Reference: QBN1701-TCEQ-2007 Page 1 of 86

Date of Issue: 28 November 2007 Signed:

Checked by: Name: Melanie Williams 

 for Managing Director 

Commercial in confidence 

Measurements of VOC emissions from petrochemical industry sites in the 

Houston area using Differential Absorption Lidar (DIAL) 

during Summer 2007. 

DRAFT FOR COMMENT 

FOR: Texas Commission 

on Environmental Quality 

 

 

FOR THE ATTENTION OF: Russell Nettles 

DATE OF TEST PERIOD: 16/07/07 to 18/08/07 

AUTHORS: Rod Robinson, Tom Gardiner, 

Bob Lipscombe
Commercial in confidence 

Reference QBN1701-TCEQ-2007 Page 2 of 85

Checked by:

Contents 

Contents ................................................................................................................................... 2 

Introduction.............................................................................................................................. 3 

Section 1. Measurements of VOC emissions from a Bulk Terminal, in the Houston nonattainment area. ........................................................................................................................ 4 

Measurement description.................................................................................................. 4

Definition of VOCs............................................................................................................. 4

Measurements on the 16th July. ........................................................................................ 6

Measurements on the 17th July ......................................................................................... 8

Measurements on the 18th July and 19th July ................................................................ 10

Night-time measurements on the 20th-21st July. ............................................................ 11

Section 2 Measurements of VOC emissions from a Refinery in the Houston non-attainment 

area......................................................................................................................................... 12 

Measurement description................................................................................................ 12

Measurements of product storage tanks........................................................................ 14

Measurements of crude oil tanks.................................................................................... 16

Measurements of VOC emissions from coker C ........................................................... 24

Measurements of VOC emissions from heated oil tanks.............................................. 27

Measurement of VOC emissions from elevated flares.................................................. 28

Section 3 Measurements of Benzene emissions from Refinery........................................... 31 

Measurement description................................................................................................ 31

Benzene concentration measurements on 17th August. ................................................ 31

Measurements of benzene fluxes from the coker .......................................................... 36

Section 4. Measurements of SO2 from the Sulphur Recovery Unit...................................... 38 

Annex 1. Description of the DIAL technique........................................................................ 39 

Overview of the Dial technique....................................................................................... 39

Description of the theory of Dial measurements........................................................... 39

Description of facility operated by NPL ........................................................................ 40

Calibration and validation .............................................................................................. 45

NPL open-path calibration facility................................................................................. 47

Annex 2 Speciated VOC measurements and Flux Correction Factors ................................. 48 

Flux Correction Factors .................................................................................................. 48

Sampling Procedure......................................................................................................... 53

Analysis of the ATD tubes............................................................................................... 54

Annex 3. Meteorological Measurements .............................................................................. 65 

 
Reference: QBN1701-TCEQ-2007 Page 3 of 85

Checked by: 

Introduction 

This report presents the results of a measurement campaign carried out using the NPL 

differential absorption LIDAR (DIAL) system at two petrochemical facilities in the The 

Houston non-attainment area region of South East Texas, between 16th July to 18th August 

2007. The project was carried out for the Texas Commission on Environmental Quality 

(TCEQ). This report covers the measurements undertaken by NPL, and does not cover 

additional measurements undertaken by other contractors. 

The primary objective of the study was to assess emission fluxes of VOCs and benzene from 

a number of identified potential sources, including storage tanks, a delayed coker unit, waste 

water treatment areas and flares. 

The report provides a summary of the VOC fluxes measured using the DIAL technique at a 

Bulk Terminal in the Houston non-attainment area (hereafter the Bulk Terminal) (Section 1) 

and a Refinery in the Houston non-attainment area (hereafter the Refinery) (Sections 2 and 

3). Annex 1 provides an overview of the DIAL technique, and discusses the calibration and 

validation procedures. Annex 2 presents the results of speciation measurements of air 

samples, and Annex 3 presents a summary of the meteorological measurements undertaken 

during the campaign.
Reference: QBN1701-TCEQ-2007 Page 4 of 85

Checked by: 

Section 1. Measurements of VOC emissions from a Bulk 

Terminal, in the Houston non-attainment area. 

Measurement description. 

DIAL measurements of the emissions of VOCs from storage tanks at the Bulk Terminal 

facility were carried out on 16th, 17th , 18th, 19th July and on the night of the 20th-21st July. 

The tanks selected by TCEQ/Bulk Terminal for measurement were naphtha storage tanks, 

numbers 22,23, 27, 28, and 29. Tank 3792 was also included in some of the measurements, 

though no specific identifiable emissions were observed that could be attributed to this tank. 

Two measurement locations were used for the DIAL measurements; these were both on 

Avenue H, the southern road within the plant. The GPS coordinates for these measurement 

locations were: 

DIAL Location 1. 

North side of Ave H, due south of Tank 3770 

29°21'23.64"N 

94°55'2.82"W 

DIAL Location 2 

South side of Ave H, south of Tank 3792. 

29°21'23.47"N 

94°54'52.79"W 

Measurements of VOC fluxes were carried out using the NPL DIAL as described in Annex 

1. Fluxes were obtained by scanning the DIAL measurement line-of-sight in vertical planes, 

downwind of the target emissions sources. Measurements were also made upwind of the 

target sources to check for any upwind VOC fluxes. The measurement lines are shown in 

Figure 1.1. 

Definition of VOCs 

The DIAL technique, as operated during these measurements, provides a measurement of 

mass emission in gasoline vapour equivalent. The DIAL measures VOCs by measuring the 

differential absorption of two wavelengths of light sensitive to hydrocarbons of C3 and 

above. 

This has been calculated for each air sample taken, and Annex 2 presents a set of correction 

factors for each measurement location. For the measurements at the Bulk Terminal the 

factors range from between 0.8 to 1.6. 
Reference: QBN1701-TCEQ-2007 Page 5 of 85

Checked by: 

Figure 1.1.DIAL locations and scan lines used for VOC measurements at the Bulk Terminal. 
Reference: QBN1701-TCEQ-2007 Page 6 of 85

Checked by: 

Measurements on the 16th July. 

From Location 1, scans were made which measured the emissions from tanks 23,27,28,29 

and 3792. Tank 22 emissions would also have been observed if these had been significant. 

Table 1.1 presents these results. The wind direction was generally from the SE, with speeds 

of 3 to 6 m/s. 

A small flux was measured, at a range consistent with emissions from tanks 27, 28 and 23. 

This is shown in Figure 1.2. No observable emissions were seen from tank 22 or tank 3792. 

The average emission observed was 28 lbs/hr with a standard deviation of ± 5 lbs/hr. It 

should be noted the standard deviation of the results includes both the inherent uncertainty 

in the DIAL measurements and any real variability in the emissions (whether due to source 

variability or variable dispersion). 

Upwind scans (Scan IDs 16 and 21) gave results at or below the detection limit, which for 

the conditions prevailing at the Bulk Terminal was 1 lbs/hr. 

Table 1.1. VOC fluxes measured on 16th July at Bulk Terminal. 

The DIAL provides a range resolved measurement of VOC concentrations. A DIAL scan 

can provide not only a measurement of the mass emissions flux, but also a visual indication 

of the location of the emission plume. Figure 1.2 shows an example of such a visualisation, 

for Scan ID 12 on the 16th July. The plot illustrates the vertical plane through which the 

DIAL scanned, and indicates the distribution of VOCs within this plume. The wind direction 

is indicated by the red arrow. The intensity of the colour plot is related to the concentration 

of the VOCs. The maximum VOC concentration in this plot is 300 ppb. 
Reference: QBN1701-TCEQ-2007 Page 7 of 85

Checked by: 

Figure 1.2. Example of the VOC distribution seen in a vertical scan at the Bulk Terminal 

(Scan 12, 16th July). The green arrow represents the average wind direction. The peak VOC 

concentration observed in this scan was 300 ppb.

DIAL 
Reference: QBN1701-TCEQ-2007 Page 8 of 85

Checked by: 

Measurements on the 17th July 

A further series of measurements were made of tanks 27,28,29 and 23 from Location 1. The 

wind was from the south, shifting slightly to south-westerly during the day with wind speeds 

ranging between 2.8 and 8.7 m/s. The results are presented in Table 1.2. The average flux 

observed for these tanks on the 17th July was 21 lbs/hr with a standard deviation of ± 5 

lbs/hr. Upwind scans were below the detection limit, indicating no contribution from other 

sources. 

In order to separate out and directly measure fluxes from tank 22, the DIAL was moved to 

Location 2, to the south of tank 3792. Scans could then be made isolating the emissions 

from tank 22. It should be noted that this measurement configuration is not ideal for flux 

measurements, as the measurement line of sight is very close to tank 22. Other locations 

were not possible due to construction work on the road to the north of tank 22. Scans made 

from location 1 had indicated that the emissions observed from tank 22 were not significant. 

This was apparent because no significant concentrations were observed at ranges which 

would have been consistent with a plume from tank 22. Moving to a measurement line of 

sight further away from tank 22, to the north of Ave G, would have reduced the chance of 

measuring any small emissions from tank 22 due to dispersion. The fluxes observed, even 

close to tank 22, were very small, with an average flux of 3 lbs/hr and a standard deviation 

of 1.3 lbs/hr. The peak concentrations observed were less than 100 ppb, and these emissions 

would generally be considered insignificant in the context of a DIAL survey. 

Table 1.2. VOC fluxes measured on 17th July at the Bulk Terminal. 
Reference: QBN1701-TCEQ-2007 Page 9 of 85

Checked by: 

Figure 1.3. Example of a horizontal scan showing the VOC distribution above naphtha tanks 

at the Bulk Terminal (Scan 17, 17th July). The green arrow represents the average wind 

direction. The peak VOC concentration observed in this scan was 288 ppb.
Reference: QBN1701-TCEQ-2007 Page 10 of 85

Checked by: 

Measurements on the 18th July and 19th July 

Further scans were made of tank 22 on both the 18th and 19th July, tables 1.3 and 1.4 present 

these data. The average emissions fluxes measured were 5 lbs/hr with a standard deviation 

of 2.4 lbs/hr on the 18th and 3 lbs/hr with a standard deviation of 2.4 lbs/hr on the 19th. 

Two scans were made on the 18th July to measure the emissions from tanks 23 and 28 from 

location 2. These scans may also have included the contribution from tanks 29 and 22. 

However, the emissions from these tanks would be quite dispersed and are probably not 

included in the measured fluxes. The scans are not ideal for flux determination, as the wind 

field would be very disturbed by the proximity of the tanks. The scans gave flux results that 

are much lower than those measured on the previous days for these tanks, with an average 

value of 3.5 lbs/hr. This indicates either, that the larger emissions originated from tank 27 

(included in earlier measurements), and are not included in these scans. A more likely 

explanation, given subsequent measurements on the 19th, is that the wind field was not ideal 

and the scans did not capture the emissions from the tanks. On the 19th July similar scans 

measured an average emission flux of 18 lbs/hr, which is consistent with the measurements 

made on the 16th and 17th July for these tanks. 

Table 1.3. VOC fluxes measured on 18th July at the Bulk Terminal

Table 1.4. VOC fluxes measured on 19th July at the Bulk Terminal
Reference: QBN1701-TCEQ-2007 Page 11 of 85

Checked by: 

Night-time measurements on the 20th-21st July. 

