APPENDIX A 

T&B FIELD MONITORING STUDY 

 
1. MONITORING STRATEGY 

The planning and execution of the monitoring program was designed to provide measurements of 

key emissions activities during periods of high PM10 levels, and have the flexibility to adjust sampling 

strategies as additional information was gathered and analyzed. Going into the monitoring program 

there were a number of unknowns, so the program was designed to provide for the ability to change 

how data were collected and analyzed. This section describes the goals and design of the sampling 

program and how the data collection efforts were planned and executed. 

1.1 Sampling Goals 

At the outset of the program there were specific goals established to help guide the data collection 

design and sampling efforts. These goals were provided in the form of specific tasks to help define 

the work to be performed, how it would be collected, and how it would be analyzed. These tasks 

can be summarized as follows: 

Task 1 - Refine the Work Scope -- During the course of the study, refinements were proposed and 

made to the sampling program that responded to findings from the initial analyses of past data, to 

inputs received from the MAG project manager and stakeholders during the kick-off meeting, and 

initial sampling in the study area. This ability to refine the work plan allowed an appropriate 

response to the observed conditions so as to optimize the usefulness of the data collected fulfill the 

goals of the data analyses task. 

Task 2 - Conduct Analyses of Meteorological Data During High PM Episodes – Prior data collected 

in the Salt River Basin for the period November 2005 through February 2006 were analyzed to 

better understand the contribution of potential transport to high PM loadings at key Maricopa County 

monitors and help identify conditions that led to the high PM values in the Salt River Basin. This 

analysis helped define the measurements, technologies, and locations that were most useful for the 

air monitoring work performed in measurements task (Task 3). 

Task 3 - Perform Particulate Matter Source Attribution and Deposition Monitoring – This task 

provided the basis for all measurements made and was designed to address the following specific 

questions: 

1. Where are the specific source areas and/or sources in the Salt River region that contribute to the 

PM loading at the Durango Complex and West 43rd monitoring sites? 

2. To obtain useful results from models such as AERMOD, can the regional particle size distribution 

be characterized on an area basis, i.e., is there an area of uniformity that can be generalized? 

3. What are the causes of the heavy PM loading during the morning hours at the Durango Complex 

and West 43rd? Are the diurnal variations of PM10 and peaks due to reentrainment of paved road 

dust, or due to other activities in the surrounding source areas that are coincident with traffic peaks? 

1.2 Sampling Methodology 

To address the sampling goals and answer the specific questions in Task 3, several types of 

monitoring platforms were required. The approach was to employ monitoring systems that can 

measure the spatial distribution of particulate matter in and around the Salt River basin with a focus 

on identifying the source areas that can contribute to the observed loading at the existing monitoring 

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sites. This source identification was performed using both particulate matter and meteorological 

measurement technologies, and by video documentation. Sampling efforts were coordinated with 

the State of Arizona and Maricopa County for particulate matter and meteorological measurements 

they provided to augment the study. Measurements made during the program included the 

following: 

Particulate Matter – Measurements included the existing network instrumentation operated by 

Maricopa County, along with enhancements to that network which consisted of mobile 

measurements using two mobile vans, fixed site measurements at a site added for the study, and 

remotely sensed measurements made by Arizona State University (ASU), under contract to the 

State of Arizona. 

Meteorological – Measurements included the existing network operated by Maricopa County, along 

with enhancements to that network consisting of mobile measurements made from one of the vans 

during periods of non-moving operations, wind measurements in the lowest 200 meters using a 

miniSodar provided by the State of Arizona at the West 43rd monitoring site, fixed site 

measurements at a site added for the study, and remotely sensed measurements made by ASU 

under contract to the State of Arizona. 

More details on the specific measurements are provided in Section 3. 

1.3 Data Collection Planning and Execution 

Following the initial planning meeting, analyses were performed of the existing data during high 

PM10 episodes. Meteorological conditions were evaluated in an attempt to identify the most 

prominent wind flow patterns that produced the high values at the Durango Complex (DC) and West 

43rd (WF) sites. As this initial analysis continued, it became clear that there were other potential 

local sources near the monitors that had not been accounted for in the existing inventory. No clear 

pattern of source areas emerged from the existing data set. 

On the basis of the preliminary findings, and consistent with the goals of Tasks 1 and 2 of the work 

scope, the sampling program was refined to provide measurements in a two phased approach. The 

first phase focused on the identification of local sources near the DC and WF monitors, which may 

be contributing to the exceedances at the monitors. This phase consisted of primarily mobile 

measurements of PM10 and PM2.5, as well as visual documentation of the sources around the 

monitors. The results from Phase 1 of the monitoring were then used to refine the measurements to 

be made in the Phase 2 effort. A monitoring period of one month during the period of midNovember through mid-December was selected for field measurement tasks based on the analysis 

of the historical exceedance periods. Deployment to the field occurred on November 13 with Phase 

1 sampling performed from November 15 through November 19, 2006. The results from this 

sampling were analyzed during the week of November 20 and revisions made to the sampling 

strategies that then resumed in Phase 2 on November 30, and continued through December 14, 

2006. Additionally, during the Phase 2 sampling, coincident measurements were planned and 

executed with the road emissions measurements made by CECERT during the week of December 

4, and with lidar measurements by Arizona State University (ASU) who were under contract to the 

State of Arizona. 

Throughout the data collection efforts, close coordination was maintained with the program 

management regarding the findings of each day’s sampling results. Preliminary data plots were 

submitted daily that highlighted the sampling findings and provided timely information to both MAG 

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and Sierra on key findings, and immediate feedback on how that information could be used to plan 

subsequent sampling missions. A key finding during the Phase 1 sampling was that mobile 

sampling provided a primary data input and sampling platform for the identification of what were 

previously unidentified sources of PM10, such as open burning and truck driving schools adjacent to 

the WF and DC monitoring sites. On the basis of the Phase 1 sampling results, a second sampling 

van was added to the measurement program for Phase 2. This sampling van included the 

continuous particulate matter measurements as well as adding an Aerodynamic Particle Sizer (APS) 

to help refine the size distribution of particulate matter from the various identified sources. 

Phase 2 of the sampling effort used both sampling vans to identify and characterize source areas as 

well as adding a continuous optical PM10 monitoring station at a location half way between the West 

43rd and Durango Complex stations. The Phase 2 operations also included a concerted quality 

assurance effort to audit the measurements made and help establish uncertainties in the collected 

data. This allowed a more complete understanding of the data collected. 

