2008 Ozone Standard Designation 

Recommendation for DeSoto County, Mississippi 

Response to U.S. Environmental Protection Agency’s 120 Day Letter 

Mississippi Department of Environmental Quality 

Air Division 

February 2012 
Mississippi Department of Environmental Quality 

February 2012 

- 2 -

Summary 

In 2004, DeSoto County was excluded from the Memphis Non-Attainment Area as EPA 

determined that the county did not significantly contribute to ozone levels in the 

Memphis area. Since that time, ozone concentrations have dropped significantly for all 

of the monitors in the area and both Crittenden and Shelby Counties have subsequently 

attained the 1997 ozone standard. Therefore, this exclusion did not adversely effect the 

ozone concentrations. Since the ozone levels have declined and DeSoto County is 

attaining the standard, there is no valid basis to reverse the previous determination. 

Based on current monitoring data, the Governor of Mississippi recommended the 

designation of attainment for Desoto County. This recommendation is supported by 

current monitoring data, which shows that the Hernando monitor, located in DeSoto 

County, is attaining the standard of 75 ppb. The monitoring data shows that there has 

been a decline in concentration at the DeSoto County Monitor since 2007 and that 

DeSoto County has been attaining the 2008 standard for the last 2 years. 

Pursuant to the Clean Air Act, Section 107(d)(1)(B)(ii), EPA is only required to use the 

Metropolitan Statistical Area as the presumptive boundary if the area will be designated 

as a Serious, Severe, or Extreme Area. Based on EPA’s proposed implementation rule, 

the Memphis Non-Attainment Area will likely be designated as Marginal. Therefore, 

EPA has discretion on the designation of the Memphis Non-Attainment Area. 

On December 8, 2011 EPA recommended a partial non-attainment designation for 

DeSoto County. Due to the expedited review process, EPA relied on older data and 

completed only a five factor analysis for their boundary recommendation. 

In accordance with EPA policy1

, there are nine factors to be considered in evaluating 

boundaries for designations of areas as non-attainment. In this report, MDEQ has 

analyzed each of the nine factors using the latest data and analysis. The analysis reveals 

overwhelmingly that DeSoto County does not contribute to violation of the ozone 

standard in neither Crittenden County, AR nor Shelby County, TN. 

The first of the nine factors to consider is air quality data. Air monitoring data shows that 

DeSoto County has attained the standard for the last two years. Furthermore, all of the 

monitors in the proposed non-attainment designated area show a downward trend in 

ozone values. Accordingly, it is clear that DeSoto County does not contribute to the 

violations in Shelby or Crittenden counties based on analysis of this first factor. 

The second factor to be considered is emissions data. DeSoto County has only three 

facilities which are classified as major sources of emissions, while Shelby and Crittenden 

counties have exponentially more emission sources. In addition, Shelby County has the 

Memphis International Airport, the number three rail center in the country and the 

International Port of Memphis. There are significant intermodal rail facilities in both 

Crittenden and Shelby counties. There are nine major truck centers in Crittenden County, 

 

1

 Meyers Memorandum, Area Designations for the 2008 Revised Ozone National Ambient Air Quality 

Standards, Dec. 4, 2008 
six in Shelby County, and only one in DeSoto County. EPA erred in attributing only 

population based and general traffic factors as indicators of contribution, as the proof is 

overwhelming that the commerce activity in these areas is a much higher contributor with 

the emissions in closer proximity to the violating monitors than the emissions in DeSoto 

County. Thus, the complete analysis of this factor clearly supports that DeSoto County 

does not contribute to the violations in Shelby or Crittenden Counties. 

The third factor for consideration is population density and degree of urbanization. In 

support of its proposed designation, EPA states that DeSoto County has the second 

highest population in the area; however, a broader analysis reveals that DeSoto County is 

a very, very distant second compared to Shelby County. Further, the area of DeSoto 

County which is proposed to be included in the designated area is only moderately 

populated, and is a mere percentage of the total population and degree of urbanization of 

Shelby County. Based on this analysis, DeSoto County does not contribute to the 

violations of the ozone standard in Shelby County, Tennessee or Crittenden County, 

Arkansas. 

The fourth factor for consideration is traffic and commuting patterns. An evaluation of 

commuter traffic and Vehicle Miles Traveled (VMT) reveals that DeSoto County pales in 

comparison to the commuting within Shelby County. Further, Shelby and Crittenden 

counties are both dissected by I-40, one of the busiest routes for heavy duty diesel trucks 

in the country. The percentage of traffic from heavy duty diesel trucks in Shelby County 

and Crittenden counties is almost two and three times, respectively, higher than that of 

DeSoto County. Significantly, the Shelby County Fraser monitor and the Crittenden 

County monitors are both in close proximity to I-40. When the level of commerce traffic 

is properly considered in evaluating this fourth factor, it is clear that DeSoto County does 

not contribute to the violations of the ozone standard in Shelby County, Tennessee or 

Crittenden County, Arkansas. 

The fifth factor to be considered is growth rates and patterns. EPA cites a growth rate of 

48% in Desoto County in the last decade, but the use of a percentage based rate of growth 

is misleading when looking at the total population in the entire Memphis MSA. Because 

of the relatively low 2000 population in Desoto County, even a 48% increase is still 

insignificant when compared to Shelby County and the entire Memphis MSA. Further, 

even while Desoto experienced this growth rate, the ozone values within the county, as 

well as the other monitors in the area, have steadily decreased. This plainly disproves 

EPA’s reasoning that Desoto’s growth rate contributes to violations of the ozone standard 

in Shelby and Crittenden counties. 

The sixth factor to consider is meteorology. EPA relies in error on back trajectories to 

reach its determination that Desoto County should be included in the designated area; 

however, EPA failed to consider issues related to back trajectories specific to the Shelby 

County Fraser monitor. A more complete analysis reveals that light winds and distant 

monitoring of those light winds cause the back trajectory analysis to be unreliable. 

Available modeling from Crittenden County, as well as EPA itself, reveals that Desoto 

Mississippi Department of Environmental Quality 

February 2012 

- 3 -
County does not significantly contribute to ozone concentrations in Shelby County or 

Crittenden counties. 

The seventh factor to be considered is geography and topography. Analysis of the 

geography in the area does not reveal any conditions which would affect the contribution 

of Desoto to the Shelby and Crittenden County monitors. The topography of the area 

ranges from the flat lowland of the Mississippi Delta in the west to rolling hills in the 

central and eastern part of the MSA. This factor does not appear to have a significant 

impact on the overall evaluation of the designation. 

The eighth factor to be considered is jurisdictional boundaries. Desoto County is in a 

different state with different governances than Shelby County, TN and Crittenden 

County, AR. Since the emissions in Desoto County are such a small fraction of those in 

the other two counties, there is nothing Desoto County can do to impact violations in the 

other counties. If Desoto County were included in the designation area, Desoto County 

and the State of Mississippi would be significantly negatively impacted by a designation 

over which it has no control and over which it has no regulatory authority to impact in 

any way. Based on consideration of this factor, it would be an error to include Desoto in 

the non-attainment designation. 

The ninth and final factor for consideration is the level of emission sources. Considering 

the low emissions in Desoto County, there are few measures that could be applied that 

would yield significant reductions. The few facilities in the county are well controlled. 

Further, both the county and the cities therein have already undertaken voluntary 

measures to reduce mobile and area source emissions, which measures have had a 

positive effect in lowering ozone in Desoto County. The EPA failed to examine the level 

of control of emissions in the area in making its proposed designation. MDEQ’s 

thorough analysis of this factor reveals that in addition to industry meeting strict 

standards, the citizens and leadership of Desoto County have been proactive in reducing 

emissions. To now include Desoto in a non-attainment designation after all they have 

done to successfully reduce emissions would be counterproductive in every sense of the 

word. 

MDEQ’s more thorough evaluation of all nine factors which EPA is to consider in 

determining boundaries for areas of non-attainment reveals overwhelmingly that no part 

of Desoto County should be included in the designated area. Eight of the nine factors 

demonstrate powerfully that Desoto does not contribute to the violations of the standard 

in Crittenden and Shelby counties, and the ninth factor bears no impact either positively 

or negatively in the analysis. It would be an error to include Desoto County in the area 

designated for non-attainment. 

Mississippi Department of Environmental Quality 

February 2012 

- 4 -
Mississippi Department of Environmental Quality 

February 2012 

- 5 -

Nine Factor Analysis

EPA recommends that the Metropolitan Statistical Area (MSA) or Combined Statistical 

Area (CSA) serve as the starting point for determining the geographic boundaries of an 

ozone non-attainment area. According to the Clean Air Act, Section 107(d)(1)(B)(ii), 

EPA is only required to use the Metropolitan Statistical Area as the presumptive 

boundary if the area will be designated as a Serious, Severe, or Extreme Area. Based in 

EPA’s proposed implementation rule, the Memphis Non-Attainment Area will likely be 

designated as Marginal. Therefore, EPA has discretion on the designation of the 

Memphis Non-Attainment Area. 

There are nine factors2

 that need to be evaluated in making the boundary determination. 

These factors are:

• Factor 1: Air quality data 

• Factor 2: Emissions data (location of sources and contribution to ozone 

concentrations) 

• Factor 3: Population density and degree of urbanization (including commercial 

development) 

• Factor 4: Traffic and commuting patterns 

• Factor 5: Growth rates and patterns 

• Factor 6: Meteorology (weather/transport patterns) 

• Factor 7: Geography/topography (mountain ranges or other air basin boundaries) 

• Factor 8: Jurisdictional boundaries (e.g., counties, air districts, Reservations, 

metropolitan planning organizations) 

• Factor 9: Level of control of emission sources 

MDEQ has analyzed all factors using the latest data. Based on that analysis, eight of the 

nine factors clearly indicate that DeSoto County does not contribute to violation of the 

ozone standard in neither Crittenden County, AR nor Shelby County, TN. The analysis 

reveals that the ninth factor, Geography, gives no evidence of contribution and is not a 

significant factor in the analysis. 

