6. Sampler Maintenance by Site Operators.pdf

Sampler Maintenance UCD SOP #201; Version 3.6

July 15, 2022

UCD IMPROVE Standard Operating Procedure #201

Sampler Maintenance by Site Operators

Interagency Monitoring of Protected Visual Environments Air Quality Research Center

University of California, Davis

Version 3.6

Prepared By: ____________________________________ Date: _________________

Reviewed By: ___________________________________ Date: _________________

Approved By: ___________________________________ Date: _________________

DocuSign Envelope ID: B7FD5BBA-530F-4157-9CF8-96D687049791

9/26/2022

July 15, 2022

DOCUMENT HISTORY

Date Modified

Initials Section/s Modified

Brief Description of Modifications

04/09/21 SRS All Added sections (2, 3, 4, 5, 6, 7, 10, 11, 12) and moved sections (2 to 7, 3 to 8, 5 to 9);

redistributed content to fit document guidelines.

5/19/21 IVP 4,5,10,11 Added missing sections

6/13/22 IVP 2,3,9 Small clarifying changes. Removed redundant information

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TABLE OF CONTENTS

1. Purpose and Applicability

2. Summary of the Method

3. Definitions

4. Health and Safety Warnings

5. Cautions

6. Interferences

7. Personnel Qualifications

8. Equipment and Supplies

8.1 Collocated “X” Module Sampling

8.2 Special Studies

9. Procedural Steps

9.1 Schedules

9.1.1 Sampling Schedule

9.1.2 Sample Change Schedule

9.1.3 Maintenance Schedule

9.2 Sampler Controller

9.2.1 Normal Mode

9.2.2 Changing Cartridge Mode

9.2.3 Diagnostic Mode

9.2.4 Initializing Mode

9.3 PM2.5 Sampling Modules

9.3.1 PM2.5 Module Inlet and Cyclone

9.3.2 Critical Orifice Flow Control

9.3.3 PM2.5 Module Flow Rate Measurement

9.3.4 PM2.5 Module Filter Cassettes and Cartridges

9.4 PM10 Sampling Module

9.4.1 PM10 Module Inlet and Cyclone

9.4.2 PM10 Module Flow Rate Measurement

9.4.3 PM10 Module Filter Cassettes and Cartridges

9.5 Sampler Installation

9.6 Tuesday Sample Changes

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9.6.1 Preparation

9.6.2 Sample Change Procedures

9.7 Troubleshooting Guide

9.7.1 Common Sampler Problems

9.7.2 Sampler Configuration

10. Data and Records Management

11. Quality Assurance and Quality Control

12. References

LIST OF FIGURES

Figure 1. Photo of the IMPROVE aerosol sampling modules inside a shelter Figure 2. Picture of a blue box showing the three filter bags Figure 3. Picture of the contents of one re-sealable bag Figure 4. Sample cartridge for the 2B module (yellow sticker) with four cassettes Figure 5. Sampling calendar for November and December 2015 Figure 6. Standard IMPROVE aerosol sampler configuration Figure 7. Controller module Figure 8. Controller connections and relays Figure 9. Controller connections and relays Figure 10. Current status, sampling is active Figure 11. Current status, idle screen Figure 12. Current status, sampling complete, filter change required Figure 13. PM2.5 module from the IMPROVE aerosol sampler Figure 14. Flow diagram for IMPROVE PM2.5 module Figure 15. PM10 module from the IMPROVE sampler Figure 16. Field logsheet for sample cartridges with three cassettes Figure 17. Photos illustrating the removal of position 3 cassette Figure 18. Home screen with filter readings button Figure 19. Select operator initials screen Figure 20. Start Exposed Filter Readings screen Figure 21. Flow rate and pressure readings screen Figure 22. Continue screen Figure 23. Change filter screen Figure 24. PM2.5 cassette orientation Figure 25. PM10 cassette orientation Figure 26. Active sampling Tuesday sample change Figure 27. Verify movable filter position is installed Figure 28. Clean (Initial) filter readings screen Figure 29. Low flow through cyclone warning