2. FIELD MEASUREMENT INSTRUMENTATION 

The types of instrumentation used in the sampling program evolved as more was learned about the 

types of sources of PM. Described below are the measurement platforms used and the procedures 

used to assure the quality of the data were understood. 

2.1 MAG Network Enhancements 

Through the initial analyses performed it became clear that higher time-resolved wind and 

particulate matter information could greatly enhance the understanding of the PM problem in the 

Salt River Basin. With only hourly data available, and the analysis showing that the highest 

concentrations occurred during a short period of four hours or less, increasing the time resolution 

could greatly enhance the understanding of the processes involved.. During this short time period, 

the reported winds were always very light and variable. Part of the reason for the very light reported 

winds was the vector averaging technique used.. With highly variable wind directions, the resulting 

vector average over the relatively long hour period would show very low reported wind speeds, and 

hence, suggest not much transport. To better understand the low wind speed conditions, the 

Maricopa County monitoring group added higher time resolution measurements with 5-minute 

averages. Additionally, scalar wind calculations were recorded, in addition to the standard vector 

winds. Modifications were also made to the PM10 measurements to record 5-minute averages from 

the TEOM samplers. A refined trajectory analysis based on the higher temporal resolution winds 

revealed a slow but definable movement of parcels around the Salt River Basin which allowed a 

greater understanding of the origin of the high concentrations. The modifications to the network 

were made to the Durango Complex, West 43rd, West Phoenix, Central Phoenix, South Phoenix and 

Greenwood stations. 

2.2 West 43rd Site Monitoring Enhancements 

The WF site, because of the history of exceedances and its central proximity in the Salt River Basin, 

was selected as the base for field operations. In addition to the enhancements of the recorded 

averaging intervals to include 5-minute data, additional measurements were made at the site, as 

described below. 

Wind measurements using a miniSodar – The Arizona Department of Environmental Quality 

(ADEQ) provided an AeroVironment model 4000 miniSodar for measurement of winds and mixing in 

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the lowest 200 meters of the atmosphere. The system was installed by ADEQ at the outset of the 

program and the operation verified by T&B Systems’ personnel prior to the start of the data 

collection effort. The system was programmed to collect and report 10-minute average winds and 

provide the facsimile display of the acoustic backscatter. This facsimile display was subsequently 

used to evaluate the mixed layer depth during the high PM10 concentration episodes. Figure 2-1 

shows the miniSodar system. 

Figure 2-1. MiniSodar at the West 43rd monitoring station. 

An automated digital camera was installed at the site to document the environment around the WF 

site. The camera was originally installed facing east to document sources along Broadway. The 

pointing direction was changed on November 15 to face the northeast, in the direction looking 

across the Salt River toward the DC site. On December 6 the camera was turned to the southwest 

to document local sources adjacent to the WF site. Figure 2-2 shows the camera system. High 

temporal resolution pictures were taken at intervals from 3 seconds to 30 seconds, depending on 

the pointing direction of the camera. Each picture was in a 640x496 pixel resolution with the date 

and time stamp embedded into the picture. Over 400,000 pictures were taken over the course of 

the study from this camera. Example views are shown in Figure 2-3. 

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Figure 2-2. Camera mounted at the West 43rd monitoring site. The view shown had the camera 

aiming to the northeast. 

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Looking East Looking Northeast 

Looking Southwest 

Figure 2-3. Example views from the West 43rd site camera. 

During the last week of Phase 2 monitoring ASU installed the particle lidar at the WF site. The lidar 

performed horizontal and vertical scans of the atmosphere to provide relative concentrations of 

particulate matter around the site. Additionally, the system estimated the wind field through an 

analysis of the Doppler shifted signals from the lidar pulses. More details on the measurements are 

provided in a separate report of findings from ASU submitted to the ADEQ. Figure 2-4 shows the 

lidar system installed at the WF site. 

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Figure 2-4. ASU lidar installed at the West 43rd site. 

2.3 Additional Fixed Site Monitoring at the 35th Site 

Following the Phase 1 monitoring, a key issue that arose was whether the high PM10 concentrations 

observed at the WF and DC sites were due primarily to local sources immediately adjacent to the 

sites, or some distance away from the local sources, but still within the Basin. To help answer this 

question a monitoring site was established near the Salt River, east of 35th Avenue, and away from 

any immediately local sources. The monitoring station was comprised of a PM10 configured 

DustTrak, recording average optical PM10 concentrations at 5-minute and 60 minute intervals. The 

values collected were adjusted using a K-factor derived from the filter sampler to DustTrak 

measurements in the monitoring van, and the DustTrak to TEOM measurements made at both WF 

and DC. Wind measurements were also made using a RM Young Wind Monitor AQ wind speed 

and wind direction sensor. Data were polled via radio modem from a computer at the WF site every 

5-minutes and uploaded to a web page for a near real-time display of the values. Figure 2-5 shows 

the location of the station relative to the WF and DC sites. Figure 2-6 shows the monitoring site with 

the view looking to the south, over the Salt River. 

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Figure 2-5. Location of the 35th site relative to the WF and DC sites. 

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Figure 2-6. View of the 35th site. 

2.4 Mobile Monitoring 

Mobile monitoring was performed using two vehicles. The primary vehicle, referred to as Van 1, or 

the Pilot, performed measurements during both Phase 1 and Phase 2 of the sampling program. 

The second vehicle, referred to as Van 2, or the Kia, was added for sampling in Phase 2. The 

equipment used in each of the mobile vans is shown in Table 2-1. Figures 2-7 and 2-8 show the 

Pilot and Kia, respectively. 

Table 2-1. Measurement equipment in the two sampling vans. 

Measurement Equipment 

Pilot 

(Van 1) 

Kia 

(Van 2) 

TSI 8520 DustTrak (PM10) X X 

TSI 8520 DustTrak (PM2.5) X X 

TSI 3321 Aerodynamic Particle Sizer X 

Airmetrics minivol (PM10) X 

Airmetrics minivol (PM2.5) X 

Garmin GPS receiver (van 3-D position) X X 

Campbell Scientific CR1000 (Data logging) X X 

RM Young Wind Monitor (Wind speed and direction) X 

RTD temperature sensor (outside air temperature) X 

RM Young Electronic Compass (van direction) X 

Intellinet Network IP camera with recording laptop X 

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Vehicle with top mounted probes and wind and 

temperature sensors. The camera is dash 

mounted. 