 

2 See Footnote 1 
Mississippi Department of Environmental Quality 

February 2012 

- 6 -

Factor 1: Air quality data 

Table 1 shows the 4th maximum concentrations for the 2008-2011 as well as the 2008-

2010 and 2009-2011 design values. DeSoto County has attained the standard for the last 

two years. Figure 1 shows a downward trend in ozone values for all of the monitors in 

the area. 

4th Annual Maximum 

County Site 8-hour Ozone 

2008 2009 2010 2011

3-Year 

Average 

2008-2010 

3-Year 

Average 

2009-2011

DeSoto, MS Hernando 74 71 76 73 73 73 

Shelby. TN Frayser 84 69 76 79 76 74 

Shelby, TN Orgill Park 77 70 73 77 73 73 

Crittenden, AR Marion 74 71 78 82 74 77 

Table 1: Monitoring Data for the Memphis CSA3

Memphis Area 8-Hour Ozone Data 2001-2011

70

75

80

85

90

95

100

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Year

Design Value (ppb)

DeSoto Shelby - Orgill Shelby - Frayser Crittenden

Figure 1: Ozone Design Value Trends for monitors in the Memphis CSA3

 

3

 Mississippi Department of Environmental Quality, Shelby County Health Department, Arkansas 

Department of Environmental Quality 
 EPA’s Technical Support Document (EPA-TSD), attached as Appendix 1, says that a 

county (or partial county) should be designated if it contributes to a violation in a nearby 

county. Several recent air quality modeling studies have shown that Mississippi counties 

do not significantly contribute to ozone concentrations in Shelby County, TN or 

Crittenden County, AR. The “Analysis of Three 2005 Crittenden County Ozone Study 

(CCOS) Episodes Using Air Quality Modeling Tools” (ADEQ, June 2007) report found 

that DeSoto County had an insignificant impact on the Shelby or Crittenden County 

Monitors. 

Additionally, the analysis EPA performed for Clean Air Interstate Rule (CAIR) and 

Cross-State Air Pollution Rule (CSAPR) did not find any significant linkages for 8-hour 

ozone between Mississippi and Shelby County or Crittenden County. An analysis of the 

remaining factors also finds that DeSoto County does not contribute to the violations in 

Crittenden or Shelby Counties. 

Since Desoto County is attaining the current standards and an analysis of data relevant to 

the other factors finds that it does not contribute to the violations in Shelby or Crittenden 

counties, DeSoto County, or any part thereof, should not be included in the Memphis 

Non-Attainment Area.

Mississippi Department of Environmental Quality 

February 2012 

- 7 -
Factor 2: Emissions data 

Figure 2 is a detailed map of DeSoto, Shelby, and Crittenden Counties. Each of the four 

monitoring locations are marked with their corresponding ozone design values for 2008-

2010 and 2009-2011. There is one monitor in DeSoto County which is reading in 

attainment of the 2008 ozone standard for both design values. There are two monitors in 

Shelby County. One monitor is in northern Shelby County and is reading in attainment 

for the 2008 ozone standard for both design values. The other monitor is within 

Memphis city limits near Interstate 240. This monitor is reading over the 2008 ozone 

standard for 2008-2010 but is under the limit for 2009-2011. The Crittenden County 

monitor is near the junction of Interstates 40 and 55 and meets the 2008 ozone standard 

for 2008-2010 but is over the standard for 2009 to 2011. 

The Memphis International Airport located approximately three miles south of the central 

business district of Memphis and is home to the main FedEx Express global "SuperHub", 

which processes a significant portion of the freight carrier's packages. The airport also 

serves as a hub for Delta Airlines. Memphis is the number three rail center in the United 

States with significant intermodal rail facilities in both Crittenden and Shelby Counties. 

The International Port of Memphis is 4th largest inland Port in the United States. The 

International Port of Memphis covers the Tennessee and Arkansas sides of the 

Mississippi River. The boundaries of the International Port of Memphis include the 

McKeller Lake/Presidents Island complex, the West Memphis Harbor, the Rivergate 

Harbor, the Wolf River Harbor downtown, and Fullen dock and harbor north of 

downtown. 

Major air emission sources for each county are represented on the map as well as major 

truck centers (truck stops). As shown by the map, there are significantly more sources of 

emissions in Shelby County and in Crittenden County than in DeSoto County. There are 

nine truck centers in Crittenden County, six in Shelby County, and one in DeSoto 

County. All of the truck centers in Crittenden County are located within five miles of the 

ozone monitor. There are two locations in Crittenden County where major truck centers 

are too close to be accurately represented by separate markers. In these cases, the 

number of truck centers located at those points are labeled on top of the marker. 

Mississippi Department of Environmental Quality 

February 2012 

- 8 -
Figure 2: Monitor Locations in the Memphis CSA and Major Emission Sources

Mississippi Department of Environmental Quality 

February 2012 

- 9 -
Mississippi Department of Environmental Quality 

February 2012 

- 10 -

DeSoto County has a small number of major emission sources as shown in Figure 2. 

DeSoto County currently has two facilities that are classified as major sources of 

Nitrogen Oxides (NOx) and one facility classified as major sources of Volatile Organic 

Compounds (VOCs). Charts 1 and 2 show the NOx and VOC emissions from all source 

categories in DeSoto, Shelby, and Crittenden Counties. These charts demonstrate that the 

total emissions from DeSoto County are small in comparison to those from Shelby 

County. 

2008 NOx Emissions

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

Shelby Crittenden DeSoto

NOx Emissions (tons)

Area

Point

Non-Road

Mobile

On-Road

Mobile

Chart 1: NOx and VOC Emission Comparison for Memphis CSA4

 

4

 U.S. Environmental Protection Agency, 2008 National Emissions Inventory (NEI) 
Mississippi Department of Environmental Quality 

February 2012 

- 11 -

2008 VOC Emissions

0

5,000

10,000

15,000

20,000

25,000

30,000

Shelby Crittenden DeSoto

VOC Emissions (tons)

Area

Point

Non-Road

Mobile

On-Road

Mobile

Chart 2: NOx and VOC Emission Comparison for Memphis CSA5

The EPA-TSD identifies that mobile and area source emissions are the primary 

contributors of ozone precursors in the area. However, it incorrectly identified 

population based and general traffic factors as the indicators of contribution. The 

Memphis area is a very busy freight hub that results in a high level of commerce based 

emissions. Interstate 40 runs through Shelby and Crittenden Counties and is one of the 

busiest interstates in the nation for heavy duty diesel truck traffic. 

The Memphis/ West Memphis area is the number three rail center in the United States 

with significant intermodal rail facilities in both Crittenden and Shelby Counties. West 

Memphis Arkansas also has the highest diesel sales in the nation with nine truck centers. 

Many of the truck centers are grouped together and in close proximity to the Crittenden 

County monitor. Note from Figure 2 the proximity of the violating monitors to Interstate 

40 and railroad lines. In addition, the Mississippi River carries a high volume of barge 

traffic that generates emissions and runs between Shelby and Crittenden Counties, both 

of which have river ports. The Memphis Airport is also the number one freight airport in 

the nation that has aircraft related emissions and generates a lot of truck traffic. 

Emissions from these sectors are not population based and are not centered in DeSoto 

County. This commerce activity is a much higher contributor with the emissions in 

closer proximity to the violating monitors than emissions in DeSoto County. 

The overwhelming evidence of the emissions data demonstrates that DeSoto County does 

not contribute to violations of the ozone standard in Shelby County, TN or Crittenden 

County, AR and should not be included in the Memphis Ozone Non-Attainment Area.

 

5 See Footnote 5 
Mississippi Department of Environmental Quality 

February 2012 

- 12 -

Factor 3: Population density and degree of urbanization 

The EPA-TSD states that “areas of dense population or commercial development are an 

indicator of area source and mobile source NOx and VOC emissions that may contribute to 

ozone formation.” DeSoto County is also cited as having the second highest in population 

in the area. Chart 3 and 4 show the population density and degree of urbanization for 

DeSoto, Shelby and Crittenden Counties. While DeSoto County is second, it is a very, 

very distant second compared to Shelby County. As noted in Chart 3, DeSoto County is 

not densely populated. The southern portion of the county is largely rural with the 

northern portion being a moderately populated suburban area. 

2010 Population Density

0

200

400

600

800

1,000

1,200

1,400

Shelby Crittenden DeSoto 

Population/square mile

Chart 3: Population Density of Memphis CSA6

 

 

6

 2010 U.S. Census 
Mississippi Department of Environmental Quality 

February 2012 

- 13 -

2010 Total Population and Degree of Urbanization

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

Shelby Crittenden DeSoto 

Population

Urban Population Rural Population Non-Specified

Chart 4: Total Population and Degree of Urbanization for Memphis CSA7

Based on the analysis of the population density and degree of urbanization, DeSoto 

County does not contribute to violations of the ozone standard in Shelby County, TN or 

Crittenden County, AR and should not be included in the Memphis Ozone NonAttainment Area.

 

7 See Footnote 7 
Mississippi Department of Environmental Quality 

February 2012 

- 14 -

Factor 4: Traffic and commuting patterns 

The overall amount of traffic from Mississippi Counties in the CSA is much smaller than 

that of Shelby County. Likewise, the number of commuters from the Mississippi 

Counties is much less than those from Shelby County. The amount of traffic is measured 

in Vehicle Miles Traveled (VMT) and is developed by the Mississippi and Tennessee 

Departments of Transportation. Chart 5 compares the traffic data for the Counties in the 

Memphis CSA. 

