REVIEW OF 

ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY’S 

TECHNICAL SUPPORT DOCUMENT 

FOR THE DEPARTMENT’S 

PROPOSED BOUNDARY RECOMMENDATION 

FOR THE 2008 REVISION OF THE NAAQS FOR LEAD 

Prepared for: 

ASARCO LLC 

5285 EAST WILLIAMS CIRCLE, SUITE 2000 

TUCSON, ARIZONA 85711-7711 

Prepared By: 

ZEPHYR ENVIRONMENTAL CORPORATION

10420 LITTLE PATUXENT PARKWAY, SUITE 320 

COLUMBIA, MARYLAND 21044 

NOVEMBER 10, 2009 
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CONTENTS 

EXECUTIVE SUMMARY .............................................................................................................. 3

1.0 BACKGROUND ................................................................................................................... 5

2.0 ISSUES IDENTIFIED ........................................................................................................... 7

2.1 EXCEPTIONAL EVENTS ................................................................................................. 7

2.1.1 Dates Deemed to Have Exceptional Wind Speeds ...................................... 10

2.1.2 Impact of Removing Exceptional Events ...................................................... 12

2.2 SUITABILITY OF MONITOR LOCATION .......................................................................... 13

2.3 QUALITY ASSURANCE ................................................................................................ 15

2.4 DATA COMPLETENESS (VALIDATION OF THREE-MONTH MEANS) .................................. 16

2.5 UNCERTAINTY REGARDING DESIGN VALUE ................................................................. 21
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APPENDICES 

Appendix A Hayden Air Quality Monitoring Results, Received from EPA on September 23, 

2009 

 
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EXECUTIVE SUMMARY

In a September 28, 2009 document entitled “Arizona Air Quality Designations Technical Support 

Document Boundary Recommendation for the 2008 Revision to the National Ambient Air Quality 

Standard for Lead” (TSD), the Arizona Department of Environmental Quality (ADEQ) made a 

proposal that the Governor should recommend to the U.S. Environmental Protection Agency 

(EPA) that portions of Gila and Pinal Counties (hereinafter the Hayden area) be designated as 

being in nonattainment of the National Ambient Air Quality Standard (NAAQS) for lead. The 

ADEQ’s proposal is based on air monitoring data collected in the Hayden area as part of a 

remedial investigation in a CERCLA proceeding between the EPA, ADEQ and ASARCO LLC 

(Asarco). 

Asarco retained Zephyr Environmental Corporation (Zephyr) to review the TSD underlying the 

ADEQ’s proposal. 

 

Zephyr’s review identified the following issues: 

• Some of the monitored lead values relied upon in the TSD are associated with 

“exceptional events” under 40 CFR Part 50 and ADEQ guidance and should therefore 

not be counted toward determining whether the Hayden area is in nonattainment of the 

NAAQS for lead. When these “exceptional events” values are excluded there are no 

monitored values above the NAAQS. 

• The Hayden monitor is located on top of the Town of Hayden maintenance building. 

Given the soldering/welding activities and vehicle traffic that take place at the 

maintenance yard, the potential exists for contamination of the samples obtained using 

the monitor. 

• The Quality Assurance (QA) plan governing the Hayden monitor and the results of the 

various tests and calibrations required under the quality assurance rules governing 

ambient air monitors were not available at the time of Zephyr’s review. As of the date of 

the TSD, the ADEQ had not reviewed information on the required quality assurance 

checks of the Hayden monitor, and it remains uncertain whether such checks occurred. 

This calls into question the validity of the data generated using the monitor. 

• In support of the ADEQ’s proposal, the TSD (at Table 4-1) compares 3-month means to 

the NAAQS. However, the TSD does not demonstrate the ADEQ validated the 3-month 

means according to 40 CFR Part 50, Appendix R Section 4(c) procedures. If these 

procedures were followed, it would be found that all the 3-month means above the lead 

NAAQS do not meet the specific 75% data completeness requirement. 

• The Design Value (i.e., the single mean concentration that is required under the rules to 

be compared to the NAAQS to demonstrate attainment or nonattainment) was not 

clearly identified or adequately discussed in the TSD. 

Based on these findings, the proposed nonattainment designation for the Hayden area is 

unwarranted. In order to make a defensible proposal of a nonattainment designation, more 

representative, quality controlled and quality assured data are needed, and the data need to be 
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evaluated properly under the rules at 40 CFR Part 50, Appendix R and ADEQ guidance, 

including the effect of exceptional events and data validation. 

 
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1.0 BACKGROUND

ASARCO LLC (Asarco) conducts beneficiation and smelting of copper ores at its Ray ComplexHayden Operations in Hayden, Arizona, approximately 80 miles east-southeast of Phoenix and 

60 miles north of Tucson. In April 2008 a CERCLA Administrative Settlement Agreement and 

Order on Consent (Settlement Agreement) was entered into by the U.S. Environmental 

Protection Agency (EPA), the Arizona Department of Environmental Quality (ADEQ) and 

Asarco. One of the stipulations of the Settlement Agreement was that Asarco conduct a 

Remedial Investigation/Feasibility Study (RI/FS), which among other things called for the 

continuation of air quality monitoring that the EPA had already begun in the Hayden area. That 

monitoring addressed several air pollutants, one of which was lead. 

On November 12, 2008 the EPA revised the National Ambient Air Quality Standard (NAAQS) for 

lead.1

 The revised NAAQS was established at 0.15 μg/m3 on a rolling three-month averaging 

period. 

