# 1.0 Title Page

**Standard Operating Procedures**

**Thermo Environmental Instruments Model 48C Trace Level**

**Gas Filter Correlation Carbon Monoxide Analyzer**

**Approvals:**

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Author Date

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OAQPS QA Manager Date

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OAQPS Project Manager Date

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OAQPS QA Coordinator Date

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  **Annual                                                    
  Review                                                      
  by:**                                                       

  **Date of                                                   
  Review:**                                                   
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# 2.0 Table of Contents

[1.0 Title Page 1](#title-page)

[2.0 Table of Contents 2](#table-of-contents)

[3.0 Introduction 5](#introduction)

[3.1 Scope 5](#scope)

[3.2 Method Description 5](#method-description)

[3.4 Data Quality Objectives 7](#data-quality-objectives)

[3.5 Personnel Qualifications and Training
8](#personnel-qualifications-and-training)

[4.2 Cautions 8](#cautions)

[5.0 Siting and Sampling 10](#siting-and-sampling)

[5.1 Site Characteristics 10](#site-characteristics)

[5.2 Air Sample Routing 10](#air-sample-routing)

[5.3 Equipment and Supplies 10](#equipment-and-supplies)

[6.0 48C TLE Analyzer Installation, Operation, Calibration, and
Maintenance
12](#c-tle-analyzer-installation-operation-calibration-and-maintenance)

[6.2 Startup 14](#startup)

[6.2.1 Analyzer setup 14](#analyzer-setup)

[6.2.2 Tubing and gas delivery 14](#tubing-and-gas-delivery)

[6.2.3 Electrical connections 14](#electrical-connections)

[6.3 Operation and Range Setting 15](#operation-and-range-setting)

[6.3.1 Display 15](#display)

[6.3.2 Run Screen 15](#run-screen)

[6.3.3 Range Displays 15](#range-displays)

[6.4 Diagnostic Checks 15](#diagnostic-checks)

[6.5 Initial and Periodic Multipoint Calibration
18](#initial-and-periodic-multipoint-calibration)

[6.5.1 Pre-calibration checks 18](#pre-calibration-checks)

[6.5.2 Adjustment to Zero Air 18](#adjustment-to-zero-air)

[6.5.3 Adjustment to Calibration Gas (Span point)
19](#adjustment-to-calibration-gas-span-point)

[6.5.4 Multipoint Calibrations 20](#multipoint-calibrations)

[6.5.4.1 Frequency of calibrations 20](#frequency-of-calibrations)

[6.5.4.2 Periodic Quality Control Checks
20](#periodic-quality-control-checks)

[6.5.5 Auto-Zero Function 20](#auto-zero-function)

[7.1. Inspect Shelter Condition and Status
21](#inspect-shelter-condition-and-status)

[7.2 Operational Requirements for Entering the Station
21](#operational-requirements-for-entering-the-station)

[7.3 Data Acquisition Systems 22](#data-acquisition-systems)

[7.4 Calibration System 24](#calibration-system)

[7.5 Return Systems to Monitoring Mode
25](#return-systems-to-monitoring-mode)

[7.6 Other Maintenance Checks 25](#other-maintenance-checks)

[7.7 Operational Requirements---Exiting the Station
25](#operational-requirementsexiting-the-station)

[8.0 Quality Indicators 25](#quality-indicators)

[8.1 Precision Evaluation 26](#precision-evaluation)

[8.2 Bias Evaluation 26](#bias-evaluation)

[8.3 Representativeness 26](#representativeness)

[8.4 Completeness 26](#completeness)

[8.5 Comparability 27](#comparability)

[8.6 Method Detection Limits 27](#method-detection-limits)

[8.7 Measurement Quality Objectives 27](#measurement-quality-objectives)

[9.3 Performance Evaluation Audits 30](#performance-evaluation-audits)

[9.4 Technical Systems Audits 30](#technical-systems-audits)

[9.5 Procedures in the Event of an Audit Failure
30](#procedures-in-the-event-of-an-audit-failure)

[10.0 Preventive Maintenance 31](#preventive-maintenance)

[10.1 Instrument Troubleshooting 31](#instrument-troubleshooting)

[11.0 References 32](#references)

**List of Figures**

[Figure 1. Front Panel of the TEI 48C TLE CO Analyzer
12](#__RefHeading___Toc185131904)

[Figure 2. Pneumatic Diagram for TEI Model 48C TLE CO Analyzer
13](#__RefHeading___Toc185131905)

[Figure 3. Menu Tree for Diagnostic Checks
16](#__RefHeading___Toc185131906)

[Figure 4. Data Form for Diagnostic Checks and Quality Control Checks:
TEI 48C TLE CO Analyzer 17](#__RefHeading___Toc185131907)

[Figure 5. ENVIDAS FW Dynamic Tabular Channel Display
22](#__RefHeading___Toc185131908)

[Figure 6. ESC 8832 Main Menu Display 23](#__RefHeading___Toc185131909)

**List of Tables**

[Table 1. Operating Parameters for the TEI 48C TLE CO Analyzer
19](#__RefHeading___Toc185132001)

[Table 2. Measurement Quality Objectives for Carbon Monoxide: Burdens
Creek Site 28](#__RefHeading___Toc185132002)

[Table 3. Preventive Maintenance Schedule for the TEI 48C TLE
31](#__RefHeading___Toc185132003)

# 3.0 Introduction

This standard operating procedure (SOP) document describes the
procedures used by members of the Ambient Air Monitoring Group (AAMG) to
operate a continuous carbon monoxide (CO) analyzer at the Environmental
Protection Agency, Office of Air Quality Planning and Standards (EPA
OAQPS) Burdens Creek monitoring site located in Research Triangle Park,
North Carolina. The procedures given in this SOP are to be used in
conjunction with the monitoring site's Quality Assurance Project Plan
(QAPP), the latest information published in the Code of Federal
Regulations, and the Operator's manual for the Thermo Environmental
Instruments Model 48C-Trace Level (TEI 48C TLE) CO analyzer .

Mr. Lewis Weinstock, EPA/OAQPS/AAMG, is the Burdens Creek Project
Manager. His telephone number is 919-541-3661 and his email address is
<Weinstock.Lewis@epa.gov>. Mr. Solomon Ricks is the lead person for CO
monitoring at the site. His telephone number is 919-541-5242. His e-mail
address is <ricks.solomon@epa.gov>.

# 3.1 Scope

For trace level measurement of CO the analyzer must have a sensitive
detector. The TEI model 48C TLE is a state-of-the-science instrument for
the determination of trace levels of CO by non-dispersive infrared
(NDIR) spectrophotometry using gas filter correlation (GFC). This SOP
will describe the monitor and its operation.

# 3.2 Method Description

The analytical principle is based on absorption of IR light by the CO
molecule. NDIR-GFC analyzers operate on the principle that CO has a
sufficiently characteristic IR absorption spectrum such that the
absorption of IR by the CO molecule can be used as a measure of CO
concentration in the presence of other gases. CO absorbs IR maximally at
2.3 and 4.6 *u*m. Since NDIR is a spectrophotometric method, it is based
upon the Beer-Lambert law. The degree of infrared radiation reduction
depends on the length of the sample cell, the absorption coefficient,
and CO concentration introduced into the sample cell, as expressed by
the Beer-Lambert law shown below:

> T = I/Io = e^(-axC)^ (equation 1)
>
> where:
>
> T =Transmittance of light through the gas to the detector
>
> I = light intensity after absorption by CO
>
> I~o~ = light intensity at zero CO concentration
>
> a = specific CO molar absorption coefficient
>
> x = path length, and
>
> C = CO concentration

For GFC, there is only one sample cell. This cell acts as the sample and
reference cell. The broad band of IR radiation is emitted from an IR
source. The IR light passes through a very narrow band pass filter which
screens out most wavelengths and allows only the light that CO absorbs
to enter the sample cell. The GFC analyzer has a chopper wheel with
cells containing two pure gases: nitrogen (N~2~) and CO. As the chopper
wheel rotates and allows the IR energy to enter "CO side" of the wheel,
all IR energy that could be absorbed by CO in the sample stream is
absorbed by the CO in the wheel. This technique effectively "scrubs out"
any light that could possibly be attenuated. The single detector records
the light intensity (I~o~). As the wheel spins, the "N~2~ side" of the
wheel enters the IR energy beam. This side of the wheel allows all IR
light to pass through the wheel and be absorbed by any CO that might be
in the sample gas. This light level is CO sensitive (I). The detector
records the attenuation of this light, compares the two light levels
(I/I~o~) and sends a signal to the electrometer board that calculates
the concentration. The voltage is related to the CO concentration
according to the Beer-Lambert law in equation 1 shown above. In this way
the TEI 48C TLE can measure CO continuously. The 48C TLE version has
four distinct features that allow it to measure CO at ppb levels:

> sample stream dried using permeation dryer;
>
> analyzer baseline determined and corrected using heated Carolite
> catalytic converter;
>
> frequent auto-zero through the catalytic converter;
>
> an ultra-sensitive or "hot" detector.