2010 County Population and Vehicle Miles Traveled 

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

Shelby Crittenden DeSoto

Population

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Vehicle Miles Traveld (million miles)

Population VMT

Chart 5: 2010 Population and Traffic Data8, 9

 

8 See Footnote 7 9

 U.S. Department of Transportation, Federal Highways Administration, Highway Performance Monitoring 

System 
Mississippi Department of Environmental Quality 

February 2012 

- 15 -

Commuting Patterns

0 50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000

DeSoto Crittenden Shelby

Residence County

Commuters

DeSoto 

Shelby

Crittenden

Chart 6: Commuting Patterns for Memphis CSA10

Because commuting data is not yet available for the 2010 census, data from the 2000 

census was used to determine the commuting patterns. Chart 6 summarizes this 

information and shows that while there is some commuting between the Mississippi 

Counties and Shelby County, it pales in comparison to the commuting within Shelby 

County. The majority of all commuters remain in their perspective counties for their 

travel. 

 

10 2000 U.S. Census 
Mississippi Department of Environmental Quality 

February 2012 

- 16 -

Figure 3: Average Daily Heavy Duty Diesel Truck Traffic (2007)11

Of particular significance is the concentration of heavy duty diesel truck in Shelby and 

Crittenden Counties versus that of DeSoto County. Heavy duty diesel truck emissions 

are a significant source of NOx emissions. Figure 3 shows the truck traffic along the 

interstates across the southeast portion of the country. 

Interstate 40 traverses from Wilmington, NC, across Tennessee and Arkansas (including 

Shelby and Crittenden Counties), to the west coast. I-40 is one of the busiest routes for 

heavy duty diesel truck traffic in the nation. Along I-40 over 50% of the traffic in 

Crittenden County12 and 35% in Shelby County13 is from heavy duty diesel trucks. In 

DeSoto County14, 18% of the rural interstate traffic along I-55 is from heavy duty diesel 

trucks, which is slightly below the national rural interstate average14 of 19%. It should be 

 

11 U.S. Department of Transportation, Federal Highways Administration, Office of Freight Management, 

Average Daily Long-Haul Truck Traffic on National Highway System, 2007 12 Arkansas State Highway and Transportation Department, 2010 Truck Percentages on the State Highway 

System Map 

13 Memphis MPO, Travel Demand Model 

14 U.S. Department of Transportation, Federal Highways Administration, Highway Statistics
Mississippi Department of Environmental Quality 

February 2012 

- 17 -

noted that, as seen in Figure 2, the Shelby County - Frayser monitor and the Crittenden 

County Monitor are both in close proximity to Interstate 40. 

There are few local controls that can significantly reduce vehicle emissions. However, 

national vehicle emissions standards that EPA has implemented are resulting in 

significant reductions. MDEQ contracted with a consultant to model 2010 and 2020 peak 

hour on-road mobile emissions for DeSoto, Shelby and Crittenden Counties. The final 

report for the modeling is attached in Appendix 2 and the results are presented in Table 2. 

It is projected that there will be in an approximately 64% reduction in on-road mobile 

NOx emissions and a 56% reduction from on-road mobile VOC emissions across the 

three counties due to road and traffic improvement and emission reductions from tighter 

vehicle emission standards and fleet turnover. These reductions will result in decreases in 

ozone levels in the future and are independent of the ozone designations. 

County 2010 to 2020 NOx 

Reductions (%) 

2010 to 2020 VOC 

Reductions (%) 

Shelby 63.68 56.26 

Crittenden 65.63 58.40 

DeSoto 63.55 55.25 

Table 2: Projected Peak-Hour On-Road Mobile-Source Emissions Reductions15

Based on the analysis of the traffic and commuting patterns, DeSoto County does not 

contribute to violations of the ozone standard in Shelby County, TN or Crittenden 

County, AR and should not be included in the Memphis Ozone Non-Attainment Area.

 

15 Mississippi Department of Environmental Quality, Neel-Schaffer, Inc., On-Road Mobile-Source 

Emissions Forecast For Desoto County, Mississippi (2010 to 2020), 2012 
Mississippi Department of Environmental Quality 

February 2012 

- 18 -

Factor 5: Growth rates and patterns 

DeSoto County has experienced moderate growth, approximately 5% per year sine 2000. 

However, the growth rate has slowed significantly since 2006. The EPA-TSD cites a 

growth rate of 48% over the last decade, but using a percentage based rate is misleading 

because of the counties relatively low 2000 population. The real increase in numbers is 

53,000 people over the last decade. Compared to the population of Shelby County 

(927,000) or the entire Memphis MSA (1,316,000), the growth is not significant. 

DeSoto County Growth versus Ozone Design Values

70

75

80

85

90

95

100

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Year

Design Value (ppb)

100,000

125,000

150,000

175,000

200,000

DeSoto County Population

DeSoto Shelby - Orgill Shelby - Frayser Crittenden DeSoto Population

Chart 7: DeSoto County Growth versus Ozone Design Values16

In addition, while DeSoto County has experienced this growth, the ozone values in the 

County, as well as other monitors in the area, have steadily decreased. Chart 7 shows the 

growth trend and the ozone values since 2000. If the growth and population in DeSoto 

County were a contributing factor, then it be evidenced by increased ozone readings by 

the DeSoto County monitor. 

Based on the analysis of the growth rate and patterns, DeSoto County does not contribute 

to violations of the ozone standard in Shelby County, TN or Crittenden County, AR and 

should not be included in the Memphis Ozone Non-Attainment Area.

 

16 See Footnotes 3 and 7 
Factor 6: Meteorology (weather and transport) 

Back Trajectories 

In the EPA Technical Support Document, EPA used the NOAA HYSPLIT model to run 

24-hour and 72-hour back trajectories at the Frayser – Shelby County ozone monitoring 

site during ozone exceedance days for the period of 2006 – 2010. The results seemed to 

indicate that many of the back trajectory centerlines passed through DeSoto County. 

However, the following issues should have been considered when performing such an 

analysis: 

• On most days, 24-hour back trajectories were less than 200 miles long for the 

Frayser site during the period of 2006-2010. 

• This indicates that the average wind speeds were less than 8 mph. 

• When there is a light wind regime wind directions can vary significantly at the 

surface. 

• HYSPLIT uses surface and upper air wind conditions to calculate back 

trajectories. In this case, surface winds from the Memphis NWS station were 

used, but the closest upper-air wind data site is located in Little Rock, Arkansas - 

~130 miles from Memphis. 

• HYSPLIT is not accurate under light wind conditions because of the light wind 

direction variability. 

Because of these issues, a back trajectory analysis is unreliable in determining if transport 

was occurring on the ozone exceedance days. Therefore, it should not have been used as 

a factor in the determination of the Memphis Non-Attainment Area boundary. 

Modeling 

In the past, there have been air quality modeling studies that show that Mississippi 

counties do not significantly contribute to ozone concentrations in Shelby County, TN or 

Crittenden County, AR. The “Analysis of Three 2005 Crittenden County Ozone Study 

(CCOS) Episodes Using Air Quality Modeling Tools” (ADEQ, June 2007) report found 

that DeSoto County had an insignificant impact on the Shelby or Crittenden County 

Monitors. This can be seen in Chart 8. 

Mississippi Department of Environmental Quality 

February 2012 

- 19 -
Mississippi Department of Environmental Quality 

February 2012 

- 20 -

Contribution to Ozone from Regions

0

10

20

30

40

50

60

SW Ind Area Rest of Memphis Rest of Shelby

County

Crittenden County DeSoto County Other

Ozone Contribution (ppb)

Crittenden County Monitor Shelby County - Frayser Monitor

Chart 8: Contribution to Ozone from Regions17

In addition, the analysis that EPA performed for Clean Air Interstate Rule (CAIR) and 

Cross-State Air Pollution Rule (CSAPR) did not find any significant linkages for 8-hour 

ozone between Mississippi and Shelby County or Crittenden County. These rules were 

developed to particularly address the contribution of emissions from upwind states to 

downwind non-attainment or maintenance areas. While the rules address the emissions 

from Electric Generating Units, the analysis to determine contribution included emissions 

from all source categories. 

Therefore, the available modeling data indicates that DeSoto County does not 

significantly contribute to ozone concentrations in Shelby County or Crittenden County. 

Based on the analysis of the meteorology, back trajectories, and modeling, DeSoto 

County does not contribute to violations of the ozone standard in Shelby County, TN or 

Crittenden County, AR and should not be included in the Memphis Ozone NonAttainment Area. 

 

17 Arkansas Department of Environmental Quality, Analysis of Three 2005 Crittenden County Ozone Study 

(CCOS) Episodes Using Air Quality Modeling Tools, June 2007
Factor 7: Geography and topography 

The Mississippi counties in the Memphis MSA are located in northwestern Mississippi. 

DeSoto and Tunica counties border the Mississippi River. DeSoto and Marshall Counties 

border Tennessee while Tate is directly south of DeSoto County. The topography of the 

area ranges from the flat lowland of the Mississippi Delta in the west to rolling hills in 

the central and eastern part of the MSA. Analysis of the geography and topography does 

not show a DeSoto County contribution to violations of the ozone standard in Shelby 

County, TN or Crittenden County, AR and should not be factored in to include DeSoto 

County in the Memphis Ozone Non-Attainment Area.

Factor 8: Jurisdictional boundaries 

DeSoto County is in a separate state with different governances than Shelby or Crittenden 

County. The DeSoto County monitor is attaining the standard. The emissions in the 

County are a small fraction of those in Shelby County and the evidence indicates that 

they are not contributing the violations in other counties. If Desoto County were 

included in the non-attainment area, neither DeSoto County nor Mississippi would be 

able to impact the monitors by controlling emissions and would have no authority to 

control emissions in the other states. DeSoto County and the State of Mississippi would 

be significantly negatively impacted by a designation over which it has no control and 

over which it has no regulatory authority to impact in any way. 

DeSoto County was excluded from the Memphis Non-Attainment Area in 2004 because 

it was determined that the county did not significantly contribute to ozone levels in the 

Memphis area. Ozone concentrations have dropped significantly for all of the monitors 

in the area since the designation and both Crittenden and Shelby Counties have 

subsequently attained the 1997 ozone standard. Therefore, this exclusion did not 

adversely effect the ozone concentrations. Since the ozone levels have declined and 

DeSoto County is attaining the standard, there is no valid basis to reverse the previous 

determination. 