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Figure 30. Problem still detected Figure 31. Lost Ebox connection error screen Figure 32. Software connection error screen Figure 33. Check sample logsheet values Figure 34. Replace memory card screens Figure 35. Memory card warning Figure 36. Home screen with current status Figure 37. Filter Readings interrupted Figure 38. Low ET warning Figure 39. Settings menu Figure 40. Change date and time screen Figure 41. Change Time Zone screen Figure 42. Advanced Menu Password screen Figure 43. Site configuration Figure 44. Shutdown Figure 45. Edit schedule Figure 46. Maintenance menu Figure 47. Edit module Figure 48. Controller Part Number Figure 49. Site info Figure 50. Help screens 1 and 2

LIST OF TABLES

Table 1. Types of cartridges for 1-in-3-day sampling Table 2. Elevation factors for a range of elevations

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1. PURPOSE AND APPLICABILITY

This standard operating procedure describes the maintenance procedures of IMPROVE samplers deployed in the field across a diverse landscape.

IMPROVE (Interagency Monitoring of Protected Visual Environments) is a cooperative program of the National Park Service, National Forest Service, Bureau of Land Management, Fish and Wildlife Service, Environmental Protection Agency, and state and tribal organizations. IMPROVE was established in 1985 to aid the creation of Federal and State implementations for the protection of visibility in Class I areas (156 national parks and wilderness areas) as stipulated in the 1977 amendments to the Clean Air Act.

The first IMPROVE samplers were deployed in 1988 at twenty sites. The number of sites has increased significantly over the years, which includes sites in the United States, the Virgin Islands, Canada, and South Korea. 1

Every IMPROVE site employs an aerosol sampler to collect particulate matter samples below 2.5 µm (PM2.5) and below 10 µm (PM10). The Version 1 IMPROVE aerosol sampler was used in the network from 1988 to 2000. In 2000, the Version 2 IMPROVE aerosol sampler was introduced, and the sampling protocol changed from twice a week to every third day. The new schedule meant consistency with the EPA-designated schedule for the speciation trends network (STN), which operates in urban areas. The Version 3 controller and Eboxes were developed in 2010 through 2012 and 2013, but never made it to field deployment. The Version 4 IMPROVE sampler controller deployment completed in 2019 and are the current operating electronics. The V4 controller and Eboxes offer digital I2C pressure sensors, touch screen interface, and internet capability for remote control and data transfer.

2. SUMMARY OF THE METHOD

The sampler consists of four modules used to collect aerosol samples, labeled 1A, 2B, 3C, and 4D. An additional module, usually located in the center, is the controller. The controller contains a single board computer with pre-programmed operation software, a 7” touchscreen interface, and other electronic equipment required to operate the sampler.

During a sampling period, each of the four modules collects a filter sample simultaneously. The four modules are used to collect four different types of samples.

• Module 1A collects PM2.5 particles on Teflon filters. These filters are analyzed by four methods at UC Davis:

a. gravimetric analysis for PM2.5 mass

b. hybrid-integrating plate and sphere (HIPS) for optical absorption

1 For a current list of sites and a map of the network, please visit:

http://views.cira.colostate.edu/fed/DataWizard/Default.aspx and http://views.cira.colostate.edu/fed/SiteBrowser/Default.aspx?sskeyse=10001&smmkeys=57

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c. X-ray fluorescence (XRF) for elements: sodium (Na) to lead (Pb)

d. Fourier Transform Infrared (FT-IR) spectroscopy can be used to determine black carbon (BC) and organic carbon (OR)

• Module 2B collects PM2.5 particles on nylon filters. A denuder before the nylon filter removes nitric acid and sulfur dioxide vapors. These filters are analyzed by ion chromatography for nitrate, chloride, sulfate, and nitrite by Research Triangle Institute (RTI).