**3.3 Interferences**

Interferences are physical or chemical entities that cause measurements
to be higher (positive) or lower (negative) than they would be without
the entity. Studies have shown conclusively that NDIR analyzers have
interference from water vapor. Water absorbs very strongly across
several bands of IR spectra. Water vapor interference occurs because in
the IR region it absorbs of light at 3.1, 5.0 -5.5 and 7.1 -10.0 *u*m.
As a result, there is a quenching effect on the absorption of infrared
light by CO. The TEI 48C TLE is equipped with a permeation dryer, which
effectively removes all water and water vapor. No maintenance is
required on the dryer.

Carbon dioxide (CO~2~) absorbs in the IR spectrum at wavelengths of 2.7,
5.2, and 8.0 to 12.0 *u*m. This is very close to the regions that CO
absorbs within as well. Because atmospheric CO~2~ is much higher in
concentration than CO, this UV spectral range must be avoided. To
prevent light in this spectral region, the TEI 48C TLE analyzer has a
band pass filter that blocks these wavelengths.

In order to measure in the ppb range, it is important for the detector
to be operated at a very stable temperature. To obtain a stable
baseline, the temperature of the detector and optical bench must be
maintained within ±1.0 degree Celsius (°C) of the set value.

# 3.4 Data Quality Objectives

The Burdens Creek site provides the EPA/OAQPS/AAMG with the ability to
test new monitoring and data acquisition/data transfer technologies and
to train monitoring organizations in these technologies. Data are
gathered at the Burdens Creek site in a manner similar to state, local,
and tribal monitoring organizations in order to assist or guide others
and to test two data acquisition systems' ability to transfer data to
information management programs like AIRNow and the AQS system. Carbon
monoxide will be measured year-round on a range setting of either 0 to 2
ppm (0 to 2000 ppb) or 0 to 5 ppm (0 to 5000 ppb) and reported at a
minimum frequency of one-hour averages.

The decision rule for determining the quality of the Burdens Creek CO
data is not based on comparison to the National Ambient Air Quality
Standard (NAAQS), but rather on whether or not the data meet the
measurement quality objectives of precision and bias. Precision and bias
will be estimated from the quality control (QC) precision checks that
are made automatically by the calibration system or manually by the site
operator at least every two weeks.

The Burdens Creek site will use the data quality objectives (DQOs)
developed by EPA for determining whether or not a particular monitoring
system is performing properly and what corrective actions might be
needed. The goal for acceptable measurement uncertainty for trace-level
CO measurements is defined for precision as an upper 90 percent
confidence limit for the coefficient variation (CV) of 15 percent, for
bias as an upper 95 percent confidence limit for the absolute bias of 10
percent, and a minimum data completeness of 90 percent . Thus, the
Burdens Creek site data set will be assumed to have met the DQO if the
measurement quality objectives (MQO) of 15% or better for precision and
10% or better for bias are consistently met over the months and years of
site operation. A tabular presentation of the MQOs for CO is given in
Table 2 of Section 8.

# 3.5 Personnel Qualifications and Training

The person(s) assigned to operate the 48C TLE CO analyzer should receive
classroom instructions, hands-on sampler training, and safety briefings
from an experienced site operator. The desired qualifications for an
operator include: a good understanding of basic chemistry and
electronics; understanding of digital circuitry; coursework and/or
experience in ambient air data processing and validation.

**4.0 Health and Safety Procedures**

CO is a poisonous gas. The CO, or any other calibration span gas, should
be vented to the atmosphere rather than into the shelter or other
sampling area. If this is impossible, limit operator exposure to CO by
getting fresh air every 5 to 10 minutes. The operator must leave the
area immediately if he experiences light headedness, headache or
dizziness.

**4.1 Preventing Personal Injury**

To prevent personal injury, the following warnings and cautions must be
observed when operating the 48C TLE.

1.  Always unplug the analyzer when servicing or replacing parts.

2.  Always use a third ground wire on all instruments.

3.  The IR source is a filament resistor that has an electrical current
    running through it and can become very hot. When troubleshooting, if
    the IR source is the suspected cause of the problem, allow the
    source to cool sufficiently.

4.  If it is mandatory to work inside an analyzer while it is in
    operation, use extreme caution to avoid contact with high voltages.
    The analyzer has a 110- Volt Alternating Current (VAC) power supply.
    Refer to the manufacturer\'s instruction manual and know the precise
    locations of the VAC components before working on the instrument.

5.  Avoid electrical contact with jewelry. Remove rings, watches,
    bracelets, and necklaces to prevent electrical burns.

# 4.2 Cautions

> To prevent damage to the analyzer, the following precautions should be
> taken:
>
> 1\. In the event that it is necessary to clean the optical bench, be
> careful to avoid damaging the interior of the sample chamber. In
> addition, some GFC instruments have a series of mirrors that deflect
> the light in order to increase the path length. The mirrors are
> aligned at the factory. If the mirrors become misaligned, the IR light
> beam will not be directed to the detector. Use extreme caution when
> cleaning or servicing the sample chamber(s). In addition, the mirrors
> are very fragile. Avoid dropping the instrument. This may damage,
> misalign or crack the mirrors and cause expensive repairs.
>
> 2\. Keep the interior of the analyzer clean.
>
> 3\. Inspect the system regularly for structural integrity.
>
> 4\. To prevent major problems with leaks, make sure that all sampling
> lines are reconnected after required checks and before leaving the
> site.
>
> 5\. Inspect tubing for cracks and leaks. The permeation dryer may rest
> upon parts that vibrate, such as the air pump. Check the areas of the
> permeation dryer where they come into contact with other parts.
>
> 6\. It is recommended that the analyzer be leak checked after
> replacement of any pneumatic parts.
>
> 7\. If cylinders are used in tandem with mass flow control (MFC)
> calibrators, use and transport of cylinders are a major concern. Gas
> cylinders can sometimes contain pressures as high as 2000 pounds per
> square inch. Handling of cylinders must be done in a safe manner. If a
> cylinder is accidentally dropped and the valve breaks off, the
> cylinder can become explosive or a projectile.
>
> 8\. Transportation of cylinders is regulated by the Department of
> Transportation (DOT). It is strongly recommended that all agencies
> contact the DOT or Highway Patrol to learn the most recent regulations
> concerning transport of cylinders.
>
> 9\. CO is a highly poisonous gas. Long term exposure can cause
> problems with motor coordination and mental acuity. It is strongly
> recommended that all agencies have material safety data sheets (MSDS)
> at all locations where CO cylinders are stored or used. MSDS can be
> obtained from the DOT or from your vendor.
>
> 10\. It is possible (and practical) to blend other compounds with CO.
> If this is the case, it is recommended that MSDS for all compounds be
> made available to all staff that use and handle the cylinders.
>
> 11\. Shipping of cylinders is governed by the DOT. Contact the DOT or
> your local courier about the proper procedures and materials needed to
> ship high-pressure cylinders.