Based on the precedence set by EPA in 2004 and the fact that DeSoto County has no 

control or authority over emissions impacting other monitors, it is illogical to include 

DeSoto County in the Memphis Non-Attainment Area. Therefore, DeSoto County 

should be excluded from the non-attainment designation.

Mississippi Department of Environmental Quality 

February 2012 

- 21 -
Factor 9: Level of control of emission sources 

Considering the low air emissions in DeSoto County, there are few measures that could 

be applied that would yield significant reductions. Overall, the few facilities in 

Mississippi are well controlled. Southaven Power is a newer gas cogeneration plant that 

meets BACT standards, Rexam Beverage Can has VOC capture and control devices to 

control emissions beyond NSPS requirements, and Texas Gas has voluntarily opted to 

include operational restrictions in its permit that reduces NOx emissions during Ozone 

Season. 

There have also been measures taken to reduce mobile and area source emissions in 

DeSoto County. Mississippi has revised the Air Pollution Regulations to prohibit all 

open burning on Ozone Action Days. Open Burning is banned on all days in Hernando. 

Also, DeSoto County and the cities within the county have enacted strict idle reduction 

policies to reduce mobile source emissions from the county. The program to develop Idle 

Reduction Policies in DeSoto County and sample policies from within the county are 

shown in Appendix 2. 

Additionally, ninety-three of DeSoto County’s school buses have been retrofitted with 

diesel oxidation catalysts (DOC). All of DeSoto County's buses have either DOCs 

installed or other technologies to meet current diesel emission standards. In the 

surrounding counties, MDEQ has retrofitted an additional 57 buses with DOCs. 

Furthermore, there have been nine MDEQ Diesel Emission Reduction Projects reflecting 

35 pieces of diesel equipment in and around DeSoto County. Private companies have 

spent over $100,000 of their own money as matching funds for these projects. 

The DeSoto Planning Commission began the Ozone Action Group to engage public and 

private groups in finding emission reductions and providing public outreach. This group 

meets monthly to promote and encourage behavior by the general public that will result 

in beneficial emission reductions. MDEQ, DeSoto County Ozone Action Group, and the 

DeSoto County Planning Commission have engaged in numerous outreach events 

throughout the county. A puppet show was also developed as an additional outreach tool 

for schools and public outreach. Outreach activities are listed in Appendix 4. 

The Mississippi Department of Transportation (MDOT) has spent over $1 million in the 

Safe Routes to School program, sidewalks, and bike path improvements in DeSoto 

County and has conducted an I-69 Corridor Alternatives Analysis to study preferred mass 

transit options for DeSoto County. 

The EPA-TSD fails to examine the level of control of emissions in the area. A proper 

examination of this factor shows that in addition to industry that meets strict standards, 

the citizens and leadership of DeSoto County have also been proactive in reducing 

emissions. 

As shown in this section, DeSoto County, MDEQ, and their strategic partners have been 

proactive in reducing emissions in the county. An arbitrary decision by EPA to include 

Mississippi Department of Environmental Quality 

February 2012 

- 22 -
DeSoto County in a non-attainment area would hinder these efforts. Therefore, DeSoto 

County should be excluded from the Memphis Non-Attainment Area.

Conclusion 

Based on the analysis of the nine factors specified by EPA to be considered in 

determining the boundaries of the area to be designated as non-attainment, the evidence is 

overwhelming that Desoto does not contribute to the violation of standards in Crittenden 

County, AR, and Shelby County, TN. Eight of the nine factors fall in favor of excluding 

Desoto County from the area of non-attainment, and the ninth factor bears no impact on 

the analysis. Desoto was properly excluded from the designation in 2004, and since that 

time, has only improved upon its efforts to control and reduce emissions in the county. 

EPA should re-evaluate its decision in light of the additional information provided in this 

report, and should exclude Desoto County from the designated area.

Mississippi Department of Environmental Quality 

February 2012 

- 23 -
Appendix 1: EPA’s Technical Support Document -

Mississippi Area Designations for the 2008 Ozone 

National Ambient Air Quality Standards

Mississippi Department of Environmental Quality 

February 2012 

- 24 -
1

Mississippi

Area Designations for the 

2008 Ozone National Ambient Air Quality Standards

The table below identifies the areas and associated counties or parts of counties in Mississippi that EPA 

intends to designate as nonattainment for the 2008 ozone national ambient air quality standards (2008 

ozone NAAQS). In accordance with section 107(d) of the Clean Air Act, EPA must designate an area 

(county or part of a county) “nonattainment” if it is violating the 2008 ozone NAAQS or if it is 

contributing to a violation of the 2008 ozone NAAQS in a nearby area. The technical analyses 

supporting the boundaries for the individual nonattainment areas are provided below.

Intended Nonattainment Areas in Mississippi

Area 

Mississippi’s Recommended 

Nonattainment Counties

EPA’s Intended Nonattainment 

Counties

Memphis, TN-MS-AR* None DeSoto(partial)

*Memphis, TN-MS-AR is a multi-state nonattainment area. Table 1 below identifies the counties in the 

other states that EPA intends to designate as part of the nonattainment area.

EPA intends to designate the remaining counties in Mississippi that are not listed in the table above as 

“unclassifiable/attainment” for the 2008 ozone NAAQS. 

The analysis below provides the basis for intended nonattainment area boundaries. It relies on our 

analysis of whether and which monitors are violating the 2008 ozone NAAQS, based on certified air 

quality monitoring data from 2008-2010 and an evaluation of whether nearby areas are contributing to 

such violations. EPA has evaluated contributions from nearby areas based on a weight of evidence 

analysis considering the factors identified below and other relevant information. EPA issued guidance 

on December 4, 2008 that identified these factors as ones EPA would consider in determining 

nonattainment area boundaries and recommended that states consider these factors in making their 

designations recommendations to EPA.1 

1. Air quality data (including the design value calculated for each Federal Reference Method 

monitors or Federal Equivalent Method (FEM) monitor in the area);

2. Emissions and emissions-related data (including location of sources and population, amount of 

emissions and emissions controls, and urban growth patterns);

3. Meteorology (weather/transport patterns);

4. Geography and topography (mountain ranges or other basin boundaries);

5. Jurisdictional boundaries (e.g., counties, air districts, existing nonattainment areas, Indian 

country, metropolitan planning organizations (MPOs))

Ground-level ozone generally is not emitted directly into the air, but is created by chemical reactions 

between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. 

Because NOx and VOC emissions from a broad range of sources over a wide area typically contribute to 

violations of the ozone standards, EPA believes it is important to consider whether there are contributing 

emissions from a broad geographic area. Accordingly, EPA chose to examine the 5 factors with respect 

 

1 The December 4, 2008 guidance memorandum “Area Designations for the 2008 Revised Ozone National Ambient Air 

Quality Standards” refers to 9 factors. In this technical support document we have grouped the emissions-related factors 

together under the heading of “Emissions and Emissions-Related Data,” which results in 5 categories of factors.
2

to the larger of the Combined Statistical Area (CSA) or Core Based Statistical Area (CBSA) associated 

with the violating monitor(s).

2 All data and information used by EPA in this evaluation are the latest 

available to EPA and/or provided to EPA by states or tribes.

In EPA’s designations guidance for the 2008 ozone NAAQS EPA recommended examining 

CSA/CBSAs because certain factors used to establish CSAs and CBSAs are similar to the factors EPA is 

using in this technical analysis to determine if a nearby area is contributing to a violation of the 2008 

ozone NAAQS. Congress required a similar approach in 1990 for areas classified as serious or above 

for the 1-hour ozone standard and EPA used the same basic approach in the designation process for the 

1997 ozone NAAQS. Where a violating monitor is not located in a CSA or CBSA, EPA’s guidance 

recommended using the boundary of the county containing the violating monitor as the starting point for 

considering the nonattainment area’s boundary. 

 

2 Lists of CBSAs and CSAs and their geographic components are provided at 

www.census.gov/population/www/metroareas/metrodef.html . The lists are periodically updated by the Office of 

Management and Budget. EPA used the most recent update, based on 2008 population estimates, issued on December 1, 

2009 (OMB Bulletin No. 10-02).
3

Technical Analysis for Memphis, TN-MS-AR

Figure 1 is a map of the Memphis, TN-MS-AR intended nonattainment area. The map provides other 

relevant information including the locations and design values of air quality monitors, county and other 

jurisdictional boundaries, relevant statistical area boundaries, the nonattainment area boundary for 1997 

ozone NAAQS, and major transportation arteries.

Figure 1. TN-MS-AR Nonattainment Area

For purposes of the 1997 8-hour ozone NAAQS, portions of this area were designated nonattainment. 

The boundary for the nonattainment area for the 1997 ozone NAAQS included the entire counties of 

Crittenden County, Arkansas, and Shelby County, Tennessee.

In March 2009, Mississippi recommended that DeSoto County, Mississippi be designated as a 

nonattainment area separate from the Memphis nonattainment area for the 2008 ozone NAAQS based 

on air quality data from 2006-2008. Mississippi provided an update to the original recommendation in 

October 2011 based on air quality data from 2008-2010, and preliminary data from 2009-2011. In its 

updated recommendation, Mississippi recommended that all counties in the State be designated 
4

attainment for the 2008 ozone NAAQS. Letter from Haley Barbour, Governor of the State of 

Mississippi to A. Stanley Meiburg, ActingRegional Administrator, US EPA Region 4 (March 3, 2009) 

and Gwendolyn Keyes Fleming, Regional Administrator US EPA Region 4 (October 27, 2011) (on file 

with US EPA Region 4). Also, in March 2009, Tennessee recommended that Shelby County be 

designated “nonattainment” for the 2008 8-hour ozone standard based on air quality data from 2006-

2008. Letter from James H. Fyke, Commissioner, State of Tennessee Department of Environment and 

Conservation to A. Stanley Meiburg, Acting Regional Administrator, US EPA Region 4 (March 10, 

2009) (on file with US EPA Region 4). Tennessee provided an update to its original recommendation in 

November 2011 based on preliminary 2009-2011 air quality data. In Tennessee’s updated 

recommendation, the state did not provide a specific update to its 2009 recommendation for the 

Memphis TN-MS-AR but stated that all other counties (with the exception of those recommended for 

Knoxville) should be designated unclassifiable/attainment. Letter from Robert J. Martineau Jr, 

Commissioner, State of Tennessee Department of Environment and Conservation to Gwendolyn Keyes 

Fleming, Regional Administrator, US EPA Region 4 (November 8, 2011) (on file with US EPA Region 

4).