A series of measurements was made on the night of the 20th-21st July from Location 2, the 

results of these scans are given in Table 1.5. These repeated the scans made from this 

location during the daytime. The wind was initially from further to the east, which was not 

ideal for this location, however it subsequently shifted further south, providing useable 

measurements of tank 22 and tanks 23/28. The average emission flux measured from tank 22 

was 1 lbs/hr, which is at the detection limit. 

The measurements of the emissions from tanks 23 and 28 gave an average emission flux of 

14 lbs/hr, with a standard deviation of 7 lbs/hr. Although this emission is lower than that 

measured during the day. That, coupled with the variable wind pattern close to the tanks and 

the fact that the wind speed itself was lower during these measurements, suggests that 

conclusions about the relationship between day and night-time emissions cannot be drawn 

from these data, except to recognise that emissions are observed during the night-time, and 

therefore night time cannot be discounted from annualisation calculations based on day time 

measurements. 

A series of air samples, using canisters and pumped sorbent tubes was also taken, and the 

results of these are reported in Annex 2. Figure A1.1 indicates the locations of these 

samples at the Bulk Terminal. 

Table 1.5. VOC fluxes measured on the night of 20th July at the Bulk Terminal 
Reference: QBN1701-TCEQ-2007 Page 12 of 85

Checked by: 

Section 2 Measurements of VOC emissions from a Refinery in 

the Houston non-attainment area. 

Measurement description. 

This section of the report describes the results of measurements of VOC emissions from 

various sources within the Refinery. Measurements of VOC emissions were carried out from 

the 25th July to the 11th August. Table 2.1 lists the measurements days and the sources 

monitored on each day. The DIAL measurement locations are identified on individual maps 

in the following Sections. 

Date DIAL Location Sources monitored 

25th July Refinery Location 1 Product tanks 

26th July Refinery Location 1 Product tanks 

28th July Refinery Location 2 Crude oil tanks, coker 

29th July Refinery Location 2 Crude oil tanks 

30th July Refinery Location 3 Gasoline tanks and flare 6 

31st July Refinery Location 2, 2C Crude oil tanks and coker 

1st August Refinery Location 2 Coker 

2nd August Refinery Location 4 Waste water treatment and 

crude oil tanks 

3rd August Refinery Location 2 Coker 

5th –6th August (Night) Refinery Location 2 Crude oil tanks 

6th – 7th August (Night) Refinery Location 3 Gasoline tanks, coker and 

flare 6 

7th – 8th August (Night) Refinery Location 5,6,7 Product tanks 

Hot oil tanks 

9th August Refinery Location 8 Flares 

10th August Refinery Location 8 Flares 

11th August Refinery Location 8 Flares 

Table 2.1 Summary of DIAL VOC flux measurements at the Refinery 

The GPS positions for the DIAL locations were: 

Refinery Location 1 

By Muster Point 8 

29°22'1.48"N 

94°56'23.11"W 

Refinery Location 2 

E 4th street, next to tank 1020

29°22'4.56"N 

94°55'13.56"W 
Reference: QBN1701-TCEQ-2007 Page 13 of 85

Checked by: 

Refinery Location 2C 

Further north on E 4th street

29°22'5.58"N 

94°55'14.09"W 

Refinery Location 3 

Avenue J, North of tank 1045 

29°22'10.26"N 

94°55'29.40"W 

Refinery Location 4 

Avenue N, south of Surge Basin 2 

29°21'52.38"N 

94°55'17.22"W 

Refinery Location 5 

Outside Gate 16 

29°22'3.78"N 

94°56'27.42"W 

Refinery Location 6 

On W 4th St, by tank 17 

29°22'21.36"N 

94°56'10.98"W 

Refinery Location 7 

Avenue G, south of ARU 

29°22'23.52"N 

94°56'15.36"W 

Refinery Location 8 

Grant Avenue, South of tank 20. 

29°22'35.45"N 

94°56'29.47"W 

The measurement results are presented in the following sections, grouped by the sources 

measured. It is important to note that the potential emission sources measured were 

identified by TCEQ and the refinery, and measurements were focussed on these sources. 

This study did not include a full survey of all sources within the refinery, and was not aimed 

at determining total refinery emissions. 
Reference: QBN1701-TCEQ-2007 Page 14 of 85

Checked by: 

Measurements of product storage tanks. 

A small number of distillate product storage tanks were identified as being of interest. These 

included tanks 55 and 53. Scans were made of these tanks on the 25th 26th July and during 

the night of 7th August. These measurements were made from Location 1 on the 25th and 26th

and from Location 5 on the 7th August. The results are presented in Table 2.2. The emissions 

from tank 55 were not significant, with average emission fluxes measured of 5 lbs/hr (not 

counting the negligible fluxes measured during very low and variable wind conditions). 

Upwind scans were in general below the detection limit, however one scan down Avenue K 

and upwind of the hydrogen plants No.1 and No.2 measured a small flux of 7 lbs/hr. 

Measurements of tank 55 during the evening of the 7th August showed similar emission 

fluxes, with an average of 6 lbs/hr. Tank 57 was too close to the DIAL to enable it to be 

measured on the 7th August. Measurements of tank 53 were made during the evening of the 

7th August and an average flux of 24 lbs/hr with a standard deviation of 8 lbs/hr was 

measured. Upwind measurements were below detection limits. 

Table 2.2 Measurements of VOC fluxes from product storage tanks 
Reference: QBN1701-TCEQ-2007 Page 15 of 85

Checked by: 

Figure 2.1. DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from the product storage tanks at the Refinery. 
Reference: QBN1701-TCEQ-2007 Page 16 of 85

Checked by: 

Measurements of crude oil tanks 

A series of measurements of the emissions from the crude oil storage tanks was made over 

several days. Measurements were made on the 28th 29th 31st July, 2nd August and on the 

night of the 6th August. The results of measurements of different tanks are summarised in 

Table 2.3, all flux results are presented in Table 2.4. 

Measurements were made from Location 2, apart from the measurements of tanks 1020 and 

1021 on the 31st July, for which the DIAL was moved north to Location 2C. 

Tanks Average emission flux 

Lbs/hr 

1020 <2 

1021 16 

1024 5 

1025 11 

1052 22 28th July 

39 2nd August 

24 5th August, Night 

1053 7 

1055 <5 

Table 2.3 Summary of VOC fluxes from crude storage tanks 

 

In order to assign emission fluxes to individual tanks, some interpretation of the flux results 

in Table 2.4 has had to be made. In some cases, flux measurements were made which were 

downwind of a number of tanks. Where these tanks were also measured separately on other 

occasions then the split of the flux between the possible sources has been made based on 

these individual measurements. For the measurements made on the 2nd August from 

Refinery Location 4, the measurements of tanks 1055 and 1053 probably include a 

component of the emissions observed from tank 1052. The flux is not significantly higher 

than that measured from tank 1052 alone, and so it is clear there is no significant emission 

flux from either tank 1055 or tank 1053. This is consistent with the previous measurements 

of these tanks, which did not include emissions upwind from tank 1052. Similarly 

measurements of tanks 1020 and 1021 on the 29th July may have included some emissions 

from tanks 1025 and 1024, however, the wind direction was such that this is unlikely. The 

wind direction, and location of the observed flux, also indicate that most of the observed 

emission flux is attributable to tank 1021, and so the average emissions have been assigned 

to tank 1021. This is supported by measurement of tank 1020 only, on the 31st July, which 

gave very low fluxes, many below 1 lbs/hr. 

No significant emissions were observed from tank 1055, which was in the near field during 

a number of scans. 

In summary, most of the tanks observed during these measurements did not have significant 

emission fluxes, and in general, the emission fluxes from individual tanks were < 10 lbs/hr. 
Reference: QBN1701-TCEQ-2007 Page 17 of 85

Checked by: 

A VOC emission was observed from tank 1052, with an average emission of 39 lbs/hr 

observed on the 2nd August. 

Figure 2.2.DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from the crude oil tanks at the Refinery.
Reference: QBN1701-TCEQ-2007 Page 18 of 85

Checked by: 

 

Table 2.4 Measurements of VOC fluxes from crude oil storage tanks 
Reference: QBN1701-TCEQ-2007 Page 19 of 85

Checked by: 

 

Table 2.4 (continued) Measurements of VOC fluxes from crude oil storage tanks 
Reference: QBN1701-TCEQ-2007 Page 20 of 85

Checked by: 

Measurements of gasoline tanks and flare 6. 

Measurements of gasoline storage tanks 501, 502, 503, and 504 were carried out from 

location 3 on the 30th July and on the night of the 6th August. The results are presented in 

Table 2.5. 

The wind directions for these measurements were not ideal for flux determination; however, 

any significant emissions would have been observed. Upwind measurements from location 3 

included measurements of emissions from flare 6, which was operational during the 

measurement periods. As can be seen from the results presented in Table 2.5, there was no 

significant VOC flux observed from these tanks; the measurements are consistent with an 

emission of approximately 5 lbs/hr from individual tanks. Night time measurements found 

slightly lower emissions; however as these measurements were close to the detection limit, 

drawing any conclusion from these results about night versus day emissions is not 

recommended. Owing to the wind direction during the night time measurements, it is also 

likely these scans would not have fully captured emissions from tank 502.

Measurements of emissions from flare 6 on the 30th July gave an average flux of 4 lbs/hr. 

During the night time measurements on the 6th August, an average flux of 22 lbs/hr was 

measured from flare 6. 

It should be noted that these emissions could act as an upwind source for the gasoline tank 

measurements. However, they were spatially separated from the emissions from the gasoline 

tanks and were not included in these measured fluxes. Therefore this upwind source did not 

have to be subtracted from the tank measurements, which can lead to a significant source of 

uncertainty and is something that is avoided if possible. 

Table 2.5 Measurements of VOC fluxes from gasoline storage tanks
Reference: QBN1701-TCEQ-2007 Page 21 of 85

Checked by: 

Figure 2.3. DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from the gasoline tanks at the Refinery.
Reference: QBN1701-TCEQ-2007 Page 22 of 85

Checked by: 

Measurements of Water Treatment area. 

Measurements were made of the water treatment plant on the 2nd August. Measurements 

were also made of crude tanks on this day and these have been reported in the relevant 

Section above. 

The emissions fluxes observed from the waste treatment areas are given in Table 2.6. The 

average flux seen from the waste water treatment area, and specifically from the west side of 

the secondary and tertiary effluent treatment facilities, was 30 lbs/hr. Scans upwind of the 

water treatment plant measured less than 1 lbs/hr. Two scans were also made of the flux 

from the API separator located at the NE corner of Surge Basin 2, and these measured a 

small average emission flux of 7 lbs/hr. 

Table 2.6 Measurements of VOC fluxes water treatment areas 

Figure 2.4. DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from the waste water treatment areas at the Refinery. 
Reference: QBN1701-TCEQ-2007 Page 23 of 85

Checked by: 

 

Figure 2.5. Example of the VOC distribution seen in a vertical scan at the Refinery (Scan 

285). This scan measured the VOC emissions from tank 1052. The green arrow represents 

the average wind direction. The peak VOC concentration observed in this scan was 495 ppb. 

DIAL

Tank 

1052 
Reference: QBN1701-TCEQ-2007 Page 24 of 85

Checked by: 

Measurements of VOC emissions from coker C 

Measurements were made of the VOC emissions from the operating coker, unit C, on the 

28th July, 31st July, 1st 3rd August. 