# 5.0 Siting and Sampling

# 5.1 Site Characteristics

The Burdens Creek site is located within 0.5 mile of the EPA/OAQPS
facility in Research Triangle Park, NC. The site is adjacent to
Alexander Drive and N.C. Route 147 and is intended to represent a
neighborhood scale location. The site conforms to many of the network
and siting requirements for air monitoring as stated in Title 40 of the
Code of Federal Regulations (CFR), Part 58, Appendix D (40 CFR Part 58,
Appendix D). While the site is like an NCore site in many respects, it
is not intended to be an officially approved NCore site.

# 

# 5.2 Air Sample Routing

The CO sample inlet probe is an inverted glass funnel, located on the
roof of the shelter, approximately 5 meters above ground level. The
funnel inlet is greater than 1 meter vertically and horizontally away
from any supporting structures; the drip-line of the nearest tree is
greater than 20 meters from the probe inlet. Sampling for trace level CO
is performed by using a vacuum pump to continuously draw ambient air
from the station's glass sampling manifold directly into the analyzer.
The air inlet probe and sampling manifold for CO monitoring are designed
so that residence time in the assembly is less than 20 seconds; a
squirrel-cage blower maintains airflow through the manifold to meet this
residence time requirement specified in 40 CFR Part 58, Appendix E.

# 5.3 Equipment and Supplies

**TEI 48C TLE CO Analyzer**: The Burdens Creek site uses the TEI 48C TLE
CO analyzer. For this site, its range is typically set to 0 to 5.0 ppm
(0 to 5000 ppb). All fittings and tubing associated with the delivery of
ambient air CO samples, or calibration and QC gases, are composed of
Teflon or glass. The features of the analyzer are fully described in the
operator's manual. The three main components of the 48C TLE are the:

> [Pneumatic System]{.underline}: Consists of sample inlet line,
> particulate filter, filter holder, permeation dryer, reaction chamber,
> flow meter, and pump, all used to bring ambient air samples to the
> analyzer inlet.
>
> [Analytical System]{.underline}: This portion of the instrument
> consists of the IR source, the correlation wheel, motor, mirrors,
> detector and band pass filter.
>
> [Electronic Hardware:]{.underline} The part of the analyzer that
> generally requires little or no maintenance. The brain of the 48C
> series is the CPU. It monitors and regulates motor speed,
> temperatures, flows and pressure. It also monitors and stores
> diagnostic information. If the 48C TLE is operated above the
> manufacturer\'s recommended temperature limit, individual integrated
> chips can fail and cause problems with data storage or retrieval.

**Instrument Shelter:** A shelter is required to protect the analyzer
from precipitation and adverse weather conditions, maintain operating
temperature within a ± 2 °C range within the analyzer\'s temperature
range requirements, and provide security and electrical power. The
acceptable shelter temperature range is 20-30 °C. An ideal range of
temperature control would be 25 ± 1 °C.

**Calibration System**: The Burdens Creek site uses a model 9100
Environics® calibration system to create concentrations of CO by
diluting the contents of a NIST traceable compressed gas cylinder. For
details on the operation of the calibration system, refer to the
Environics Operator's Manual and to the SOP "*Standard Operating
Procedures, Environics Series 9100, Computerized Ambient Monitoring
Calibrations System*. The compress gas cylinders at the site are
multi-blend mixture of the target analytes with a nitrogen base. The
zero air at the site is produced by pumping room air through an Advanced
Pollution Instruments (API) model 701 zero air module. For removal of CO
the air is passed through a heated catalytic oxidizer in addition to the
Purafil and charcoal scrubbers. All gas must be delivered to the
instrument at atmospheric pressure.

**DAS**: The ENVIDAS for Windows (EFW) data system is the primary
digital data acquisition system for the Burdens Creek site. The ENVIDAS
system uses non-proprietary desktop or industrial personal computer
hardware to run flexible, Windows-based data acquisition software. Data
can be averaged, archived, displayed, and reported in various formats,
including display of data as an "electronic strip chart." ENVIDAS is
designed to communicate with and control a variety of precursor gas
analyzers and dynamic dilution calibrators. The ESC 8832 data logger is
used as the backup system for recording analog data at the Burdens Creek
station. For more details, refer to the individual ENVIDAS or ESC 8832
operator's manual and to the Burdens Creek SOP for DAS operations.

**Wiring, Tubing and Fittings***:* Teflon™ and borosilicate glass are
inert materials that should be used exclusively throughout the ambient
air intake system. It is recommended that Polytetrafluoroethylene (PTFE)
or Fluoroethylpropylene (FEP) Teflon™ tubing be used. PTFE or FEP Teflon
is the best choice for the connection between the intake manifold and
the 48C TLE bulkhead fitting. Examine the tubing and discard if
particulate matter has collected on the tube's interior. All fittings
and ferrules should be made of Teflon™ or stainless steel. Connection
wiring to the DAS should be shielded two-strand wire or RS-232 cables
for digital connections.

**Reagents and Standard:** The TEI 48C TLE does not require any reagents
since the instrument uses the gas filter correlation method to analyze
for CO. All gas calibration and quality control concentrations for the
CO method are obtained by dynamic dilution of gas from cylinders whose
contents must be traceable to NIST Standard Reference Material (SRM)
gases via EPA Protocol procedures.

**Spare Parts and Incidental Supplies:** See Chapter 5 (Preventive
Maintenance) and Chapter 7 (Servicing) in the TEI 48C TLE operating
manual for specific maintenance and replacement requirements.

# 48C TLE Analyzer Installation, Operation, Calibration, and Maintenance

**6.1 Overview**

The TEI 48C TLE instrument has a front panel screen with digital
display. The screen and a set of push button operating switches located
below it allow the user to check functions, switch operating parameters,
adjust zero and span, and read warnings messages.

  -----------------------------------------------------------------------
  **Caution:** It is extremely important that the users familiarize
  themselves with the menus available. Inadvertently changing parameters
  within the analyzer can damage the instrument and possibly invalidate
  data as well. Please reference the TEI 48C TLE owner's manual and read
  it carefully before adjusting any parameters that are set by the
  factory.

  -----------------------------------------------------------------------

Section 2.0 of the operator's manual must be consulted to understand or
carry out the following initial setup procedures, including:

-   How to unpack and inspect the exterior and interior of the analyzer,

-   Setup procedures for making pneumatic connections for sample and
    calibration gases, and

-   How to make electrical connections for: output, status outputs,
    control inputs, serial ports, and other features.

Refer to Figure 1 for an illustration of the analyzer's front panel and
to Figure 2 for an illustration of the pneumatic connections.

![](media/image1.png){width="2.5in" height="1.5in"}

[]{#__RefHeading___Toc185131904 .anchor}Figure 1. Front Panel of the TEI
48C TLE CO Analyzer

![](media/image2.wmf){width="6.025in" height="3.575in"}

[]{#__RefHeading___Toc185131905 .anchor}Figure 2. Pneumatic Diagram for
TEI Model 48C TLE CO Analyzer

> The 48C TLE instrument operates in the following fashion:
>
> 1\. The sample stream first passes through a sample filter, which
> removes particles and thus preventing their build-up on the mirror and
> sample chamber and attenuation of the IR beam.
>
> 2\. In sample mode, ambient air is pulled in through the particulate
> filter and goes into the rear bulkhead sample port. The first solenoid
> encountered is in its "Normally Open" (NO) mode. The ambient air flows
> through the solenoid to the permeation dryer, which removes the
> moisture and water from the air stream.
>
> 3\. The sample then enters the sample cell. A major difference between
> a non- trace level and a trace level ambient air analyzer is the
> detector construction. The trace level instrument has a detector that
> is more sensitive to the light emitted and absorbed in the sample
> cell. This detector must be more sensitive because the degree of
> attenuation by the low concentrations of CO gas in the sample stream
> is much lower and must be detected to give reliable low concentration
> values. Temperature control of the sample cell is also critical. The
> sample cell and detector must be maintained at a constant temperature
> in order for the detector to keep a stable background. Fluctuations of
> more than 1°C can cause the baseline to drift, giving false readings
> at low levels.
>
> 4\. The detector sends the signal to the demodulator which interprets
> the signal. The demodulator sends a digital value to the Central
> Processor Unit (CPU).
>
> 5\. At the end of the hour, the CPU sends a voltage signal to the
> first solenoid and switches it to the "Normally Closed" (NC) position.
> This allows room air to be drawn into the instrument and to pass
> through the catalytic converter. The catalytic converter uses a
> Carolite bed heated to 50°Centrigrade to convert all CO to CO~2~
> (2CO + O2 ---\> 2CO~2~). This effectively scrubs all CO from the
> sample stream. The "CO-free" air flows through the sample cell and the
> CPU interprets the signal from the demodulator as the "background" or
> "baseline" value. The baseline is then adjusted at that time. The
> baseline adjustment takes 10 minutes.
>
> 6\. The CPU then switches the first solenoid to its "Normally Open"
> (NO) position and ambient air is again drawn into the analyzer.

