIGHEST EIGHT-HOUR CA RBON MONOXIDE CONCENTRA T IONS A

T MONITORS IN MA RICOPA COUNTY FOR 1996-2011 (units = ppm)

Site ID Site Name A bbr 2 n d highest non-ov erlapping 8-hour CO concentrations 1996 1997 1998 1999 2000 2001 2002 2003 2 004 2005 2006 2 007 2008 2009 2010 2 011 04-013-0013 South Phoenix (old) * SP 5.1 4.4 4.7 4.1 04-013-0016 W Indian Sc hool Rd W I 8.3 7.2 8.1 7.6 6.8 6.0 5.4 5.3 4.6 4.8 4.5 3.9 2.8 3.3 2.3 04-013-0019 W es t Phoenix W P 8.2 7.0 7.1 7.5 7.2 6.6 5.5 5.5 5.1 4.6 4.6 4.1 3.0 3.3 3.2 2.9 04-013-0022 Grand Av e GA 10.0 7.8 6.8 8.1 6.0 6.2 5.5 04-013-1003 M es a M E 3.8 4.5 3.7 4.0 3.2 2.7 3.5 2.2 1.7 2.4 2.0 2.0 1.3 1.3 1.4 1.3 04-013-1004 North Phoenix NP 3.7 3.4 5.6 3.5 3.1 2.5 2.7 2.1 2.0 2.2 1.9 1.6 1.3 1.3 1.6 1.5 04-013-2001 Glendale GL 3.7 3.0 3.4 3.5 3.2 2.8 2.7 2.3 2.1 2.3 1.8 1.6 1.5 1.2 1.5 1.2 04-013-3002 Central Phoenix CP 7.5 7.2 6.3 6.0 5.2 4.1 4.1 3.8 3.3 3.8 3.2 2.9 2.2 2.1 2.2 2.1 04-013-3003 South Sc otts dale SS 4.9 4.2 3.5 4.1 3.1 3.1 2.8 2.2 2.4 2.4 1.9 1.6 1.4 1.4 1.6 1.3 04-013-3005 Gilbert GI 2.2 2.7 2.4 2.0 04-013-3006 M aryv ale M A 6.3 5.9 6.7 7.0 5.3 5.0 4.1 2.9 04-013-3009 W es t Chandler (old) * W C 2.7 2.7 2.8 2.3 04-013-3010 Greenw ood GR 6.9 6.8 6.7 5.6 4.6 5.1 5.1 4.3 4.1 3.5 3.0 2.4 2.4 2.3 2.5 04-013-4003 South Phoenix (new ) * SP 4.4 4.8 3.4 3.7 3.3 3.3 3.2 2.7 2.3 2.0 2.2 3.1 2.0 04-013-4004 W es t Chandler (new ) * W C 2.2 2.1 2.2 2.6 2.1 2.0 2.0 1.5 1.4 1.5 1.6 1.3 04-013-4005 T em pe T E 3.2 3.1 3.4 2.4 1.7 2.4 2.4 1.9 1.4 2.1 1.6 2.9 04-013-4007 Surpris e SU 1.1 1.1 0.8 04-013-4010 Dy s art DY 1.1 1.1 1.2 0.8 1.3 1.0 0.8 0.6 0.5 04-013-4011 Buc k ey e BE 0.4 0.9 0.6 0.8 0.5 0.5 0.6 0.8 04-013-9997 Super Site SUPR 6.5 6.5 5.2 4.2 4.2 4.0 3.6 2.9 2.9 2.4 2.3 2.1 2.1

M aximum 10.0 7.8 8.1 8.1 7.2 6.6 5.5 5.5 5.1 4.8 4.6 4.1 3.0 3.3 3.2 2.9
* South Phoeni x and W es t Chandl er m oni tors (ol d) w ere rel oc ated to the new South Phoeni xand W es t Chandl er s i tes i n 1999 and 2000, res pec t i v el y

.