It had been suggested that refinery coker units could be a significant source of emissions, 

and figures of several hundred lbs/hr were discussed. One of the primary aims of these 

measurements was therefore to determine if the emissions from this coker were of a similar 

level. Over a number of measurement days, with different conditions, and through several 

cycles of the coker, the highest emission flux observed during a DIAL scan from the coker 

was 44 lbs/hr 

The average emission fluxes observed from the coker are given in Table 2.7, and all 

individual flux results are presented in Table 2.8. 

Date Average emission flux from 

coker 

Average upwind flux 

28th July 10 lbs/hr 2 lbs/hr 

31st July 31 lbs/hr 3 lbs/hr 

1st August 12 lbs/hr 4 lbs/hr 

3rd August 32 lbs/hr 8 lbs/hr 

6th August - Night 4 lbs/hr N/A 

Table 2.7, Summary of VOC emissions fluxes measured from Coker ‘C’ 

Measurements upwind of the cokers identified some small fluxes intermittently on the 31st

July and 3rd August. These presumably arise from process units close to the cokers, 

including potentially, the coker vapour recovery unit. These upwind concentrations have not 

been subtracted from the observed coker results, however, their potential impact on the 

uncertainty of the results should be considered. 

During the coker measurements on the 3rd August a small, localised emission was observed 

south of tank 1010. This was consistent with emissions from waste water vent pipes, located 

at the north end of E-4th street. The average emission flux observed from this source was 9 

lbs/hr. 
Reference: QBN1701-TCEQ-2007 Page 25 of 85

Checked by: 

Figure 2.6.DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from coker C at the Refinery.

Figure 2.7. Example of the VOC distribution seen in a vertical scan at the Refinery (Scan 

263), downwind of coker C. The green arrow represents the average wind direction. The 

peak VOC concentration observed in this scan was 234 ppb. 
Reference: QBN1701-TCEQ-2007 Page 26 of 85

Checked by: 

Table 2.8. Measurements of VOC emission fluxes from coker ‘c’. 
Reference: QBN1701-TCEQ-2007 Page 27 of 85

Checked by: 

Measurements of VOC emissions from heated oil tanks 

A small number of heated tanks containing fuel oil were measured. These tanks were 

monitored on the night of the 7th August. The emissions from two tanks 43, and 60 were 

measured, and the results are given in Table 2.9. 

The average emission flux from Tank 43 was 6 lbs/hr and from Tank 60 the average 

emission flux was 9 lbs/hr. Upwind fluxes were less than 1 lbs/hr. These results show the 

emissions from these tanks are very low and they are not significant sources of VOC 

emissions. 

Table 2.9. Measurements of VOC emission fluxes from hot oil tanks. 

Figure 2.8. DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from the hot oil tanks at the Refinery. 
Reference: QBN1701-TCEQ-2007 Page 28 of 85

Checked by: 

Measurement of VOC emissions from elevated flares. 

Measurements of a temporary flare stack located in the NW corner of the refinery were 

undertaken. This flare had a very visible flame, and the aim was to determine any emission 

due to incomplete combustion in the flare. The DIAL was located in Grant Avenue and 

measured downwind and upwind of the flare to identify any plume of un-burnt 

hydrocarbons. These measurements identified very low levels of hydrocarbon downwind of 

the flare, and the VOC emission flux measured from this flare was ~ 6 lbs/hr. This is not 

surprising given that the flare was reported to be mainly burning hydrogen. 

However, during the measurement of the temporary flare, a high concentration VOC plume 

was observed at a closer range than the temporary flare stack. This plume was consistent 

with emissions from another elevated flare, the ULC flare. This flare had an almost invisible 

flame during daylight, but was observed to be lit at night. Table 2.11 lists all the measured 

fluxes from these flares, and Table 2.10 provides a summary of the emissions from the ULC 

flare. 

Date Average VOC emission flux 

9th August 147 lbs/hr 

10th August 167 lbs/hr 

11th August 263 lbs/hr 

Table 2.10 Summary of measurements of VOC emissions from ULC flare. 

The measurements of the ULC plume showed a fairly high degree of variability, and this 

will be due to a combination of variability in the flare emissions and the possibly to 

movement of the narrow plume during the period of each DIAL scan. 
Reference: QBN1701-TCEQ-2007 Page 29 of 85

Checked by: 

Figure 2.9. DIAL locations and scan lines used for DIAL measurements of VOC emission 

fluxes from flare stacks at the Refinery 

Figure 2.10 Example of the VOC distribution seen in a vertical scan at the Refinery (Scan 

432) downwind of the ULC flare. The green arrow represents the average wind direction. 

The peak VOC concentration observed in this scan was 3.86 ppm. 
Reference: QBN1701-TCEQ-2007 Page 30 of 85

Checked by: 

Table 2.11. Measurements of VOC flux from ULC and temporary flares. 
Reference: QBN1701-TCEQ-2007 Page 31 of 85

Checked by: 

Section 3 Measurements of Benzene emissions from Refinery 

Measurement description 

Measurements of benzene were carried out on the 17th and 18th August 2007 at the Refinery. 

Measurements were made of the Aromatic Recovery Unit (ARU) on the 17th and the 

operational Coker (Coker Unit C) on the 18th. Measurements on the 17th were carried out in 

parallel with a UV Open Path DOAS spectrometer, operated by the EPA and were made for 

comparison purposes. Measurements on the 18th were carried out to obtain emissions flux 

measurements from the coker operations, and were timed to include the period during which 

the unit was cutting coke. 

Benzene concentration measurements on 17th August. 

The measurements on the 17th August were carried out to compare the concentrations 

measured by DIAL with those obtained by the open-path UV-DOAS system operated by 

Cary Secrest from EPA. Both systems were set up to measure a 200m path close to the 

ground, downwind of the ARU. Figure 1 shows the DIAL and DOAS locations and also the 

locations of 2 air samples, which were taken during the tests. The DIAL was located in 

Avenue C, South of Tank 5, GPS location 29°22'35.28"N, 94°56'2.10"W. The wind was 

from directions between 130° to 170° from N, at speeds of between 6 mph to 16 mph. 

Figure 3.1, Location for measurements of benzene concentrations from the ARU 

During these measurements the DIAL beam was kept at a fixed line of sight, in a similar 

configuration to the UV-DOAS, and not scanned to obtain concentration profiles. Therefore, 

benzene fluxes were not determined. The two measurement-paths for the DIAL and the UV-
Reference: QBN1701-TCEQ-2007 Page 32 of 85

Checked by: 

DOAS were as close as was logistically possible. The DIAL data were processed to assess 

the total integrated concentration over the assigned path. The path length of the DOAS was 

stated by the EPA operators to be from 247m to 440m from the DIAL. The ARU unit was 

measured from the site map to be 100m long from 280 to 380 m from the DIAL. The DIAL 

and UV-DOAS results are plotted for comparison in Figures 2 and 3. The DIAL results are 

tabulated in Tables 1 and 2. The results plotted for the UV-DOAS are as supplied by Cary 

Secrest (US EPA). There is no difference between the UV-DOAS results in figures 2 and 3, 

only the DIAL pathlength has been varied, the UV-DOAS pathlength is a fixed parameter 

dependant on the instrument configuration. The DIAL results shown in the tables are the 

averages of a number of measurements taken during the periods indicated, and the standard 

deviations of the concentrations is also given. Where no standard deviation is given this is 

because the result is for a single measurement. 

Table 3.1, DIAL results – ppb benzene determined over a 193m path comparable to the UVDOAS. 
Reference: QBN1701-TCEQ-2007 Page 33 of 85

Checked by: 

Table 3.2, DIAL results – ppb benzene determined over a 100m path comparable to the 

extent of the ARU. 

Air samples were taken in canisters and with pumped sorbent tubes, at the locations shown 

in Figure 1. Table 3 shows the results of the analyses of these canisters for benzene. The 

samples were taken between 17:29 and 18:29 for the EPA line of sight and 17:53 and 18:53 

for the DIAL line of sight. 

Table 3.3, Air sample analyses for ARU measurements. 

The concentrations of benzene measured using the pumped sorbent tubes are similar to the 

levels measured with both the UV-DOAS and the DIAL. The concentrations measured by 

the DIAL are close to the limit of detection for the DIAL system and the standard deviations 

of the results reflects this.

Benzene Toluene Ethylbenzene m/p-Xylene o-Xylene

Tubes CanistersTubes Canisters Tubes Canisters Tubes CanistersTubes Canisters

ARU ppb ppb Ppb ppb ppb Ppb ppb ppb ppb ppb 

DIAL LOS 12.87 <2.00 18.79 12.26 2.33 2.04 9.36 5.51 3.05 <2.00 

DOAS LOS 6.71 <1.88 9.79 20.52 1.90 2.46 5.29 8.49 1.44 2.59 
Reference QBN1701-TCEQ-2007 Page 34 of 85

Checked by:

Figure 3.2, Comparison of DIAL and UV-DOAS benzene concentrations. DIAL integrated path correpathlength. 
Reference: QBN1701-TCEQ-2007 Page 35 of 85

Checked by: 

Figure 3.3, Comparison of DIAL and UV-DOAS benzene concentrations. DIAL results for 100m pat

ARU unit. 
Reference QBN1701-TCEQ-2007 Page 36 of 85

Checked by:

Measurements of benzene fluxes from the coker 

Measurements were made of the benzene concentrations downwind of coker, unit C, during 

the operation of this coker on the 18th August. The measurements were carried out from 

17:20 to 20:45. The coker was cutting coke between 19:50 and 20:38. 

The configuration of the measurements and location of the DIAL during these 

measurements is shown in Figure 4 
Reference: QBN1701-TCEQ-2007 Page 37 of 85

Checked by: 

Figure 3.4. Location of DIAL for measurements of benzene fluxes from coker Unit C. 

The DIAL was located on Avenue J, to the west of Tank 1010, at GPS coordinates 

29°22'10.98"N, 94°55'19.50"W. The wind during the measurements was from directions 

between 125° to 143° from N, with speeds between 6 mph to 9 mph. Vertical scans were 

made downwind of the coker; scans were also made upwind of the coker to check for any 

other sources of benzene. The results are given in Table 4. During most of the period of 

measurements the DIAL values are at or below the detection limits. For these measurements, 

the detection limits, in terms of lbs per hr flux, were of the order of 0.5 to 1 lbs per hr. 

During the period before the coker commenced cutting, the fluxes measured were often 

below the detection limit and have been reported as 0 lbs per hr. In some cases, a figure of 

less than a given flux is reported. In these cases, a detectable concentration was recorded, 

but the uncertainty in the results is such that only an upper limit is reported. Detected 

concentrations of benzene were in general around 0.1 ppm. During the coker cut, a small but 

observable flux of benzene was measured, the two results giving fluxes of 1.5 lbs per hr and 

2.1 lbs per hr. Upwind scans showed no significant source of benzene. 

The results of the analyses of the air sample taken downwind of the coker are shown in 

Table 5. This sample was taken during the period of the coker cut, and a low concentration 

of benzene ~ 1 to 2 ppb was measured. 

Table 3.4. Measured fluxes during coker operation. 

Table 3.5, results of air sample analyses downwind of coker. 