Additionally, in March 2009, Arkansas recommended that Crittenden County, Arkansas be designated 

nonattainment based on 2006-2008 air quality data. Arkansas did not update its 2009 ozone 

recommendation. These data are from FEM monitors sited and operated in accordance with 40 CFR 

Part 58. Letter from Mike Beebe, Governor of the State of Arkansas to Lawrence E. Starfield, Acting

Regional Administrator, US EPA Region 6 (March 10, 2009) (on file with US EPA Region 6).

After considering these recommendations and based on EPA's technical analysis described below, EPA 

intends to designate one county in Arkansas, one county (partial) in Mississippi, and one county in 

Tennessee (identified in Table 1 below) as nonattainment for the 2008 ozone NAAQS as part of the 

Memphis, TN-MS-AR multi-state nonattainment area. 

Table 1. State's Recommended and EPA’s Intended Designated Nonattainment Counties for Memphis, 

TN-MS-AR.

Memphis, TN-MS-AR State-Recommended 

Nonattainment Counties

EPA Intended

Nonattainment Counties

Arkansas Crittenden Crittenden

Mississippi None DeSoto (partial)

Tennessee None Shelby

Factor Assessment

Factor 1: Air Quality Data 

For this factor, we considered 8-hour ozone design values (in parts per billion (ppb)) for air quality 

monitors in counties in the Memphis, TN-MS-AR area based on data for the 2008-2010 period (i.e., the 

2010 design value, or DV), which are the most recent years with fully-certified air quality data. A 

monitor’s DV is the metric or statistic that indicates whether that monitor attains a specified air quality 

standard. The 2008 ozone NAAQS are met at a monitor when the annual fourth-highest daily maximum 

8-hour average concentration, averaged over 3 years is 75 ppb or less. A DV is only valid if minimum 

data completeness criteria are met. See 40 CFR part 50 Appendix P. Where several monitors are 

located in a county (or a designated nonattainment area or maintenance area), the DV for the county or 

area is determined by the monitor with the highest level.
5

The 2010 DVs for the ozone NAAQS for counties in the Memphis and nearby surrounding area are 

shown in Table 2. 

Table 2. Air Quality Data3.

County State Recommended 

Nonattainment?

2008-2010 Design Value 

(ppb)

Crittenden, AR Yes 74

DeSoto, MS No 73

Shelby, TN No 76

Shelby County, Tennessee shows a violation of the 2008 ozone NAAQS, therefore this county is

included in the nonattainment area. A county (or partial county) must also be designated nonattainment 

if it contributes to a violation in a nearby area. Each county without a violating monitor that is located 

near a county with a violating monitor has been evaluated, as discussed below, based on the five factors 

and other relevant information to determine whether it contributes to the nearby violation. 

Factor 2: Emissions and Emissions-Related Data

EPA evaluated emissions of ozone precursors (NOx and VOC) and other emissions-related data that 

provide information on areas contributing to violating monitors.

Emissions Data

EPA evaluated county-level emission data for NOx and VOC derived from the 2008 National Emissions 

Inventory (NEI), version 1.5. This is the most recently available NEI. (See 

http://www.epa.gov/ttn/chief/net/2008inventory.html) Significant emissions levels in a nearby area 

indicate the potential for the area to contribute to observed violations. We will also consider any 

additional information we receive on changes to emissions levels that are not reflected in recent 

inventories. These changes include emissions reductions due to permanent and enforceable emissions

controls that will be in place before final designations are issued and emissions increases due to new 

sources. The precursor emission source-category percentages used below and throughout the document 

were derived from emissions data from the 2008 NEI version 1.5 referenced above.

Table 3 shows emissions of NOx and VOC (given in tons per year (tpy)) for violating and nearby

counties that we considered for inclusion in the Memphis, TN-MS-AR area. 

Table 3. Total 2008 NOx and VOC Emissions.

County

State Recommended 

Nonattainment NOx (tpy) VOC (tpy)

Crittenden, AR Yes 4,047 3,805

DeSoto, MS No 5,080 5,222

Fayette, TN No 2,385 1,406

Marshall, MS No 1,769 1,527

 

3 Only counties in the Memphis CBSA that have ozone monitors are included in this table.
6

Shelby, TN No 39,519 27,929

Tate, MS No 3,102 1,392

Tipton, TN No 2,119 2,251

Tunica, MS No 1,598 1,096

Areawide: 59,619 44,628

*Counties that EPA intends to designate as nonattainment are shown in bold.

DeSoto County contributes about 9 percent NOx and 12 percent VOC precursor emissions in the CBSA. 

The County’s 5,080 NOx emissions are mostly comprised of 45 percent area sources, 35 percent mobile 

sources. DeSoto County’s total VOC emissions include 44 percent area sources and 34 percent mobile 

sources.

Shelby County contributes about 66 percent of the NOx and 63 percent of the VOC precursor emissions 

in the CBSA. Shelby makes up 23 percent of the entire CBSA NOx emissions and 22 percent of the 

area’s VOC emissions. Of the county’s 39,519 NOx emissions, 35 percent are from point and mobile 

emissions and 20 percent from area source emissions. The County’s 27, 929 VOC emissions include 36 

percent mobile sources and 32 percent area sources.

Crittenden County contributes less than 10 percent of the precursor CBSA emissions. Of the County’s 

total NOx emissions listed in Table 1, 45 percent are from mobile sources and 34 percent from area 

sources. The County’s total VOC emissions include 35 percent from area sources and 31 percent from 

mobile sources. Only 5 percent of the County’s NOx emissions are from point sources. Both Crittenden 

and DeSoto Counties represent less than 1 percent of the entire area’s NOx and VOC point source 

emissions

Fayette and Tipton Counties in Tennessee and Marshall, Tate, and Tunica counties in Mississippi all 

contribute 5 percent or less NOx and VOC precursor emissions in the CBSA. 

Together, Crittenden, DeSoto and Shelby Counties account for 82 percent of the NOx emissions and 83 

percent of the VOC emissions for the 8-county area. The emissions from Fayette and Tipton Counties in 

Tennessee and Marshall, Tate and Tunica Counties in Mississippi are not thought to contribute to the 

violations of the 2008 ozone NAAQS that have been observed by monitors in Shelby County, Tennessee 

and Crittenden County, Arkansas.

Population density and degree of urbanization

EPA evaluated the population and vehicle use characteristics and trends of the area as indicators of the 

probable location and magnitude of non-point source emissions. These include ozone-creating 

emissions from on-road and off-road vehicles and engines, consumer products, residential fuel 

combustion, and consumer services. Areas of dense population or commercial development are an 

indicator of area source and mobile source NOx and VOC emissions that may contribute to ozone 

formation. Rapid population or VMT growth (see below) in a county on the urban perimeter signifies 

increasing integration with the core urban area, and indicates that it may be appropriate to include the 

area associated with the area source and mobile source emissions as part of the nonattainment area. 

Table 4 shows the population, population density, and population growth information for each county in 

the area.
7

Table 4. Population and Growth.

County

State 

Recommended 

Nonattainment?

2010 

Population

2010 

Population 

Density 

(1000 pop/sq 

mi)

Absolute 

change in 

population 

(2000-2010)

Population 

% change 

(2000-

2010)

Crittenden, 

AR Yes 50,902 0.08 (75) <1%

DeSoto, MS No 161,252 0.32 52,584 +48%

Fayette, TN No 38,413 0.05 9,313 +32%

Marshall, MS No 37,144 0.05 2,093 +6%

Shelby, TN No 927,644 1.18 29,393 +3%

Tate, MS No 28,886 0.07 3,444 +14%

Tipton, TN No 61,081 0.13 9,545 +19%

Tunica, MS No 10,778 0.02 1,557 +17%

Areawide: 1,316,100 0.28 107,854 +9%

*Counties that EPA intends to designate as nonattainment are shown in bold.

Sources: U.S. Census Bureau population estimates for 2010 as of August 4, 2011 

(http://factfinder2.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=DEC_10_PL_GCTP

L2.STO5&prodType=table)

DeSoto County, Mississippi is moderately populated in the northern portion of the county and mostly 

rural in the remaining portion of the County. DeSoto County contains 12 percent of the CBSA 

population, but experienced 48 percent growth from 2000-2010. Tate, Tunica and Marshall Counties in 

Mississippi all make up 3 percent or less of the CBSA population and are sparsely populated. 

Shelby County, Tennessee is densely populated containing 70 percent of the CBSA population. From 

2000-2010, the County only had 3 percent growth in population. Fayette and Tipton County in 

Tennessee had moderate growth from 2000-2010 but are sparsely populated. 

Crittenden County, Arkansas had less than 1 percent population growth from 2000-2010 and contains 

only 4 percent of the CBSA population. The County is mostly rural with little urbanization. 

The attachment to this document contains Figure 2, Memphis Area Ozone and Ozone Precursor 

Monitoring Network, and Figure 3, Population Density Change Percentage Between 2000 and 2010 

Census for Memphis Ozone and Ozone Precursor Monitoring Network, which present graphical 

information on population density and growth for the Memphis area.
8

Traffic VMT Data and Commuting Patterns

EPA evaluated the total VMT for each county in the Memphis CBSA. In combination with the 

population/population density data and the location of main transportation arteries (see above), this 

information helps identify the probable location of non-point source emissions. A county with high 

VMT is generally an integral part of an urban area and indicates the presence of motor vehicle emissions 

that may contribute to ozone formation that contributes to nonattainment in the area. Rapid population or 

VMT growth in a county on the urban perimeter signifies increasing integration with the core urban 

area, and indicates that the associated area source and mobile source emissions may be appropriate to 

include in the nonattainment area. Table 5 shows total 2008 VMT for each county.