On September 28, 2009 the ADEQ completed a Technical Support Document2

 (TSD) in which it 

proposed that the Governor recommend to the EPA a designation of portions of Gila and Pinal 

Counties as being in nonattainment of the revised NAAQS for lead. The proposed 

nonattainment area is presented in Figure 1-1. 

Asarco retained Zephyr Environmental Corporation (Zephyr) to review the ADEQ’s proposal. In 

its review, Zephyr evaluated both the technical and the regulatory merits of the ADEQ’s 

proposal. 

This report documents Zephyr’s findings. 

 

1

 73 Fed. Reg. 66964. 

2

 “Arizona Air Quality Designations Technical Support Document Boundary Recommendation for the 2008 

Revision to the National Ambient Air Quality Standard for Lead,” Air Quality Division, ADEQ. 
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Figure 1-1 

ADEQ Proposed Lead Nonattainment Area for Hayden, Arizona 

(taken from ADEQ’s TSD)
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2.0 ISSUES IDENTIFIED 

Zephyr identified several issues which, to varying degrees, call into question the ADEQ’s 

proposal of the Hayden area as nonattainment for lead. These issues are elaborated upon 

below. 

2.1 EXCEPTIONAL EVENTS

40 CFR Part 50 defines an exceptional event as “an event that affects air quality, is not 

reasonably controllable or preventable, is an event caused by human activity that is unlikely to 

recur at a particular location or a natural event...” 40 CFR 50.14(c)(3)(iv) presents the criteria 

that must be met for an event to be deemed exceptional under this rule: 

• The exceptional event is a cause of the monitored value, 

• The event in question is beyond normal historical fluctuations, and 

• There would not have been an exceedance of the NAAQS without this event. 

Should a monitored value be excluded for being associated with an exceptional event, 40 CFR 

50.14(b) stipulates that those excluded data are not to be included in a determination of an 

exceedance of a NAAQS. 

On October 15, 2009, the ADEQ issued a 

report entitled “The Impact of Exceptional 

Events ‘Unusual Winds’ on PM10

Concentrations in Arizona”3

 that provides 

guidance as to how to determine what 

constitutes an exceptional event in terms of 

winds. The report considered historical 

environmental and meteorological data, 

including data from Hayden. One of the 

conclusions of the report was as follows: 

For exceptional events purposes, “unusual winds” can be defined as any wind that has 

the ability to create wind blown dust. Literature and data from monitors indicate that the 

phenomenon of blowing dust can occur over a broad range, but generally is associated 

with hourly averaged wind speeds that are above 10 miles per hour, which are 

commonly associated with wind gusts over 20 miles per hour. 

As a first step Zephyr reviewed both lead concentrations and wind speeds for the entire year of 

2008 to identify any potential relationship between the two. As shown in Figure 2-1, there 

clearly is a correlation between three-month average lead concentrations observed at the 

 

3

 “The Impact of Exceptional Events ‘Unusual Winds’ on PM10 Concentrations in Arizona”, ADEQ Air 

Quality Division (October 15, 2009). 

Recent ADEQ guidance supports the

determination that three days in late

2008 are “exceptional events.”  When

they are removed, the revised Design

Concentration is below the NAAQS.
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Hayden monitor and three-month average wind speeds observed at the same monitor. Both the 

three-month average lead concentrations and wind speeds are at their lowest in the spring, then 

attain an intermediate maximum in June, and then reach their greatest values in the late fall. 

Figure 2-1 

Average Lead Concentrations and Wind Speed Observed at Hayden Monitor, 2008

A single short-term (e.g., an hour) concentration at a monitor that is extraordinarily high can lead 

to a high 24-hr concentration (even with the rest of the 24-hr period having fairly low impacts). 

This is illustrated, by way of example, by the data in Figure 2-2, taken from a continuous PM10

monitor located at the University of Texas at El Paso (EPA ID # 481410037). 

0.000

0.050

0.100

0.150

0.200

Pb Concentration (ug/m3)

Rolling 3‐Month Lead Averages

Hayden Monitor, 2008

4.0

4.5

5.0

5.5

6.0

Wind Speed (mph)

Rolling 3‐Month Average Wspd

Hayden Monitor, 2008
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Figure 2-2 

Example of One Hour of Elevated Concentration Leading to High 24-hr Concentration

As shown in the figure above, the vast majority of the hourly PM10 concentrations on this day 

are below the 24-hr NAAQS of 150 μg/m3

. However, the overall daily average is radically 

affected by several very high individual hourly monitored values (although not indicated on this 

plot, the high concentrations were associated with winds in excess of 10 mph), ultimately 

leading to a 24-hr concentration greater than the NAAQS. 

Therefore, a day that has a single hourly average wind speed of 10 mph or greater is a 

candidate for being an exceptional event (note that this discussion focuses on average winds, 

not a wind gust which would be higher than the hourly average) in the context of 40 CFR 

50.14(c)(3)(iv). However, for the sake of conservatism Zephyr decided to focus only on days 

with more than one hour of average wind speeds greater than 10 mph. 

An examination of the meteorological data gathered at Hayden during the months of July 

through November, inclusive, in 2008 (the months whose data are associated with all calculated 

lead NAAQS exceedances as presented in the TSD) revealed that only three days had more 

than one average hourly wind speed greater than 10 mph. Details on these days are presented 

below (note that the plots show both average hourly winds as well as average 30-minute winds). 

 
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2.1.1 Dates Deemed to Have Exceptional Wind Speeds 

2.1.1.1 August 5, 2008 

On August 5, 2008 there were two hourly average wind speeds at 

the Hayden monitor in excess of 10 mph. These two wind 

speeds occurred at 7:00 PM and 8:00 PM (with the 6:00 PM wind 

speed being 9.6 mph). Therefore, this day experienced a 

concentrated period of exceptionally high winds in the evening. 

