UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX

75 Hawthorne Street

San Francisco, CA 94105



### July 10, 2012

Memorandum

Subject: EPA evaluation of Clark County minor source emissions

From: Laura Yannayon , EPA Region 9, Air Division, Pe rmits Office (AIR

- 3 )

To: Docket No. EPA

- R09

- OAR

- 201 2

- 0 xxx, Clark County NSR Programs

The attached spreadsheet contains emission data included in Appendix D of Clarks submittal entitled

“ Proposed Revision To The Clark County Part Of The Nevada State Imp lementation Plan: Minor Source

New Source Review Program Rule Adoptions And Revisions,” January 29, 2009. EPA has reviewed

and analyzed this data to determine the contribution of minor source emissions to the overall inventory

for VOC, NOx, CO and PM10, a s these are the pollutants for which Clark is or has recently been

classified as nonattainment.

“Point Sources” include all major sources and for sources with NOx emissions, those with actual

emissions greater than 25 tpy, and with VOC emissions, those w ith actual emissions greater than 10 tpy.

The area sources are made up of a combination of both permitted and non

- permitted area sources. For

each pollutant, the contributors to the area source inventory were examined and all non

- permitted source

catego ries were summed to determine what percentage of the area source emissions were definitely not

minor source permitted emissions. The remaining percentage was assumed to be from permitted

sources, which is a conservative estimate because within each source category some sources may not

require a permit. This data was then used to calculate the worst case estimate of the minor source

emissions as a percentage of all emissions for each pollutant.

## Evaluation of Minor Source Emissions as Percent of Overall Emissions

2003 (TPY) VOC Assumed %

permitted in

catogory? Total

permitted

emissions Permitted emissions

as a percentage of

total emissions Minor Source Permitted

emissions as a percentage

of total emissions

Point sources 1,674 100% 1,674

Areas Sourc es 16,789 63% 10,527

Mobile 15,301 0

On Road Mobile 20,289 0

Airports 722 0

Totals 54,775 12,201 22% 19.22%

Source: Table 3

- 1., Appendix D, pg. D

- 8

2003 (TPY) CO Assumed %

permitted in

catogory? Total

permitted

emissions P ermitted emissions

as a percentage of

total emissions Minor Source Permitted

emissions as a percentage

of total emissions

Point sources 5,147 100% 5,147

Areas Sources 4,541 17% 772

Mobile 171,187 0

On Road Mobile 185,323 0

Airports 16,29 0 0

Totals 382,488 5,919 2% 0.20%

Source: Table 3

- 1., Appendix D, pg. D

- 8

2003 (TPY) NOx Assumed %

permitted in

catogory? Total

permitted

emissions Permitted emissions

as a percentage of

total emissions Minor Source Permitted

emissions as a percentage

of total emissions

Point sources 33,555 100% 33,555

Areas Sources 1,870 100% 1,870

Mobile 14,355 0

On Road Mobile 36,355 0

Airports 3,013 0

Totals 89,148 35,425 40% 2.10%

Source: Table 3

- 1., Appendix D, pg. D

- 8

2006 (TPD) PM10 Assumed %

permitted in

catogory? Total

permitted

emissions Permitted emissions

as a percentage of

total emissions Minor Source Permitted

emissions as a percentage

of total emissions

Point sources 3 100% 3

Areas Sources 146 3% 4

Mobile 4 0

On Road Mobile 65 0

Airports 0 0

Totals 218 7 3% 1.87%

Source: Table 3

- 1., Appendix D, pg. D

- 2

Source: Appendix D

– Emission Inventory Tables, in “Proposed Revision To The Clark County Part Of The Nevada

Sta te Implementation Plan: Minor Source New Source Review Program Rule Adoptions And Revisions,” January 29, 2009.