Conformity Adequacy Review: Region 9

State Implementation Plans (SIP) Submissions that EPA has Found Adequate or Inadequate
Region 9: Arizona, California, Hawaii, Nevada, and
the territories of Guam and American Samoa

For more information about adequacy review, return to the main adequacy page.

Contacts: Karina O'Connor, (CA, NV) at 775-434-8176 or
John J. Kelly, (CA) at 415-947-4151 or
Lindsay Wickersham, (AZ) at 415-947-4192 or
Michael Dorantes, (CA) at 415-792-3934 or
R9.adequacy@epa.gov, U.S. EPA Region 9, 75 Hawthorne St., San Francisco, CA 94105.

Arizona
Area	Pollutant	SIP Submission	Finding (date budgets apply)	Additional Information/ Comments
Ajo, AZ	1987 PM10	maintenance plan	Adequate (8/4/2020) Final FR (printed 8/4/2020 85 FR 47032)	Budgets found adequate through the SIP approval process.
Bullhead City	pm10	limited maintenance plan	Adequate (8/26/2002) FR Notice	Budgets found adequate through SIP approval process.
Miami	pm10	limited maintenance plan		Adequacy not completed on PM10 maintenance plan budgets. SIP submittal dated July 2008.
Phoenix-Mesa	2008 8-hour ozone	attainment demonstration	Adequate (7/2/2020) FR Notice printed 6/2/2020 85 FR 33571	Budgets found adequate through the SIP approval process.
	2008 8-hour ozone	attainment demonstration	Adequate (6/13/2012) FR Notice	Budgets found adequate through SIP approval process.
	1997 8-hour ozone	attainment demonstration	Adequate (11/9/2007) Letter FR Notice	Budgets found adequate through the adequacy review process.
Nogales	pm10	attainment demonstration	Adequate (9/25/2012) FR Notice	Budgets found adequate through SIP approval process.
Nogales	2006 pm2.5	maintenance plan and redesignation	Adequate (printed 8/15/2022) FR Notice	Budgets found adequate through the SIP approval process.
Payson City	pm10	limited maintenance plan	Adequate (5/19/2014) FR Notice	Budgets found adequate through the SIP approval process.
Payson City	pm10	limited maintenance plan	Adequate (8/26/2002) FR Notice	Budgets found adequate through SIP approval process.
Pima County	carbon monoxide	maintenance plan	Adequate (12/8/1999) Letter 1 Letter 2 FR Notice	Budgets found adequate through the adequacy review process.
Phoenix (Maricopa and Pinal Counties)
	pm10	5% plan	Adequate (12/20/2013) Letter FR Notice	Budgets found adequate through the adequacy review process.
		5% plan	Withdrawn (1/31/2011) Letter	Budgets previously found adequate on the 7/1/08 FR Notice.
		attainment demonstration	Adequate (4/21/2000) Letter FR Notice	PM10 budget for Maricopa County applies to entire non-attainment area including Pinal County. Budgets found adequate through the adequacy review process.
		attainment demonstration	Inadequate (12/27/1999) Letter FR Notice
Phoenix (Maricopa County)	carbon monoxide	maintenance plan	Adequate (3/3/2016) FR Notice	Budgets found adequate through the SIP approval process.
		maintenance plan	Adequate (10/14/2003) Letter FR Notice	Budgets found adequate through the adequacy review process.
		attainment demonstration (serious area)	Adequate (11/1/2001) Letter FR Notice	Revision to budget from 12/14/99. Budgets found adequate through the adequacy review process.
		attainment demonstration (serious area)	Adequate (12/14/1999) Letter FR Notice	Budgets found adequate through the adequacy review process.
		attainment demonstration (moderate area)	Inadequate (5/5/1999)	Determination made under old process
Tucson	carbon monoxide	limited maintenance plan	Adequate (12/21/2009) FR Notice	Budgets found adequate through the SIP approval process.