Benzene Toluene Ethylbenzene m/p-Xylene o-Xylene

Tubes Canisters Tubes Canisters Tubes Canisters Tubes Canisters Tubes Canisters

ppb ppb ppb ppb ppb ppb ppb ppb ppb ppb 

Downwind 

Coker 1.33 <2.00 0.61 2.11 0.44 <2.00 0.49 <2.00 <0.3 <2.00 
Reference: QBN1701-TCEQ-2007 Page 38 of 85

Checked by: 

Section 4. Measurements of SO2 from the Sulphur Recovery 

Unit 

A series of measurements was carried out on the 14th August to measure the SO2 flux from 

the Sulphur Recovery Unit wet gas scrubber plume. Close to the stack this appeared as a 

visible plume, mainly consisting of water vapour. The measurements were made through the 

plume, roughly at the point at which it became invisible to the unaided eye. The enhanced 

backscatter from the plume was used to check that the scans did intercept the plume. The 

aim of the measurements was to compare the measured flux with an emission rate 

determined from the stack flow rate and measurements of the stack gas SO2 concentration 

determined from an installed continuous emissions monitor. However, prior calculations 

indicated that the likely concentration within the plume would be at or below the DIAL 

detection limit, and this was found to be the case. The average flux measured by the DIAL 

was 0.003 lbs/hr, with a standard deviation of 0.008 lbs/hr. Table 4.1 lists the measured SO2

fluxes. 

Table 4.1. Measurements of SO2 flux from SRU. 

The DIAL location was: 

Refinery Location 13 

Avenue F, north of flare 5. 

29°22'28.42"N 

94°54'54.56"W 
Reference: QBN1701-TCEQ-2007 Page 39 of 85

Checked by: 

Annex 1. Description of the DIAL technique. 

Overview of the Dial technique 

The Differential Absorption Lidar (DIAL) technique is a laser-based remote monitoring 

technique which enables range-resolved concentration measurements to be made of a wide 

range of atmospheric species. This section explains the theory of the DIAL technique and 

describes the NPL system in detail. 

Description of the theory of Dial measurements 

The atmospheric return signal measured by a DIAL system is given by the Light Detection and 

Ranging (Lidar) equation, a simplified form of which is given in Equation 1. 

where Dx is a range independent constant, C(r) is the concentration of an absorber with 

absorption coefficient αx and Ax(r) is the absorption coefficient due to all other atmospheric 

absorption, Ex is the transmitted energy and Bx is the backscatter coefficient for the atmosphere 

at wavelength x. 

The equation has three basic components: 

 - a backscatter term based on the strength of the signal scattering medium 

 - parameters associated with the DIAL system 

 - a term which is a measure of the amount of absorption of the signal which has occurred 

due to the presence of the target species. 

In the DIAL technique, the laser is operated alternately at two adjacent wavelengths. One of 

these, the "on-resonant wavelength", is chosen to be at a wavelength which is absorbed by the 

target species. The other, the "off-resonant wavelength", is chosen to be at a wavelength which 

is not absorbed significantly by the target species. 

Pairs of on- and off-resonant signals are then acquired and averaged separately until the 

required signal to noise ratio is achieved. 

The two wavelengths used are close together, hence the atmospheric terms Ax(r) and Bx(r) in 

the lidar equation can be assumed to be the same for both wavelengths. These terms are then 

cancelled by taking the ratio of the two returned signals. 

The path-integrated concentration (CL) may be derived (Equation 2) by multiplying the 

logarithm of the ratio of the signals by the ratio of the absorption of the two wavelengths by the 

target species. 

x x

x

2 x

0

r

P (r)= E x x

D

r

B (r) {-2 [ exp A (r )+ C(r )]d r} ∫ ′ ′′ α (1)
Reference: QBN1701-TCEQ-2007 Page 40 of 85

Checked by: 

where N is the number of pulse pairs averaged, Δα = αOFF-αON is the differential absorption 

coefficient and S represents the received power after normalisation for the on- and off-resonant 

signals respectively. 

This path-integrated concentration represents the total concentration of the target species in the 

atmosphere along the measured line-of-sight out to the range r. 

The range-resolved concentration can then be derived by differentiating the path-integrated 

concentration (Equation 3). 

where C(r) is the point concentration at range r along the line-of-sight. 

Description of facility operated by NPL 

The DIAL system operated by NPL is housed in a mobile laboratory. It can operate in the 

infrared and ultraviolet spectral regions allowing coverage of a large number of atmospheric 

species. A scanner system directs the output beam and detection optics, giving almost full 

coverage in both the horizontal and vertical planes. 

The system also contains ancillary equipment for meteorological measurements, including an 

integral 10 m meteorological mast with wind speed, direction, temperature and humidity 

measurements. 

The system is fully self contained, with power provided by an on board generator, and has full 

air conditioning to allow operation in a range of ambient conditions. 

The following sections describe the DIAL system in more detail. 

Source 

The source employs a combination of Nd-YAG and dye lasers together with various non-linear 

optical stages to generate the tuneable infrared and ultraviolet wavelengths. The source has a 

pulse repletion rate of 10 Hz and an output laser pulse duration of ~10 ns. A small fraction of 

the output beam in each channel is split off by a beam splitter and measured by a pyroelectric 

detector (PED) to provide a value for the transmitted energy with which to normalise the 

measured backscatter return. 

Detection 

The returned atmospheric backscatter signal is collected by the scanning telescope. This directs 

the collected light into separate paths for the infrared and ultraviolet lidar channels. The 

CL(r)=

1

2

1

N

S (r)

S (r) i=1

N

ON,i

Δα OFF,i

∑log (2)

C(r)= dCL(r)

dr (3)
Reference: QBN1701-TCEQ-2007 Page 41 of 85

Checked by: 

returned light passes through band pass filters relevant to each detection channel and is then 

focused onto the detection elements. Solid-state cryogenically-cooled detectors are used in the 

infrared channel and low-noise photomultipliers in the ultraviolet. 

After amplification the signals from these detectors are digitised using high speed digitisers. 

The digitisers are clocked using a clock generator triggered by an optical detector in the 

transmission chain. This ensures the range gating is correctly synchronised to the laser pulse 

transmission. The signals from the PED monitoring the transmitted energy are also digitised 

and stored. 

Data Analysis 

The data acquired are analysed, using the DIAL techniques described below, to give the rangeresolved concentration along each line-of-sight. 

The data analysis process consists of the following steps : 

i) Background subtraction 

Any DC background value is subtracted from the signals. This measured background takes 

account of any DC signal offset which may be present due to electronic offsets and from 

incident background radiation. The background level is derived from the average value of the 

far field of the returned lidar signal where no backscattered light is present. 

ii) Normalisation for variation in transmitted energy 

The two signal returns are normalised using the monitored values of the transmitted energy. 

The mean transmitted energy is used to normalise the averaged return signal. For this 

application, this has been shown to be equivalent to normalising individual shots against 

transmitted energy and then averaging the normalised values. 

iii) Calculation of path-integrated concentration 

The path-integrated concentration of the target species, out to the range r, is calculated by 

multiplying the log of the ratio of the returned normalised signals by the differential absorption. 

The absorption coefficients used in this calculation are derived from high-resolution 

spectroscopy carried out using reference gas mixtures at NPL. 

iv) Derivation of range-resolved concentrations. 

In order to better visualise the data the integrated concentration profiles are piecewise 

differentiated to give the range-resolved concentration along the line-of-sight. 

v) Calculation of emission fluxes 

Range-resolved concentration measurements along different lines-of-sight are combined to 

generate a concentration profile. This is carried out using algorithms developed at NPL which 

reduce artefacts due to the difference in data density at different ranges, due to the polar 

scanning format of the data. The emission flux is then determined using the concentration 

profile together with meteorological data. 

The emitted flux is calculated using the following mathematical steps:- 
Reference: QBN1701-TCEQ-2007 Page 42 of 85

Checked by: 

(a) The product is formed of the gas concentration measured with the DIAL technique at a 

given point in space, and the component of the wind velocity perpendicular to the 

DIAL measurement plane at the same location. 

(b) This product is computed at all points within the measured concentration profile, to 

form a two-dimensional array of data. 

(c) This array of results is then integrated over the complete concentration profile to 

produce a value for the total emitted flux. 

Considerable care is needed in applying the meteorological data, particularly when the 

concentration profile measured by the DIAL technique has large and complex spatial variations 

since, for example, errors in the wind speed in regions where large concentrations are present 

will significantly affect the accuracy of the results. In such cases, a more complex procedure is 

used which employs a further software package to combine the data from the set of 

anemometers with that of an additional meteorological model, to generate the complete wind 

field over the concentration profile. This model calculates the variation of wind speed with 

height, as a function of various parameters (such as the roughness of the terrain). The calculated 

wind field is then combined with the measured gas concentration profile using the procedure 

described above. 

A summary of the ultraviolet and infrared performance capabilities of the NPL DIAL 

facility are given in Tables A1.1 and A1.2. The values given in these tables are based on the 

actual levels of performance of the system obtained during field measurements, rather than 

calculations based on theoretical noise performances. For simplicity the numbers are 

presented as a single concentration sensitivity and maximum range values. However, the 

detailed performance behaviour of a DIAL system is much more complex and there are a 

number of key points that should be noted : 

• The DIAL measurement is of concentration per unit length rather than just 

concentration. So the sensitivity applies for a specified pathlength – 50 metres in this 

case. Measurements over a shorter path would have a lower sensitivity, and would be 

more sensitive over a longer path. 

• Since the backscattered lidar signal varies with range, generally following a (range)-

2 function, the sensitivity is a function of range. The sensitivity values given in the 

table apply at a range of 200 metres, and these will get poorer at longer ranges. 

• The maximum range of the system is generally determined by the energy of the 

emitted pulse and the sensitivity of the detection system, except in the case of nitric 

oxide where range is limited by oxygen absorption at the short ultraviolet 

wavelengths required for this species. 

• In all cases the performance parameters are based on those obtained under typical 

meteorological conditions. For the ultraviolet measurements the meteorological 

conditions do not have a great effect on the measurements as the backscattered signal 

level is predominantly determined by molecular (Rayleigh) scattering, and this does 

not vary greatly. However, in the infrared the dominant scattering mechanism is 

from particulates (Mie scattering). So the signal level, and therefore the sensitivity, is 

dependant on the particular loading of the atmosphere, and this can vary dramatically 

over relatively short timescales. 
Reference: QBN1701-TCEQ-2007 Page 43 of 85

Checked by: 

The NPL DIAL has a theoretical range resolution of 7 metres along the measurement beam, 

and a vertical or horizontal scan resolution which can be less than 1 metre at 100 metres. 

However, the actual range resolution determined by the signal averaging used, will depend 

on atmospheric conditions and the concentration of the measured pollutant, and may be of 

the order of 30 m. 

The DIAL is able to make measurements of a wide range of compounds, including benzene 

and other aromatics, individual VOCs and total VOCs, see Tables 2a and 2b. The 

methodology for obtaining measurements of the total VOC content from C3 to C15 is 

provided below. It consists of the combination of DIAL measurements with air sampling 

and GC analysis. The system is able to monitor individual aromatic compounds and VOC 

species, which have absorption features in the IR and UV spectral regions covered by the 

DIAL system. NPL has the spectral expertise, access to spectral libraries and in-house 

spectroscopic capability to assess the DIAL sensitivity for additional individual species. 

The general hydrocarbon measurement listed in Table A1.2 uses an infrared absorption that 

is common to all hydrocarbons with three or more carbon atoms, linked to the stretch 

frequency of the carbon-hydrogen bond. As such it provides a measure of the mixture of 

volatile organic compounds (VOCs) that are present at an oil or petrochemical site. The pair 

of infrared wavelengths used for this DIAL measurement are selected so that the absorption 

per unit mass is relatively invariant with respect to the mix of different hydrocarbons that are 

present. However, the sensitivity of this measurement in terms of ppb of hydrocarbon 

depends on the mixture of species present, and the value given in the table reflects the 

typical mix of hydrocarbons found at oil refineries. 

