# APPENDIX A

Back Trajectories

Texas and California Maintenance-Only Monitors

2005-2006

1997 Ozone NAAQS Exceedance Days

Note



### The attached trajectories were generated by EPA Region 8 using the HYSPLIT 4.9 online

computer application. 1 

### The HYSPLIT default parameters were used, except for the

following: Eta Data Assimilation System (EDAS) 40 km meteorological data set;

duration 72 hours; height at end point1500 m above ground le vel; end point start time 22

Coordinated Universal Time (UTC), equivale nt to 4:00 pm CST. Exceedance days are

days of ozone concentrations 85 ppb or above.

1 NOAA ARL READY Website at http://ready.arl.no aa.gov/HYSPLIT.php . NOAA Air Resources Laboratory,

Silver Spring, MD.Figure 1.1. Back Trajectories for DallasCSA Maintenance-Only Ozone MonitorsNOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 1.1.aBack Trajectories for Dallas,Hinton Monitor, Site ID 48-113- 0069NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 1.1.b Back Trajectories for Dallas, Executive Airport Monitor, Site ID 48-113-0087NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 1.1.c Back Trajectories for Tarrant, Keller Monitor, Site ID 48-439-2003NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 2.1. Back Trajectories for Houston CSA Maintenance-Only Ozone MonitorsFigure 2.1.a Back Trajectories for Houston, Aldine Monitor, Site ID 48-201-0024NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 2.1.b Back Trajectories for Houston, Northwest Harris Co. Monitor, Site ID 48-201-0029NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 2.1.c Back Trajectories for Houston,Lynchburg Ferry Monitor, Site ID 48-201-1015NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 2.1.d Back Trajectories for Houston, Clinton Monitor, Site ID 48-201-1035NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006Figure 2.1.e Back Trajectories forHouston, Seabrook Friendship Park Monitor, Site ID 48-201-1050NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursAll days≥85 ppb2005-2006NOAA Hysplit Moldel, v4.9Height: 1500m AGLStart Time: 22:00 UTCLength: 72 hoursHigh O3 days (≥85 ppb)2005-2006Figure 3.1 Back Trajectories for California Maintenance-Only Monitors on High Ozone DaysNote:This map combines back trajectories starting at each maintenance monitor on highozone days. High ozone days include the top one third of the exceedance-days registered ateach monitor in 2005 and in 2006.

### Table 1

Dallas CSA Maintenance-Only Monitors

Exceedance-Days/Concentrations for the 1997 8-Hour O3 NAAQS

2005-2006

County: Dallas Site Name: Dallas Hinton St.

Site ID #: 48-113-0069 Lat/Long: 32.819722/-96.860000

Exceedance

Date Exceedance

Concentration

(ppb) Exceedance

Date Exceedance

Concentration

(ppb)