Yuma County	pm10	maintenance plan	Inadequate (6/16/2022) FR Notice	Budgets found inadequate through the adequacy review process.
		maintenance plan	Adequate (6/27/2007) Letter FR Notice	Budgets found adequate through the adequacy review process; reversed by FR notice above (effective 6/16/2022).
		attainment demonstration	Inadequate (11/16/1999) Letter FR Notice
California
Area	Pollutant	SIP Submission	Finding (date budgets apply)	Additional Information/ Comments
Bakersfield Metropolitan Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Chico Urbanized Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Coso Junction	pm10	Maintenance plan and insignificance finding	Adequate (8/13/2024) FR Notice	Found adequate through the SIP approval process.
Coso Junction	pm10	maintenance plan	Adequate (9/3/2010) FR Notice	Budgets found adequate through SIP approval process.
East Kern County	8-hour ozone	early progress plan	Adequate (12/10/2008) FR Notice	Budgets found adequate through adequacy review process.
Fresno Urbanized Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Imperial County	2006 pm2.5	attainment plan		Plan withdrawn (7/11/2017) Letter
Imperial County	8-hour ozone	early progress plan	Adequate (5/20/2008) Letter Enclosure FR Notice	Budgets found adequate through the adequacy review process.
Indian Wells	pm10	maintenance plan	Adequate (5/7/2003) FR Notice	Budgets found adequate by virtue of SIP approval.
Indian Wells	pm10	2nd maintenance plan	Adequate (2/17/2023) FR Notice (pdf) (270 KB, January 18, 2023)	Budgets found adequate through the SIP approval process
Lake Tahoe North Shore Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Lake Tahoe South Shore Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Los Angeles (Coachella)	pm10	attainment demonstration	Adequate (4/9/2004) Letter FR Notice	Budgets found adequate through the adequacy review process.
			Adequate (4/18/2003) Letter FR Notice	Budgets found adequate through SIP approval process.
			Inadequate (1/4/2000) Letter FR Notice
Los Angeles - San Bernadino Counties (Western Mohave Desert)	8-hour ozone	early progress plan	Adequate (5/20/2008) Letter Enclosure FR Notice	Budgets found adequate through the adequacy review process.
Mammoth Lakes	pm10	maintenance plan	Adequate (10/5/2015) FR Notice	Budgets found adequate through SIP approval process.
Modesto Urbanized Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Portola	2012 PM2.5	attainment plan	Adequate (3/25/2019) FR Notice	2012 PM2.5 budgets originally posted for adequacy on May 8, 2017. Adequacy restarted on January 5, 2018 to include 2021 as well as 2019 and 2022 budgets. Budgets approved for 2019 and 2021 through the SIP approval process.
Riverside County (Coachella Valley)	8-hour ozone	early progress plan	Adequate (5/22/2008) Letter Enclosure FR Notice	Budgets found adequate through the adequacy review process.
Riverside County (Coachella Valley)	2008 8-hour ozone	reasonable further progress	Adequate (4/12/2022) FR Notice (pdf) (198 KB, published March 28, 2023)	Budgets found adequate through the adequacy review process.
Sacramento Metro Area	pm10	maintenance plan	Adequate (12/8/2011) Letter FR Notice (PDF)(1 pp, 140K, published November 23, 2011, About PDF)	Budgets found adequate through the adequacy review process.
	2008 8-hr ozone	attainment demonstration and reasonable further progress	Adequate (10/22/2021) FR Notice	Budgets found adequate through the SIP approval process.
	1997 8-hr ozone	attainment demonstration and reasonable further progress	Adequate / Inadequate (1/29/2015) FR Notice	Budgets found adequate through the SIP approval process.
		attainment demonstration and reasonable further progress	Adequate / Inadequate (8/12/2009) Letter FR Notice	Budgets found adequate / inadequate through the adequacy review process.
		reasonable further progress	Adequate (3/29/2006) Letter FR Notice	Budgets found adequate through the adequacy review process.