Although the general hydrocarbon measurement provides a good estimate of the overall 

amount of hydrocarbons present, the accuracy of this measurement can be improved, and the 

total VOC concentration calculated, by combining the DIAL measurements with the results 

of gas chromatography (GC) analysis of the emitted gases. The standard procedure for this 

involves taking whole air samples around the site in locations where the DIAL 

measurements show the emitted plumes are present. The VOCs present in these samples are 

identified and quantified by GC analysis. The results provide the relative levels of all the 

VOCs present with a concentration of 0.1 ppb or higher. The results of this analysis are 

combined with NPL’s unique spectral library of quantified infrared absorptions of an 

extensive set of VOCs to calculate the combined absorption coefficient for the actual VOC 

mixture present at the site. Appling this absorption coefficient to the DIAL results enables 

the total VOC emission rates to be calculated. 
Reference: QBN1701-TCEQ-2007 Page 44 of 85

Checked by: 

Species Sensitivity(1) Maximum range(2)

Nitric oxide 5 ppb 500 m 

Sulphur dioxide 10 ppb 3 km 

Ozone 5 ppb 2 km 

Benzene 10 ppb 800 m 

Toluene 10 ppb 800 m 

Table A1.1 Ultraviolet capability of NPL DIAL Facility 

Species Sensitivity(1) Maximum range(2)

Methane 50 ppb 1 km 

Ethane 20 ppb 800 m 

Ethene 10 ppb 800 m 

Ethyne 40 ppb 800 m 

General hydrocarbons 40 ppb 800 m 

Hydrogen chloride 20 ppb 1 km 

Methanol 200 ppb 500 m 

Nitrous oxide 100 ppb 800 m 

Table A1.2 Infrared capability of NPL DIAL Facility 

Note 1. The concentration sensitivities apply for measurements of a 50 metre wide plume at 

a range of 200 metres, under typical meteorological conditions. 

Note 2. The range value represents the typical working maximum range for the NPL DIAL 

system. 
Reference: QBN1701-TCEQ-2007 Page 45 of 85

Checked by: 

Calibration and validation 

The NPL DIAL system has several in-built calibration techniques and procedures. The most 

important are the in-line gas calibration cells. The gas cells are filled with known 

concentrations of the target species, from NPL standard gas mixtures, which are directly 

traceable to national standards. A fraction of the transmitted beam is split off and directed 

through a gas cell to a PED, in the same way as the beam for the transmitted energy monitors. 

This provides a direct measurement of the differential absorption at the operating wavelengths 

by the target gas. The transmission through the gas cells is continuously monitored during the 

operation of the system to detect any possible drift in the laser wavelengths. The system also 

employs a wavemeter to monitor the wavelengths transmitted during operation. The calibration 

cells are also periodically placed in the output beam to show the concentration response of the 

whole system is as expected. 

A number of field comparisons have been undertaken to demonstrate the accuracy of the 

measurements obtained with DIAL. Examples of these carried out by NPL are detailed below: 

i) Intercomparisons have been carried out in the vicinity of chemical and petrochemical 

plants where a large number of different volatile organic species are present. In these 

intercomparisons, the DIAL radiation was directed along the same line of sight as a 

line of point samplers. The point samplers were operated either by drawing air into 

internally-passivated, evacuated gas cylinders or by pumping air at a known rate, for a 

specified time, through a series of absorption tubes which efficiently absorb all 

hydrocarbon species in the range C2 - C8. The results obtained for the total 

concentrations of VOCs measured by the point samplers and those measured by the 

infrared DIAL technique agreed within ± 15%. The concentrations of atmospheric 

toluene measured by the ultraviolet DIAL system agreed with those obtained by the 

point samplers to within ± 20%. 

ii) The ultraviolet DIAL system was used to monitor the fluxes and concentrations of 

sulphur dioxide produced from combustion and emitted by industrial stacks. These 

stacks were instrumented with calibrated in-stack sampling instruments. The results of 

the two sets of measurements agreed to within ± 12%. 

iii) DIAL Measurements of controlled releases of methane from a stack agreed with the 

known emission fluxes to within ± 15%. 
Reference: QBN1701-TCEQ-2007 Page 46 of 85

Checked by: 

Measurements of gas cell concentrations during the Texas measurement 

campaign. 

A series of measurements was made of a 10 cm gas cell filled with a pentane standard gas 

mixture provided by TCEQ/REFINERY. The measurements were made by placing the gas cell 

in the output transmitted beam. This introduces an absorption into the DIAL signal at zero 

range, which has the effect of introducing an offset in the signals, equivalent to the total 

concentration-pathlength of the gas in the cell. The differential absorption for pentane at the 

wavelengths used for the VOC DIAL measurements was determined from the NPL quantified 

spectral database, and this was used to calculate the concentration of pentane in the gas cell. In 

addition a number of other gas cell measurements were made of propane and benzene. 

The results of these measurements are given in Table A1.3 below. These present the means of a 

series of measurements made of the gas cells on different days. 

Date Scans Cell Measured 

column 

Concentration (ppm) 

 Predicted Actual 

27/07/2007 110-112 10 cm propane 0.57 ± 0.04 8180 ± 530 8413 

27/07/2007 117-123 10 cm pentane 1.16 ± 0.12 7100 ± 700 7500 

30/07/2007 222-223 10cm pentane 1.34 ± 0.20 8200 ± 1200 7500 

07/08/2007 371-372 10cm pentane 1.24 ± 0.01 7600 ± 100 7500 

17/08/2007 557-558 20cm benzene 0.09 900 ± 70 1000 

Table A1.3, Measurements of gas cell concentrations. 

The uncertainty figures are based on the standard deviation of the individual measurements. 
Reference: QBN1701-TCEQ-2007 Page 47 of 85

Checked by: 

NPL open-path calibration facility 

NPL has also developed and operate a full-scale facility for the calibration of open path 

monitors, including DIAL. This consists of a 10 m long windowless cell able to maintain a 

uniform, independently-monitored concentration of a gaseous species along its length. This 

provides a known controlled section of the atmosphere with traceable concentration over a 

defined range (10m). The absence of windows removes reflections and other artefacts from 

measurements made using optical techniques, providing a direct way to validate and assess the 

calibration of DIAL instruments. 

The calibration facility is windowless with a 1 m diameter, to minimise any beam reflections 

from the cell walls and ends. At each end of the cell is an annular calibration-gas feed ring with 

multiple outlets injecting the calibration gas mixture into the cell. A ring of tangential fans 

around the centre of the cell extract gas and entrained air pulled in through the open ends of the 

cell. This ensures the backscatter in the cell approximates to the ambient air conditions. Each 

fan has a long exhaust tube to avoid recirculation of the gas into the cell. 

This facility has been employed to directly validate VOC measurements by the NPL DIAL 

facility [2]. 

Figure A1.1 The NPL 10m calibration cell. 

The facility provides the ability to generate a defined concentration path and so it also provides 

range-resolution validation for DIAL and lidar instruments. The system was used to validate 

the DIAL with a number of measurements of propane and methane, as a part of its acceptance 

tests for Siemens, Shell and British Gas. 

[1] Measurements of the Emissions to Atmosphere of Volatile Organic Compounds 

from the Hellenic Aspropyrgos Oil Refinery; T D Gardiner, M.J.T. Milton, R.A. 

Robinson, P.T.Woods, A.S.Andrews, H. D’Souza, D Alfonso, N.R Swann; NPL 

Report QM S99, Sept 1996 

[2] Calibration of DIAL and Open Path Systems Using External Gas Cells; M.J.T. Milton, 

P.T. Woods, R.H. Partridge, B.A Goody; Proc. Europto, Munich 1995. 
Reference: QBN1701-TCEQ-2007 Page 48 of 85

Checked by: 

Annex 2 Speciated VOC measurements and Flux Correction 

Factors 

The DIAL measures VOCs by measuring the differential absorption of two wavelengths of 

light. The wavelengths used, at around 3000 cm-1, are chosen to measure, in effect, the C-H 

stretch in the hydrocarbons for C3 and above. The sensitivity of the DIAL is slightly 

different to different hydrocarbons, and for example an oxygenated hydrocarbon will give a 

different absorption per mass than a straight chain alkane. The differential absorption 

strength used was calibrated to give a mass emission rate for a gasoline vapour. A different 

‘cocktail’ of hydrocarbons would give a slightly different response per unit mass. Air 

samples were taken at locations which would provide an indication of the actual speciation 

of the emission fluxes sampled by the DIAL. If the actual (relative) composition is known, 

from the air sample analyses, then by determining the absorption of each constituent it is 

possible to determine a correction factor which will provide the true ‘mass value’ assuming 

the emissions measured have a similar relative composition to the sampled air. 

Flux Correction Factors 

The multi-component analysis of the ambient air sample results was used to determine the 

differential absorption coefficient (in m2

g-1) for the particular cocktail of hydrocarbons in 

each sample. This was done by taking the differential absorption coefficient for each species 

from the NPL quantified database of the infrared absorption of industrial organic species, 

and scaling it by the mass-fraction of that species in the sample. The standard DIAL 

differential absorption coefficient for VOC measurements is 0.49 m2g-1, based on the 

infrared absorption of gasoline vapour. 

These results are summarised in Table A2.1, which show the differential absorption 

coefficients, and the factor by which the standard DIAL VOC flux results need to be 

multiplied by to take into account the particular VOC mix present. 
Reference: QBN1701-TCEQ-2007 Page 49 of 85

Checked by: 

Table A2.1. Flux correction factors determined from each of the air samples. 

Air samples were taken at a number of locations around the plants. Figures A2.1, A2.2, A2.3 

and A2.4 show the locations of the samples. The Air samples were taken using SUMO 

canisters and pumped Perkin Elmer Automatic Thermal Desorption (ATD) tubes. 

The ATD tubes were sampled at a flow rate of 40ml/min, to enable a comparison between 

the SUMO canisters and the ATD tubes; a flow restrictor was fitted to canister, so each 

sample was taken over the same time period. 

The sampler tubes are approximately 6mm OD and length 90mm long. The sampler tubes 

contained approximately 200milligrams to 300 milligrams of sorbent. Two sorbent tubes 

were used in series containing two sorbent materials used, a porous polymer (Tenax TA) 

and a carbon black (Carbopack X). Different sorbents are needed to cover the diverse 

boiling point ranges and chemical functional groups of VOCs. 

The SUMO canister analysis gave results in the Carbon number range of C2-C10, whilst the 

linked ATD tubes containing Tenax TA and Carbopack-X gave a Carbon number range of 

C4-C22

Tube Sample diff abs flux factor

DTTS1 0.62 0.8 

DTTS2 0.39 1.3 

DTTS3 0.55 0.9 

DTTS4 0.31 1.6 

DTTS5 0.29 1.7 

DTTS6 0.41 1.2 

DTTS7 0.37 1.3 

DTTS8 0.41 1.2 

DTTS9 0.44 1.1 

DTTS10 0.46 1.1 

DTTS11 0.24 2.0 

DTTS12 0.43 1.1 

DTTS13 0.24 2.1 

DTTS14 0.50 1.0 

DTTS15 0.44 1.1 

DTTS16 0.47 1.0 
Reference: QBN1701-TCEQ-2007 Page 50 of 85

Checked by: 

Figure A2.1 Location of air samples around the naphtha tanks at the Bulk Terminal 
Reference: QBN1701-TCEQ-2007 Page 51 of 85

Checked by: 

Figure A2.2 Location of air samples in the crude oil storage areas at the Refinery. 