### 5/20/05 .087 8/31/06 .090

5/21/05 .100 9/1/06 .096

6/15/05 .104

6/21/05 .090

7/02/05 .089

7/11/05 .087

7/14/05 .090

7/29/05 .088

8/02/05 .089

8/06/05 .085

8/22/05 .095

9/01/05 .098

County: Dallas Site Name: Dallas Executive Airport

Site ID #: 48-113-0087 Lat/Long: 32.676667/-96.871944

5/21/05 .095 6/13/06 .089

6/15/05 .086 6/27/06 .091

6/20/05 .085 7/07/06 .088

6/21/05 .091 8/22/06 .091

7/06/05 .088 8/31/06 .086

7/11/05 .088 9/01/06 .095

7/29/05 .089

County: Tarrant Site Name: Keller

Site ID#: 48-439-2003 Lat/Long: 32.922500/-97.281944

6/15/05 .100 6/03/06 .088

6/20/05 .094 6/09/06 .097

6/21/05 .110 6/12/06 .093

6/22/05 .098 6/14/06 .103

6/23/05 .085 6/15/06 .085

7/02/05 .087 6/18/06 .094

7/08/05 .091 6/28/06 .089

7/29/05 .085 6/30/06 .087

7/30/05 .087 7/18/06 .096

8/01/05 .089 7/19/06 .086

8/02/05 .115 7/20/06 .090

9/01/05 .093 7/21/06 .089

9/02/05 .094 8/18/06 .090

9/03/05 .086 8/21/06 .087

### 9/06/05 .088 8/31/06 .093

9/08/05 .091 9/01/06 .094

9/09/05 .098

9/20/05 .085

9/22/05 .090

### Table 2

Houston CSA Maintenance-Only Monitors

Exceedance-Days/Concentrations for the 1997 8-Hour O3 NAAQS

2005-2006

County: Harris Site Name: Aldine

Site ID #: 48-201-0024 Lat/Long: 29.901111/-95.326111

Exceedance

Date Exceedance

Concentration

(ppb) Exceedance

Date Exceedance

Concentration

(ppb)



### 5/14/05 .098 6/5/06 .100

5/27/05 .096 6/8/06 .089

6/2/05 .101 9/1/06 .102

8/23/05 .086

10/18/05 .087

County: Harris Site Name: Northwest Harris Co.

Site ID #: 48-201-0029 Lat/Long: 30.039444/-95.673889

5/6/05 .097 4/13/06 .090

5/27/05 .116 6/5/06 .103

6/2/05 .094 6/6/06 .086

6/22/05 .093 6/29/06 .093

6/23/05 .096 8/31/06 .087

6/24/05 .091 9/7/06 .087

6/26/05 .088 9/14/06 .097

6/27/05 .088 9/27/06 .086

8/3/05 .087

County: Harris Site Name: Lynchburg Ferry

Site ID#: 48-201-1015 Lat/Long: 29.764444-95.077778

6/2/05 .104 6/4/06 .099

6/15/05 .088 6/8/06 .089

8/21/05 .118 6/12/06 .085

10/18/05 .090 8/17/06 .085

9/1/06 .111

9/7/06 .087

County: Harris Site Name: Clinton

Site ID#: 48-201-1035 Lat/Long: 29.733611/-95.257500

8/1/05 .092 6/29/06 .090

9/5/05 .098

10/12/05 .088

10/17/05 .092

County: Harris Site Name: Seabrook Friendship Park

Site ID#: 48-201-1050 Lat/Long: 29.583056/-95.015556

4/8/05 .088 6/2/06 .091

6/2/05 .087 6/4/06 .102

6/15/05 .086 6/14/06 .086

6/22/05 .085 9/1/06 .119

7/28/05 .095

### 8/22/05 .107

8/30/05 .118

10/18/05 .085

### Table 3

California Maintenance-Only Monitors

High Ozone Days/Concentrations

2005-2006

County: Sacramento

Site ID #: 06-067-0006 Lat/Long: 38.6142/-121.3669

Exceedance

Date Exceedance

Concentration

(ppb) Exceedance

Date Exceedance

Concentration

(ppb)



### 7/13/05 .109 7/22/06 .093

7/14/05 .117 7/23/06 .095

7/15/05 .106 9/01/06 .095

7/17/05 .096 9/12/06 .102

County: Riverside

Site ID #: 06-065-2002 Lat/Long: 33.7085/-116.2154

5/23/05 .090 5/12/06 .086

5/26/05 .091 7/24/06 .090

6/01/05 .094

7/01/05 .092

7/16/05 .095

8/27/05 .094

County: Placer

Site ID#: 06-061-0002 Lat/Long: 38.9378/-121.1039

5/25/05 .087 6/24/06 .098

7/01/05 .092 7/18/06 .098

7/18/05 .096 7/20/06 .094

7/26/05 .107 7/21/06 .114

8/03/06 .095

8/09/06 .093

9/06/06 .094

9/13/06 .098

County: Merced

Site ID#: 06-047-0003 Lat/Long: 37.2817/-120.4336

7/14/05 .093 6/22/06 .094

6/23/06 .091

Note

High ozone concentration days include the top one third of the ozone exceedances registered on

each of the 2005-2006 years at each of the four maintenance-only monitors. Dates and

concentrations are from EPA’s AQS exceedances reports.