Sacramento Urbanized Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
San Bernardino County	pm10	attainment demonstration	Inadequate (1/4/2000) Letter FR Notice
San Diego Area	2015 8-hour ozone	Attainment plan	Adequate (10/19/2021) San Diego 2008 and 2015 Letter (pdf) (287.01 KB, October 2021) 86 FR 54692 (printed 10/4/2021)	budgets found adequate through the adequacy review process.
	2008 8-hour ozone	Attainment plan	Adequate (10/19/2021) San Diego 2008 and 2015 Letter (pdf) (287.01 KB, October 2021) 86 FR 54692 (printed 10/4/2021)	budgets found adequate through the adequacy review process.
	2008 8-hour ozone	reasonable further progress plan	Adequate (12/4/2017) Letter FR Notice (printed 11/17/17, 82 FR 54339)	Budgets found adequate through the adequacy review process.
	1997 8-hour ozone	maintenance plan	Adequate (4/4/2013) Letter FR Notice	Budgets found adequate through the adequacy review process.
	1997 8-hour ozone	attainment plan	Adequate (6/9/2008) Letter and Enclosure FR Notice	Budgets found adequate through the adequacy review process.
	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
San Francisco Bay Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
San Joaquin Valley	2008 8-hour ozone	Attainment demonstration	Adequate (7/14/2017) 82 FR 29547 (Printed 6/29/2017) Letter	Budgets found adequate through the adequacy process
	1997 8-hour ozone	attainment demonstration	Adequate (3/01/2012) FR Notice	Budgets found adequate through SIP approval process.
	1997 8-hour ozone	attainment demonstration and reasonable further progress plan	Adequate (2/6/2009) Letter and Enclosure FR Notice	Budgets found adequate through the adequacy review process.
	2012 annual pm2.5	Attainment Plan (Serious area)	Plan Withdrawn (10/27/2022) CARB requesting letter (pdf) (835.09 KB, October 27, 2022)
	2012 annual pm2.5	Attainment plan (moderate area)	Adequate (11/26/2021) FR Notice	Budgets found adequate through the SIP approval process.
	2006 pm2.5	attainment plan	Adequate (7/22/2020) Final Rule (printed 7/22/2020 85 FR 44193)	Budgets found adequate through the SIP approval process.
	2006 pm2.5	attainment plan	Adequate (5/2/2016) Letter FR Notice	Budgets found adequate through the adequacy review process.
	1997 annual pm2.5	attainment plan revision	Adequate (2/10/2022) Letter (pdf) (311.42 KB) FR Notice	Budgets found adequate through the adequacy review process.
	1997 24-hour pm2.5	attainment plan	Adequate (1/28/2022) FR Notice	Budgets found adequate through the SIP approval process.
	1997 pm2.5	attainment plan	no adequacy action	The 2018 Plan supersedes this past submittal. See May 9, 2019 letter from CARB to EPA.
		attainment plan	Adequate (11/9/2011) FR Notice (PDF)(32 pp, 427 K, published November 9, 2011, About PDF)	Regional insignificance finding for re-entrained road dust made through the SIP approval process.
		reasonable further progress and attainment plan	Adequate / Inadequate (5/27/2010) Letter FR Notice	Regional insignificance finding for PM2.5 and NOx made through the adequacy review process.
	pm10	maintenance plan	Adequate (11/12/2008) FR Notice	Budgets found adequate through SIP approval process.
		attainment demonstration	Adequate (5/26/2004) FR Notice	Budgets found adequate through SIP approval process.
		attainment demonstration	Inadequate (5/5/1999)	Determination made under old process.
Searles Valley	pm10	attainment demonstration	Inadequate (1/4/2000) Letter FR Notice
South Coast	2006 24-hour pm2.5 (serious area)	attainment plan	Adequate (10/12/2021) Letter (pdf) (269.89 KB) FR Notice	Budgets found adequate through the adequacy review process.
	2006 pm2.5	attainment plan	Adequate (1/22/2018) Letter 83 FR 679 (Printed 1/5/2018)	Budgets found adequate through the adequacy review process.
	2006 pm2.5	impracticability demonstration	Adequate (4/14/2016) FR Notice	Budgets not acted on due to demonstration of impracticability.