Instrumentation 

Figure 2-7. Van 1 (Pilot). 

Vehicle with top mounted probes Instrumentation 

Figure 2-8. Van 2 (Kia) 

Measurements using the Pilot were made in both a mobile and fixed modes. The primary use was 

to map the region to obtain relative concentrations throughout the Salt River Basin and identify “hot 

spot” regions to be studied in more depth. The Kia was used to obtain the particle size distribution. 

Data were collected and stored in two-second intervals with all values stored in non-volatile memory 

within the data logger, and polled in real-time as well as on a backup local computers in each of the 

respective vans. 

As the continuous optical method used in the TSI DustTraks for particulate matter concentration 

determination is not the same sampling principal as the filter based high volume method or the 

TEOM sampler, filter based measurements made with minivols were used to establish the “K” factor, 

or correction factor for the optical to filter based relationship. The filter samplers were allowed to run 

over multiple sampling periods to assure enough particulate matter had been collected to obtain an 

accurate weight difference between the initial and final weighings. Separate samplers were used to 

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collect samples for both PM10 and PM2.5. Additionally, comparisons were made between the 

DustTraks and the real-time PM10 and PM2.5 samplers at WF and DC. All of these data were used to 

establish the relationship of the DustTraks to the site monitors. 

2.5 Quality Assurance and Quality Control 

Integral to the data collection program was the quality assurance effort employed during the period 

of measurements. T&B Systems had an independent auditor visit the field sites and evaluate the 

measurements made during Phase 2 of the data collection program. A summary of the checks 

made and the findings is provided below. 

In addition to the quality assurance procedures described, the data collection effort had quality 

control measures in place to internally monitor and establish data quality parameters that were used 

to verify data validity and provide support documentation used in the final processing of the data. 

Those measures are described following the quality assurance discussion. 

Quality Assurance 

Mobile Vans 

The following performance checks were conducted: 

− Flow checks of all samplers, including the APS, using a Gilibrator flow standard 

− Zero checks of the DustTraks and APS 

− Leak checks of the MiniVols 

− Quasi-quantitative check of the APS by placing a PM10 inlet on the APS inlet 

− Four-point check of the wind direction sensor on the Pilot, including orientation relative to the 

van 

− Six-point check of the wind speed sensor using a constant speed motor 

− A one-point ambient comparison of the temperature sensor 

All checks were conducted using standards independent of those used for the monitoring effort. 

Figure 2-9 provides a picture of the audit. 

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Figure 2-9. The Pilot being audited for the accuracy of the instrumentation. 

In addition, the auditor rode in each van to review operations, data collection equipment and 

procedures, and the representativeness of the collected data. Results of all performance checks 

were very good. The only recommendation from the systems review was to include recording of the 

MiniVol elapsed time meter readings as part of the daily checks in order to verify the actual sampling 

period for the collected samples. 

To further investigate the representativeness of the collected PM data, the following special tests 

were conducted at the auditor’s request. All tests were conducted near the T&B Systems 35th

Avenue site under stable and relatively low PM10 conditions (less than 50 μg/m3

), which allowed for 

the identification of any interferents being investigated. In addition, wind conditions were steady but 

light (less than 2 m/s) and representative of typical sampling conditions during the study. 

To investigate whether exhaust emissions from the van affected readings, the KIA was parked with 

the tailpipe upwind, and sampling conducted alternatively with the motor turned on and turned off. A 

total of seven 7-minute sampling intervals were measured, four with the motor off and three with the 

motor on. No difference in readings was noted, indicating that the van exhaust is not an interferent. 

To investigate whether dust kicked up by the van influence readings while the van was moving, the 

KIA was driven down a dirt road at 15 MPH, representing a worst case scenario for possible 

interference. The test was also conducted on a paved, though lightly used, road at 25 MPH. Tests 

were repeated both heading into the wind and away from the wind. No changes from background 

ambient readings were noted, indicating that dust generated by the movement of the van does not 

significantly affect readings. 

As an extension to the above test, measurements were monitored to see how the plume of dust 

generated by travel affected readings once the vehicle stopped. Even in the case of the very dusty 

plume generated on the dirt road, the affect of the plume was gone within 15 seconds after 

stopping. 

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35th Avenue Monitoring Site 

A zero check was conducted on the DustTrak sampler at the site. Lowering the wind sensor at the 

site was considered undesirable in that it potentially affected measurement consistency. Thus, 

performance checks of the wind direction sensor were conducted by noting true bearing of the wind 

vane during steady conditions and comparing these readings with the simultaneous readings on the 

data logger. All such checks showed agreement to within 1°. Reported wind speeds were deemed 

to be in agreement with actual conditions. 

Maricopa County Air Quality Department Monitoring 

A systems review of the MCAQD monitoring effort was conducted at the Maricopa County office. 

The review concentrated on PM and meteorological measurements, and consisted of discussions 

with key personnel regarding monitoring QA/QC procedures and data validation. All personnel 

showed a high degree of concern for data quality, and no serious issues were noted. However, the 

following observations were made: 

− The top range of the PM10 TEOM sampler was set at 1000 μg/m3. Values higher than this 

were measured as 1000 μg/m3

. The data were flagged for two situations: exceeding a set 

upper limit and unstable readings (usually due excessive rates of PM loading on the filter to 

which the sampler cannot adjust for). It is the MCAQD’s policy to invalidate any hour that 

has greater than 25% of the hour affected by these flags, consistent with the EPA 75% data 

recoverability criteria. The auditors initial concern was that hours of high PM10

concentrations were being invalidated because they exceeded the upper limit. However, 

they have set the upper limit criteria to 1200 μg/m3

, which can never physically be reached 

since it is beyond the set range. Thus, only electronic spikes were flagged. The period of 

time during which the sampler may have been over-ranging was therefore not recorded, and 

the extent of this is issue was therefore unknown. The second flag, regarding unstable 

readings, appeared to have affected data in the past. At both the Higley and Buckeye sites, 

some PM10 hourly concentrations were invalidated on both May 17 and May 22, 2006. The 

hours invalidated appeared to occur during very high PM concentrations, so high that the 

TEOM readings became unstable for more than 25% of the hour. This was a limitation with 

this method, and no further action was required other than to realize its potential affect on 

the data. 