More information concerning the winds of that day is presented in 

the table to the right. 

Figure 2-3 

Hayden Monitor Average 30-Minute and Hourly Wind Speeds 

August 5, 2008

 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

1:00 AM2:00 AM3:00 AM4:00 AM5:00 AM6:00 AM7:00 AM8:00 AM9:00 AM

10:00 AM11:00 AM

12:00 PM

1:00 PM2:00 PM3:00 PM4:00 PM5:00 PM6:00 PM7:00 PM8:00 PM9:00 PM

10:00 PM11:00 PM

12:00 AM

Wind Speed (mph)

Wind Speed, Hayden, Arizona

August 5, 2008

30‐min Wspd

Hrly Wspd

August 5, 2008 Wind Speed 

Information 

Maximum 30-min 

Wind Speed 

18.6 mph 

Maximum Hourly 

Wind Speed 

16.1 mph 
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2.1.1.2 September 30, 2008 

On September 30, 2008 there were five hourly average wind 

speeds at the Hayden monitor in excess of 10 mph. These five 

wind speeds occurred between 6:00 AM and 11:00 AM, with the 

8:00 AM wind speed being just below 10 mph. Therefore, this 

day experienced a concentrated period of exceptionally high 

winds in the morning. More information concerning the winds of 

that day is presented in the table to the right. 

Figure 2-4 

Hayden Monitor Average 30-Minute and Hourly Wind Speeds 

September 30, 2008

2.1.1.3 October 22, 2008 

On October 22, 2008 there were ten hourly average wind speeds 

at the Hayden monitor in excess of 10 mph. Eight of these wind 

speeds occurred between 10:00 AM and 5:00 PM (note the 9:00 

AM wind speed was 9.9 mph), with the other two occurring at 

11:00 PM and midnight. Therefore, this day experienced a 

concentrated period of exceptionally high winds throughout a 

substantial portion of the day. More information concerning the 

winds of that day is presented in the table to the right. 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

1:00 AM2:00 AM3:00 AM4:00 AM5:00 AM6:00 AM7:00 AM8:00 AM9:00 AM

10:00 AM11:00 AM

12:00 PM

1:00 PM2:00 PM3:00 PM4:00 PM5:00 PM6:00 PM7:00 PM8:00 PM9:00 PM

10:00 PM11:00 PM

12:00 AM

Wind Speed (mph)

Wind Speed, Hayden, Arizona

September 30, 2008

30‐min Wspd

Hrly Wspd

September 30, 2008 Wind 

Speed Information 

Maximum 30-min 

Wind Speed 

12.9 mph 

Maximum Hourly 

Wind Speed 

12.3 mph 

October 22, 2008 Wind Speed 

Information 

Maximum 30-min 

Wind Speed 

18.5 mph 

Maximum Hourly 

Wind Speed 

18.1 mph 
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Figure 2-5 

Hayden Monitor Average 30-Minute and Hourly Wind Speeds 

October 22, 2008

2.1.2 Impact of Removing Exceptional Events 

As mentioned above, 40 CFR 50.14(b) states that if a monitored value is deemed to be caused 

by an exceptional event that that value is not to be included in the determination of an 

exceedance of the NAAQS. Accordingly, the three NAAQS exceedances identified in Table 4-1 

of the ADEQ’s TSD were recalculated without the inclusion of data from the three days identified 

above. The revised results are presented below. 

 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

1:00 AM2:00 AM3:00 AM4:00 AM5:00 AM6:00 AM7:00 AM8:00 AM9:00 AM

10:00 AM11:00 AM

12:00 PM

1:00 PM2:00 PM3:00 PM4:00 PM5:00 PM6:00 PM7:00 PM8:00 PM9:00 PM

10:00 PM11:00 PM

12:00 AM

Wind Speed (mph)

Wind Speed, Hayden, Arizona

October 22, 2008

30‐min Wspd

Hrly Wspd
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Table 2-1 Three-Month Rolling Average Lead Concentrations During Late 2008 

Period 

Three-Month Rolling Average Lead Concentration (μg/m3

) 

Originala Revisedb

July-September 2008 0.172 0.096 

August-October 2008 0.184 0.079 

September-November 2008 0.152 0.047 

a) Calculated with data as presented in TSD. 

b) Calculated with data as presented in TSD, with the exception of data for August 5, 

September 30, and October 22 being removed. 

As shown in the table above, the exclusion of data from these three days—days that according 

to ADEQ guidance have exceptional wind speeds—results in no lead concentrations greater 

than the NAAQS. 

2.2 SUITABILITY OF MONITOR LOCATION

The Hayden monitor has been placed on the roof of the maintenance building at the Town of 

Hayden maintenance yard. The location of the maintenance yard is given in Figure 2-6, while 

Figure 2-7 shows the placement of the monitor on the roof. 

Figure 2-6 

Location of Hayden Maintenance Yard
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Figure 2-7 

View of Monitor on Roof of Town of Hayden Maintenance Building 

(looking to the southeast)

Asarco spoke with Bob Larona, the Town of Hayden General Superintendent, to ascertain 

whether there are any activities that take place at the maintenance yard that could affect 

monitored lead concentrations at the roof of the maintenance building. Based on the 

conversation there are activities conducted at the yard that could affect lead concentrations at 

the roof. Those activities include soldering/welding (which could produce lead emissions) and 

vehicular traffic (which could disturb particulates on the ground in and around the maintenance 

building, leading to increased amounts of lead in the sampler). These activities occur 

throughout the week, not just for isolated periods. 