3-13FIGURE 3-4

HISTORICAL ONE-HOUR AND EIGHT-HOUR CARBON MONOXIDE MONITORING DATA AND PROJECTIONS FOR THE WEST PHOENIX MONITORING SITE

3-14 West P hoenix S i te
40 .--------------------------------------------------------------------. 1

- HourCO S tandard ( 3 5 ppm) 3 5

.. .... .. ...... .. .... ........ .. ...... .. .. .. .. .. ...... .. ...... .. .. . .... . ........ . ........ . .**~** ••
- ...**~** .. ................... -

3 0

10 8

- HourCO Sta ndard (9 ppm)**-:: ~-~** **;: :fa** **----** 3

. 6 pp;n -

.. . . . ;t :. '

... 2

.0 pm



### ...... . .. .**.'I..'** 0**+-------,-------.--------.-------.-------.-------.------ .7** **ppm** ____________**pm** 5

198 0 198 5 1990 199 5 2000 200 5 20 1 0 20 1 5 2020 202 5 Y e a r

-- 2nd Highe s t 1

- Ho ur CO

- 2nd Highe s t 8

- Ho ur COtrends in the second-hig hest one-hour and eig ht-hour CO concentr a t io n s at the W est

Phoenix m onitor. T he W est Phoenix site has the hig hest projected e i gh t

- h o u r CO concentratio n s o f 2

. 7 ppm in 2015 and 1.6 ppm in 2025. Sim ilar g raphs for the other thirteen m onitors are prov ided in Sec t i o n I V

- 3

- 1 of the T SD (Appendix A, Ex hibit 2). T he projected carbon m onox ide concentrations based on historical data prov ide a d ditional ev idence that the Mar ic opa C ounty area w ill continue to maintain the one-hour and eig hthour standards throug h 2025. Meteorological A nalysis
A m eteorolog ical analy sis w as perform ed to support the prem ise that the m easured decreases in carbon m ono x ide concentrations are attributable to perm anent and enforceable em ission reductions, not unu s u a l ly fav orable m eteorolog ical conditions. T he perm anent and enforceable measures that hav e achiev ed c ontinuing reductions in carbon m onox ide concentrations, despite m ajor increases i n population, em ploy ment and v ehicle trav el i n the reg ion, are described in the R ev ised MAG 1999 Serious Area Carbon Monox ide Plan (MAG, 2001). For this purpose, long -term historical conditions for key m eteorolog ical param eters, i ncluding tem perature, w ind speed, w ind d irection, atm ospheric stability , and m ix ing heig ht, hav e been a n a lyz ed. T he detailed results of this analy s is are docum ented in Section IV-3-2 ofthe T SD (AppendixA, Ex hibit 2).
Four dif ferent m eteorolog ical analy ses w ere perform ed to dem onstrate that the continuing trend i n declining c arbon m onox ide concentrations in the Maricopa County area has not been due to fav orable m eteorolog ical conditions. Fig ure 3-5 show s the re s u l t s of one of these four analy ses. T his analy s is w as perform ed using m eteorolog ical data and eig ht-hour carbon m onox ide concentrations for the w inter seasons of 1994-2011. T his g raph show s c l e a rl y that m ax im um CO concentrations hav e declined, w hile daily w ind speeds, tem peratures, and m ix ing heig hts hav e not v aried sig nif icantlyov er the sam e period.
T he conclusions ofthe f our m eteorolog ical analy ses are sum m ariz ed below :

• T he m ax im um eig ht-hour CO concentrations hav e continued to decline, ev en thoug h m eteorolog i cal c onditions during those y ears hav e not dif fered s ig nif icantly f rom the 1994 episode m eteorolog ical conditions.

• T he eig ht-hour CO c oncentrations hav e declined, w hile the daily v ariations in w ind speeds, tem peratures and m i x ing heig hts hav e not v aried sig nif icantlyov er tim e.

• T he one-hour CO concentrations hav e continued to decrease ov er tim e reg ardless of m eteorolog i cal conditions.

• Da i l y m a x im um eig ht-hour CO concentrations below the CO s tandard w ere predom in a n t d u ring the period 1997 throug h 2011 under the s am e rang e of w ind speeds and m ix ing heig hts.