Figure A2.3 Location of air samples in the gasoline tanks and coker areas at the Refinery. 

DTTS 5

DTTS 6 

DTTS 7 

DTTS 11 

DTTS 8 

DTTS 12 

DTTS 9 & 10 

DTTS 16 
Reference: QBN1701-TCEQ-2007 Page 52 of 85

Checked by: 

Figure A2.4 Location of air samples in the gasoline tanks and coker areas at the Refinery. 

DTTS 13

DTTS 

DTTS 15
Reference: QBN1701-TCEQ-2007 Page 53 of 85

Checked by: 

Sampling Procedure 

The ATD tubes were attached to the flow restrictor so as the tubes were at the same height 

as the top of flow restrictors sample entry point. 

The samples were taken at a height of approximately 2m by mounting the sampling array on 

a Tripod. The samples were taken by opening the valve on the SUMO canister and starting 

the sampling pumps. The flow restrictors had been set so as they sampled over a period of 

1.25 hours. 

ATD Tubes 

Flow restrictor 
Reference: QBN1701-TCEQ-2007 Page 54 of 85

Checked by: 

Analysis of the ATD tubes 

The method of analysis was based on EN ISO 16017-2 [1] and was carried out using UKAS 

(United Kingdom Accreditation Service) accredited method QPDQM/B/526. This method 

combines Automatic Thermal Desorption with Gas Chromatography, with a Flame 

Ionisation Detector [1] 

The analysis instrument used is an Automated Thermal Desorber autosampler coupled to a 

Gas Chromatograph usually with a flame ionisation detector. The VOCs are released from 

the sampler tube using a heated oven in an inert gas stream of helium. The VOCs are 

refocused onto a small cold trap prior to transfer onto the gas chromatography column. 

Generally a coated fused silica gas chromatography column of diameter 320 micrometers 

and length 60 meters is used to separate the individual VOCs collected. Using VOC 

standard materials, the identification of the individual VOC components are compared to the 

column elution time (retention time) of the standard VOC materials. The mass of VOCs 

collected is quantified using the flame ionisation detector. A series of calibrations standards 

are used to calibrate the flame ionisation detector response. The concentration of the VOC 

in ambient air is then calculated using from the mass collected and the volume of air 

sampled. 

Tables A2.2 and A2.3 present the results from the canister and tube analyses respectively. 

The tube analyses were carried out by NPL’s in house accredited analysis laboratory, the 

canister samples were analysed by EAS Environmental Analytical Service, Inc, California. 
Reference: QBN1701-TCEQ-2007 Page 55 of 85

Checked by: 

Table A2.2 Full results of the speciation analyses on the Canister Samples. 

Sample No. DTTS1 DTTS2 DTTS3 DTTS4 DTTS5 DTTS6 DTTS7 DTTS8

Date 17-Jul07 18-Jul07 19-Jul07 21-Jul07 28-Jul07 28-Jul07 29-Jul07 30-Jul07 

Start time 17:17 16:20 12:31 03:57 14:25 14:40 16:56 16:39 

End time 18:09 17:27 13:44 05:06 15:47 16:00 18:12 17:51 

Average Wind Direction/deg 164 128 322 95 170 174 149 159 

Average Wind Speed/mph 4.5 2.4 4.6 2.3 4.3 4.3 3.9 4.2 

Cannister Number 169 610 708 881 190 996 762 606 

 

Species ppb V ppb V ppb V ppb V ppb V ppb V ppb V ppb V 

Ethene <1.93 <1.91 4.76 <1.91 <1.96 <1.94 <2.00 20.24 

Acetylene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Ethane <1.93 1.98 15.93 3.14 2.83 10.86 7.01 223.95

Propene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Propane <1.93 6.32 10.65 2.15 <1.96 5.45 12.16 23.61 

I-Butane 3.73 5.17 12.74 8.22 6.02 16.72 8.00 72.47 

Methanol <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1-Butene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,3-Butadiene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 4.88 

n-Butane <1.93 <1.91 24.44 2.43 <1.96 3.97 6.69 11.16 

t-2-Butene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 4.70 

c-2-Butene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Ethanol <1.93 <1.91 <2.09 7.52 <1.96 <1.94 <2.00 2402.7

3-Methyl-1-butene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Acetone <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

i-Pentane 323.89 5.67 63.51 17.78 4.80 26.94 8.13 36.51 

1-Pentene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Isopropanol <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methyl-1-butene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Pentane <1.93 <1.91 38.65 <1.91 <1.96 2.65 2.35 39.77 

Isoprene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

t-2-Pentene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

c-2-Pentene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Tert butyl alcohol <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methyl-2-butene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,2-Dimethylbutane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Cyclopentene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Propanol <1.93 <1.91 2.78 <1.91 <1.96 <1.94 <2.00 4.66 

Cyclopentane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Methyl tert butyl ether <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,3-Dimethylbutane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methylpentane <1.93 <1.91 8.13 <1.91 <1.96 <1.94 <2.00 <2.06 

3-Methylpentane <1.93 <1.91 5.33 <1.91 <1.96 <1.94 <2.00 <2.06 

1-Hexene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Hexane <1.93 <1.91 10.26 <1.91 <1.96 <1.94 <2.00 12.04 

Diisopropyl ether <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

3-Methylcyclopentene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Ethyl tert butyl ether <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Methylcyclopentane <1.93 <1.91 3.77 <1.91 <1.96 <1.94 <2.00 <2.06 

2,4-Dimethylpentane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Benzene <1.93 <1.91 3.17 <1.91 <1.96 <1.94 5.19 <2.06 

Cyclohexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methylhexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,3-Dimethylpentane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

3-Methylhexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methyl-1-hexene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 
Reference: QBN1701-TCEQ-2007 Page 56 of 85

Checked by: 

Sample No. DTTS1 DTTS2 DTTS3 DTTS4 DTTS5 DTTS6 DTTS7 DTTS8

Date 17-Jul07 18-Jul07 19-Jul07 21-Jul07 28-Jul07 28-Jul07 29-Jul07 30-Jul07 

Start time 17:17 16:20 12:31 03:57 14:25 14:40 16:56 16:39 

End time 18:09 17:27 13:44 05:06 15:47 16:00 18:12 17:51 

Average Wind Direction/deg 164 128 322 95 170 174 149 159 

Average Wind Speed/mph 4.5 2.4 4.6 2.3 4.3 4.3 3.9 4.2 

Cannister Number 169 610 708 881 190 996 762 606 

 

Tert amyl methyl ether <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,2,4-Trimethylpentane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Heptane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Methylcyclohexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,5-Dimethylhexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,4-Dimethylhexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2,3,4-Trimethylpentane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Toluene <1.93 <1.91 3.03 <1.91 1.99 <1.94 3.35 28.65 

2,3-Dimethylhexane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methylheptane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

4-Methylheptane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Ethyl-3-methylpentane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

3-Methylheptane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Methyl-1-heptane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Octane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 2.12 

Ethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

m,p-xylene <1.93 2.74 <2.09 <1.91 <1.96 <1.94 <2.00 2.84 

Styrene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

o-xylene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1-Nonene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Nonane <1.93 4.09 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

i-Propylbenzerne <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Propylbenzerne <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

a-Pinene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

3-Ethyltoluene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

4-Ethyltoluene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,3,5-Trimethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

2-Ethyltoluene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

b-Pinene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,2,4-Trimethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 2.07 <2.06 

n-Decane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,2,3-Trimethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 2.28 

Indan <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

d-Limonene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,3-Diethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,4-Diethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

n-Butylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,4-Dimethyl-2-ethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,3-Dimethyl-4-ethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,2-Dimethyl-4-ethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Undecane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,2,4,5-Tetramethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

1,2,3,5-Tetramethylbenzene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Napthalene <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 

Dodecane <1.93 <1.91 <2.09 <1.91 <1.96 <1.94 <2.00 <2.06 
Reference: QBN1701-TCEQ-2007 Page 57 of 85

Checked by: 

Sample No. DTTS9 DTTS10 DTTS11 DTTS12 DTTS13 DTTS14 DTTS15 DTTS16

Date 3-Aug07 3-Aug07 5-Aug07 6-Aug07 7-Aug07 17-Aug07 17-Aug07 18-Aug07 

Start time 13:30 15:37 04:48 04:30 04:55 17:53 17:29 20:05 

End time 14:47 17:28 06:03 05:54 06:19 18:58 18:30 20:57 

Average Wind Direction/deg 84 113 183 140 201 131 131 128 

Average Wind Speed/mph 4.3 5 3.4 2.6 2 4.4 4.7 2.4 

Cannister Number 2968 711 782 2962 2970 758 732 656 

 

Species ppb V ppb V ppb V ppb V ppb V ppb V ppb V ppb V 

Ethene 9.65 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Acetylene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Ethane 24.58 27.98 5.36 117.36 3.35 9.17 6.96 15.92 

Propene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Propane 28.92 14.99 8.47 48.25 80.36 13.33 16.46 10.30 

I-Butane 15.23 9.19 7.12 39.59 5.26 20.06 15.94 5.97 

Methanol <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1-Butene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,3-Butadiene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 3.09 <2.00 

n-Butane 16.33 9.88 4.99 64.73 <1.93 11.47 29.96 5.95 

t-2-Butene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

c-2-Butene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Ethanol <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

3-Methyl-1-butene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Acetone <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

i-Pentane 19.88 <1.97 <1.94 <1.96 8.87 53.05 110.80 16.86 

1-Pentene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Isopropanol <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methyl-1-butene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Pentane <1.94 <1.97 <1.94 <1.96 <1.93 4.64 39.57 11.68 

Isoprene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

t-2-Pentene <1.94 <1.97 <1.94 2.85 <1.93 <2.00 <1.88 <2.00 

c-2-Pentene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Tert butyl alcohol <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methyl-2-butene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,2-Dimethylbutane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 5.39 <2.00 

Cyclopentene <1.94 2.91 <1.94 9.48 <1.93 <2.00 <1.88 <2.00 

n-Propanol <1.94 2.11 <1.94 2.86 <1.93 <2.00 <1.88 <2.00 

Cyclopentane <1.94 <1.97 <1.94 <1.96 <1.93 2.25 <1.88 <2.00 

Methyl tert butyl ether <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,3-Dimethylbutane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methylpentane <1.94 <1.97 <1.94 <1.96 <1.93 5.21 <1.88 10.70 

3-Methylpentane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 5.76 

1-Hexene 2.88 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Hexane <1.94 <1.97 <1.94 <1.96 6.72 <2.00 <1.88 <2.00 

Diisopropyl ether <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

3-Methylcyclopentene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Ethyl tert butyl ether <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Methylcyclopentane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,4-Dimethylpentane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Benzene <1.94 <1.97 <1.94 <1.96 4.58 <2.00 <1.88 <2.00 

Cyclohexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methylhexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,3-Dimethylpentane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 7.20 

3-Methylhexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methyl-1-hexene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 
Reference: QBN1701-TCEQ-2007 Page 58 of 85

Checked by: 