Given the activities at the maintenance yard and the frequency of those activities, the potential 

exists for lead concentrations to be monitored at elevated levels that are not representative of 

the overall area or an appropriately sited source-oriented monitor. If the goal of the Hayden 

monitor is to support a designation, then an alternative location should be considered.
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2.3 QUALITY ASSURANCE

40 CFR Part 58 Appendix A establishes quality assurance (QA) requirements for air monitoring 

data collected for State and Local Air Monitoring Stations (SLAMS) network, Special Purpose 

Monitoring (SPM), or for purposes of Prevention of 

Significant Deterioration (PSD) permitting. While the 

Hayden monitor apparently was not established under 

any of these programs—it was established pursuant to 

a remedial investigation in a CERCLA proceeding—

the data gathered at the Hayden monitor must 

nonetheless meet the QA requirements of 40 CFR 58 

Appendix A if they are to be used to define a 

nonattainment area. 

The QA requirements specified by 40 CFR 58 

Appendix A are presented in Table 2-2. 

Table 2-2 QA Requirements of 40 CFR 58 Appendix A 

QA Requirement Citation Description 

Quality System Requirements 40 CFR 58, Appendix A 

Section 2 

Prescribes a means to manage 

quality of monitoring 

information; includes Quality 

Management Plan and Quality 

Assurance Project Plan 

Measurement Quality Check 

Requirements 

40 CFR 58, Appendix A 

Section 3 

Prescribes requirements for 

performing measurement quality 

checks to assess data quality; 

includes quarterly audits of 

sampling system 

Calculations for Data Quality 

Assessments 

40 CFR 58, Appendix A 

Section 4 

Prescribes calculations for 

assessing data quality; includes 

precision estimate, bias 

estimate, and flow rate 

calculation 

Reporting Requirements 40 CFR 58, Appendix A 

Section 5 

Prescribes reporting 

requirements for SLAMS and 

PSD monitoring 

Appendix D of the TSD is labeled “ADEQ Memo Certifying Air Quality Data for the Hayden 

Area” and contains an internal ADEQ memo prepared on August 13, 2009 from Jon Midgley to 

ADEQ has not reviewed the

QA procedures/information

for the data it used to

propose a nonattainment

designation for lead
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Ira Domsky. That memo states that “(i)nformation about quality assurance checks performed on 

the samplers is not available at this time.”4

Zephyr, accordingly, has not been able to review the QA procedures applicable and QA 

information required to be generated for the Hayden monitor under 40 CFR Part 58 Appendix A. 

Without the procedures/information, Zephyr cannot determine whether the data meet the QA 

requirements, and neither can the ADEQ. The ADEQ should review the procedures and 

information required under 40 CFR Part 58 Appendix A for the monitor, before it makes a 

proposal to designate an area nonattainment based on data from the monitor. 

2.4 DATA COMPLETENESS (VALIDATION OF THREE-MONTH MEANS) 

Section 4.1 of the TSD briefly discusses the three consecutive three-month means that are 

greater than the lead NAAQS. The sampling dataset on which the three-month means 

assessment is based spans data collected at the Hayden monitor from November 2007 through 

November 2008. Table 2-3 gives the three-month means of interest. 

Table 2-3 Three-month Means (Lead) Given in Table 4-1 of ADEQ Technical Support 

Document 

3-month Period 3-month Mean (μg/m3

) 

July, August, September 2008 0.172 

August, September, October 2008 0.184 

September, October, November 2008 0.152 

According to 40 CFR 50, Appendix R Section 1(c), the design value upon which lead NAAQS 

compliance is based is selected, according to procedures specified in Appendix R, from among 

the valid three-month mean concentrations for the design value period. Validity of the threemonth mean is determined following procedures given in 40 CFR 50, Appendix R Section 4(c). 

According to 40 CFR 50, Appendix R Section 4(c)(i), “A 3-month parameter mean is considered 

valid (i.e., meets the completeness requirements) if the average capture rate of the three 

constituent monthly means (i.e., the 3-month data capture rate) is greater than or equal to 75 

percent.” 

The first step in determining the validity of a three-month mean is to calculate the relevant 

monthly capture rates. According to 40 CFR 50, Appendix R Section 4(c)(i), 

Monthly data capture rates (expressed as a percentage) are specifically calculated as 

the number of creditable samples for the month (including any make-up samples taken 

the subsequent month for missed samples in the month in question, and excluding any 

 

4

 Several requests apparently have been made to the EPA and its contractors for quality assurance 

documentation. Asarco has not yet received copies of any responses to those requests. 
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make-up samples taken in the month in question for missed samples in the previous 

month) divided by the number of scheduled samples for the month, the result then 

multiplied by 100 but not rounded. 

Creditable samples, according to 40 CFR 50, Appendix R Section 1(c), “...are samples that are 

given credit for data completeness. They include valid samples collected on required sampling 

days and valid ‘make-up’ samples taken for missed or invalidated samples on required sampling 

days.” 

To calculate the monthly data capture rate properly one must identify the required sampling 

days in order to identify creditable samples (the number of which is the numerator of the 

monthly capture rate) and to determine the number of scheduled samples (the denominator of 

the monthly capture rate). Required sampling days are equivalent to scheduled sampling days. 