	8-hour ozone	attainment demonstration	Adequate (3/1/2012) FR Notice	Budgets found adequate through SIP approval process.
	pm2.5	attainment plan	Adequate (11/9/2011) FR Notice (PDF)(29 pp, 400 K, published November 9, 2011, About PDF)	Budgets found adequate through SIP approval process.
	8-hour ozone and pm2.5	reasonable further progress, attainment plan, and out-year budgets	Adequate / Inadequate (5/30/2008) Letter Attachment FR Notice	Budgets found adequate / inadequate through the adequacy review process. The May 15, 2008 adequacy FR notice incorrectly stated that the 2017 NOx budget for the 8-hour ozone standard was 32 tpd. The adequate 2017 NOx budget for ozone is actually 232 tpd. This typographical error was corrected in a June 18, 2008 FR notice
	nitrogen dioxide	maintenance plan	Adequate (1/4/2010) Letter FR Notice	Budgets found adequate through the adequacy review process.
	nitrogen dioxide	maintenance plan	Adequate (4/9/2004) Letter FR Notice	Budgets found adequate through the adequacy review process.
	pm10	attainment demonstration	Adequate (4/18/2003) Letter FR Notice	Budgets found adequate through SIP approval process. Budgets replace those posted on 06/24/99.
Stockton Urbanized Area	carbon monoxide	maintenance plan	Adequate (1/30/2006) FR Notice	Budgets found adequate through SIP approval process.
Ventura	8-hour ozone	early progress plan	Adequate (5/20/2008) Letter Enclosure FR Notice	Budgets found adequate through the adequacy review process.
Nevada County, Western part, CA	2008 8-hour ozone	attainment plan	Adequate (5/21/2021) Final FR (printed 5/21/2021 86 FR 27524)	Budgets found adequate through the SIP approval process.
Yuba City-Marysville	pm2.5	maintenance plan	Adequate (9/9/2014) FR Notice	Budgets found adequate through the adequacy review process
Nevada
Area	Pollutant	SIP Submission	Finding (date budgets apply)	Additional Information/ Comments
Clark County (Las Vegas)	8-hour ozone	maintenance plan	Adequate (2/7/2013) FR Notice	Budgets found adequate through SIP approval process.
	8-hour ozone	early progress plan	Adequate (5/29/2009) FR Notice	Budgets found adequate through the adequacy review process.
	carbon monoxide	maintenance plan	Adequate (9/27/2010) FR Notice	Budgets found adequate through the SIP approval process.
		attainment demonstration	Adequate (12/15/2000) Letter FR Notice	Budgets found adequate through the adequacy review process.
			Inadequate (2/17/2000) Letter FR Notice
			Inadequate (5/5/1999)	Determination made under old process
	pm10	maintenance plan	Adequate (10/16/2014) FR Notice	Budgets found adequate through the SIP approval process
		attainment demonstration	Adequate (1/26/2002) Letter FR Notice	Response to Comments, Adequacy Review Table. Budgets found adequate through the adequacy review process
		attainment demonstration	Inadequate (11/16/1999) Letter FR Notice
Lake Tahoe	carbon monoxide	limited maintenance plan	Adequate (2/13/2004) FR Direct Final Rule	Budgets found adequate through SIP approval process.
Reno (Truckee Meadows, Washoe County)	pm10	maintenance plan	Adequate (12/8/2015) FR Notice	Budgets found adequate through SIP approval process.
	pm10	maintenance plan	Adequate (6/2/2010) Letter FR Notice	Budgets found adequate through the adequacy review process.
	carbon monoxide	second maintenance plan	Adequate (10/31/2016) FR Notice (PDF)(10 pp, 278 K, published August 30, 2016, About PDF)	Budgets found adequate through the SIP approval process
	carbon monoxide	maintenance plan	Adequate (3/30/2006) Letter FR Notice	Budgets found adequate through the adequacy review process.

Conformity Adequacy Review: Region 9

State and Local Transportation