Table 5. Traffic and VMT Data

County

State Recommended 

Nonattainment? 2008 VMT (million miles)

Crittenden, AR Yes 903

DeSoto, MS No 1,629

Fayette, TN No 573

Marshall, MS No 725

Shelby, TN No 8,789

Tate, MS No 376

Tipton, TN No 401

Tunica, MS No 337

Areawide: 13,733

*Counties that EPA intends to designate as nonattainment are shown in bold.

* MOBILE model VMTs are those inputs into the NEI version 1.5. 

DeSoto County has the second highest VMT in the Memphis CBSA (12% of the total Memphis CBSA). 

Additionally, DeSoto County has a 48 percent growth in population from 2000-2010 with approximately 

35 and 34 percent of the County’s NOx and VOC emissions (respectively) deriving from mobile 

sources.

Shelby County is the only county in the Memphis CBSA violating the 2008 ozone NAAQS with 2008-

2010 air quality data and is considered the core CBSA county, with 64 percent of the VMT in the 

Memphis CBSA; Approximately 35 percent of Shelby County’s NOx emissions and 34 percent VOC 

emissions are from mobile sources. 

Crittenden County, has less than 10 percent of the CBSA VMT (third highest in the Memphis CBSA). 

From 2000-2010, Crittenden County had less than 1 percent population growth with 45 percent and 31 

percent of the County’s NOx and VOC emissions(respectively) deriving from mobile sources.

The remaining counties in the Memphis CBSA all have low total population and population growth with 

little urbanization and low precursor emission contribution suggesting negligible contribution of 

population-based emissions.
9

Factor 3: Meteorology (weather/transport patterns)

For this factor, EPA analyzed 30-years of National Weather Service (NWS) wind speed and wind 

direction data collected at the Memphis International Airport (NWS Station 13893) to help determine 

transport patterns and source contributions. EPA assessed wind direction and speed for the 2008-2010 

“ozone season” (March through October) in the Memphis CBSA as well as on days when area ozone 

monitors exceeded the 2008 ozone NAAQS. Additionally, EPA evaluated wind back trajectories (which 

are an analysis of meteorological patterns) specifically on days when the current ozone design value 

monitor in Shelby County (Frayser monitor) exceeded the 2008 NAAQS. These analyses were 

conducted to better understand the fate and transport of precursor emissions contributing to ozone 

formation. 

EPA’s analysis of the NWS data indicate predominate south and south-southwest component for the 

Memphis CBSA. However, an examination on days when monitors in DeSoto County (Hernando) 

exceeded the 2008 ozone NAAQS suggested a northerly component. Additionally, on days when 

monitors in Shelby County exceeded the 2008 NAAQS, the data indicated a southerly wind component. 

Figure 2, Memphis Area Ozone and Ozone Precursor Monitoring Network, and Figure 4 present 

graphical information on 24-hour back trajectories for exceedances in 2008-2010 at the Frayser monitor, 

locations of major stationary sources, and locations of ambient monitors with their design values. An 

examination of the meteorological data indicates that, for the 2008-2010 days with ozone concentrations 

above 75 ppb at the Memphis 2008-2010 Design Value site (Frayser monitor), the wind back trajectories 

primarily go back through Shelby County, TN (on 10 out of 10 days) and DeSoto County, MS (on 7 out 

of 10 days), with back trajectories going back through Crittenden County, AR on only 1 out of 10 days. 

As mentioned in Factor 1, the Shelby County monitor is the only monitor in the Memphis CBSA with a 

2008-2010 violation of the 2008 ozone NAAQS.

Since the 2008-2010 data is only for three years and has only 10 exceedance days, we evaluated more 

years to better understand the meteorological transport conditions that exist during ozone exceedances. 

Normally when we are developing a conceptual model understanding of what yields ozone exceedances 

in an area we will evaluate 5 to 10 years worth of meteorological data. Therefore we decided to evaluate 

all days that had ozone exceedances at the Design Value monitor (Frayser) for the 2006-2010 period. 

The 2006 and 2007 years had more meteorology that was conducive for ozone formation than the years 

of 2008, 2009, and 2010. Figure 5 in the attachment to this document includes 72-hour back trajectories 

for 2006-2010 ozone exceedances at the Frayser monitor using the National Oceanic and Atmospheric 

Administration Hybrid Single Particle Lagrangian Integrated Trajectory Model (NOAA HYSPLIT). To 

further understand the meteorological transport conditions within the regional area around Memphis, we 

also evaluated24-hour back trajectories for the 2006-2010 time-periods using the NOAA HYSPLIT 

model. The results of these back trajectories are included in the attachment to this document as Figure 6 

with a further zoom in view in Figure 7.

Evaluation of Figures 6 and 7 further supports our previous conclusions based on the 2008-2010 back 

trajectories when the Memphis area Frayser monitor has ozone exceedances. The 2006-2010 data further 

supports that most of the centerlines of the back trajectories passes through Shelby County TN, and 

many of the back trajectory centerlines pass through DeSoto county in northern Mississippi with smaller 

percentage passing through Crittenden County, Arkansas. 

EPA’s meteorological assessment of the area monitors ozone exceedances and specifically the wind 

back trajectory analysis at the Frayser monitor indicate that Shelby County is likely an emission 
10

contributor to exceedances of the 2008 NAAQS at the Frayser monitor. Furthermore, the assessment 

also suggests that DeSoto and Crittenden Counties should be considered for potential inclusion in the 

intended Memphis nonattainment area. 

Factor 4: Geography/topography (mountain ranges or other air basin boundaries)

The geography/topography analysis evaluates the physical features of the land that might affect the 

airshed and, therefore, the distribution of ozone over the area.

The Memphis area does not have any geographical or topographical barriers limiting air pollution 

transport within its air shed. Therefore, this factor did not play a significant role in this evaluation.

Factor 5: Jurisdictional boundaries

Once we identified the general areas we anticipated we would recommend for nonattainment, we then 

considered existing jurisdictional boundaries for the purposes of providing a clearly defined legal 

boundary and to help identify the areas appropriate for carrying out the air quality planning and 

enforcement functions for nonattainment areas. Examples of jurisdictional boundaries include 

existing/prior nonattainment area boundaries for ozone or other urban-scale pollutants, county lines, air 

district boundaries, township boundaries, area covered by an MPO, state lines, Reservation boundaries,

and urban growth boundaries. Where existing jurisdictional boundaries were not adequate or 

appropriate to describe the nonattainment area, other clearly defined and permanent landmarks or 

geographic coordinates were considered.

The Memphis Area MPO is comprised of two study areas; the Memphis Urban Area MPO and the West 

Memphis MPO. Both organizations are considered multi-jurisdictional agencies responsible for the 

implementation and coordination of urban transportation planning and establishing transportation 

conformity infrastructure within their respective boundaries. The Memphis Urban jurisdiction is 

comprised of all of Shelby County, Tennessee, the western four miles of Fayette County, Tennessee and 

the northern twelve miles of DeSoto County. The portion of the Memphis Urban MPO in DeSoto 

County captures the more urbanized portion of the county that has experience continuous growth as well 

as the ozone air quality monitor. The West Memphis jurisdiction is comprised of the current and 

potential future urbanized portion of Crittenden County (including the ozone air quality monitor) with 

the following legal description:

That area west from the Mississippi River along the southern right of way line of County Road 

18 (Miller Road and Caldwell Road) to the western right of way line of County Road 205 

(Hinkley Road); then north along said right of way line and continuing north to the intersection 

of the southern right of way line of the St. Louis-Southwestern Railroad; then in a southwesterly 

direction along said right of way line to the intersection of eastern right of way line of State 

Highway 147; then north along said right of way to the intersection of the southern right of way 

line of State Highway 131; then west along said right of way line to the western right of way line 

of County Road 51(Eubank Road); then north along said right of way line to U.S. 70; then 

continuing north along the western right of way line of County Road 25 (Katie Goodhope) to the 

northern right of way line of County Road 12 (Buck Lake Road); then east along said northern 

right of way line to State Road 306; then continuing east along the northern right of way line of 

State Road 306 to the western right of way line of County Road 165; then north along said right 

of way line to the northern right of way line of County Road 168; then northeasterly along said 
11

right of way line to the intersection of the northern right of way of County Road 172; then east 

along said right of way line to the intersection of the western right of way line of County Road 5; 

then north along said right of way line to the intersection of the northern right of way line of 

James Mill Road; then east along said northern right of way line to the Mississippi River being 

the eastern boundary of the study area.

Memphis, TN-MS-AR Area has previously established nonattainment boundaries associated with both 

the 1-hour ozone and 1997 8-hour ozone NAAQS. The Memphis nonattainment boundary for the 1-

hour ozone NAAQS included Shelby County, Tennessee in its entirety. Whereas the Memphis 

nonattainment boundary for the 1997 8-hour ozone NAAQS included Crittenden County, Arkansas and 

Shelby County, Tennessee in their entireties. Tennessee has recommended a different boundary for the 

2008 ozone NAAQS for their portion of this Area. Arkansas recommended the same as the previous 

boundary for their portion of this Area. In addition, there is current infrastructure for meeting the 

transportation conformity requirements in Shelby County and the urbanized portions of DeSoto County 

and Crittenden County since both the Memphis Urban area and West Memphis MPO are currently 

implementing these requirements for the 1997 8-hour ozone standard.

Even though, DeSoto and Crittenden Counties do not have violating monitors for the 2008 ozone 

NAAQS based on air quality data from 2008-2010, our analysis suggest that both are likely contributing 

to the violation in Shelby County due to potential population-based emissions from mobile sources 

(VMT) and area source, meteorology and population growth.