According to 40 CFR 50, Appendix R Section 1(c), “Scheduled sampling day means a day on 

which sampling is scheduled based on the required sampling frequency for the monitoring site, 

as provided in section 58.12 of this chapter.” 40 CFR 58.12(b) provides “For Pb manual 

methods, at least one 24-hour sample must be collected every 6 days except during periods or 

seasons exempted by the Regional Administrator.” More importantly, 40 CFR 50, Appendix R 

confirms this scheduled sampling frequency by explicitly specifying the every sixth day 

frequency under Section 4(c)(i), that is, “For purposes of assessing data capture, Pb-TSP and 

Pb-PM10 data collected before January 1, 2009 will be treated with an assumed scheduled 

sampling frequency of every sixth day.” 

Since a specific list of scheduled sampling days was not available for the Hayden monitor, the 

scheduled sampling days were determined by examining the monitoring data collected at the 

Hayden monitor given in Appendix A of the TSD. Even though the focus of the validity 

assessment is the three consecutive three-month periods near the end of 2008 (including the 

months of July 2008 through November 2008, inclusive), Zephyr reviewed the entire monitoring 

record (November 13, 2007 to November 30, 2008) as provided to establish patterns in 

sampling and sampling frequency in order to identify scheduled sampling days. Table 2-4 is the 

result of this review. The table indicates determined scheduled sampling days (double-lined, 

bordered boxes). The table also indicates when monitored samples were collected. Specifically, 

the table indicates scheduled samples (red X’s) and extra samples (blue X’s). Sample 

indicators with a light green filled background correspond to collected samples that were 

invalidated or rejected by the monitoring contractor. 
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Table 2-4 Determined Scheduled Sample Days 
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The process of determining the scheduled sampling days was as follows (also, see Table 2-4). 

From the beginning of this dataset record through April 5, 2008 there is a clear, every sixth day 

sampling pattern based on the actual dates of sample collection. The only exception to this 

pattern is the three samples collected between March 14, 2008 and March 26, 2008, inclusive 

(see black X’s in Table 2-4). These three samples are collected every sixth day, but the 

sampling does not fall into the regular scheduled pattern. Note that the Technical 

Memorandum, which is Appendix A of the TSD, states that extra samples began to be collected 

(three days after the scheduled samples) after March 28, 2008. However, extra sampling three 

days after scheduled sampling was not apparent until April 2008. Then, around April 11/12, 

2008 the actual sample collection seems to indicate a shift in sampling pattern, as the 

scheduled pattern moves ahead by one day. This “new” pattern continues into early May 2008 

(around May 6/7, 2008 based on an extra sample collected on May 10, 2008) when the actual 

sample collection seems to indicate another shift in sampling pattern. Again, the scheduled 

pattern moves ahead by one day. This “new” pattern continues until the end of the dataset 

record. The only exception to this pattern is the samples collected in September 2008 through 

early October 2008 (through October 12, 2008). These samples are collected every sixth day 

but on a shifted schedule. However, because these samples are collected every sixth day with 

no extra samples collected (during a period when extra samples also are supposed to be 

collected three days after the scheduled sample), these actual samples are assumed to be 

collected on scheduled sampling days. 

During the period of interest of July 2008 through November 2008, there are seven scheduled 

samples that are missing, and four scheduled samples that are invalid (i.e., rejected). In other 

words only 56% [(25-11)/25] of the scheduled samples are available during this period. The 

Technical Memorandum states that “...due to apparent power surging issues at the Hayden 

station, 13 samples (October through December 2008) were not collected.” It goes on to state 

that “...the resulting data set is considered sizable enough for evaluation purposes in this TM.” 

However, this is a subjective opinion and did not include a strict data validation following the 

procedures under 40 CFR 50, Appendix R Section 4(c). 

40 CFR 50, Appendix R Section 4(c)(i) allows make-up samples to replace missed or 

invalidated required scheduled samples. However, the dataset record does not indicate any 

make-up samples were collected. Only extra samples are indicated. Extra samples, according 

to 40 CFR 50, Appendix R section 1(c), “...are non-creditable samples. They are daily values 

that do not occur on scheduled sampling days and that can not be used as ‘make-up samples’ 

for missed or invalidated scheduled samples.” Therefore, the creditable samples are the valid, 

samples collected on the scheduled sampling days. Table 2-5 presents the number of 

creditable samples, the number of scheduled samples and the calculated monthly data capture 

rates (i.e., number of creditable samples divided by number of scheduled samples, multiplied by 

100 but not rounded) for the months of July 2008 through November 2008. 

 
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Table 2-5 Creditable Samples, Scheduled Sampling Days and Capture Rates by 

Month 

Month 

No. of Creditable 

Samples 

No. of Scheduled 

Samples 

Capture Rate 

(%) 

July 2008 4 5 80 

August 2008 3 5 60 

September 2008 4 5 80 

October 2008 2 5 40 

November 2008 1 5 20 

Table 2-6 presents the three-month data capture rates for the time periods of interest. 

Table 2-6 Three-Month Data Capture Rates by Time Period 

Time Period 3-month Capture Rate (%) 

July, August, September 2008 73 

August, September, October 2008 60 

September, October, November 2008 47 

According to 40 CFR 50, Appendix R Section 4(c)(i), “The three-month data capture rate is the 

sum of the three corresponding unrounded monthly data capture rates divided by three (3) and 

the result rounded to the nearest integer (zero decimal places).” As an example, the calculated 

three-month data capture rate for the July, August, 

September 2008 period is 73% or [(80+60+80)/3]. 

Because the three-month data capture rates are less 

than 75%, the corresponding three-month lead means 

(see Table 2-3) are considered not valid (i.e., they do 

not meet the data completeness requirements of 40 

CFR 50, Appendix R Section 4(c)(i). 