3-15FIGURE 3-5

NORMA LIZED DIURNA L CY CLES OF W IND SPEED, TEMPERATURE, MIXING HEIGHT A ND MA

XIMUM EIGHT-HOUR CA RBON MONOXIDE CONCENTRA TIONS

3-16Maintenance Demonstration Summary

T og ether, the three m odeling and tw o w eig ht of ev i dence analy s es described abov e support a def initiv e conclusion that carbon m onox ide concentrations w ill rem ain w ell below the oneh o u r and eig ht-hour standards throug h 2025. T he follow ing m ax im um eig ht-hour c a r b o n m onox ide concentrations w ere projected f or 2025:
Em issions Inv entory Com parison - 2.7 p p m ( m odeling dom ain); 2.2 ppm (m aintenance area)
Scaled U AM/CAL3QHC Max im um Eig ht-Hour Concentrations - 4.0 ppm ( m odeling dom ain) Intersection Hotspot Analy sis - 1.7 ppm (near tw o hig h traf f ic/cong ested intersections)
Continued Monitored Attainm ent - 1.6 ppm (2nd-hig h at the W est Phoenix m onitor)
T he m ax im um 2025 eig ht-hour c a rbon m onox ide concentration projected by these four analy ses w as 4.0 ppm , w hich w as based on scaled UAM/CAL3QHC m odeling results f rom the 2003 CO Maintenance Plan. T his m ax im um concentration in 2025 is less than half the eig ht-hour carbon m onox ide standard of9 ppm

. T he Meteorolog ical Analy sis prov ides additional conv incing ev i dence that t he major reductions in car bon m onox ide concentrations since 1994, despite increases in reg ional population, em ploy m ent, and v ehicle trav el ov er this period, can be attributed to perm anent and enforceable federal and local m easures in the EPA-approv ed carbon m onox ide plans for the reg ion (MAG, 2001; MAG, 2003), rather than f av orable m eteorolog ical conditions.
MONIT ORING NET W ORK AND VERIFICAT ION OF CONT INUED AT T AINMENT
T h e a m b i ent air q uality m onitoring netw ork in Maricopa County is desig ned to assess t h e extent of air pollution, ensure com pliance w ith national leg islation, ev aluate control options, and prov ide data for air q uality m odeling

. In accordance w ith 40 CFR Part 58, the Maricopa County Air Quality Departm ent (MCAQD) c urrently m aintains tw elv e c a r b on m onox ide m onitoring sites in Maricopa County , w hile the Ariz ona Departm ent of Env ironm ental Quality (ADEQ) operates the S u p e r s ite in central Phoenix

. T able 3-8 lists the carbon m onox ide m onitoring sites and their addresses.
M C A Q D a n d ADEQ w i ll continue to operate an appropriate air q uality m onitoring netw ork to collect and prov i de air q uality data for use i n dem onstrating o n go i n g attainm ent of the carbon monox ide standards. If the am bient lev els of carbon m onox ide concentrations rise and threaten to ex c eed the federal standard s, the reasons for these occurrences w ill be inv estig ated and appropriate actions w ill be taken. I n c o m p liance w ith 40 CRF Part 58 Subpart B, an annual air m onitoring netw ork rev iew w ill be conducted to determ ine w hether the netw ork m eets the m onitoring objectiv es def i ned in Appendix D of 40 CFR Part 58, w hether new sites are needed, and w hether ex isting sites are no long er needed and can be term inated.
3-17TA BLE 3-8 C A RBON MONOXIDE MONITORING SITES IN MA RICOPA COUNTY

Site ID Site Name A bbr Address City
0 4-013-0016 W es t Indi an Sc hool Rd * W I 33 rd Av e & W Indi an Sc h ool Rd Phoeni x 0 4-013-0019 W es t Phoeni x W P 39 th Av e & Earl l Dr Phoeni x 0 4-013-1003 Mes a ME Broadw a y Rd & Al m a Sc hool Rd Mes a 0 4-013-1004 North Phoeni x NP 7 th St & Dunl a p Av e Phoeni x 0 4-013-2001 Gl endal e GL 59 th Av e & W O l i v e G l endal e 0 4-013-3002 Central Phoeni x CP 16 th St & Roos ev el t St Phoeni x 0 4-013-3003 South Sc otts dal e S S Mi l l er Rd & T h om as Rd Sc otts dal e 0 4-013-3010 G reenw ood G R 27 th Av e & Inters tate 10 Phoeni x 0 4-013-4003 South Phoeni x S P Central Av e & Broadway Rd Phoeni x 0 4-013-4004 W es t Chandl e r W C El l i s St & Frye Rd Chandl er 0 4-013-4005 T e m p e T E Col l ege Av e & Apac he Bl v d T em pe 0 4-013-4010 Dys a rt DY Dys a rt Rd & Bel l R d Surpri s e 0 4-013-4011 Buc k eye B E Hwy 85 & MC 85 Buc k eye 0 4-013-9997 Supers i te SUPR 4530 N 17 th Av e Phoeni x * Cl os ed i n 2010.