− Personnel were incorrectly calculating wind direction starting threshold torque. Due to 

confusion in interpreting the scale on newer RM Young torque meters, the calculated torque 

was only a tenth of the actual torque. In the case of both the West 43rd Avenue and Durango 

Complex sites’ most recent calibrations, the torque was reported as 2.5 gm cm when it 

actually should have been reported as 25 gm cm. Relative to a torque criteria of 11 gm cm 

required for the RM Young wind sensors in order to have a starting threshold less than 0.5 

m/s, these torque readings would have required changing of sensor bearings. Personnel 

were instructed on the correct method of measuring wind direction starting threshold torque. 

It is unlikely that the potentially higher starting thresholds of the sensors seriously affect the 

wind data. 

− There were some inconsistencies in the delta temperature calibration at the West 43rd site. 

The top bath point showed the responses at the two levels differing by 0.2°F, though the 

actual delta temperature value reported by the data logger was only 0.04°F. Also, there was 

some confusion as to whether the criterion for the delta temperature check was 0.1 or 0.5°F. 

Different forms showed different criterion. The actual EPA criterion is 0.18°F. Thus, the 0.1°

criterion is applicable, consistent with the MCAQD policy of having calibration criteria that are 

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tighter than the actual EPA-required monitoring objectives. Bottom line, the delta 

temperature sensor at West 43rd Avenue appeared to be calibrated correctly, despite these 

inconsistencies. 

− As an additional check, the auditor checked the wind direction sensor alignment at both the 

West 43rd Avenue and Durango Complex sites. The sensor alignment at the West 43rd

Avenue site was perfect. However, the Durango Complex sensor was oriented 4° low 

(aimed at 356° instead of 360°), relative to the EPA audit criteria of ±2°. Again, it is unlikely 

that this seriously affects the representativeness of the data collected at this site. 

SCAMPER 

A brief review of the CeCert SCAMPER monitoring was conducted through an informal discussion 

with Kurt Bumiller, the SCAMPER operator. Mr. Bumiller is very conscientious about data quality, 

and was addressing two issues at the time of the discussions. First, he was having trouble with high 

zero readings for one of the DustTraks, apparently related to sensitivity to light. He had solved this 

problem by the next day by wrapping the sampler in aluminum foil. Second, he was having trouble 

with both the device used to record sample flow rate for the PM10 sampler used to calculate K 

factors, as well as the flow standard used to check this device. At his request, he had the auditor 

check the flow using the audit standard in order to confirm flow rates for the day in question. The 

measured flow was 18.25 lpm with no filter installed versus his last measured flow rate of 17.5 lpm 

with a filter installed, showing good agreement. 

Study Design Review 

In general, the study design appeared to be appropriate in order to meet study goals. The auditor’s 

one recommendation was to conduct longer north/south and east/west transects in order to better 

define the dimensions of the particulate matter plume. In this manner, transects would travel as far 

as necessary to demonstrate the edge of the high readings. Such transects were thought 

necessary in order to properly address the issue regarding the role that transport does or does not 

have on high concentrations in the Salt River area. 

Quality Control 

Separate from the quality assurance activities were procedures for the internal quality control of the 

measurements. Described below were the QC measures employed for each of the measurements 

made. 

At the outset of the monitoring program, the four DustTraks provided by ADEQ were all run to verify 

proper operation. The test was performed at the WF site with all samplers operated on top of the 

shelter with the sample heads all in close proximity. The results showed all samplers to be reporting 

concentrations within ±3 μg/m3

 of each other in ambient concentrations up to 137 μg/m3. Figure 

2-10 shows the test setup. The mounting of the digital camera and the sodar antenna can also be 

seen in the picture. 

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Figure 2-10. Checkout of ADEQ provided DustTrak samplers. 

To establish the link between the optical method for measuring PM10 (DustTrak) to the site method 

at the Maricopa County stations (TEOM) one DustTrak was allowed to operate for 45 hours with the 

DustTrak sampler inlet in close proximity to the TEOM inlet. The results of the comparison, shown 

in Figure 2-11, showed a “K-Factor” of about 1.7 that needed to be applied to the DustTrak 

measurements in order to provide “equivalent” measurements under the observed conditions. The 

results of the comparisons made from both the Pilot and Kia on December 1, 2006 at the DC and 

WF sites, respectively, showed K-Factors for PM10 of about 1.7 for the Pilot and 1.9 for the Kia. A 

comparison of the Pilot to DC PM2.5 values showed a K-factor of 0.71. A further comparison was 

made using the minivol data collected during the Pilot measurements which incorporated moving 

sampling. The correction factor derived from these measurements showed a K-Factor of about 1.6 

for the PM10 and 0.6 for the PM2.5. 

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WF TEOM vs. DustTrak

12/01/06 - 12/03/06

y = 1.68x

0

100

200

300

400

500

0 100 200 300 400 500

DustTrak (μg/m3

)

TEOM (

μg/m3

)

Figure 2-11. TEOM to DustTrak comparison at WF for a 45 hour comparison. 

On the basis of all of the data collected, the K-factors selected for the DustTrak measurements are 

shown below. The reason for the slightly different Kia PM10 factor was the noticeable difference in 

response that may have been due to a slight anomaly in the sample inlet. This anomaly also 

resulted in an apparent speed dependency of the Kia PM10 data that defined the use of the data only 

when the Kia speeds were less than about 4 m/s. 

Measurement K Factor

Pilot PM10 1.65 

Pilot PM2.5 0.70 

Kia PM10 1.90 

Kia PM2.5 0.70 

35th Site PM10 1.65 

Mobile Vans 

Optical PM10 using the DustTrak – Flow rates were measured at the beginning and end of each 

sample day, adjusted as necessary in accordance with the manufacturer’s instructions to obtain the 

1.7 lpm flow rate, and documented in the respective van’s log book. A zero filter was inserted in the 

sample line to obtain an instrument zero at the beginning and end of each sample day. Per the 

manufacturers instructions, adjustments were made to the zero if the resulting reading exceeded 

±2 μg/m3

. Results of the checks were documented in the van log books. 

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Optical PM2.5 using the DustTrak – Flow rates were measured at the beginning and end of each 

sample day, adjusted as necessary in accordance with the manufacturer’s instructions to obtain the 

1.7 lpm flow rate, and documented in the respective van’s log book. A zero filter was inserted in the 

sample line to obtain an instrument zero at the beginning and end of each sample day. Per the 

manufacturers instructions, adjustments were made to the zero if the resulting reading exceeded 

±2 μg/m3

. The impactor plate was cleaned and regreased at approximately four-sample day 

intervals. Results of the checks were documented in the van log books. 