Sample No. DTTS9 DTTS10 DTTS11 DTTS12 DTTS13 DTTS14 DTTS15 DTTS16

Date 3-Aug07 3-Aug07 5-Aug07 6-Aug07 7-Aug07 17-Aug07 17-Aug07 18-Aug07 

Start time 13:30 15:37 04:48 04:30 04:55 17:53 17:29 20:05 

End time 14:47 17:28 06:03 05:54 06:19 18:58 18:30 20:57 

Average Wind Direction/deg 84 113 183 140 201 131 131 128 

Average Wind Speed/mph 4.3 5 3.4 2.6 2 4.4 4.7 2.4 

Cannister Number 2968 711 782 2962 2970 758 732 656 

 

Tert amyl methyl ether <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,2,4-Trimethylpentane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Heptane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 5.54 <2.00 

Methylcyclohexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,5-Dimethylhexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,4-Dimethylhexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2,3,4-Trimethylpentane 3.92 <1.97 2.58 <1.96 <1.93 <2.00 <1.88 <2.00 

Toluene <1.94 <1.97 <1.94 <1.96 1.96 12.26 20.52 2.11 

2,3-Dimethylhexane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methylheptane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

4-Methylheptane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Ethyl-3-methylpentane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

3-Methylheptane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Methyl-1-heptane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Octane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 2.09 <2.00 

Ethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 2.04 2.46 <2.00 

m,p-xylene <1.94 <1.97 <1.94 <1.96 <1.93 5.51 8.49 <2.00 

Styrene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

o-xylene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 2.59 <2.00 

1-Nonene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Nonane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

i-Propylbenzerne <1.94 2.13 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Propylbenzerne <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

a-Pinene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

3-Ethyltoluene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

4-Ethyltoluene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,3,5-Trimethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

2-Ethyltoluene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

b-Pinene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,2,4-Trimethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 2.06 <2.00 

n-Decane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,2,3-Trimethylbenzene 2.54 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Indan <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

d-Limonene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,3-Diethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,4-Diethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

n-Butylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,4-Dimethyl-2-ethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,3-Dimethyl-4-ethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,2-Dimethyl-4-ethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Undecane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,2,4,5-Tetramethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

1,2,3,5-Tetramethylbenzene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Napthalene <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 

Dodecane <1.94 <1.97 <1.94 <1.96 <1.93 <2.00 <1.88 <2.00 
Reference: QBN1701-TCEQ-2007 Page 59 of 85

Checked by: 

Table A2.3 Full results of the speciation analyses on the Sorbent Tube Samples. 

Sample No. 

TRV BLK 

A 

TRV BLK 

B DTTS1 DTTS2 DTTS3 DTTS4 DTTS5 

Date 17-Jul-07 18-Jul-07 19-Jul-07 21-Jul-07 28-Jul-07

Start time 17:17 16:20 12:31 03:57 14:25 

End time 18:09 17:27 13:44 05:06 15:47 

Sample Volume/ml 2500.5 3230.8 2970.4 3297.5 3948.6 

Average Wind Direction/deg 164 128 322 95 170 

Average Wind Speed/mph 4.5 2.4 4.6 2.3 4.3 

 ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v 

i-Butane 0.8 0.7 4.4 1.6 13.1 7.5 2.4 

n-Butane <0.6 <0.6 <0.6 0.6 19.3 1.0 <0.6 

trans-2-Butene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1-Butene <0.6 <0.6 <0.6 <0.6 0.8 <0.6 <0.6 

2-methylpropene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cis-2-butene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,3 Butadiene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

i-pentane <0.6 <0.6 60.8 0.9 13.7 1.9 0.6 

1-pentene <0.6 <0.6 2.8 <0.6 0.9 <0.6 <0.6 

2 me-1-butene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

isoprene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-pentane <0.6 <0.6 <0.6 1.4 34.6 1.1 <0.6 

cis-2-pentene (Z)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

trans-2-pentene (E)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2 dime cyclopropane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,2-di me butane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cyclo pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-me-1-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,3-di me butane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cyclo pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-me pentane <0.6 <0.6 <0.6 <0.6 7.1 <0.6 <0.6 

4-me-cis-2-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-me-trans-2-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3-me pentane <0.6 <0.6 <0.6 <0.6 3.6 <0.6 <0.6 

1-hexene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-hexane <0.6 <0.6 6.5 <0.6 11.8 <0.6 <0.6 

cis-2-hexene (Z)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

trans-3-hexene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

trans-2-hexene (E)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

methylcyclopentane <0.6 <0.6 <0.6 <0.6 3.0 <0.6 <0.6 

2,4 di me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,2,3-trimethyl-1-butene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,2,3-tri-me butane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

benzene <0.2 <0.2 0.2 0.2 5.0 1.8 0.2 

cyclohexane <0.6 <0.6 <0.6 <0.6 1.5 <0.6 <0.6 

2-methyl hexane <0.6 <0.6 <0.6 <0.6 1.2 <0.6 <0.6 

2,3 di me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3-me hexane <0.6 <0.6 <0.6 <0.6 1.6 <0.6 <0.6 

cyclohexene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1-heptene <0.6 <0.6 <0.6 <0.6 0.9 <0.6 <0.6 

2,2,4 tri me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-heptane <0.6 <0.6 <0.6 <0.6 2.3 <0.6 <0.6 

methylcyclohexane <0.6 <0.6 <0.6 <0.6 2.0 <0.6 <0.6 

2,3,4 tri me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,3,3-tri me pentane <0.6 <0.6 <0.6 <0.6 2.7 2.4 <0.6 
Reference: QBN1701-TCEQ-2007 Page 60 of 85

Checked by: 

Sample No. TRV BLK 

A 

TRV BLK 

B 

DTTS1 DTTS2 DTTS3 DTTS4 DTTS5 

Date 17-Jul-07 18-Jul-07 19-Jul-07 21-Jul-07 28-Jul-07

Start time 17:17 16:20 12:31 03:57 14:25 

End time 18:09 17:27 13:44 05:06 15:47 

Sample Volume/ml 2500.5 3230.8 2970.4 3297.5 3948.6 

Average Wind Direction/deg 164 128 322 95 170 

Average Wind Speed/mph 4.5 2.4 4.6 2.3 4.3 

ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v 

toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-methyl heptane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-methyl heptane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cycloheptene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cycloheptane <0.6 <0.6 <0.6 <0.6 1.0 <0.6 <0.6 

n-octane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

ethylbenzene <0.6 <0.6 <0.6 <0.6 1.5 <0.6 <0.6 

m/p-xylene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2 me octane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3 me octane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

styrene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

o-xylene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

nonane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cis-cyclooctene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

isopropylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cyclooctane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-propylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 1.0 <0.6 

3-ethyl toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-ethyl toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,3,5 tri me benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-ethyl toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-me nonene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2,4 tri me benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-decane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2,3-Trimethylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2,3,5-tetra me benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-butyl benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-undecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-pentylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-dodecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

naphthalene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-tridecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-tetradecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-pentadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-hexadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-heptadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-octadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-nonadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-cosane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-docosane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 
Reference: QBN1701-TCEQ-2007 Page 61 of 85

Checked by: 

Sample No. DTTS6 DTTS7 DTTS8 DTTS9 DTTS10 DTTS11 DTTS12

Date 28-Jul-07 29-Jul-07 30-Jul-07 3-Aug-07 3-Aug-07 5-Aug-07 6-Aug-07

Start time 14:40 16:56 16:39 13:30 15:37 04:48 04:30 

End time 16:00 18:12 17:51 14:47 17:28 06:03 05:54 

Sample Volume/ml 3927.9 3637.8 3409.8 5289 3600.9 3980.4 

Average Wind Direction/deg 174 149 159 84 113 183 140 

Average Wind Speed/mph 4.3 3.9 4.2 4.3 5 3.4 2.6 

ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v 

i-Butane 7.5 9.6 24.8 6.5 9.4 3.2 11.8 

n-Butane 8.7 4.2 9.8 <0.6 13.8 3.4 21.6 

trans-2-Butene <0.6 <0.6 1.3 <0.6 <0.6 <0.6 1.1 

1-Butene <0.6 <0.6 1.4 <0.6 <0.6 <0.6 1.0 

2-methylpropene <0.6 <0.6 1.4 <0.6 <0.6 <0.6 0.9 

cis-2-butene <0.6 <0.6 1.0 <0.6 <0.6 <0.6 <0.6 

1,3 Butadiene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

i-pentane 5.4 2.6 16.5 0.7 7.3 2.2 21.4 

1-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2 me-1-butene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

isoprene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-pentane 3.6 1.5 1.6 <0.6 6.4 0.8 4.0 

cis-2-pentene (Z)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

trans-2-pentene (E)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2 dime cyclopropane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,2-di me butane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cyclo pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-me-1-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,3-di me butane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cyclo pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-me pentane 0.7 <0.6 <0.6 <0.6 0.8 <0.6 1.7 

4-me-cis-2-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-me-trans-2-pentene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3-me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 1.0 

1-hexene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-hexane 0.9 <0.6 <0.6 <0.6 1.7 <0.6 1.9 

cis-2-hexene (Z)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

trans-3-hexene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

trans-2-hexene (E)- <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

methylcyclopentane 0.6 <0.6 <0.6 <0.6 0.7 <0.6 1.1 

2,4 di me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,2,3-trimethyl-1-butene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2,2,3-tri-me butane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

benzene 0.9 4.4 0.5 0.2 0.7 0.3 1.6 

cyclohexane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-methyl hexane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 0.7 

2,3 di me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3-me hexane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 0.7 

cyclohexene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1-heptene <0.6 <0.6 0.9 <0.6 <0.6 <0.6 1.1 

2,2,4 tri me pentane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-heptane <0.6 <0.6 <0.6 <0.6 0.9 <0.6 <0.6 

methylcyclohexane 0.6 4.8 <0.6 <0.6 0.8 <0.6 0.8 

2,3,4 tri me pentane <0.6 1.7 <0.6 <0.6 <0.6 <0.6 <0.6 

2,3,3-tri me pentane 1.6 0.9 1.4 <0.6 0.8 1.5 2.1 
Reference: QBN1701-TCEQ-2007 Page 62 of 85

Checked by: 

Sample No. DTTS6 DTTS7 DTTS8 DTTS9 DTTS10 DTTS11 DTTS12

Date 28-Jul-07 29-Jul-07 30-Jul-07 3-Aug-07 3-Aug-07 5-Aug-07 6-Aug-07

Start time 14:40 16:56 16:39 13:30 15:37 04:48 04:30 

End time 16:00 18:12 17:51 14:47 17:28 06:03 05:54 

Sample Volume/ml 3927.9 3637.8 3409.8 5289 3600.9 3980.4 

Average Wind Direction/deg 174 149 159 84 113 183 140 

Average Wind Speed/mph 4.3 3.9 4.2 4.3 5 3.4 2.6 

ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v ppb v/v 

toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-methyl heptane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-methyl heptane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cycloheptene <0.6 <0.6 <0.6 <0.6 <0.6 10.0 <0.6 

cycloheptane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-octane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

ethylbenzene <0.6 <0.6 1.5 <0.6 <0.6 <0.6 1.4 

m/p-xylene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2 me octane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3 me octane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

styrene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

o-xylene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

nonane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cis-cyclooctene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

isopropylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

cyclooctane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-propylbenzene 0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

3-ethyl toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

4-ethyl toluene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,3,5 tri me benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

2-ethyl toluene <0.6 <0.6 <0.6 <0.6 <0.6 1.3 <0.6 

2-me nonene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2,4 tri me benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-decane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2,3-Trimethylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