• Module 3C collects PM2.5 particles on quartz filters. These filters are analyzed for organic and elemental carbon using Thermal Optical Reflectance (TOR) in house at UC Davis or by Desert Research Institute (DRI).

• Module 4D collects PM10 particles on Teflon. These filters are analyzed by gravimetric analysis for PM10 mass at UC Davis.

Figure 1. Photo of the IMPROVE aerosol sampling modules inside a shelter.

3. DEFINITIONS

• AQMT: Air Quality Monitoring Team—maintenance, analysis, and validation part of AQRC

• AQRC: Air Quality Research Center of UC Davis

• BC: Black Carbon

• CSN: Chemical Speciation Network

• FT-IR: Fourier Transform Infrared spectroscopy

• HIPS: Hybrid-integrating Plate and Sphere

• IMPROVE: Interagency Monitoring Program of Visual Environments

• OC: Organic Carbon

• PM: Particulate Matter

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• QA: Quality Assurance

• QC: Quality Control

• SOP: Standard Operating Procedure

• TOC: Table of Contents

• TOR: Thermal Optical Reflectance

• TI: Technical Instruction

• XRF: X-ray Fluorescence

4. HEALTH AND SAFETY WARNINGS

Be aware that various stinging insects, venomous creatures, and large mammals (such as bears) can be found at many of the IMPROVE sites. Be cautious when stepping in tall grass surrounding a site or when opening pump boxes.

Inclement weather is often an issue at many IMPROVE sites. If severe weather is impending, wait it out in the vehicle or reschedule visiting the site.

Always carry a first aid kit when working in the field.

Some IMPROVE sites are remote and require hiking to the site or driving off-road. Be sure to have detailed maps of the area when walking or off-road driving.

Many IMPROVE sites do not have cellular reception. Take this into consideration when planning visits.

5. CAUTIONS

It is the responsibility of the local operators to promptly troubleshoot equipment issues as they occur with phone and email assistance from the IMPROVE field technicians.

Depending on the severity of the issue this could include making multiple visits to the site in a week, installing replacement equipment as it arrives, or spending considerable time on the phone.

The agency hosting the IMPROVE Site is ultimately responsible for keeping the structural and electrical infrastructure of the site in good working order. The local operator must keep a close eye on the state of the sampling structure and initiate repairs on any leaks, mold, exposed wires, broken hinges, or rodent infestations. Inaction on small problems can result in sample loss or costly repairs down the line.

6. INTERFERENCES

The IMPROVE network is designed to measure regional air quality with sites located in remote areas with limited heavily influence by local sources. If a new activity begins close to the site (i.e., you can see or smell emissions when you are at the site), please

July 15, 2022 inform UC Davis of the possible interference at once. Examples of activities that might influence the air quality samples are:

• Fires

• Road or building construction

• Gas or diesel-powered generator

• Increased traffic

• Mining operations or timber harvesting

The IMPROVE siting criteria are detailed in UCD IMPROVE SOP #126: Site Selection.

The quality of the samples is dependent upon careful handling of the samples. Careless handling of the samples can lead to contamination.

• Do not leave the samples sitting out in the open air for longer than a few minutes.

• Do not touch the surfaces of the filters.

• Be careful not to drop the samples.

• Ship the used samples back to UC Davis as soon as possible.

• Protect the samples from water contamination when changing samples in the rain or snow.

Store the samples at room temperature (i.e., do not leave the samples in a hot car or in the sun).

7. PERSONNEL QUALIFICATIONS

A UC Davis technician will train the site operator during their biennial site maintenance visits. If a new operator starts outside of maintenance season, they will be provided training documentation from the UC Davis team on request. The operator must pay attention to details, perform the work in a timely manner, and communicate any problems to UC Davis. The operator should have a general familiarity with the following: electrical connections, pipe air flow, and the IMPROVE sampler pumps.