# 

# 6.2 Startup

# 6.2.1 Analyzer setup

After the analyzer is removed from the shipping container and placed on
a sturdy bench top or in an instrument rack, remove the outer cover and
any packing material from the internal compartment. Next, the internal
components should be inspected for damage. After reinstallation of the
instrument cover, sample lines are connected to the bulkhead on the rear
panel.

# 6.2.2 Tubing and gas delivery

All tubing should be constructed of Teflon™ with an outside diameter
(OD) of ¼ inch and a minimum inside diameter (ID) of ⅛ inch. The length
of the tubing should be less than 10 feet. For delivery of gases at
atmospheric pressure it might be necessary to use an atmospheric bypass
plumbing arrangement or to attach the analyzer inlet line to a ambient
air intake manifold that is vented to the atmosphere. An exhaust line of
the same dimensions as previously noted is connected to a suitable vent.
For proper analyzer operation, it is essential that no tubing be
restricted or kinked.

# 

# 6.2.3 Electrical connections

The 48C TLE is supplied with a three-wire grounding cord. Under no
circumstances should this grounding system be defeated. The instrument
must be plugged into an outlet of the appropriate voltage and frequency.
For these specifications, see page 1-3 in Chapter 1 of the operator's
manual.

# 6.3 Operation and Range Setting

Refer to Chapter 3 of the operator's manual for detailed descriptions
and views of the pushbuttons, menus and displays. When the power to the
instrument is turned on, the exhaust fan and the front panel display
will come on. Next, the central processing unit (CPU) will boot the
system and load the firmware. While an overnight warm-up is recommended,
a minimum 30-minute warm-up time should occur before proceeding.

# 6.3.1 Display

The front panel of the instrument has a 4 line by 20 character
alphanumeric display that shows the sample concentration, instrument
parameters, instrument controls and help/warning messages. The
pushbuttons on the front panel are used to access the menu driven
software. Some menus contain more items that can be displayed at one
time. If this is the case, the ↑ and ↓ pushbuttons are used to move the
cursor through the available choices.

# 6.3.2 Run Screen

Once the instrument loads the firmware, the display will read the CO
concentration as "CO PPM XX.XX", and show the time and the word "REMOTE"
below this. The instrument is now at the "RUN" menu and should always be
left in this mode when it is collecting ambient data. Press the "Menu"
button to access the main menu.

# 6.3.3 Range Displays

Use the down arrow to move to the "Range" menu. Press "Enter." The
"Range" menu contains the gas units (ppm), CO ranges, or the custom
ranges. In the upper right corner of the display, the word "SINGLE",
"DUAL", or AUTO" is displayed to indicate the active mode. The default
range is the "SINGLE" mode. Refer to page 3-11 of the operator's manual
for the beginning of the discussion of setting the limits for the CO
range and custom ranges.

# 6.4 Diagnostic Checks

Diagnostic checks to determine whether the 48C TLE is working properly
should be performed every time the site is visited---even though the
purpose of the visit may be to work with another instrument. The
diagnostic checks for the 48C TLE can be conducted manually or by using
the computer software. Figure 3 shows a menu tree for the diagnostic
checks that was taken from the manual for a similar instrument, the TEI
48 C-TL.

![](media/image3.png){width="6.375in" height="3.841666666666667in"}

[]{#__RefHeading___Toc185131906 .anchor}Figure 3. Menu Tree for
Diagnostic Checks

By pressing the "menu" button and following the menu tree, the desired
location can be easily reached. Note that because the TEI 48C TLE has
set upper and lower ranges for some of these diagnostic checks, the
operator's manual should be referenced for working with these ranges.
Use the following instructions to manually perform the diagnostic
checks.

> 1\. While in the "Run" menu, press the "Menu" button. This will put
> you into the main menu.
>
> 2\. From the main menu use the ↑ and ↓ pushbuttons move the cursor
> down so that the arrow is next to "Diagnostics" selection. Press
> "Enter."
>
> 3\. In the "Diagnostics Menu', toggle the arrow using the ↑ and ↓
> pushbuttons to align the arrow to the diagnostic to be evaluated. To
> view the results, press "Enter" record the information on a diagnostic
> data form. Figure 4 is the diagnostics data form used at the Burdens
> Creek site to record the results. The top portion of the form is used
> to record the diagnostic checks. The latter section is used to record
> the results of the QC checks discussed in Section 7 of this SOP.

**Environmental Protection Agency**

**Quality Control and Maintenance Records**

**TEI 48C TLE CO Analyzer**

Site Name/Location Date Time

Technician Instrument ID# Date of Last Calibration

  ---------------------- ----------------- -------------------- -------------
  TEI Diagnostics        Actual Reading    Acceptance Criteria  Acceptable?

  Range                                    0-5.000 ppm          

  Averaging Time                           10-300 seconds       

  CO Background                            0-12                 

  CO Span Coefficient                      0.900-1.100          

  Basic Voltage                            -105 to -115V        

  Power                                    ±0.1V, \>3.0V        
  (+5/+15/-15/Battery)                                          

  Internal Temperature                     8-47 °C              

  Chamber Temperature                      48-52 °C             

  Chamber Pressure                         650-760 mm Hg        

  Sample Flow                              0.35-1.0 L/min       

  S/R Ratio                                1.14-1.18            

  AGC Intensity                            150,000-250,000 Hz   

  Motor Speed                              100%                 

  Change Particle Filter Y N               Auto Zero Freq (Hrs) 
  ---------------------- ----------------- -------------------- -------------

**[Quality Control Results]{.underline}**

Calibrator Type/SN Certification Date Expiration Date

+----+-------+----------+------------+------------+--------+--------+
| P  | Exp   | Actual   | Observed   | Observed   | \%     | \%     |
| oi | ected |          |            |            | Dev    | Dev    |
| nt | CO,   | Cal      | 1-min.     | 1-minute   | iation | iation |
| \# | ppb   | ibrator, | average,   | average,   | EFW    | ESC    |
|    |       | ppb (Y)  |            | ppb, ESC   |        |        |
|    |       |          | ppb EFW    |            |        |        |
|    |       |          |            |            |        |        |
|    |       |          | \(X\)      |            |        |        |
+----+-------+----------+------------+------------+--------+--------+
| 1  |       |          |            |            |        |        |
+----+-------+----------+------------+------------+--------+--------+
| 2  |       |          |            |            |        |        |
+----+-------+----------+------------+------------+--------+--------+
| 3  |       |          |            |            |        |        |
+----+-------+----------+------------+------------+--------+--------+
| 4  |       |          |            |            |        |        |
+----+-------+----------+------------+------------+--------+--------+
| 5  |       |          |            |            |        |        |
+----+-------+----------+------------+------------+--------+--------+
| 6  |       |          |            |            |        |        |
+----+-------+----------+------------+------------+--------+--------+

STD#, PPM, PSIG Certification Date Expiration Date

Unadjusted 3-point Calibration Unadjusted M-P Calibration Adjusted M-P
Calibration

Zero pt [+]{.underline} 20 ppb □Y □N Precision Point [+]{.underline} 15%
of expected value □Y □N All calibration points ± 10% □Y □N

EFW Regression Criteria: XY (0.9800 \< M \<1.0200) \_\_\_\_\_\_\_
(-40.00 \<B\< 40.00) \_\_\_\_\_\_\_ R^2^ (\> .9950) \_\_\_\_\_\_\_

Comments:
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

[]{#__RefHeading___Toc185131907 .anchor}Figure 4. Data Form for
Diagnostic Checks and Quality Control Checks: TEI 48C TLE CO Analyzer

> 4\. Press "Menu" and then "RUN" to return the analyzer to the main
> menu. Once the diagnostic checks have been established and recorded
> for the 48C TLE, it is time to check the calibration of the analyzer
> and, if required or scheduled, to calibrate the instrument.

