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, Permits Office (AIR-3)

To: Docket No. EPA-R09-OAR-2012-0xxx, 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 Implementation 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, as 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 with 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 

categories 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 Sources 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

Permitted 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 16,290 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

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