However, according to 40 CFR 50, Appendix R Section 4(c)(ii), “A 3-month parameter mean 

that does not have at least 75 percent data capture and thus is not considered valid under 

4(c)(i) shall be considered valid (and complete) if it passes either of the two following ‘data 

substitution’ tests, one such test for validating an above NAAQS-level (i.e., violating) 3-month 

Pb-TSP or Pb-PM10 mean (using actual ‘low’ reported values from the same site at about the 

same time of the year (i.e., in the same month) looking across three or four years),...” 

The three-month means of interest are above the NAAQS level. Therefore, the “data 

substitution” test of interest is the above NAAQS-level test. The above NAAQS-level test, 

according to 40 CFR 50, Appendix R Section 4(c)(ii), is as follows: 

Data substitution will be done in each month of the 3-month period that has less than 75 

percent data capture; monthly capture rates are temporarily rounded to integers (zero 

The 3­month capture rates

are below the 75%

completeness threshold.
REVIEW OF ADEQ’S TSD FOR PROPOSED LEAD NAAQS BOUNDARY RECOMMENDATION

ZEPHYR ENVIRONMENTAL CORPORATION 21 

decimals) for this evaluation. If by substituting the lowest reported daily value for that 

month (year non-specific; e.g., for January) over the 38-month design value period in 

question for missing scheduled data in the deficient months (substituting only enough to 

meet the 75 percent data capture minimum), the computation yields a recalculated test 

3-month parameter mean concentration above the level of the standard, then the 3-

month period is deemed to have passed the diagnostic test and the level of the standard 

is deemed to be exceeded in that 3-month period. 

Following the above NAAQS-level diagnostic test would require substitution of one missing 

sample in August 2008, two missing/invalid samples in October 2008 and five missing/invalid 

samples in November 2008. All reported monitoring data at the Hayden Monitoring Station 

(starting October 22, 2006) through the end of 2008 were reviewed to identify the lowest 

reported daily values for the months of interest. According to 40 CFR 50, Appendix R Section 

4(c )(ii), “..substitution is permitted only if there are available data points from which to identify 

the high or low 3-year month-specific values, specifically if there are at least 10 data points from 

at least two of the three (or four for November and December) possible year-months.” This 

criterion is met for the months of August and November, but not for the month of October. Only 

7 data points from two of the three possible year-months (5 reported values in October 2007 

and 2 reported values in October 2008) are available. Therefore, the substitution is not 

permitted for the month of October, and, thus, the diagnostic test cannot be performed for the 

August, September, October 2008 and September, October, November 2008 time periods. For 

these time periods the data completeness requirements (at least 75% data capture) are not met 

and the three-month means are considered not valid. 

The data substitution diagnostic test was performed for the July, August, September 2008 time 

period. One missing scheduled data for August 2008 was substituted with the lowest reported 

value for the month of August. The lowest reported lead value for the month of August is 

0.0142 μg/m3

 collected on August 6, 2007. The recalculated July, August, September 2008 test 

three-month mean is 0.166 μg/m3

 [(0.0718 + 0.1387 + 0.2884)/3]. This value is above the level 

of the lead standard, thus the three-month period is deemed to have passed the diagnostic test. 

2.5 UNCERTAINTY REGARDING DESIGN VALUE

As defined in 40 CFR 50, Appendix R, the Design 

Value is the concentration “...that is compared to the 

NAAQS level to determine compliance; the design 

value for the Pb NAAQS is selected...from among the 

valid three-month (lead) arithmetic mean 

concentration(s)...” In practice it is the highest of the 

rolling three-month averages that are calculated. 

The TSD does not contain a discussion of the Design 

Value. A discussion of concentrations greater than the 

NAAQS is contained in Section 4.1 of the TSD; in that section it refers to Appendix A of the TSD 

The Design Value should be

clearly defined before

proposing to classify an area

as nonattainment.
REVIEW OF ADEQ’S TSD FOR PROPOSED LEAD NAAQS BOUNDARY RECOMMENDATION

ZEPHYR ENVIRONMENTAL CORPORATION 22 

for more details pertaining to the monitoring results that confirm the Hayden area is in 

nonattainment for lead. 

Appendix A of the TSD is labeled as “EPA’s Air Quality Study of the Hayden Area,” and consists 

of a Technical Memorandum prepared on December 31, 2008 from CH2M Hill to John 

Hillenbrand of EPA. The Technical Memorandum includes a summary of monitoring conducted 

at Hayden and provides tables of all monitoring results (pollutant and meteorological) on a daily 

basis (Table 1 in Appendix A of the TSD contains the Hayden information). 

Following these detailed tables there is an individual page that presents a Design Value of 0.21 

μg/m3

 for lead for the Hayden monitor for the period 2006-2008. However, there is no 

explanation as to the derivation of this value; furthermore, a close inspection reveals that the 

data presented in Appendix A of the TSD do not support the 0.21 μg/m3

 value. 

Zephyr looked into this discrepancy further and ascertained that the Design Value of 0.21 μg/m3

may be based on data provided in electronic format by John Hillenbrand of EPA to Jack Garrity 

of Asarco on September 23, 2009 (these data are presented in the spreadsheet in Appendix A 

of this report). It is not clear the spreadsheet data have been vetted for exceptional events, 

quality assurance and data completeness. 