# 6.5 Initial and Periodic Multipoint Calibration

The next step is to conduct an initial or periodic adjusted multipoint
(MP) calibration of the 48C TLE analyzer. Adjusted MP calibrations are
conducted every 90 days. Before beginning the calibration process,
ensure that both the ENVIDAS FW DAS and the ESC 8832 DAS are set "off
line." This section of the SOP will describe how to compare and adjust
the digital response of the 48C TLE to various calculated concentrations
of CO. The calibration points are generated by diluting a higher
concentration of CO from a NIST-traceable calibration gas to a target
concentration. The recommended ranges for the MP calibration points are
detailed in Table 1. As each calibration point is generated, the
responses shown by the DAS should be compared to the calculated value.
If the difference exceeds +/-10%, the instrument's response should be
adjusted as detailed in the following sections.

# 6.5.1 Pre-calibration checks

Prior to conducting any calibrations, it is important to ensure that the
analyzer is properly warmed up and leak-free. To ensure proper
operation, the maintenance procedures described in Section 10 of this
SOP should be reviewed and conducted as necessary.

# 6.5.2 Adjustment to Zero Air

> The instrument response to zero air is adjusted by performing the
> following steps:

1.  For a minimum of 15 minutes, allow the instrument to sample zero air
    from a manifold that is at near atmospheric pressure.

2.  Bring up the main menu by pressing the "Menu" button on the front
    panel of the instrument.

3.  Use the ↑ or ↓ button to move the cursor to align with "Calibration"
    on the screen. Continue to press the arrow button(s) until the
    cursor is aligned with the "Calibrate Zero" position on the screen
    and then press "Enter."

4.  The next screen available will show a CO concentration (e.g., CO PPM
    X.X) above the words "SET TO ZERO?" Once the analyzer has reached a
    stabilized reading for zero air, press "Enter", "Menu", and then
    press "Run." The baseline is now adjusted to reflect the
    instrument's response to zero air.

[]{#__RefHeading___Toc185132001 .anchor}Table 1. Operating Parameters
for the TEI 48C TLE CO Analyzer

+-----------------+-----------------+-----------------------------------+
| Item            | Range           | Comments                          |
+-----------------+-----------------+-----------------------------------+
| Units           | Parts per       | Recommended                       |
|                 | million (ppm)   |                                   |
+-----------------+-----------------+-----------------------------------+
| Full scale      | 0 to 5.000 ppm  | Suggested range.                  |
| range           |                 |                                   |
+-----------------+-----------------+-----------------------------------+
| Compressed gas  | 250-300 ppm     | NIST traceable EPA Protocol #1    |
| cylinder        |                 | cylinder.                         |
+-----------------+-----------------+-----------------------------------+
| Calibration     | []{.mark}       |                                   |
| point:          |                 |                                   |
+-----------------+-----------------+-----------------------------------+
| > a\. zero      | 0-0.010 ppm     | There are a number of             |
|                 |                 | commercially available vendors of |
|                 |                 | zero air sources.                 |
+-----------------+-----------------+-----------------------------------+
| > b\. Level 1   | 4.000-5.000 ppm | NIST traceable EPA Protocol #1    |
| > span          |                 | cylinder                          |
+-----------------+-----------------+-----------------------------------+
| > c\. Midpoint  | 2.000-2.500 ppm | NIST traceable EPA Protocol #1    |
| > span          |                 | cylinder                          |
+-----------------+-----------------+-----------------------------------+
| > d\. Precision | 0.250-0.500 ppm | NIST traceable EPA Protocol #1    |
| > point         |                 | cylinder                          |
+-----------------+-----------------+-----------------------------------+

# 6.5.3 Adjustment to Calibration Gas (Span point)

The instrument response to the NIST traceable calibration gas is
adjusted by performing the following steps:

  -----------------------------------------------------------------------
  **NOTE**: Do not perform calibrations during the time that the analyzer
  is undergoing the automated internal auto-zero function.

  -----------------------------------------------------------------------

> 1\. Adjust the Environics® 9100 calibration unit to generate a known
> concentration of CO. Allow the instrument to sample calibration gas
> from a manifold that is at near atmospheric pressure for a minimum of
> 15 minutes.

2.  On the front panel of the 48C TLE press the "Menu" button. This will
    bring up the main menu. Use the ↑ or ↓ button to move the cursor
    until it aligns with the "Calibration" selection and then press
    "Enter."

3.  This next screen is the "Calibration" screen. In this screen press
    the ↓ ↑ buttons until the cursor aligns with the "Calibrate CO"
    selection and then press "Enter."

4.  The first line of the display shows the current CO concentration
    reading. The second line shows the instrument range and the third
    line states, "SET TO...... XX.XX." The next line shows "↓ ↑
    INC/DEC." The cursor should be under one of the digits in the third
    line. Use the "↓↑→←" buttons on the front panel to enter in the
    concentration that is being generated by the calibration system.
    Press "Enter."

5.  Press "Menu" and then press "Run." This will adjust the response of
    the instrument to the calibration gas concentration. The zero and
    span of the instrument is now set.

# 6.5.4 Multipoint Calibrations

Use the calibration system instructions given in section 7.4 to continue
generating the desired concentrations that fall within the calibration
ranges shown in Table 1. Record the data in the lower section of the
data form shown in Figure 4. Generate a linear regression by plotting
the analyzer response against the calculated concentration. Observe that
the calculated values for the regression parameters do not exceed the
regressions limits: slope (M), 0.9800 \< M \< 1.0200; intercept (B),
-40.00\< B \< 40.00, and R^2^ \> 0.9950.

# 6.5.4.1 Frequency of calibrations

> The operating manual recommends that a multipoint calibration be
> performed: every three months; any time any major disassembly or
> servicing of components is performed; and any time that zero or span
> checks give results outside of the performance criteria.

# 6.5.4.2 Periodic Quality Control Checks 

> For the Burdens Creek site, periodic zero, span, and precision checks
> may be conducted during a routine site visit by the operator
> responsible for the CO monitoring operations. The details for
> conducting these checks are provided in Section 7.

# 6.5.5 Auto-Zero Function

The TEI 48C TLE analyzer is equipped with an automatic zero calibration
function. In the default setting, this auto-zero function will occur at
the end of the hour. The auto-zero function can be modified to occur at
a frequency from once per hour to any increment up to once per day. It
is important that the operator be aware of the auto-zero function in
that no calibrations or QC procedures should be conducted at or near the
scheduled time for the auto-zero.

When the auto-zero function is activated, the 48C TLE output will be at
or close to zero, since the detector is sampling air with the CO
"scrubbed out," and the display will show "ZERO." If the auto-zero data
is recorded, the operator must flag the data in the DAS.

The suggested initial minimum frequency of auto-zero cycles is two times
per day, or every 12 hours. Based on instrument performance and
assessment of zero drift during external manual or automatic
calibrations, the auto-zero cycle frequency can be modified, although at
least one auto-zero cycle per day is highly recommended due to the
inherent zero drift characteristics of all trace-level CO analyzers.