3-18CONT INGENCYPROVISIONS

Section 175A(d) of the Clean Air Act req uires that the m aintenance plan contain conting ency prov isions to ensure prom pt actions to correct any v iolation of the carbon m onox i de standard w hich occurs af

ter redesig nation to attainm ent. A conting ency plan is not req uired to contain f ully adopted contingency m easures. How ev er, the plan should contain clearly identif ied conting ency m easures to be adopted, a schedule and procedur e fo r a d option and im plem entation, and a specif i c tim e lim it for action by the State. In addition, specif ic indicators should be identif ie d w hich w ill be used to determ ine w hen the conting ency m easures need to be im plem ented (EPA, 1992). T he 2013 Carbon M onox i de Maintenance Plan addresses each of these req uirem ents below

. T w o conting ency m easures in this p l a n w ere also conting ency m easures i n the EPAapprov ed 2003 C O Maintenance Plan: Gross Polluter Option for I/M Prog ram W aiv ers and Increased W aiv er Repair Lim it Options (MAG, 2003). A third conting ency m easure, Reinstatem ent of the VEI Prog ram for Motorcy cles, has been added to the 2013 CO Maintenance Plan.
Consistent w ith EPA g uidance on early im plem entation ofconting encym easures, the tw o conting ency m easures that w ere approv ed in the 2003 CO Maintenance Plan hav e already been im plem ented in the CO maintenance area (EPA, 1993). No em i ssion reduction credit for these tw o conting encym easures w as taken in this m aintenance dem onstration.
A description of the conting e n c y m e asures in the 2003 CO M aintenance Plan is prov ided in Section VII-2-2 of the Technical Support Docum ent i n Appendix A, Ex hibit 2 ( MAG, 2003). T he reaso n s for conv erting the Ex pansion of Area A Boundaries f rom a conting ency m easure i n the 2003 CO Maintenance Plan to a maintenance measure in the 2013 Carbon Monox ide Main t e n a n c e P l a n and the addition of a new c onting ency m easure, Reinstatem ent of the VEI Prog ram for Motorcy cles, are discussed below

. In Nov em ber 2012, EPA proposed to approv e the 110(l) SIP rev ision subm it t e d by the Ariz ona Departm ent of Env ironm ental Quality (ADEQ, 2009; ADEQ, 2011) that w ill elim inate the req uirem ent for m oto rcy cles to participate in the Ariz ona v ehicle em issions inspection and m aintenance (VEI) prog ram (EPA, 2012a). EPA has i ndicated that the benef its of the conting ency m easure, Ex pansion of Area A Boundaries, in the 2003 CO Maintenance Plan m ay be used to of

fset the increase in em issions attributable to the ex em ption of m otorcy cles f rom the VEI prog ram

. Like other conting ency m easures in the 2003 CO Maintenance Plan, this m easure w as im plem ented early , in accordance w ith EPA g uidance (EPA, 1993).
T he m otorcy cle ex em ption is estim ated to increase total c arbon monox ide em i ssions in Area A b y 0 .264 m etric tons per day or 0.027 percent, w hile the 2003 CO Maintenance Plan estim ated that the ex pansion of Area A boundaries mandated by S.B. 1427 in 1998 reduced total CO em issions by 0.1 percent in 2000. Since the Ex pansion of Area A Boundaries w ill be used to of

fset the VEI ex em ption, it has been conv erted f rom a conting ency m easure in the 2003 Maintenance Plan to a com m i t t e d m a i ntenance m easure in the 2013 Carbon Monox ide Maintenance Plan.