It is unclear, therefore, which, if any, dataset is appropriate to use. While the ADEQ apparently 

makes its proposal based on the data in Appendix A of the TSD, the TSD’s sole actual 

reference to a Design Value may rely on a completely different set of data which may or may 

not have undergone validation under the rules. The ADEQ should clearly establish and validate 

the Design Value for comparison to the NAAQS. Without a clearly established and properly 

validated Design Value a designation of nonattainment is not justified. 
REVIEW OF ADEQ’S TSD FOR PROPOSED LEAD NAAQS BOUNDARY RECOMMENDATION

ZEPHYR ENVIRONMENTAL CORPORATION 23 

APPENDIX A 

HAYDEN AIR QUALITY MONITORING DATA 

RECEIVED FROM EPA ON SEPTEMBER 23, 2009 
Result Qualifier NAAQS

Hayden 10/22/06 μg/m30.0024 * 0.15

Hayden 11/03/06 μg/m30.0266 0.15

Hayden 11/09/06 μg/m30.0141 0.15

Hayden 11/11/06 μg/m3

0.044 0.15

Hayden 11/21/06 μg/m30.5947 0.15

Hayden 11/27/06 μg/m30.0191 0.15

Hayden 12/03/06 μg/m30.1595 0.15

Hayden 12/09/06 μg/m3

Hayden 12/15/06 μg/m30.0329 J 0.15

Hayden 12/21/06 μg/m30.0027 * 0.15

Hayden 12/27/06 μg/m3

0.0143 0.15

Average 0.0834

Hayden 01/08/07 μg/m30.47 0.15

Hayden 01/14/07 μg/m30.0167 0.15

Hayden 01/20/07 μg/m30.0043 0.15

Hayden 01/26/07 μg/m3

0.0099 0.15

Hayden 02/01/07 μg/m30.005 0.15

Hayden 02/07/07 μg/m3

0.0103 0.15

Hayden 02/13/07 μg/m3

0.037 0.15

Hayden 02/19/07 μg/m30.0173 0.15

Hayden 02/25/07 μg/m30.0105 0.15

Hayden 03/03/07 μg/m30.1444 0.15

Hayden 03/09/07 μg/m3 R R 0.15

Hayden 03/15/07 μg/m3

0.032 0.15

Hayden 03/21/07 μg/m30.0885 0.15

Hayden 03/27/07 μg/m3

0.0227 0.15

Hayden 04/02/07 μg/m3

0.028 0.15

Hayden 04/20/07 μg/m3

0.0122 0.15

Hayden 04/26/07 μg/m3

0.0324 0.15

Hayden 05/02/07 μg/m3 R R 0.15

Hayden 05/08/07 μg/m3

0.0774 0.15

Hayden 05/14/07 μg/m30.0257 0.15

Hayden 05/20/07 μg/m30.0127 0.15

Hayden 05/26/07 μg/m30.0253 0.15

Hayden 06/01/07 μg/m30.046 0.15

Hayden 06/07/07 μg/m30.0048 0.15

Hayden 06/13/07 μg/m3

0.0238 0.15

Hayden 06/19/07 μg/m3

0.0298 0.15

Hayden 06/25/07 μg/m30.0299 0.15

Hayden 07/01/07 μg/m30.0382 0.15

Hayden 07/07/07 μg/m3 R R 0.15

Hayden 07/13/07 μg/m3

0.021 0.15

Hayden 07/19/07 μg/m3

0.0986 0.15

Hayden 07/25/07 μg/m3

0.0136 0.15

Hayden 07/31/07 μg/m30.0208 0.15

Hayden 08/06/07 μg/m3

0.0142 0.15

Lead

Location

Sample

Date Units

Page 1 of 4
Result Qualifier NAAQS

Lead

Location

Sample

Date Units

Hayden 08/12/07 μg/m30.0268 0.15

Hayden 08/18/07 μg/m30.0429 0.15

Hayden 08/24/07 μg/m30.0182 0.15

Hayden 08/30/07 μg/m3

0.517 0.15

Hayden 09/05/07 μg/m30.0294 0.15

Hayden 09/11/07 μg/m30.8362 0.15

Hayden 09/17/07 μg/m30.0803 0.15

Hayden 09/23/07 μg/m3

0.0033 0.15

Hayden 09/29/07 μg/m30.0273 0.15

Hayden 10/05/07 μg/m30.0035 0.15

Hayden 10/11/07 μg/m3

0.046 0.15

Hayden 10/17/07 μg/m3

0.0194 0.15

Hayden 10/22/07 μg/m3

0.5156 0.15

Hayden 10/27/07 μg/m3

0.0242 0.15

Hayden 11/01/07 μg/m3

0.0202 0.15

Hayden 11/07/07 μg/m3

0.3183 0.15

Hayden 11/13/07 μg/m3

0.0049 0.15

Hayden 11/19/07 μg/m3

0.042 0.15

Hayden 11/25/07 μg/m3

0.0538 0.15

Hayden 12/07/07 μg/m30.2119 0.15

Hayden 12/13/07 μg/m3

0.0944 0.15

Average 0.0838

Hayden 01/12/08 μg/m30.1487 0.15

Hayden 01/18/08 μg/m3

0.0613 0.15

Hayden 02/17/08 μg/m30.0291 0.15

Hayden 02/23/08 μg/m3

0.0081 0.15

Hayden 02/29/08 μg/m3

0.0764 0.15

Hayden 03/06/08 μg/m3

0.0697 0.15

Hayden 03/12/08 μg/m3 R R 0.15