**7.0 Routine Site Visits**

Visits to the Burdens Creek site to check the CO analyzer and other
equipment are made biweekly. Pollutant monitors for oxides of nitrogen,
ozone, and sulfur dioxide, as well as other site systems are usually
checked on a routine schedule. Listed below are site visit procedures
that pertain to the TEI 48C TLE CO analyzer and the supporting
monitoring equipment. To be able to carry out these checks it is
necessary that the site visitor be fully trained and familiar with
operator's manuals for all equipment and with their specific SOPs. Any
findings indicating the need for analyzer maintenance or recalibration
must be recorded in the site logbook and reported to the site
supervisor.

# 7.1. Inspect Shelter Condition and Status

When visiting the site by vehicle, park the vehicle well away from the
ambient air sampling inlet to avoid contamination from exhaust
emissions. Before entering the Burdens Creek shelter, conduct a visual
survey of the site; checking the external sampling lines for cleanliness
and integrity; check the meteorological tower components, and search for
any evidence of damage or vandalism to the shelter and sample inlets.

# 7.2 Operational Requirements for Entering the Station

When entering the station, observe the operational requirements posted
on the far wall of the monitoring station.

1.  Sign in the site logbook with your name, the time and date, the
    purpose of the visit, etc.

2.  Check the room temperature displayed on the digital temperature
    sensor located on the far side of the station. Record the reading in
    the logbook. If the temperature is markedly different from the
    usually 24 to 26 °C range or is outside the 20 to 30°C limits,
    record these observations and report the findings to the station
    supervisor.

  -----------------------------------------------------------------------
  **Note**: Cold conditions inside the shelter can cause condensation of
  water vapor inside the glass sampling manifold and inside Teflon
  sampling tubing. If visual observation shows water condensation, notify
  the site supervisor promptly and take action to reset the shelter
  temperature, remove the condensed water, and conduct analyzer
  calibration checks

  -----------------------------------------------------------------------

3.  Before running the diagnostic check on the CO analyzer, observe the
    ENVIDAS FW display to verify that all systems in the station are
    operating properly. Conduct a visual check of each analyzer's front
    panel display for reasonableness of the pollutant concentrations and
    for indications of FAULT or other messages. Make a notation in the
    station logbook that the checks were made and write down any FAULT
    or message indicating out-of-tolerance conditions [for
    any]{.underline} analyzer.

4.  Determine and make a notation of the type of calibration to be
    executed. The unadjusted 3-point calibration is conducted every two
    weeks. The adjusted multipoint calibration is conducted every 90
    days.

# 7.3 Data Acquisition Systems 

Parallel data acquisition systems are used for data collection at the
Burdens Creek site. Use the keypad for each system to link to the data
logger. On the ENVIDAS FW (EFW) use the keypad to activate the channel
selection screen (Figure 5). The screen will promptly display all the
parameters being monitored by the EFW system. The screen updates every 5
seconds. To view the past day's data, click on the icon for the
"Reporter" program to bring up the data. Compare the instantaneous
values displayed by the EFW to those displayed on the front panel of the
48C TLE. The values should be identical.

[]{#__RefHeading___Toc185131908
.anchor}![](media/image4.png){width="6.0in" height="3.75in"}Figure 5.
ENVIDAS FW Dynamic Tabular Channel Display

When conducting calibration checks, the data acquisition systems must be
set "off line." Go to the EFW configuration menu, enter the password
("a"), locate the channel associated with the instrument, change the
online status to "Off" or "Off-Scan", and then SAVE the changes to the
channel.

Next, activate the ESC 8832 DAS by pressing any key on its laptop
keypad. The main display screen for the ESC is shown in Figure 6. Verify
that the "Digi-Trend Scheduler" program is running by looking for the
red clock icon on the program tray. Click on "Stop Scheduler" to prevent
the program from attempting to communicate through the serial port while
it is being used for manual communications in Link to Logger.

At the main menu, type the operator's initials in the "User Name" box.
No Password is required. Click on the "ESC" logo. Select "OK", select
version 540S, go to the Utilities screen, and select "Link to Logger."
Log in by entering the letter "L" and then enter the password, "EPA".
Within the configuration menu ("C"), select Disable/Mark Channel Offline
("M"), and toggle the appropriate data channel with the space bar, thus
turning the instrument to "disabled" to prevent non-valid data from
being recorded as valid.

[]{#__RefHeading___Toc185131909 .anchor}Figure
6![](media/image5.png){width="5.75in" height="3.091666666666667in"}. ESC
8832 Main Menu Display

# 

Finally, turn the ambient air solenoid to the CO analyzer to the
"normally closed" position to provide calibration air to the analyzer.
To do this go to the "setup" of the EFW, select:

> view,
>
> dynamic data,
>
> input/output, and then
>
> click the circle corresponding to the CO analyzer and listen for the
> sound of the solenoid switching on (circle changes from clear to red).

# 7.4 Calibration System

The dynamic calibration system used at the Burdens Creek site is an
Environics® Series 9100. The instrument can be programmed to
automatically perform a zero, span, and precision check, and multipoint
calibrations of ambient analyzers. Programming is executed using the
pushbuttons located on the front panel. The front panel also has a
backlit 25 line by 80 character liquid crystal display. To conduct an
unadjusted, 3-point calibration, set the calibrator so that it produces
only zero air:

> access the concentration mode on the calibrator by pushing the "F1"
> button,

-   adjust the CO concentration to read 0.0,

-   push "F1" again.

The CO analyzer is now sampling zero air. Observe the display on the
calibrator and the responses of the data acquisition systems until
stable readings are shown for each instrument. For this zero air
response, record all of the information requested in the quality control
results section of the data form used to record the diagnostic
information (Figure 4). If the responses are out of limits, refer to the
trouble shooting section of the operator's manual for the CO analyzer.

On the Environics® calibrator, adjust the CO concentration to 90% of
full-scale, wait for stable readings from the calibrator and each DAS.
Record the values observed for the stable readings from each device on
the data form.

Set a new concentration on the calibrator for a precision check (250 --
500 ppb). Record the values once stable readings are displayed on the
instruments. Set the concentration back to zero and observe the
responses shown on the DASs. The instrument zero response (baseline) can
optionally be adjusted at this time using the procedure specified in
section 6.5.2.

If an unadjusted three point calibration (zero, span, precision) is
being conducted, no further actions are necessary except for scheduled
maintenance actions such as changing a particulate filter. If an
[unadjusted]{.underline} multipoint calibration is being performed,
complete all the points specified on the data form and calculate a
linear regression. Observe that each variable of the regression is
within the specified limits; where for the slope (M), 0.9800 \< M \<
1.0200, for the intercept (B), -40.00\< B \< 40.00 and R^2^ \> 0.9950.
If the regression criteria are not met, determine a plan for
troubleshooting the calibration system, the analyzer, and/or the data
acquisition systems. Repeat the multipoint calibration (now an
[adjusted]{.underline} calibration) and use the instrument controls to
adjust the 48C-TLE response to zero and span concentrations (sections
6.5.2 and 6.5.3) before completing the remainder of the specified
points.

# 7.5 Return Systems to Monitoring Mode

Turn the ambient air solenoid to the CO analyzer to the "normally open"
position to re-connect the analyzer to the ambient air stream. To do
this go to the "setup" of the EFW, select:

> view,
>
> dynamic data,
>
> input/output, and then
>
> click the circle corresponding to the CO analyzer and listen for the
> sound of the solenoid switching off (circle changes from red to
> clear).

For the EFW DAS, put the "STATE" to "On" from "Off" or "Off-scan" for
the appropriate channel. Finally, stop the Environics calibrator and set
it to "READY" mode.

For the ESC 8832 DAS, within the configuration menu ("C"), select
Enable/Mark Channel Online ("E"), and toggle the appropriate data
channel with the space bar, thus turning the instrument to "enabled" to
commence the collection of ambient. Use the \<Esc\> key to back out of
the 8832 menu and logoff from the unit with the "O" menu choice. Exit
from the E-DAS menu program and restart the Scheduler program.