Conclusion

Based on the assessment of the factors described above, EPA has preliminarily concluded that the 

following counties should be included as part of the intended Memphis nonattainment area because they 

are either violating the 2008 ozone NAAQS or contributing to a violation in a nearby area: Crittenden 

County, Arkansas, and Shelby County, Tennessee in their entireties, and the portion of DeSoto County 

that is included in the Memphis MPO boundary. Two of these counties (i.e., Crittenden County,

Arkansas and Shelby County, Tennessee) are included in the Memphis nonattainment area for the 1997 

ozone NAAQS. One of the air quality monitors in Shelby County indicates violation of the 2008 ozone

NAAQS based on 2010 DVs, therefore this county is preliminarily included in the nonattainment area. 

Crittenden County, Arkansas, and DeSoto County, Mississippi are nearby counties that do not have

monitors indicating a violation of the standard based on 2010 DVs. However, EPA has preliminarily 

concluded that these counties (or portions thereof) contribute to the ozone concentrations in violation of 

the 2008 ozone NAAQS through population-based emissions from mobile and area sources (e.g., 

vehicles and other small area sources) and county VMT. 

Source category emissions data indicate that mobile sources and area sources are the primary 

contributors to ozone formation in the Memphis CBSA. Thus, population-based emissions such as total 

population or population growth, and precursor emission transport would indicate a county with 

contribution in the Memphis Area.

The population in DeSoto County, Mississippi has grown steadily from 2000-2010 (particularly the 

northern portion) with a 48 percent increase, even though it only makes up 12 percent of the total 

population in the CBSA. The County also has the CBSA’s second highest VMT. More than 30 percent 

of the County’s NOx and VOC emissions are from mobile sources and over 40 percent from area 
12

sources. In addition, meteorology suggests that DeSoto County is likely contributing to the violation in 

Shelby County due to potential southerly transport of mobile and area emissions.

Shelby County, Tennessee dominates the CBSA in terms of urbanization, precursor emission 

contribution and transport which indicate population-based emission (mobile and area sources) 

contribution to its own violating monitor. Although the County population growth was less than 5 

percent from 2000-2010, it is densely populated with 70 percent of the CBSA population and five times 

DeSoto County’s population. Shelby County makes up over 60 percent of the Area’s NOx and VOC 

emissions. The County’s has over 30 percent of the County’s NOx and VOC emission coming from 

mobile sources and point sources. Meteorological analysis also indicates that Shelby County is 

contributing to its own violation as well as other monitors in the Memphis CBSA.

Crittenden County, Arkansas makes up less than 5 percent of the CBSA population with less than a 1

percent population growth from 2000-2010. Crittenden County is mostly rural with the least 

urbanization compared to Shelby and DeSoto Counties. The County contributes less than 10 percent of 

the CBSA NOx and VOC precursor emissions. However, Crittenden County has over 40 percent of its 

NOx emission deriving from area sources which is considered a primary contributor to the formation of 

ozone in the Memphis area. EPA is proposing to include all of Crittenden County in the 2008 ozone 

Memphis nonattainment area because the county was included in its entirety in the 1997 ozone Memphis 

nonattainment area and because Arkansas recommended inclusion of the county in its entirety.

The remaining Tennessee (Tipton, Fayette) and Mississippi (Marshal, Tate, and Tunica) counties all 

have low population and urbanization, and precursor emission contribution and transport suggesting 

negligible contribution to the violating county. With the exception of those counties that comprise the 

Memphis, TN-MS-AR 1997 8-hour ozone boundary and the portion of DeSoto County, Mississippi 

discussed in this TSD for inclusion, EPA preliminarily concludes that the remainder of the counties in 

the CBSA do not contribute to the violations at the monitors in the CBSA and therefore are not being

considered as part of the nonattainment area. 
13

ATTACHMENTS

Figure 2. Memphis Ozone and Ozone Precursor Monitoring Network, with Population Density.

Figure 3. Population Density Change Percentage Between 2000 and 2010 Census for Memphis Ozone 

and Ozone Precursor Monitoring Network.

Figure 4. Overlay of 24-hour HYSPLIT back trajectories of all 75 ppb exceedances at the Frayser 

monitor for the 2008-2010 period.

Figure 5. NOAA HYSPLIT MODEL 72-Hour Back Trajectory Frayser Exceedances (2006-10).

Figure 6. NOAA HYSPLIT MODEL 24-Hour Back Trajectory Frayser Exceedances (2006-10).

Figure 7. NOAA HYSPLIT MODEL 24-Hour Back Trajectory Frayser Exceedances (2006-10) - Zoom 

View.
14

Figure 2. Memphis Ozone and Ozone Precursor Monitoring Network, with Population Density
15

Figure 3. Population Density Change Percentage Between 2000 and 2010 Census

for Memphis Ozone and Ozone Precursor Monitoring Network
16

Figure 4 - Overlay of 24-hour HYSPLIT back trajectories of all 75 ppb exceedances 

at the Frayser monitor for the 2008-2010 period.
17

Figure 5. NOAA HYSPLIT MODEL 72-Hour Back Trajectory Frayser Exceedances (2006-10)
18

Figure 6. NOAA HYSPLIT MODEL 24-Hour Back Trajectory Frayser Exceedances (2006-10)
19

Figure 7. NOAA HYSPLIT MODEL 24-Hour Back Trajectory Frayser 

Exceedances (2006-10) - Zoom View
Appendix 2: Mississippi Department of 

Environmental Quality, Neel-Schaffer, Inc.: On-Road 

Mobile-Source Emissions Forecast For Desoto 

County, Mississippi (2010 to 2020)

Mississippi Department of Environmental Quality 

February 2012 

- 25 -
 	


 











 
 













  

 	


 
 	 	 

  

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Appendix 3: Idle Reduction Policies in 

DeSoto County

Mississippi Department of Environmental Quality 

February 2012 

- 26 -
DeSoto County Anti-Idling Program 

Proposal

The purpose of the DeSoto County Anti-Idling Program is to protect public health and the 

environment in DeSoto County by voluntarily restricting the amount of time that county 

and municipal non-emergency vehicles, school buses, and commercial vehicles idle. 

Vehicles that require unavoidable idling to provide a service or function would be 

exempt. 

The DeSoto County Anti-Idling Program is a unique collaborative effort to reduce 

vehicle emissions while conserving fuel and lessen vehicle wear and tear. Any current 

anti-idling policies in the county or municipalities could be integrated into the DeSoto 

County Anti-Idling Program. The Mississippi Department of Environmental Quality will 

partner in this program and provide any assistance needed. Additionally, EPA is actively 

promoting anti-idling programs and will collaborate with this program. 

Background

The United States Environmental Protection Agency sets National Ambient Air Quality 

Standards (NAAQS) for the protection and well being of human health and the 

environment. DeSoto County is currently designated as attainment of all Environmental 

Protection Agency’s NAAQS. However, efforts must be made for DeSoto County to 

continue to enjoy good air quality. 

Vehicle emissions have a significant impact on human health and our environment. 

Vehicle emissions contain nitrogen oxides and volatile organics compounds which 

contribute to ozone formation as well as fine particulates. Vehicles contribute one third 

of the nitrogen oxides and one fourth of the volatile organics emissions in Mississippi. 

Reducing emissions from vehicles are important to assure NAAQS continue to be met. 

Limiting the amount of time in which vehicles idle is one of the tools to lower emissions. 

A vehicle can use up to one gallon per hour when idling and produce up to 135 grams per 

hour of nitrogen oxides and 6.5 grams per hour of volatile organics. 

An anti-idling program would provide an easy, cost-effective policy to assist in 

maintaining the air quality of DeSoto County and to reduce the exposure of people to the 

potential health impacts of vehicle emissions. It would also reduce fuel consumption and 

vehicle wear and tear which would create a cost savings for the county and 

municipalities. EPA is actively promoting anti-idling programs. 

Goal

The goal is for all county and municipal governments, school bus fleets, and commercial 

fleets participating in the DeSoto County Anti-Idling Program to voluntarily adopt a 

policy restricting non-emergency vehicles from unnecessary idling. Vehicles that require 

unavoidable idling to provide a service or function would be exempt. 

Mississippi Department of Environmental Quality 

February 2012 

- 27 -
DeSoto County Anti-Idling Policy

1.0 Purpose:

DeSoto County, Mississippi is committed to reducing unnecessary county 

and municipal vehicle/equipment idling as a means of reducing air 

pollution and fuel expense. 

The purpose of this policy is to establish guidelines for unnecessary idling 

of county and municipal vehicles and equipment. Limiting idling times 

reduces air pollution and contributes to healthier work environments and 

the efficient use of county/municipality resources. 

2.0 Scope:

This policy applies to all staff operating vehicles and equipment owned or 

leased by DeSoto County and the municipalities within the county. 

3.0 Definitions:

3.1 Idling: 

the operation of a vehicle or equipment while they are not in motion and 

not being used to operate auxiliary equipment that is essential to the 

operation of the vehicle or equipment. 

3.2 Fuels:

includes all vehicles or equipment that run on fossil fuels which include 

gasoline, diesel, propane, hydrogen, and natural gas. 

3.3 Vehicles: 

any self-propelled mechanized equipment that is used for transporting 

persons or commodities on public roads utilizing fossil fuels. 

4.0 Procedures:

 4.1 Manufacturer’s Guidelines (Recommendations): 

Always follow the manufacturer’s guidelines and recommendations for 

idling unless otherwise specified. 

 4.2 Initial Warm-Up: 

Idle times up to three (3) minutes are allowed for vehicles during their 

initial shift warm up and at subsequent times when the vehicle is being 

restarted after a prolonged period of shut down that results in vehicle 

conditions similar to those prior to initial shift warm up. 

 4.3 Operation of Equipment in the Field: 

Mississippi Department of Environmental Quality 

February 2012 

- 28 -
 4.3.1 Gasoline and Alternative Fuel Vehicles 

No operator shall idle the engine of a gasoline-fueled vehicle in 

excess of one (1) minute if the vehicle is stopped for a foreseeable 

period of time. Operators making multiple or frequent stops that 

require their vehicle to be stationary for time periods of several 

minutes may idle up to three (3) minutes in such circumstances. 