3-19As indicated in the ADEQ SIP rev ision that w ill ex em pt motorcy cles f rom VEI testing , CAA

section 175A(d) req uires that the State adopt as a c onting ency m easure any control m easure that w as approv ed in the SIP pr ior to redesig nation, but w hich the State subseq uently repeals or relax es (ADEQ, 2009; EPA, 2012a). In this i nstance, because the EPA-approv ed VEI prog ram applied to m otorcy cles at the tim e the Maricopa County area w as redesig nated to attainm ent of the c arbon m onox ide standards in 2005, Reinstatem ent of the VEI Prog ram for Motorcy cles m ust also be adopted as a conting ency measure in the 2013 Carbon Monox ide Maintenance Plan.
T he ADEQ SIP re vi s i on proposes a conting ency m easure to reinstate VEI testing for m otorcy cles in Area A if a v iolation of the carbon monox ide standard occurs. If a v iolation of the eig ht-hour c arbon m onox ide standard occurs (i.e., the second-hig hest reading at the sam e monitor ov er tw o consecutiv e y ears is 9.5 ppm or hig her), reinstatem ent of the m otorcy cle VEI p r o gr am w i ll be im plem ented according to the follow ing schedule: ADEQ w ill req uest that the Ariz ona State Leg i slature reinstate em issions testing of m otorcy cles by October follow ing t h e violation. In J anuary 2013, ADEQ w i ll req uest that the Leg islature enact new leg islation to reinstate em issions testing of m otorcy cles prev iously ex em pted by the rev ised SIP in the Phoenix v ehicle em issions testing area, beg inning January 1 of the follow ing y ear (ADEQ, 2009).
In g eneral, the success of an air q uality prog ram is m eas u red by the concentrations recorded at the m onitors. In order to ensur e t h a t v iolations of the carbon m onox ide standards do not occur in the f uture, am bient air q uality m onitoring d a t a w ill be ex am ined to determ i ne if additional conting ency m easures are needed. T w o v erif ied eig ht-hour carbon m onox ide r e a ding s ex ceeding 9.0 ppm at one m onitor during the sam e w inter season (Nov em ber - January ) w ill trig g er consideration of additional m easures, w hich m ay include the streng thening of conting ency m easures that hav e already been im plem ented. W hen the trig g er is activ ated, additional m easures w ould be considered on the follow ing s chedule: (A) v erif i cation of the m onitoring data to be com pleted t h r ee m onths af ter activ ation of the trig g er; (B) applicable m easures to be considered for adoption six months af ter t he date established in (A); and (C) resultant c om m itted m easures to be im plem ented w ithin tw elv e m onths after the adoption date in (B).
T RANSPORT AT ION CONFORMIT YBUDGET
In accordance w ith the 1990 C lean Air Act Am endm ents (CAAA), transportation conform ity req uirem ents are intended to ensure that transportation activ ities do not result in air q uality deg radation. Section 176 of the Am endm ents req uires that transportation plans, prog ram s, and projects conform to applicable air q uality plans before t h e transportation action is approv ed by a Metropolitan Planning Org aniz ation (MPO). T he desig nated MPO for Maricopa Countyis the Maricopa Association of Gov ernm ents.
Section 176(c) of the 1990 CAAA prov ides the f ram ew ork for ensuring that Federal actions conform to air q uality plans under section 110. Conform ity to an im plem entation plan m eans
3-20that p r o p o s e d a c tiv ities m ust not: (1) cause or contribute to any new v i olation of any

standard in any area, (2) increase the f req uency or sev erity of any ex isting v iolation of any standard in any area, or (3) delay tim ely attainm ent of any s tandard or any req uired interim em ission reductions or other m ilestones in any area.
EPA transportation co nform ity reg ulations establish c riteria inv olv ing com parison of projected transportation plan em issions w ith the m otor v ehicle em issions assum ed in applicable air q uality plans. T hese reg ulations def ine the term “m otor v ehicle em issions budg et” as m eaning “the portion of the total allow able em issions def ined in a rev ision of the applicable im plem entation plan (or in an im plem entation plan rev ision w hich w as endorsed by the Gov ernor or his or her desig nee) for a certain date for t he purpose of m eeting reasonable f urther prog ress milestones or attainm ent dem onstrations, for any criteria pollutant or its precursors, allocated by the applicable im plem entation plan to hig hw ay and transit v ehicles.”
T he MAG 2003 C O M a i n t e n a n c e Plan, s ubm itted to EPA in May 2003, established tw o transportation conform ity budg ets for the c arbon monox i de m odeling dom ain: a 2006 CO em issions budg et of 699.7 m etric tons per day and a 2015 CO budg et of 662.9 m etric tons per d a y