Minivol PM10 and PM2.5 – The indicated flows on the minivol samplers used in the Pilot were 

calibrated at the onset of the program using a Gilibrator 2 automated bubble flow meter. These 

flows were checked at the start of each sample day using the internal flow meter in the minivol. 

Included with the exposed filters that were analyzed by Airmetrics were five unexposed filters 

shipped as blanks to establish the analytical accuracy of the total process from the initial through the 

final weighings. These filters were randomly selected from the pre-weighted filters and returned with 

the normal shipment of exposed media for routine analysis. 

Wind speed and direction – At the outset of the program, the response of the wind speed was 

verified using a RM Young selectable speed anemometer drive. The orientation of the wind 

direction sensor was oriented to true south when the vane was aimed in the forward direction of 

travel of the monitoring vehicle. This direction was corrected to 0° (true-north) in the data logger 

program and verified at the outset of the measurement program. Readings at 90° increments 

around the compass were also verified. 

Ambient temperature – A multipoint calibration of the thermistor was performed prior to the 

deployment to the field, and the measurements reviewed for reasonableness following installation. 

Electronic compass – The manufacturers recommendations for calibration of the flux gate compass 

(multiple slow 360° circles) were followed when the mounting array was installed on the top of the 

Pilot, and anytime that the array was moved or removed and reinstalled. Additionally, comparisons 

were made to the GPS vehicle heading during periods when the van was traveling in a constant 

direction. It should be noted that the data reported from the compass is in magnetic degrees. 

GPS position – The GPS position was verified in transit using a real-time mapping program 

(Microsoft Streets and Trips) to plot the position of the van. 

Digital camera pictures – The time of the computer on which images were stored was verified and 

set as necessary at the start of each sample day. This same computer time was used to date and 

time stamp the images from the Pilot (Van 1). 

Aerodynamic Particle Sizer (APS) – The computer polling the APS was verified to have the proper 

time stamp that is synchronized with the balance of the measurements. The displays of the flow 

rates reviewed to assure no fault conditions existed. 

35th Site Measurements 

Optical PM10 using the DustTrak – Measurements at this site were powered by high capacity solid 

gel batteries. The batteries were changed at approximately 5-day intervals. During the battery 

exchange the zero and flow was checked using the same procedures described for the mobile vans 

above. Battery voltage was monitored on the data logger as well as the temperature inside the 

monitoring shelter. 

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Wind speed and direction – Upon installation, the response of the wind speed was verified using a 

RM Young selectable speed anemometer drive. The orientation of the wind direction sensor was 

oriented to true south using the GPS walk-off method, and the response in the four cardinal 

directions verified. 

West 43rd Site Measurements 

Digital camera pictures – The time of the computer storing the images was verified at the outset of 

the program. As a real-time Internet connection was available through the CDMA modem, the clock 

for the time stamp on the images was set through the normal update process of the computer. 

MiniSodar wind measurements – At the outset of the program the ADEQ miniSodar system was 

reviewed for the proper orientation and level, and the setup for the recording of the data was verified 

to be optimum for the program goals. Throughout the course of the study, ADEQ provided data as it 

was downloaded, and the data was reviewed for reasonableness with the the surface meteorological 

measurements made by the Maricopa County wind system at the site. 

ASU Lidar – The lidar provided by ASU, under a separate contract with ADEQ, was installed at the 

WF site during the last week of the study. No QC checks by T&B Systems’ personnel were possible 

during the study period. 

2.6 Data Processing and Validation 

All data collected were reviewed in the field for reasonableness and proper instrument operation. 

Any issues discovered were immediately corrected. Following the field data collection program, all 

data were validated and final calibrations applied to the collected values. Described below are the 

processing and validation steps performed for each measurement type to generate the validated 

data set. 

Measurements from the Pilot (Van1) 

Optical PM10 using the DustTrak – Zero and flow check records were reviewed for anomalies and 

any needed corrections were made. The selected K-factor of 1.65 was applied to all measurement 

values. It should be noted that there were periods when values from the DustTrak were over range. 

These values will show up in the data set as greater than 1630 μg/m3

 and, it should be noted, 

represent values of at least that concentration. 

Optical PM2.5 using the DustTrak – Zero and flow check records were reviewed for anomalies and 

any needed corrections were made. The selected K-factor of 0.7 was applied to all measurement 

values. It should be noted that there were periods when values from the DustTrak were over range. 

These values will show up in the data set as greater than 693 μg/m3

 and, it should be noted, 

represent values of at least that concentration. 

Wind speed and direction – The values were reported with the caveat that corrections for vehicle 

speed will be needed to use the data in a moving mode. If fixed mode data is desired then a check 

should be performed to assure the vehicle is stopped for at least 30 seconds before the wind data is 

used. This allows the effect of vehicle wake to be removed from the reported values. 

Ambient temperature – Data were reviewed for reasonableness and reported as recorded. 

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Electronic compass – Data were reviewed for reasonableness and reported as recorded. 

GPS position – Data were reviewed for missing scans when the GPS lost lock and the position data 

filled in through interpolation. If more than four consecutive scans were missing then all data 

associated with the time of the missing scans were invalidated and removed from the data set. The 

resulting position data was plotted on a map of the region and the vehicle track was reviewed for 

reasonableness. Any obvious periods when the GPS reading appeared to wander off of roads were 

eliminated from the database. This included all associated data in the same time scans. There was 

only one period where this appeared to happen and the loss of data accounted for an interval of 

about 1 minute. 

Digital camera pictures – Data were reviewed for reasonableness and reported as recorded. 

Minivol PM10 – The filter before and after weighings were reviewed for reasonableness and internal 

consistency and compared with all filter values for filter-to-filter consistency. Average blank values 

were calculated and the average values subtracted from the net loading prior the calculation of 

concentration. The blank correction accounted for 1 to 9% of the filter loading (lightly loaded filters 

had a larger correction). The average correction for all PM10 filters was 4%. 