8. EQUIPMENT AND SUPPLIES

The laboratory at UC Davis prepares the sample cartridges for the IMPROVE sites.

Every three weeks, UC Davis sends a “Blue Box” containing the necessary sampling supplies to each site (Figure 2). Usually, there will be two Blue Boxes at a site, one box in current use and the second box ready for the next period or ready to be shipped back to UC Davis. Inside each Blue Box are three re-sealable bags and an SD memory card for storing the electronic sampling data. Each bag contains the supplies for one week (Figure 3): four sample cartridges, one for each of the four modules, and the corresponding logsheet. At a standard IMPROVE site, the cassettes are color-coded for each module:

red for module 1A, yellow for module 2B, green for module 3C, and blue for module 4D.

A sampler which has a fifth module will use orange for module 5X. All cassettes are

July 15, 2022 capped to protect the filters, and the red caps must be removed before the cassettes are installed in the modules. Each re-sealable bag is labeled with the date that the cartridges inside the bag are to be installed. The Blue Box will be labeled with the three sample install dates.

The Blue Box should be received five calendar days before the first sample-change day.

If the appropriate box is not present before the change date, the operator should contact the UCD laboratory (530-752-1123). Once all the filter samples in a Blue Box have been used, the Blue Box should be shipped back to UCD by UPS, FedEx, or USPS services.

UC Davis provides shipping labels to most sites for returning the Blue Box. If return shipping labels are lost or damaged please contact UC Davis to arrange a replacement label.

Figure 2. Picture of a blue box showing the three filter bags.

Figure 3. Picture of the contents of one re-sealable bag − supplies for one week of sampling.

The filter samples are loaded into cassettes to form an airtight seal around each filter, and the cassettes are loaded into cartridges to allow sequential samples to be collected without operator intervention. Figure 4 is a picture of a sample cartridge and four cassettes. Each cartridge contains three or four cassettes, but only two or three of the

July 15, 2022 cassettes contain sample filters since only two or three samples are collected in any given week. Table 1 lists the three cartridge configurations used for routine sampling. The unused cassettes contain pieces of paper or blank filters (blank filters do not require any special procedures of the operator). Figure 5 shows a sampling calendar for September and October, 2015 to illustrate the 3-week repeating cycle.

Figure 4. Sample cartridge for the 2B module (yellow sticker) with four cassettes. Only three of the cassettes contain sample filters (indicated by the three labels).

Table 1. Types of cartridges for 1-in-3-day sampling.

Cartridge Type Cassette 1 Cassette 2 Cassette 3 Cassette 4

Type 1 Thursday Sunday Unused or field blank Unused

Type 2 Wednesday Saturday Tuesday Unused

Type 3 Friday Monday Empty hole Unused

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Figure 5. Sampling calendar for November and December 2015 illustrating the repeating 3-week cycle.

8.1 Collocated “X” Module Sampling

Collocated (or duplicate) sampling is performed at a small number of sites. At these sites, five sampling modules are operated. The fifth module is a duplicate of one of the other four modules and is labeled as the “5X” module.

8.2 Special Studies

At times, special aerosol studies will be performed at some of the sites. These studies may require additional sampling equipment and supplies. The individual site operators will be contacted before any special studies are initiated at their sites.

9. PROCEDURAL STEPS

The standard IMPROVE aerosol sampler configuration is shown in Figure 6. Most sites will have four modules plus a controller as shown in the figure. Each module has a dedicated pump. At steady state each pump requires 3.3 amperes at 120 volts. The 1A, 2B, and 3C modules collect PM2.5 samples. The 1A and 3C modules are identical except that their flow rates are calibrated for different types of filters (as described in Section 1.2). The 2B module has a slightly different cartridge holder configuration to

July 15, 2022 accommodate the larger diameter filters that are used in the 2B module. The 4D module collects PM10 samples and has a very different configuration to accommodate a PM10 cyclone; the most noticeable operational difference is that the sample cartridges must be installed in an opposite orientation compared to the other modules.