. E P A fo u nd the 2006 and 2015 carbon m onox ide budg ets to be adeq uate for conform ity purposes, ef fectiv e October 14, 2003. In addition, these budg ets w ere approv ed by EPA as part of the MAG 2003 CO Maintenance Plan, ef fectiv e April 8, 2005. Currently , the approv ed 2006 budg et applies to conform ity horiz on y ears f rom 2006 throug h 2014 and the 2015 budg et applies to horiz on y ears after 2014.
T able 3-3 indicates that the onroad m obile s ource em issions for the CO m aintenance area w ill be 359.4 m etric tons per day in 2025. EPA has indicated a new v ersion of MOVES m ay be released in 2013 that “w ill incorporate m ultiple s ources of new em i ssions data” and “it is too early in the dev elopm ent process for us to estim ate the ov erall direction and m ag nitude of the em issions chang es” ( EPA, 2012b). T o ensure that increa s e s in carbon m onox ide em ission r ates i n f uture v ersions of the MOVES m odel do not cause ex ceedances of the 2025 conform ity budg et, it is proposed that a “ safety marg in” be applied to the 2025 onroad m obile source em issions produced by MOVES2010b.
T able 3-3 indicates that the 2008 carbon m onox ide em issions estim ated by MOVES2010b for the m aintenance area are 581.6 m etric tons per day

. T he m ax im um eig ht-hour carbon m onox ide concentration in 2008 w as 3.1 ppm (at the W est Phoenix m onitor), w hich is only one-t h i r d o f t he standard. Fig ure IV-1 in the T SD (Appendix A, Ex hibit 2) indicates that carbon monox ide concentrations hav e declined since 2008 at all m onitors and are projected to rem ain far below the 2008 c oncentrations at ev ery m onitoring site. T he hotspot analy sis also rev ealed that the traf f i c at hig h v olum e and heav ily cong ested intersections w ill increase eig ht-hour carbon m onox ide c oncentrations by a m ax im um of 0.4 ppm in 2025. T herefore, an increase in the 2025 conform ity budg et to a lev el below the 2008 em issions w ill not result in an ex ceedance ofthe carbon m onox ide standard.

3-21It is proposed that the safety m arg in represent 90 percent of t h e d i f f e r ence betw een the 2008 and 2025 c a rb o n m o nox ide em issions, w hich is 200.0 m etric tons per day

. W hen added to the 2025 carbon m onox i de em i ssions of 359.4 m etric tons per day , this establishes a new2025 conf orm ity budg et of 559.4 m etric tons per day for the CO maintenance area. It is i m portant to note that the 2025 budg et for the CO m ainten a n c e a r e a i s less than the 2006 and 2015 conform ity budg ets for the CO m o d eling dom ain, ev en thoug h the m aintenance area is m ore than tw ice the siz e of the m odeling dom ain.
Once EPA f inds the new 2025 budg et to be adeq uate (or approv es the 2025 budg et as part of the MAG 2013 CO Maintenance Plan), the 2025 budg et for the CO maintenance area w ill be applied i n reg i onal c onform ity analy ses conducted by MAG for horiz on y ears 2025 and bey ond. The 2006 and 2015 conform ity budg ets approv ed by EPA as part of the M AG 2003 CO M aintenance Plan, ef fectiv e April 8, 2005, w ill continue to b e a p p l i e d i n conform ity analy ses for horiz on y ears prior to 2025. T he approv ed 2006 carbon m onox ide budg et of 699.7 m etric tons per day for the C O m odeling dom ain w ill be applied in reg ional conform ity analy ses for horiz on y ears 2006 throug h 2014 and the approv ed 2015 c a r b o n m o n ox ide budg et of 662.9 m etric tons per day for the CO m odeling dom ain w i ll be applied for horiz on y ears 2015 throug h 2024.
SUBSEQUENT MAINT ENANCE PLAN REVISIONS
Section 175A(b) of the Clean Air Act req uires that a m aintenance plan be subm itted to EPA eig ht y ears af