Minivol PM2.5 – As with the PM10 filters, the PM2.5 filter before and after weighings were reviewed for 

reasonableness and internal consistency and compared with all filter values for filter-to-filter 

consistency. Average blank values were calculated and the average values subtracted from the net 

loading prior the calculation of concentration. The blank correction accounted for 4 to 27% of the 

filter loading (lightly loaded filters had a larger correction). The average correction for all PM2.5 filters 

was 14%. 

Measurements from the Kia (Van2) 

Optical PM10 using the DustTrak – Zero and flow check records were reviewed for anomalies and 

any needed corrections were made. The selected K-factor of 1.9 was applied to all measurement 

values. It should be noted that there were periods when values from the DustTrak were over range. 

These values will show up in the data set as greater than 1880 μg/m3

 and represent values of at 

least that concentration. 

Optical PM2.5 using the DustTrak – Zero and flow check records were reviewed for anomalies and 

any needed corrections were made. The selected K-factor of 0.7 was applied to all measurement 

values. It should be noted that there were periods when values from the DustTrak were over range. 

These values will show up in the data set as greater than 693 μg/m3

 and represent values of at least 

that concentration. 

GPS position – Data were reviewed for missing scans when the GPS lost lock and the position data 

filled in through interpolation. If more than four scans were missing then all data associated with the 

time of the missing scans were invalidated and removed from the data set. The resulting position 

data was plotted on a map of the region and the vehicle track was reviewed for reasonableness. 

Any obvious periods when the GPS readings appeared to wander off of roads were then eliminated 

from the database. This included all associated data in the same time scans. 

TSI Aerodynamic Particle Sizer – Data collected from the APS were reported as-is. Periods when 

the vehicle was moving as well as when the vehicle was moving two minutes prior to the reported 1-

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minute average were flagged in the database. Particle sizing in the moving environment was not 

valid because the sample inlet could not be made isokinetic over the speeds driven by the sampling 

van. 

There were also special processing techniques used in the analysis of the data whereby average 

concentrations along a transect were calculated. The averages were formed by parsing the 

validated two-second values during an hour period into distance bins along the axis of the traverse. 

All values in the bins were averaged for the entire hour period thus forming hourly average data 

points along the traverse. 

Measurements from the 35th Site 

Optical PM10 using the DustTrak – Zero and flow check records were reviewed for anomalies and 

any needed corrections were made. The selected K-factor of 1.65 was applied to all measurement 

values. 

Wind speed and wind direction – Data were reported as collected. 

3. FIELD OBSERVATIONS 

The measurements made during the two phases of the study are described below. The overall 

summary of intensive measurement periods is presented, along with evaluations and observations 

from key periods of sampling. 

3.1 Summary of Intensive Measurement Periods 

Phase 1 of the sampling program had data collection during Intensive Operational Periods (IOPs) 

from November 15 through November 19. A summary of each day’s sampling activities and 

significant observations from the sampling is provided in Table 3-1. The Phase 2 sampling had 

IOPs from November 30 through December 14. A summary of the daily sampling activities and 

significant observations is provided in Table 3-2. 

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Table 3-1. Summary of Phase 1 sampling activities using the Pilot 

Date 

Sample 

Times Sampling Goal Significant Observations 

11/15 0406 - 1031 Initial sample run to map the study 

area and obtain an initial 

assessment for where the “hot 

spots” were located and how they 

related to the WF and DC sites. 

The sample run started east of the Salt River 

area with some elevated concentrations, but the 

observed values were greatest in the region 

bounded by Southern on the south, Buckeye on 

the north, and Central on the east and 67th

Avenue on the west. The region in the vicinity 

of DC had significant concentrations that were 

not regional, but focused in the vicinity of the 

site, indicating a local source The regions along 

35th Avenue and 19th Avenue had significantly 

higher concentrations from dust that was 

dragged out onto the road and reentrained by 

the traffic. Winds were light during the sampling 

period 

11/16 0359 - 1054 Document area to the north as a 

potential source or region of PM 

that could be transported into the 

Salt River Basin. 

Lots of regional haze observed in the Salt River 

area, even along roads that did not have much 

in the way of traffic. Moderate concentrations of 

PM were also observed on some of the roads 

with little traffic. When the transfer station along 

Lower Buckeye opened, there was visible 

dragout of dust from the facility. This was 

deposited on the roadway and stirred up by the 

traffic passing by. This type of occurrence was 

a common sight at any of the major facilities 

where trucks were exiting a facility that was 

either unpaved or was paved, but had a layer of 

dirt or dust on top of the pavement. Between 

0700 and 0800 the Salt River area appeared 

stagnant with regional haze in all directions. 

Values along Van Buren appeared to mark a 

northern extent of the regional plume. 

Confirmation loops were made to verify 

measurements along the main streets were 

representative of the region. A final crossing 

down by the river verified higher concentrations 

in the region prior to the entire layer lifting and 

mixing out of the Salt River Basin region. 

11/17 0401 - 1016 Document the area around 

Durango Complex 

Noted the haze around the facilities along 19th 

as well as trucks exiting the transfer station 

along Lower Buckeye “dragging” a plume out to 

the street. Noted the truck yard across from the 

DC site as a potential source of dust. Regions 

along 27th were observed with values in excess 

of 1,600 μg/m3

. Significant dust was also along 

35th Avenue. The region started clearing around 

0850 with local flags showing air movement. 

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Table 3-1 (cont.) 

Date 

Sample 

Times Sampling Goal Significant Observations 

11/18 0404 - 1011 Duplicate the run made on 11/17 to 

get a better feel where the sources 

are that affect the Durango 

Complex site. 

From 0400 to 0445 the winds appeared to be 

light and from the northwest becoming calm 

around 0445. High values noted adjacent to the 

truck yard, across from the DC site. East winds 

were noted after 0500 with significant dust in the 

truck yard and increasing truck activity by 0546. 

At 0632 a distant look at the truck yard showed 

the dust reaching no higher than 100 feet. 

Overall traffic was much lighter, as this was a 

Saturday. By 0822 the overall region appeared 

to clear out with mixing and winds increasing. 

At 0915 values over 1600 were noted while 

passing the truck lot across from the DC site. 

There was significant movement of trucks in the 

yard with what appeared to be a truck school. 

11/19 0400 - 0848 Document the levels around 

Durango Complex on a day with 

less traffic (Sunday). 

Started with a loop by the facilities on 19th

Avenue. No activity was noted, but the center 

median had a significant accumulation of dirt. 