Hayden 03/14/08 μg/m30.064 0.15

Hayden 03/20/08 μg/m3

0.0152 0.15

Hayden 03/26/08 μg/m30.0125 0.15

Hayden 03/30/08 μg/m30.0024 * 0.15

Hayden 04/05/08 μg/m30.0305 0.15

Hayden 04/12/08 μg/m30.4627 0.15

Hayden 04/15/08 μg/m30.059 0.15

Hayden 04/18/08 μg/m3

0.1272 0.15

Hayden 04/21/08 μg/m3

0.0299 0.15

Hayden 04/24/08 μg/m30.0097 0.15

Hayden 05/10/08 μg/m30.022 0.15

Hayden 05/13/08 μg/m3

0.1163 0.15

Hayden 05/16/08 μg/m3

0.288 0.15

Hayden 05/19/08 μg/m3

0.0236 0.15

Hayden 05/22/08 μg/m3

0.0166 0.15

Hayden 05/28/08 μg/m30.0361 0.15

Hayden 05/31/08 μg/m3

0.028 0.15

Page 2 of 4
Result Qualifier NAAQS

Lead

Location

Sample

Date Units

Hayden 06/03/08 μg/m30.0547 0.15

Hayden 06/06/08 μg/m30.0185 0.15

Hayden 06/09/08 μg/m30.0843 0.15

Hayden 06/12/08 μg/m3

0.0746 0.15

Hayden 06/15/08 μg/m30.1255 0.15

Hayden 06/18/08 μg/m30.033 0.15

Hayden 06/21/08 μg/m30.1123 0.15

Hayden 07/09/08 μg/m3

0.3432 0.15

Hayden 07/12/08 μg/m30.0062 0.15

Hayden 07/15/08 μg/m30.0191 0.15

Hayden 07/18/08 μg/m3

0.047 0.15

Hayden 07/21/08 μg/m3

0.0205 0.15

Hayden 07/24/08 μg/m3

0.0731 0.15

Hayden 07/27/08 μg/m3

0.0011 0.15

Hayden 07/30/08 μg/m3

0.0132 0.15

Hayden 08/02/08 μg/m3

0.0347 0.15

Hayden 08/05/08 μg/m3

0.1629 0.15

Hayden 08/08/08 μg/m3

0.457 0.15

Hayden 08/11/08 μg/m3

0.0417 0.15

Hayden 08/14/08 μg/m30.1646 0.15

Hayden 08/17/08 μg/m3

0.1981 0.15

Hayden 08/20/08 μg/m30.0363 0.15

Hayden 09/12/08 μg/m30.0136 0.15

Hayden 09/18/08 μg/m3

0.0462 0.15

Hayden 09/24/08 μg/m30.1263 0.15

Hayden 09/30/08 μg/m3

0.9676 0.15

Hayden 10/06/08 μg/m30.02 0.15

Hayden 10/12/08 μg/m3

0.0234 0.15

Hayden 10/22/08 μg/m30.1968 0.15

Hayden 10/25/08 μg/m30.042 0.15

Hayden 10/28/08 μg/m3

0.3002 0.15

Hayden 11/09/08 μg/m30.0887 0.15

Hayden 11/12/08 μg/m3

0.0071 0.15

Hayden 11/21/08 μg/m3

0.984 0.15

Hayden 11/24/08 μg/m30.111 0.15

Hayden 11/27/08 μg/m30.1731 0.15

Hayden 11/30/08 μg/m30.0328 0.15

Hayden 12/06/08 μg/m30.0113 0.15

Hayden 12/12/08 μg/m30.1094 0.15

Hayden 12/15/08 μg/m30.1166 0.15

Hayden 12/27/08 μg/m3

0.0944 0.15

Hayden 12/30/08 μg/m3

0.0115 0.15

Average 0.1128

Hayden 01/02/09 μg/m30.0174 0.15

Hayden 01/19/09 μg/m30.1583 0.15

Hayden 02/01/09 μg/m3

0.1483 0.15

Page 3 of 4
Result Qualifier NAAQS

Lead

Location

Sample

Date Units

Hayden 02/04/09 μg/m30.9647 0.15

Hayden 02/06/09 μg/m30.0433 0.15

Hayden 02/12/09 μg/m30.0109 0.15

02/18/09

Hayden 02/20/09 μg/m30.0567 0.15

02/24/09

Hayden 02/26/09 μg/m30.1353 0.15

03/02/09

Hayden 03/04/09 μg/m30.0253 0.15

03/08/09

Hayden 03/10/09 μg/m30.1507 0.15

Hayden 03/13/09 μg/m30.0706 0.15

03/14/09

Hayden 03/19/09 μg/m30.0937 0.15

03/20/09

Hayden 03/26/09 μg/m30.0807 0.15

Hayden 04/01/09 μg/m3

0.1023 0.15

Hayden 04/07/09 μg/m30.4633 0.15

Hayden 04/13/09 μg/m30.0174 0.15

Hayden 04/19/09 μg/m30.0455 0.15

Hayden 04/25/09 μg/m3

0.0226 0.15

Hayden 05/01/09 μg/m3

0.0645 0.15

Hayden 05/07/09 μg/m30.0299 0.15

Hayden 05/13/09 μg/m3

0.0913 0.15

Hayden 05/19/09 μg/m3

0.0249 0.15

Hayden 05/25/09 μg/m3

0.0050 0.15

Hayden 05/31/09 μg/m3

0.0056 0.15

Hayden 06/06/09 μg/m30.0040 0.15

Hayden 06/12/09 μg/m3

0.0039 0.15

Hayden 06/18/09 μg/m30.0083 0.15

Hayden 06/24/09 μg/m30.0102 0.15

Average 0.1020

Maximum 0.9647

* = The result is less than three times the level of uncertainty.

J = Estimated value

NA = Not available

R = Rejected due to filter damage

Page 4 of 4