 4.3.2 Diesel-Fueled Vehicles/Equipment 

No operator shall idle the engine of a diesel-fueled vehicle in 

excess of three (3) minutes if the vehicle is stopped for a 

foreseeable period of time. Diesel-fueled vehicles/equipment 

should only be turned off after enough time has passed to allow the 

proper circulation and cooling of the engine oil, coolant, and turbo 

chargers, not to exceed three (3) minutes. 

4.3.3 When engines must be left running for any reason, the operator 

must remain with the vehicle. 

5.0 Exceptions:

This policy does not apply to the following vehicles, equipment, or situations. 

Operators must use their own discretion in certain situations. 

5.1 Emergency vehicles and equipment are exempted while engaged in 

operational activities such as fire, police, or ambulance services. 

5.2 Vehicles assisting in an emergency activity are exempt. 

5.3 Where engine power is necessary for an associated power need such as, 

but not limited to, electrical power, compressed air, and various power 

take-off devices such as auxiliary hydraulics. 

5.4 Vehicles may idle for the purpose of defogging, defrosting, or deicing 

windows. Idling must end when fog, frost, or ice conditions have been 

eliminated. When window ice or frost conditions are present, attempts to 

remove snow, ice, or frost from the windows with a scraper must be 

attempted before idling. 

5.5 This policy does not apply to vehicles being serviced or inspected. 

5.6 Where safety may be compromised by shutting down the engine, 

vehicles/equipment may idle at the discretion of the operator. 

Mississippi Department of Environmental Quality 

February 2012 

- 29 -
CITY OF OLIVE BRANCH 

Engine and Equipment Idling Policy 

January 23, 2006 

Idling of fleet vehicles and equipment contributes to poor air quality, 

consumes fuel unnecessarily, and is harmful to engines. It is the 

responsibility of all city personnel to operate fleet equipment in an 

environmentally and economically sound manner. 

City fleet vehicles and equipment shall not be parked with their engine 

operating for more than five minutes unless it is essential for 

performance of work. When engines must be left operating, for any 

reason other than public safety concerns, the operator must remain 

with the vehicle/equipment. Violators are subject to disciplinary action. 

Mississippi Department of Environmental Quality 

February 2012 

- 30 -
The City of Southaven 

Anti-Idling Policy 

October 16, 2007 

1.0 Purpose: 

 The City of Southaven, Mississippi is committed to reducing unnecessary 

municipal vehicle/equipment idling as a means of reducing air pollution and fuel 

expense. 

The purpose of this policy is to establish guidelines for unnecessary idling of 

county and municipal vehicles and equipment. Limiting idling times reduces air 

pollution and contributes to healthier work environments and the efficient use of 

county/municipality resources. 

2.0 Scope: 

 

This policy applies to all staff operating vehicles and equipment owned or leased 

by the City of Southaven only. 

3.0 Definitions: 

 3.1 Idling: 

the operation of a vehicle or equipment while they are not in motion and not being 

used to operate auxiliary equipment that is essential to the operation of the vehicle 

or equipment. 

3.2 Fuels: 

includes all vehicles or equipment that run on fossil fuels which include gasoline, 

diesel, propane, hydrogen, and natural gas. 

3.3 Vehicles: 

any self-propelled mechanized equipment that is used for transporting persons or 

commodities on public roads utilizing fossil fuels. 

Mississippi Department of Environmental Quality 

February 2012 

- 31 -
Appendix 4: DeSoto County Report Card 

and Table of Air Outreach Events

Mississippi Department of Environmental Quality 

February 2012 

- 32 -
DeSoto County Report Card 

EPA Region 4 staff and MDEQ – Air Division Staff held an Air Quality Workshop in 

Hernando, MS on June 20, 2007. The purpose of the meeting was to provide information 

and tools to DeSoto County citizens and officials to lower emissions across the county. 

Local citizens, elected officials, and MDEQ went above and beyond the 

recommendations given at the workshop. Currently, there is momentum in DeSoto 

County to continue steps to reduce Ozone precursor emissions. By continuing to focus 

resources toward outreach and ozone action planning, MDEQ can continue the efforts to 

reduce emissions. 

DeSoto County Air Quality Workshop 

Meeting Date: June 20, 2007 

Attendees: EPA – Region 4, MDEQ, DeSoto County Officials, Local Elected Officials, 

and Public 

EPA Recommendations MDEQ / DeSoto County Responses 

Ozone Action Program 

DeSoto County Ozone Action Group 

• The DeSoto Planning Commission began the Ozone 

Action Group to engage public and private groups in 

finding emission reductions and providing public 

outreach. 

Outreach 

DeSoto County Ozone Action Group 

• The DeSoto Planning Commission began the Ozone 

Action Group to engage public and private groups in 

finding emission reductions and providing public 

outreach. This group meets regularly and brainstorms 

creative approaches and outreach ideas to reduce 

emissions. 

• MDEQ, DeSoto County Ozone Action Group, and the 

DeSoto County Planning Commission have engaged in 

numerous outreach events throughout the county. A 

puppet show was also developed as an additional 

outreach tool for schools and public outreach. 

Idle Reduction 

DeSoto County Anti-Idling Program 

• DeSoto County and all municipalities within the county 

adopted idle reduction policies and procedures for all 

county and municipal fleets. 

Diesel Emission Reduction 

Projects 

MS School Bus Retrofit Project 

• MDEQ retrofitted 93 DeSoto County school buses with 

diesel oxidation catalysts. In the surrounding counties, 

MDEQ retrofitted an additional 57 buses with DOCs. 

Additional Projects and Efforts: 

• All open burning is banned on Ozone Action Days. Open Burning is banned on all days 

in Hernando. 

• Texas Gas Transmission voluntarily added permit conditions to reduce the load on 

several compressor engines to 90%. This reduction creates a 50% NOx reduction from 

those engines. 

Page 1 of 2 

Mississippi Department of Environmental Quality 

February 2012 

- 33 -
• MDEQ and DeSoto County have had additional outreach to companies to develop Ozone 

Action Plans. 

• DeSoto County has adopted a Greenways Master to create and enhance a comprehensive 

network of greenways, conservation trails, and natural areas. The county employs a 

County Greenways Coordinator to grow the greenways network within DeSoto County to 

preserve natural amenities, waterways, and environmental systems. The greenway system 

will connect our citizens with a variety of outdoor recreational opportunities and 

encourage the use of alternative modes of transportation including bicycle, pedestrian, 

canoe and kayak, and horseback to improve and maintain our air quality and the health of 

our citizens. 

• In 2011, DeSoto County received Two Globe certification from the Green Building 

Initiative as a result of upgrades to existing County-owned buildings to meet energy 

efficiency standards and reduce. Green Globes certified/rated buildings, like the DeSoto 

County Administration building, are committed to using less energy, conserving water 

resources, emitting fewer pollutants, and providing a healthier indoor environment for 

occupants. 

• There are currently nine MDEQ Diesel Emission Reduction Projects reflecting 35 pieces 

of diesel equipment in and around DeSoto County. Private companies have spent over 

$106,000 of their own money on these projects. MDEQ received 28 application in 

January 2012 for the 2011/2012 state grant 

• MDOT has spent over $1 million in Safe Routes to School, sidewalks and bike path 

improvements in DeSoto County and conducted an I-69 Corridor Alternatives Analysis to 

study preferred mass transit options for DeSoto County. 

Page 2 of 2

Mississippi Department of Environmental Quality 

February 2012 

- 34 -
Mississippi Department of Environmental Quality 

February 2012 

- 35 -

Table of Air Outreach Events 

Date Event 

Estimated 

Attendance 

April 2009 Safe & Healthy Schools Summit 150 

April 21, 2009 Great Green Expo-Keesler AFB 400 

April 24, 2009 DeSoto County Outdoor Day-Olive Branch 250 

May 2009 MS Asthma Coalition 85 

June 17, 2009 MS Association of Supervisors-Gulf Cost 

Convention Center-Biloxi 1,700 

June 23, 2009 Agri-Science Summer Campers-Career 

Development Center, Jackson, MS 20 

July 15, 2009 MS Municipal League-Gulf Coast Convention 

Center-Biloxi 1,700 

September 11, 2009 Mississippi Asthma Summit 125 

September 23, 2009 Arkabutla Day - DeSoto County 700 

September 25 to 

October 4, 2009 Mid South State Fair - DeSoto County 1,000 

October 2, 2009 Renewable Energy Day - Agriculture Museum 400 

November 2009 MDA Greening Local Communities 

Statewide (4 events) 400 

January 30, 2010 Moss Point Going Green Rally 200 

April 17, 2010 Waterfest - Reservoir 300 

April 22, 2010 Earth Day at the Navy Battalion - Gulfport 500 

April 24, 2010 Health Fair - Clinton 350 

May 2010 MS Asthma Coalition 75 

May 1, 2010 Moss Point Outreach Event 200 

June 23, 2010 Jackson Career Development Center Agriscience 20 

September 2010 Mississippi Asthma Summit 125 

September 22, 2010 Arkabutla Day - DeSoto County 950 

October 15, 2010 Odyssey Day - Biloxi 100 

October 16, 2010 Romp on the River - Tunica 5000 

March 19, 2011 North Mississippi Green Festival 500 

April 16, 2011 Waterfest - Reservoir 300 

April 30, 2011 Earth Day - Hernando 625 

May 2011 MS Asthma Coalition 75 

May 2011 MS Department of Health Presentation 25 

August 2011 Center for Advance Vehicle Systems 100 

September 14, 2011 Arkabutla Day - DeSoto County 950 

October 2011 State Port Leadership Group 30 

October, 2011 DeSoto County Board of Supervisors 25 

October, 7 2011 Renewable Energy Day - Agricultural Museum 400 

November 2011 State Port Leadership Group 30