The PM2.5 fraction of the total PM10 appeared 

much higher on this day. By 0454 there was 

significant dust noted throughout the truck yard 

adjacent to DC, with the dust rising only about 

50 feet above ground level. Because of the lack 

of activity in other areas, the plume from the 

truck yard was tracked and noted down on 

Lower Buckeye around 0515. By 656 it 

appeared that the general haze over the area 

surveyed seemed to be coming from the truck 

yard. A north/south traverse profile was 

performed which revealed temperature 

inversions. PM2.5 was higher north of the river 

and lower to the south. The plume from the 

truck yard adjacent to DC traced during an east 

wind within the 0800 hour along Lower Buckeye 

and to the west to 51st Avenue. This was a 

distance of about 1.5 miles. It appears that 

much of the PM was in the 2.5 size range by 

this distance. PM10 was several hundred μg/m3

and PM2.5, about 100 μg/m3

. Traveling back by 

WF the facility across from the site to the south 

was open with equipment operational and the 

site active. 

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Table 3-2. Summary of Phase 2 sampling activities using both the Pilot and the Kia. 

Date 

Sample 

Times Sampling Goal Significant Observations 

11/30 Pilot 

0432 – 0941 

Kia 

0421 – 1026 

A sampling pattern was run with 

both of the vans to the east of the 

Salt River basin in an attempt to 

view PM that may be transported 

into the WF and DC regions from 

the east. The intent was to confirm 

or deny transport into the region 

within the drainage flow, which was 

thought to flow from the east to the 

west. 

The primary traverses were north/south along 

24th Street, 16th Street, 7th Street, Central 

Avenue, 7th Avenue, 19th Avenue and 35th

Avenue. The streets were divided between both 

vans with both driving one common street for 

QC comparison purposes. The traverses 

performed in the eastern most regions did not 

show any appreciable transport of PM through 

the low terrain along the Salt River. 

Areas of highest concentration were along 

Southern Avenue in the vicinity of new roads 

where the shoulder was being used by 

commuters to obtain access to a more efficient 

right turns. There were a couple of hours during 

the commute time when the traffic backed up 

and commuters, out of frustration, used the 

unpaved shoulders for travel, creating the 

problem. 

A visit to the WF site revealed a wood burning 

smell combined with a diesel odor around 0700. 

Later that morning it was noted that a forklift 

was moving wooden utility poles around the yard 

to the west of the WF site and placing them in a 

large metal pit where they were burned. 

Elevated PM10 readings in excess of 400 μg/m3

on the station TEOM were noted with light winds 

from the west. This wood burning pit was about 

20 meters from the WF monitor and blowing 

right toward the site. 

12/01 Pilot 

0418 - 1256 

Kia 

0409 - 1314 

This day was intended to obtain 

QC data by parking the Kia at WF 

and Pilot at DC and obtaining van 

data coincident with the respective 

monitoring stations. 

12/02 Pilot 

0349 - 1022 

Kia 

0355 - 1100 

Run a north/south traverse on 51st

Avenue between Southern and 

Buckeye with the Pilot and 

east/west with the Kia going across 

51st in the region Broadway and 

Williams. The goal was to observe 

any decrease in PM10 from 51st

Avenue as the distance increased. 

Both vehicles were able to perform about 12 

passes each hour (6 in each direction). 

Observed values were elevated but no 

significant gradients were observed. 

A-23
Table 3-2. (cont.) 

Date 

Sample 

Times Sampling Goal Significant Observations 

12/04 Pilot 

0347 - 1005 

Kia 

0359 - 1015 

Perform the same test as 12/02, 

but now with the TSI Aerodynamic 

Particle Sizer (APS) installed in the 

Kia. Using the APS required 

sampling to be performed at fixed 

locations away from 51st Avenue. 

The Pilot followed the 

SCAMPER #1 route to obtain 

parallel data. 

Conditions were quite clear with little regional 

haze, allowing a more isolated and successful 

evaluation of the gradient. A light easterly wind 

during period did show decreasing levels when 

moving away from 51st Avenue. 

12/05 Pilot 

0347 - 1041 

Kia 

0434 - 1055 

Traverse Lower Buckeye between 

27th Avenue and 51st Avenue with 

the Pilot and perform north/south 

gradient traverses with the Kia on 

29th. 

Regional haze was heavy and numerous local 

facilities added many local sources. This made 

any north/south gradients from Lower Buckeye 

disappear into the local sources. A pickup truck 

was observed stirring great quantities of dust in 

a private yard and the dust drifted across the 

roadway. The truck was moving less than 10 

mph. Additionally, an agricultural field east of 

51st Avenue was being plowed, with the activity 

starting before daybreak. This created large 

quantities of dust that drifted for long distances. 

This may have impacted the 35th site monitor as 

well as the WF monitor. Pictures were taken of 

the plowing. When returning to WF, significant 

black smoke from the yard to the west WF was 

noted with the plume rising about 75 to 100 feet 

and then fanning out. This plume was from the 

burning of old utility poles. 

12/06 Pilot 

0347 - 1012 

Kia 

0359 - 0957 

Follow the SCAMPER on the #3 

route with the Pilot. Use the Kia to 

map out key locations with the TSI 

APS. 

Burning started in the yard adjacent to WF site 

and was seen during several of the passes of 

the Pilot along Broadway. The Kia mapped the 

location along Broadway and conducted 

sampling for particle size distribution at this 

location, and two additional downwind locations. 

The plume was followed out a little over 1km 

and was sensibly tagged by the smoke smell. 

Particle sizing was performed at about 0.15 km, 

0.95 km and 1.1 km from the source location. 

Additional measurements were made with the 

APS at fixed sites around the loop. Particle 

sizing was performed downwind of agricultural 

operations (seeding or similar operation) to look 

at the signature of a rather “pure” dust plume, 

without much automobile exhaust. The region 

around DC was explored and the Kia then 

returned to the WF site. Upon return a 

significant black plume was noted in the 

adjacent yard. Pictures were taken and the onsite digital camera turned in the direction of the 

yard. 

A-24
Table 3-2. (cont.) 