ter the orig i nal redesig nation req uest a n d m aintenance plan has been approv ed (i.e., by April 8, 2 0 1 3 ). The purpose of this s econd m aintenance plan i s to dem onstrate m aintenance ofthe f ederal carbon m onox ide standards f or an additional ten y ears (2016-2025) f ollow ing the f irst ten-y ear period (2006-2015).
No additional rev isions of the carbon m onox ide m a i n t e n a n ce plan are anticipated at this tim e. If EPA reduces the carbon m o nox ide standards, the Maricopa Association of Gov ernm en t s , a s t he desig nated Reg ional Air Quality Planning Ag ency for the Maricopa C o u n t y a r e a , w ill w ork w ith ADEQ, MCAQD, ADOT and EPA to rev ise the Stat e Im plem entation Plan, if necessary to dem onstrate attainm ent and m aintenance of the new carbon m onox ide standards.

3-22REFERENCES

ADEQ, 2009. Ariz ona Departm ent of Env ironm ental Quality

. Arizona State Implem entation Plan R e vision, Exemption of Motorcycles from Vehicle Em issions Inspections and Maintenance Program Requirem ents in Area A . Nov em ber 6, 2009. ADEQ, 2011. Ariz ona Departm ent of Env ironm ental Quality

. Arizona State Implem entation Plan Revision, Exemption of Motorcycles from Vehicle Em issions Inspections and Maintenance Program Requirem ents in Area A. January11, 2011. ENVIRON, 2003. Maricopa County 2002 Comprehensive Em ission Inventory for the Cap and Trade Oversight C om m ittee. Final Report prepared for Ariz ona Departm e n t of Env ironm ental Quality

. October. 8, 2003. EPA, 1992. U.S. Env i ronm ental Protection Ag ency

. Procedures for Processing Requests to Redesignate Areas to Attainm ent. Septem ber 4, 1992. EPA, 1993. U.S. Env ironm ental Protection Ag ency

. Early Implem entation o f C o n tingency Measures for Ozone and Carbon Monoxide (CO) Nonattainm ent Areas. Aug ust 13, 1993. EPA, 2005. U.S. Env ironm ental Protection Ag ency

. Approval and Prom ul g a t io n of Implem entation Plans and Designation of Areas for Air Quality Planning Purposes: Arizona. Federal Reg ister, March 9, 2005, Vol. 70, No. 45, p. 11553. EPA, 2012a. U.S. E n vironm ental Protection Ag ency

. Approval and Prom ulgation of Implem entation Plans and Designation of Areas for Air Quality Planning Purposes: Arizona; Motor Vehicle Inspection and Maintenance P rogram s. Federal Reg ister, Nov em ber 5, 2012, Vol. 77, No. 214, p. 66422. EPA, 2012b. E-m ail f rom Gary Dolce, EPA, to T aejoo Shin, MAG. October 25, 2012. MAG, 2001. Maricopa Associati o n o f Gov ernm ents. Revised MAG 1999 Serious Area Carbon Monoxide Plan for the Maricopa County Nonattainm ent Area. March 2001. MAG, 2003. M aricopa Association of Gov ernm ents. Carbon Monoxide Rede s i g n a tion Request and Maintenance Plan for the Maricopa County Nonattainm ent Area

. M ay 2003. MAG, 2007. M aricopa Association of Gov ernm ents. Socioeconom ic Projections Docum entation . May2007. MCAQD, 2012. Maricopa County Air Quality Departm ent. 2008 Periodic Emissions Inventory for Carbon Monoxide for the Maricopa C ounty, Arizona Maintenance Area

. 2012.

3-23USAF, 2012. U nited States Air Force. F-35A Training Basing Environm ental Impact

Statem ent, Final Volum e 1. June 2012.
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