1,2,3,5-tetra me benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-butyl benzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-undecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-pentylbenzene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-dodecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

naphthalene <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-tridecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-tetradecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-pentadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-hexadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-heptadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-octadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-nonadecane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-cosane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 

n-docosane <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 <0.6 
Reference: QBN1701-TCEQ-2007 Page 63 of 85

Checked by: 

Sample No. DTTS13 DTTS14 DTTS15 DTTS16

Date 7-Aug-07 17-Aug07 17-Aug07 18-Aug07 

Start time 04:55 17:53 17:29 20:05 

End time 06:19 18:58 18:30 20:57 

Sample Volume/ml 4000.8 3217.6 2833.9 2532.6 

Average Wind Direction/deg 201 131 131 128 

Average Wind Speed/mph 2 4.4 4.7 2.4 

ppb v/v ppb v/v ppb v/v ppb v/v 

i-Butane 2.1 10.7 4.0 4.0 

n-Butane 0.6 22.8 9.0 7.3 

trans-2-Butene <0.6 5.2 2.7 <0.6 

1-Butene <0.6 1.6 1.0 <0.6 

2-methylpropene <0.6 1.5 0.6 <0.6 

cis-2-butene <0.6 3.7 1.9 <0.6 

1,3 Butadiene <0.6 <0.6 <0.6 <0.6 

i-pentane 1.0 82.2 37.6 8.1 

1-pentene 1.1 0.8 0.6 <0.6 

2 me-1-butene <0.6 <0.6 <0.6 <0.6 

isoprene <0.6 7.7 2.8 4.2 

n-pentane <0.6 23.7 8.2 4.2 

cis-2-pentene (Z)- <0.6 3.1 1.3 <0.6 

trans-2-pentene (E)- <0.6 <0.6 <0.6 <0.6 

1,2 dime cyclopropane <0.6 3.8 1.5 <0.6 

2,2-di me butane <0.6 <0.6 <0.6 <0.6 

cyclo pentene <0.6 <0.6 <0.6 <0.6 

4-me-1-pentene <0.6 <0.6 <0.6 <0.6 

2,3-di me butane <0.6 2.0 0.7 <0.6 

cyclo pentane <0.6 <0.6 <0.6 <0.6 

2-me pentane 2.7 11.4 4.2 1.6 

4-me-cis-2-pentene <0.6 <0.6 <0.6 <0.6 

4-me-trans-2-pentene 0.8 <0.6 <0.6 <0.6 

3-me pentane <0.6 6.1 2.4 0.8 

1-hexene <0.6 <0.6 <0.6 <0.6 

n-hexane 5.3 13.0 4.0 1.6 

cis-2-hexene (Z)- <0.6 <0.6 <0.6 <0.6 

trans-3-hexene <0.6 0.6 <0.6 <0.6 

trans-2-hexene (E)- <0.6 <0.6 <0.6 <0.6 

methylcyclopentane <0.6 7.5 2.0 <0.6 

2,4 di me pentane <0.6 <0.6 <0.6 <0.6 

2,2,3-trimethyl-1-butene <0.6 <0.6 <0.6 <0.6 

2,2,3-tri-me butane <0.6 <0.6 <0.6 <0.6 

benzene 5.1 12.9 6.7 1.3 

cyclohexane <0.6 4.0 2.0 1.5 

2-methyl hexane <0.6 3.8 1.3 <0.6 

2,3 di me pentane <0.6 0.7 <0.6 <0.6 

3-me hexane 0.7 4.1 1.6 <0.6 

cyclohexene <0.6 <0.6 <0.6 <0.6 

1-heptene <0.6 1.3 <0.6 <0.6 

2,2,4 tri me pentane <0.6 <0.6 <0.6 <0.6 

n-heptane <0.6 5.7 1.6 <0.6 

methylcyclohexane 0.6 6.6 1.7 0.6 

2,3,4 tri me pentane <0.6 <0.6 <0.6 <0.6 

2,3,3-tri me pentane 0.7 15.2 7.9 <0.6 
Reference: QBN1701-TCEQ-2007 Page 64 of 85

Checked by: 

Sample No. DTTS13 DTTS14 DTTS15 DTTS16

Date 7-Aug-07 17-Aug07 17-Aug07 18-Aug07 

Start time 04:55 17:53 17:29 20:05 

End time 06:19 18:58 18:30 20:57 

Sample Volume/ml 4000.8 3217.6 2833.9 2532.6 

Average Wind Direction/deg 201 131 131 128 

Average Wind Speed/mph 2 4.4 4.7 2.4 

ppb v/v ppb v/v ppb v/v ppb v/v 

toluene <0.6 <0.6 <0.6 <0.6 

2-methyl heptane <0.6 <0.6 <0.6 <0.6 

4-methyl heptane <0.6 1.3 <0.6 <0.6 

cycloheptene <0.6 3.3 <0.6 <0.6 

cycloheptane <0.6 <0.6 0.9 <0.6 

n-octane <0.6 2.2 1.8 <0.6 

ethylbenzene 0.9 9.4 5.3 <0.6 

m/p-xylene <0.6 <0.6 <0.6 <0.6 

2 me octane <0.6 0.6 <0.6 <0.6 

3 me octane <0.6 <0.6 <0.6 <0.6 

styrene <0.6 3.1 1.5 <0.6 

o-xylene <0.6 1.6 <0.6 <0.6 

nonane <0.6 <0.6 <0.6 <0.6 

cis-cyclooctene <0.6 <0.6 <0.6 <0.6 

isopropylbenzene <0.6 <0.6 <0.6 <0.6 

cyclooctane <0.6 <0.6 <0.6 <0.6 

n-propylbenzene <0.6 0.6 <0.6 0.6 

3-ethyl toluene <0.6 <0.6 <0.6 <0.6 

4-ethyl toluene <0.6 0.7 <0.6 <0.6 

1,3,5 tri me benzene <0.6 <0.6 <0.6 <0.6 

2-ethyl toluene <0.6 0.6 <0.6 <0.6 

2-me nonene <0.6 1.3 <0.6 <0.6 

1,2,4 tri me benzene <0.6 0.9 <0.6 <0.6 

n-decane <0.6 0.7 <0.6 <0.6 

1,2,3-Trimethylbenzene <0.6 <0.6 <0.6 <0.6 

1,2,3,5-tetra me benzene <0.6 <0.6 <0.6 <0.6 

n-butyl benzene <0.6 0.8 <0.6 <0.6 

n-undecane <0.6 <0.6 <0.6 <0.6 

n-pentylbenzene <0.6 <0.6 <0.6 <0.6 

n-dodecane <0.6 <0.6 <0.6 <0.6 

naphthalene <0.6 <0.6 <0.6 <0.6 

n-tridecane <0.6 <0.6 0.6 <0.6 

n-tetradecane <0.6 <0.6 0.6 <0.6 

n-pentadecane <0.6 <0.6 <0.6 <0.6 

n-hexadecane <0.6 <0.6 <0.6 <0.6 

n-heptadecane <0.6 <0.6 <0.6 <0.6 

n-octadecane <0.6 <0.6 <0.6 <0.6 

n-nonadecane <0.6 <0.6 <0.6 <0.6 

n-cosane <0.6 <0.6 <0.6 <0.6 

n-docosane <0.6 <0.6 <0.6 <0.6 
Reference: QBN1701-TCEQ-2007 Page 65 of 85

Checked by: 

Annex 3. Meteorological Measurements 

Wind direction and speed were recorded during the DIAL measurements at one fixed 

location, at the north east of the Bulk Terminal site, and using a mast located on the DIAL 

facility itself. Two further meteorological stations were operated by TCEQ, located to the 

north and south of the REFINERY site (one of these stations was located at the southern 

side of Bulk Terminal during the period measurements were being made at Bulk Terminal). 

The NPL fixed mast provided wind speed and direction at two heights, ~ 3m and 11m. In 

general the fixed mast data have been used to derive the wind field for the DIAL flux 

measurements, though in some cases the DIAL wind has been used where it was observed to 

be more representative of local conditions. 

The following series of plots present the wind roses, taken from the 11m wind vane mounted 

on the fixed meteorological mast. 

Figure 3.1 Wind rose diagram – top mast – 16 July 2007
Reference: QBN1701-TCEQ-2007 Page 66 of 85

Checked by: 

Figure 3.2 Wind rose diagram – top mast – 17 July 2007
Reference: QBN1701-TCEQ-2007 Page 67 of 85

Checked by: 

Figure 3.3 Wind rose diagram – top mast – 18 July 2007
Reference: QBN1701-TCEQ-2007 Page 68 of 85

Checked by: 

Figure 3.4 Wind rose diagram – top mast – 19 July 2007
Reference: QBN1701-TCEQ-2007 Page 69 of 85

Checked by: 

Figure 3.5 Wind rose diagram – top mast – 20 & 21 July 2007
Reference: QBN1701-TCEQ-2007 Page 70 of 85

Checked by: 

Figure 3.6 Wind rose diagram – top mast – 28 July 2007 
Reference: QBN1701-TCEQ-2007 Page 71 of 85

Checked by: 

Figure 3.7 Wind rose diagram – top mast – 29 July 2007
Reference: QBN1701-TCEQ-2007 Page 72 of 85

Checked by: 

Figure 3.8 Wind rose diagram – top mast – 30 July 2007
Reference: QBN1701-TCEQ-2007 Page 73 of 85

Checked by: 

Figure 3.9 Wind rose diagram – top mast – 31 July 2007
Reference: QBN1701-TCEQ-2007 Page 74 of 85

Checked by: 

Figure 3.10 Wind rose diagram – top mast – 1 August 2007
Reference: QBN1701-TCEQ-2007 Page 75 of 85

Checked by: 

Figure 3.11 Wind rose diagram – top mast – 2 August 2007 
Reference: QBN1701-TCEQ-2007 Page 76 of 85

Checked by: 

Figure 3.12 Wind rose diagram – top mast – 3 August 2007 
Reference: QBN1701-TCEQ-2007 Page 77 of 85

Checked by: 

Figure 3.13 Wind rose diagram – top mast – 5 & 6 August 2007 
Reference: QBN1701-TCEQ-2007 Page 78 of 85

Checked by: 

Figure 3.14 Wind rose diagram – top mast – 6 & 7 August 2007 
Reference: QBN1701-TCEQ-2007 Page 79 of 85

Checked by: 

Figure 3.15 Wind rose diagram – top mast – 7 & 8 August 2007 
Reference: QBN1701-TCEQ-2007 Page 80 of 85

Checked by: 

Figure 3.16 Wind rose diagram – top mast – 9 August 2007 
Reference: QBN1701-TCEQ-2007 Page 81 of 85

Checked by: 

Figure 3.17 Wind rose diagram – top mast – 10 August 2007 
Reference: QBN1701-TCEQ-2007 Page 82 of 85

Checked by: 

Figure 3.18 Wind rose diagram – top mast – 11 August 2007 
Reference: QBN1701-TCEQ-2007 Page 83 of 85

Checked by: 

Figure 3.19 Wind rose diagram – top mast – 14 August 2007 
Reference: QBN1701-TCEQ-2007 Page 84 of 85

Checked by: 

Figure 3.20 Wind rose diagram – top mast – 17 August 2007 
Reference: QBN1701-TCEQ-2007 Page 85 of 85

Checked by: 

Figure 3.21 Wind rose diagram – top mast – 18 August 2007