# 7.6 Other Maintenance Checks

In accordance with the biweekly schedule, change the particle filter on
the CO analyzer(s). When finished, allow the instrument(s) to sample
zero air and return to stable readings. Finally, set all instrument back
to on-line conditions (i.e., sampling ambient air). See Section 9 of
this SOP for a discussion of preventive maintenance activities.

# 7.7 Operational Requirements---Exiting the Station

As a final check before leaving the station, review the operational
requirements posted on the door. Make sure that the following conditions
are in place:

> Environics calibrator is in "Ready Mode"
>
> Manifold solenoid is turned off
>
> EFW DAS channel STATE is on
>
> ESC DAS channel is enabled
>
> Normalcy of EFW readings are verified

# 8.0 Quality Indicators

Quality control for continuous electronic instruments, such as the TEI
48C TLE CO analyzer consists of performing the diagnostic checks,
maintenance and calibrations as discussed earlier in this document. In
Section 6, Figure 4 presented an example of a data form for recording QC
and maintenance information that was developed by the EPA for the 48C
TLE. In addition, information in Table 1, which shows the recommended
operation parameters for the 48C TLE, should be reviewed. The operating
parameters include recommended operating range, calibration ranges, and
recommended cylinder concentrations. The following sections note the
criteria for the quality indicators, precision, bias,
representativeness, completeness, and comparability for monitoring CO at
the Burdens Creek.

# 

# 8.1 Precision Evaluation

Precision is defined as the measure of agreement among individual
measurements of the same property taken under the same conditions. For
CO, this refers to testing the 48C TLE at concentrations between 0.250
and 0.500 ppm (250 and 500 ppb). The test must be performed, at a
minimum, once every two weeks. The measured precision point must agree
with the expected value within ±15%. The Burdens Creek site data set
will be assumed to have met the DQO if the measurement quality objective
(MQO) of 15% or better for precision is consistently met over the months
and years of site operation.

# 8.2 Bias Evaluation

Bias is defined as the degree of agreement between a measured value and
the true, expected, or accepted value. For CO, this refers to testing
the 48C TLE at various concentrations between the level of the precision
point and more upscale calibration concentrations. The test must be
performed, at a minimum, once every two weeks. The Burdens Creek site
data set will be assumed to have met the DQO if the measurement quality
objective (MQO) of 10% or better for bias is consistently met over the
months and years of site operation.

# 8.3 Representativeness

Representativeness refers to whether the data collected accurately
reflect the conditions being measured. It is the data quality indicator
most difficult to quantify. Unless the samples are truly representative,
the other indicators are meaningless. Since the NCore siting criteria
are generally intended to represent neighborhood, urban, or regional
scales, the CO trace level criteria are the same. The National
Monitoring Strategy, available on the AMTIC web site, discusses
representativeness aspects of NCore monitoring sites.

# 8.4 Completeness

Completeness is defined as the amount of data collected compared to a
pre-specified target amount. For CO, EPA requires a minimum completeness
of 75% (40 CFR 50, App.H.3) with a goal of 90%. Typical completeness of
data capture by the TEI 48C TLE CO analyzer should exceed 90%.

# 8.5 Comparability

Comparability is defined as the process of collecting data under
conditions that are consistent with those used for other data sets of
the same pollutant. The TEI 48C TLE meets the MQOs for a trace level CO
instrument.

# 

# 8.6 Method Detection Limits

The method detection limit (MDL) or detectability refers to the lowest
concentration of a substance that can be determined by a given
procedure. The TEI 48C TLE analyzer must be able to detect a minimum
value of 0.040 ppm of CO.

# 8.7 Measurement Quality Objectives

Table 2 is a tabular presentation of the measurement quality objectives
(MQOs) for CO set for the Burdens Creek site.

[]{#__RefHeading___Toc185132002 .anchor}Table 2. Measurement Quality
Objectives for Carbon Monoxide: Burdens Creek Site

+-----------+-------------+------------+----------------+------------+
| **Pa      | *           | **         | **Minimum      | *          |
| rameter** | *Criteria** | Acceptable | Frequency      | *Reference |
|           |             | Range**    | (required/     | /Comment** |
|           |             |            | recommended)** |            |
+===========+=============+============+================+============+
| **C       |             |            |                |            |
| ritical** |             |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Precision | 250-500 ppb | Percent    |                |            |
|           |             | d          |                |            |
| (single   |             | ifference: |                |            |
| analyzer) |             | ±15%       |                |            |
+-----------+-------------+------------+----------------+------------+
| Zero/span |             | Zero       | Daily          |            |
| ch        |             | drift: 20  |                |            |
| eck-level |             | ppb        |                |            |
| 1         |             |            |                |            |
|           |             | Span       |                |            |
|           |             | drift: 10% |                |            |
+-----------+-------------+------------+----------------+------------+
| **Oper    |             |            |                |            |
| ational** |             |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Shelter   |             | 20 to 30   |                | 40 CFR     |
| te        |             | °C (hourly |                | Part 53.20 |
| mperature |             | average)   |                |            |
|           |             | or operate |                |            |
|           |             | instrument |                |            |
|           |             | according  |                |            |
|           |             | to         |                |            |
|           |             | manu       |                |            |
|           |             | facturer's |                |            |
|           |             | spec       |                |            |
|           |             | ifications |                |            |
+-----------+-------------+------------+----------------+------------+
| Te        |             | ≤ ±3°C     | Daily (hourly  | digital    |
| mperature |             | over 24    | values)        | t          |
| control   |             | hours      |                | emperature |
|           |             |            |                | recording  |
|           |             |            |                | r          |
|           |             |            |                | ecommended |
+-----------+-------------+------------+----------------+------------+
| Precision |             | Precision  |                |            |
| and bias  |             | : 95% CI   |                |            |
|           |             | \< 15%     |                |            |
| (Site     |             |            |                |            |
| Level)    |             | Absolute   |                |            |
|           |             | bias       |                |            |
|           |             | estimate:  |                |            |
|           |             | ±10%       |                |            |
+-----------+-------------+------------+----------------+------------+
| In        |             | Mean       | Once per year  |            |
| dependent |             | absolute   | if no NPAP     |            |
| audit     |             | difference |                |            |
|           |             |            |                |            |
| (NC-DAQ)  |             | ≤ 10%      |                |            |
+-----------+-------------+------------+----------------+------------+
| Federal   | Mean        | Mean       | Once per year  |            |
| audit     | co          | absolute   | at selected    |            |
| (NPAP)    | ncentration | difference | sites          |            |
|           | level       |            |                |            |
|           |             | ≤ 10%      |                |            |
+-----------+-------------+------------+----------------+------------+
| Ca        | Multipoint  | Slope:     | Upon receipt,  |            |
| libration | calibration | 1.00 ±     | after repair   |            |
| (GPT      | (at least 4 | 0.02,      | or adjustment, |            |
| capable)  | points      |            | or once every  |            |
|           | including   | Intercept: | 90 days        |            |
|           | zero)       | ± 40 ppb,  |                |            |
|           |             | R^2^:      |                |            |
|           |             | 0.995      |                |            |
+-----------+-------------+------------+----------------+------------+
| Zero air  |             | \< 40 ppb  | Annual zero    | Check zero |
|           |             |            | air purity     | air        |
|           |             |            | check          | generator  |
|           |             |            |                | against an |
|           |             |            |                | i          |
|           |             |            |                | ndependent |
|           |             |            |                | standard   |
+-----------+-------------+------------+----------------+------------+
| Gaseous   | NIST        | ± 1%       |                |            |
| standards | Traceable   |            |                |            |
|           | 250-300 ppm |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Gaseous   | 0-20 L/min  | Accuracy ± | Once per 6     | Verify air |
| Dilution  | for zero    | 1% (NIST   | months         | and gas    |
| Systems   | air         | traceable) |                | flows with |
| (mass     |             |            |                | a NIST     |
| flow      | 0-100cc/min | Linearity: |                | traceable  |
| co        | gas flow    | ± 1%       |                | primary or |
| ntroller) |             |            |                | secondary  |
|           |             | Precision: |                | standard.  |
|           |             | ± 1%       |                | If a       |
|           |             |            |                | secondary  |
|           |             |            |                | standard   |
|           |             |            |                | is used,   |
|           |             |            |                | it must be |
|           |             |            |                | certified  |
|           |             |            |                | against a  |
|           |             |            |                | NIST       |
|           |             |            |                | primary    |
|           |             |            |                | standard   |
|           |             |            |                | annually.  |
+-----------+-------------+------------+----------------+------------+
| Detection | Noise       | 20 ppb     | Once per year  |            |
|           |             | (root mean |                |            |
|           |             | square)    |                |            |
+-----------+-------------+------------+----------------+------------+
|           | Lower       | 40 ppb     | Once per year  |            |
|           | detectable  |            |                |            |
|           | level       |            |                |            |
+-----------+-------------+------------+----------------+------------+
|           | Method      | 18 ppb     | Once per year  |            |
|           | detection   |            |                |            |
|           | limit       |            |                |            |
+-----------+-------------+------------+----------------+------------+
| **Sys     |             |            |                |            |
| tematic** |             |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Standard  |             | ppb (final | All data       |            |
| reporting |             | units in   |                |            |
| units     |             | AQS)       |                |            |
+-----------+-------------+------------+----------------+------------+
| Data      |             | Hourly     |                |            |
| reported  |             |            |                |            |
| (AQS)     |             |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Data      |             | 5 minute   |                |            |
| stored    |             | values     |                |            |
| (local)/  |             |            |                |            |
| averaging |             |            |                |            |
| interval  |             |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Com       | Annually    | 75% of     |                | Goal is    |
| pleteness |             | daily      |                | minimum of |
|           |             | values     |                | 90%        |
+-----------+-------------+------------+----------------+------------+
|           | Daily       | 75% of     |                |            |
|           |             | hourly     |                |            |
|           |             | values     |                |            |
+-----------+-------------+------------+----------------+------------+
|           | Hourly      | 75% of     |                |            |
|           |             | hour       |                |            |
+-----------+-------------+------------+----------------+------------+
| Sample    |             | \<20       | Continually    | 40 CFR     |
| path      |             | seconds    |                | Part 58,   |
| residence |             |            |                | Appendix E |
| times     |             |            |                |            |
+-----------+-------------+------------+----------------+------------+
| Sample    |             | Bo         | Continually    | 40 CFR     |
| probe     |             | rosilicate |                | Part 58,   |
| material  |             | glass, FEP |                | Appendix E |
|           |             | & PTFE     |                |            |
|           |             | (Teflon)   |                |            |
+-----------+-------------+------------+----------------+------------+
| Siting    |             | Per 40 CFR | Continually    | 40 CFR     |
|           |             | Part 58,   |                | Part 58,   |
|           |             | Appendices |                | Appendices |
|           |             | D and E    |                | D and E    |
+-----------+-------------+------------+----------------+------------+
| Equipment |             | Reference  |                |            |
|           |             | or         |                |            |
|           |             | Equivalent |                |            |
|           |             | Method (if |                |            |
|           |             | used for   |                |            |
|           |             | NAAQS      |                |            |
|           |             | deter      |                |            |
|           |             | minations) |                |            |
+-----------+-------------+------------+----------------+------------+