Date 

Sample 

Times Sampling Goal Significant Observations 

12/07 Pilot 

0345 - 1008 

Kia 

0404 - 1042 

Follow the SCAMPER on the #4 

route with the Pilot. Use the Kia to 

map the area around the truck yard 

adjacent to the DC site for particle 

size distribution 

The activity at the truck yard was less than last 

observed. There were about 4 or 5 active trucks 

at a time, with fewer trucks in the yard than the 

last observation. It is estimated that there were 

about 100 to 150 trailers and maybe 25 to 35 

tractors for pulling them. It appeared they were 

getting ready for a truck school. Levels 

throughout the region were high. The Pilot 

observed another agricultural field being worked 

with significant dust plumes picked up on the 

camera. Particle sizing was performed around 

the truck yard with noticeable differences 

observed between the areas along 27th and 22nd

Avenues. Around 0645 the Kia parked for a 

short time at the DC site for parallel 

measurements. At the conclusion of the run the 

Kia parked for a time by the 35th site for parallel 

measurements. The MAG video crew was out 

taking pictures of the activities and observing 

the operations. Audits of the two vans were 

performed following the activities at the WF site. 

Overall levels were quite high with an apparent 

“carry over” from the prior day. This carry over 

likely contributed to the observed levels. 

12/08 Pilot 

0343 - 0922 

Kia 

0400 - 0914 

The Pilot was parked outside the 

entrance to aggregate operations 

along 19th Avenue to measure the 

upwind or downwind contribution. 

The Kia was used to try and map 

the river areas for a tag of the 

plumes that may be moving 

through. 

Overall, the day was reasonably clean. No 

drainage flow along the river established, but the 

flow was from the east. The flow was more 

synoptic than local drainage. For the sampling 

time, the Pilot was upwind of the aggregate 

plant with near background levels observed for 

most, if not all, of the sampling period. 

Measurements from the Kia were conducted 

downwind of another facility off of 7th Ave. 

During the time the plume moved back and forth 

across the sampler and particle sizing was 

conducted. A QA audit was conducted on the 

35th site with no issues found. Tests were 

performed on the dirt road leading to the site to 

determine if the sampling drew in dust from the 

road while traveling. This was also repeated on 

the paved road. No issues were found. Only 

the dragging of the plume was seen when the 

vehicle initially stopped. It should be noted that 

there were extensive dust control activities in 

and around the aggregate facility on 19th

Avenue, including street sweeping that clearly 

demonstrated that they have the ability to control 

the dust problem. 

A-25
Table 3-2. (cont.) 

Date 

Sample 

Times Sampling Goal Significant Observations 

12/12 Pilot 

0343 - 1027 

Kia 

0406 - 1028 

Document the north/south 

and east/west extent of the 

PM plume in the Salt River 

region. 

The Pilot went north/south and Kia east/west. The 

highest PM10 concentrations were around Lower 

Buckeye and 51st with the east/west extent going out 

just past 99th Avenue on the west and to 7th Avene on 

the east. The highest 2.5/10 ratios were in the 

northwest, confirming the prior runs in the area. The 

north/south PM10 extent went from about Baseline in 

the south to just north of McDowell in the north, but with 

some sporadic values seen both in the extreme north 

and south from potential other local sources. Following 

the runs a survey was performed along the east side of 

51st Avenue looking north at the one facility. Here there 

were several “drag-outs” documented and some bow 

wake observations. As a matter of interest, the 35th site 

did not show high concentrations. Conversely, the WF 

site did show them during the 6 – 8 AM time frame. A 

review of the site pictures aimed to the west showed a 

fire started before sunrise (in the dark), with smoke 

observed as the area became light. It is suspected the 

high values at the site were from the adjacent source. 

12/13 Pilot 

0356 - 0908 

Kia 

0359 - 0910 

Document the area along 

51st Ave where dirt 

shoulders pose a problem. 

Document the “drag-out” of 

dust to the roadway and the 

bow wake of large trucks 

Data were collected using both vehicles along 51st

Avenue near West Miami Street. This area has a 

narrow paved shoulder (about 1 to 2 feet) with very 

dusty shoulders on the east side. The west side is 

clean with the FedEx facility having extensive paving 

and landscaping that prevents dust generation. This 

stretch of road has both drag-out and bow wake effects 

from the trucks when they are moving at sufficient 

speed and/or are near the unpaved area. Vortices are 

formed that look like little dust tornadoes when the 

trucks pass. Both sampling vehicles were near the exit 

streets that were all unpaved. Just before sunrise a 

water truck did water both streets, but the one watering 

was obviously not enough to control the dust. Other 

areas were explored for dust concentrations (transfer 

station, DC, aggregate facilities), but no unusually high 

values or visible plumes were noted, so sampling was 

only performed along 51st Avenue. It appears from the 

morning observations that only the trucks and larger 

passenger vehicles were capable of generating bow 

wake, and the passenger vehicles needed to be within 

a couple feet of the dirt shoulder to do so. Not all 

trucks created the bow wake and it really depended on 

the frontal surface area and speed. Any kind of vehicle 

can generate drag-out. Once material is on the road 

then any vehicle can stir it up and keep it airborne. In 

addition to the dust, a smoke plume from one of the 

yards east of 51st was producing significant smoke from 

about 4:30 to 5:00. Winds after this time carried the 

plume away from the road. 

A-26
Table 3-2. (cont.) 

Date 

Sample 

Times Sampling Goal Significant Observations 

12/14 Pilot 

0344 - 0913 

Kia 

0359 - 0922 

Document the extent of the higher 

PM concentrations to the east, 

north and west of the Salt River 

region. 

Documented to the north and east with the 

boundaries similar to the prior mapping. 

Profiled to the west including some sizing of the 

particulate matter around the regions of 

feedlots. During the peak periods the area 

outside of the aggregate facility along 19th

Avenue, the adjacent metal recycling plant and 

the nearby cement facility were monitored with 

high readings observed. On this morning it was 

clear that the monitoring outside of the facilities 

was not expected, as there were a number of 

dust producing activities. Pictures were taken 

along Southern, west of 51st Avenue at some of 

the exit points from active areas. Trackout was 

observed and the influence of vehicles driving 

through and creating plumes was documented 

with pictures. The lack of paved shoulders was 

clearly a contributor to the reentrainment of dust.

4. RECOMMENDATIONS 

On the basis of the measurements made and the observations of the activities and related impacts 

during the program, we have the following recommendations for follow up on the program: 

• A number of observations were made during the field study and presented at workshops 

regarding specific issues in open burning, unpaved roads and trackout. It is recommended 

that a verification be performed on the actions taken with mobile measurements to confirm 

potential reductions. This may be related to the 5% plan to estimate the amount of 

reductions from specific source types. 

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