# 

# 9.3 Performance Evaluation Audits

A performance evaluation (PE) is a quantitative comparison of results
between the Burdens Creek equipment and an independent audit system
brought to the site. The audit system produces gas concentrations that
are assayed by the 48C TLE CO analyzer. The responses of the on-site
analyzer are then compared against the calculated concentration from the
independent audit system and a linear regression is generated.

The PE is conducted through the EPA Regional Office by means of
participation in the National Performance Audit Program (NPAP). The
Burdens Creek/Ambient Air Monitoring Group will participate in the NPAP
on an annual basis. When NPAP audits are not available, performance
evaluations will be performed through a cooperative agreement with the
North Carolina Division of Air Quality, Raleigh, NC. An acceptable audit
result requires that the average difference between the designated audit
values and the site's CO analyzer be no greater than 10 percent.

A through-the-probe audit may be a component of the PE. If so, known
concentrations of CO will be introduced at the outside ambient air inlet
of the station and will traverse the all tubing and the sampling
manifold from which the 48C TLE analyzer samples.

# 9.4 Technical Systems Audits

A technical systems audit (TSA) is a thorough, systematic, on-site
qualitative examination of facilities, equipment, training, technical
procedures, record-keeping activities, data validation, data management,
and reporting aspects of a monitoring station or system. Evaluation of
the Burdens Creek site's CO measurement system is a component of
monitoring site operations. Ideally, technical systems audits are
conducted by the EPA Regional Office at least once every 3 years.

The OAQPS/AAMG also performs an annual internal technical systems audit
of the site operations. For this type of assessment, the AAMG will use
the technical systems audit forms found in Appendix 15 of the *Quality
Assurance Handbook for Air Pollution Measurement Systems*, Volume II,
Part 1.

# 9.5 Procedures in the Event of an Audit Failure

An unacceptable audit result (average difference between the designated
audit values and the site's CO analyzer greater than 10 percent) must be
followed up with appropriate corrective action. These actions may
include:

-   Repeating the audit with another independent calibrator and/or gas
    standard

-   Verification of the station calibrator flow calibration and/or gas
    standard certification

-   Investigating for potential leaks between audit device(s) and
    instrument and/or calibration manifold

-   Insuring that sufficient audit airflow is being provided for a
    through-the-probe audit, or that the station manifold blower has
    been disconnected as necessary

-   Reviewing the analyzer diagnostics and/or review of maintenance
    procedures to investigate instrument malfunction

Once the source of the audit discrepancy has been identified and
corrected, the audit should be repeated to obtain an acceptable result
with the average difference between the designated audit values and the
site's CO analyzer of no greater than 10 percent.

# 10.0 Preventive Maintenance

Preventive maintenance should be a deterrent to down-time and data loss.
Table 3 lists the preventive maintenance items that are should be
performed. Please see section

5-1 of the owner's manual. Section 5-1 also has a list of the spare
parts that the operator should keep in stock.

[]{#__RefHeading___Toc185132003 .anchor}Table 3. Preventive Maintenance
Schedule for the TEI 48C TLE

  ------------------------------------ -----------------------------------
  Event                                Frequency

  Replace particle filter              Biweekly to monthly depending on
                                       ambient particulate levels

  Diagnostics checks                   Biweekly

  Perform QC gas challenge             Bi-weekly (daily recommended)

  Replace IR source                    As needed

  Leak check and pump check out        Annually by contractor

  Inspect pneumatic lines              Semi-annually

  Clean inside of chassis              As needed

  Rebuild or replace pump              As needed

  Clean optic bench                    As needed

  Replace wheel motor                  As needed

  Replace gases in correlation wheel   As needed
  ------------------------------------ -----------------------------------

# 10.1 Instrument Troubleshooting

The TEI 48C TLE manual has an excellent troubleshooting guide in Section
6-1 of the manual. For details on using the Test Functions for
predicting failures, please reference this section.

# References

1.  Standard Operating Procedures. Thermo Electron Corporation Model 48C
    TLE Trace Level CO Instrument. Version 1.10, Final. March 17, 2005

2.  Ambient Air Surveillance, [Code of Federal Regulations]{.underline}.
    Title 40, Part 58.

3.  Model 48C Trace Level Gas Filter Correlation CO Analyzer.
    Instruction Manual P/N 14023. THERMO Environmental Instruments Inc.
    8 West Forge Parkway. Franklin, Massachusetts 02038.

4.  Technical Assistance Document (TAD) for Precursor Gas Measurements
    in the NCore Multi-pollutant Monitoring Network. Version 4. U.S.
    Environmental Protection Agency. Office of Air Quality Planning and
    Standards. Emissions, Monitoring, and Analysis Division. Research
    Triangle Park, North Carolina. 27711. EPA-454/R05-003. September
    2005.