Selected sites will have a fifth module used to perform sampling for quality assurance purposes. The fifth module will be a duplicate of one of the other modules and will be referred to as a 5X module. The sampling modules are protected from direct sunlight and rain by a shelter. The shelter will also protect the operator and filters during sample changes in rain or snow. The shelter will vary from an outdoor stand with a sunshield to a fully enclosed but well-ventilated shelter. The shelters at IMPROVE sites should not be heated or air-conditioned and have lots of external vents.

Figure 6. Standard IMPROVE aerosol sampler configuration.

9.1 Schedules

9.1.1 Sampling Schedule

9.1.2 Sample Change Schedule

The sample cartridges should be changed every Tuesday as described in Section

5. If the operator cannot change the samples on Tuesday, contact UC Davis (530- 752-1123) for instructions on when to change the samples. Alternative days for sample changes are also shown on the IMPROVE calendar and vary each week. It

Module A

PM 2.5

Teflon

Module C

PM 2.5

quartz

Module B

PM 2.5

nylon denuder

Module D

PM 10

Teflon

Controller

July 15, 2022 takes approximately fifteen minutes to change the sample cartridges every Tuesday. For two of every three Tuesday sample changes, the sampler will not be actively collecting samples. For one of every three Tuesday sample changes, the sampler will be actively collecting samples and the sampling will be interrupted to change the filter cartridges. The procedures required to change the cartridges on sampling days are slightly more complicated than on the non-sampling days.

9.1.3 Maintenance Schedule

A maintenance crew from UC Davis will visit the site every other year to perform routine maintenance. The routine maintenance consists of:

• Cleaning and refurbishing the sampler

• Replacing parts when necessary

• Making scheduled modifications to the sampler and controller program

• Checking the existing calibrations of the sample modules

• Verifying the calibration equation for the sampler module flow rates

• Discussing procedures with the site operator

• Providing training for any site operators

9.2 Sampler Controller

The sampler controller is used to control the sample collection and acquire data during sampling. The Version 4 controller consists of a Beaglebone Black Rev C microcontroller, an LCD touchscreen, plus appropriate electronic components. The controller is shown in Figure 7, with Figure 8 depicting the connectors on the bottom of the controller. The controller can currently accommodate up to five filter sampling modules.

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Figure 7. Controller module.

Figure 8. Controller connections and relays.

The controller performs the following functions:

• Provides a status of current sampler operations to the site operator.

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• Provides an interface for recording clean (initial) and exposed (final) measurements of the flow rate through each filter during sample changes to the site operator.

• Provides options for configuring sampling protocols of the site and filter types of each module. This is normally performed by a UC Davis technician at the time of installation.

• Keeps the current date and time.

• Switches the filter solenoids and pump relays on and off.

• Records pressure transducers measurements. A standard configuration has 8 transducers, two in each module. Measurement is done many times a second and averages are recorded on the roughly every second.

• Records ambient temperature measurements. This is on the same schedule as that of the pressure transducers.

• Records the solenoid valve number that is open.

• Download all the measurements to the removable SD memory card.

• Communicate over a network to send and receive data remotely.

The controller is running Linux Debian 8 operating system and the sampling program is written in Python and preloaded on the controller. Most software changes are made with remote ssh access but SD card software updates are also possible. More detailed instructions will be provided to the site operator(s) if a software upgrade is necessary.

Fifteen-minute average temperature and pressure transducer measurements are stored on a removable SD memory card. The SD card is replaced every three weeks. Most sites with a Version 4 controller will send data back to UC Davis over a network. The used card is sent back to UC Davis and the data are uploaded to a database only if a network is unavailable. The SD card has the capacity to store more than three weeks of sampling data if necessary, and will act as a backup in case the network fails or data is lost.

The Home Screen is shown in greater detail in Figure 9. The LCD touchscreen is used to navigate the menu with user friendly buttons and instructions. These are pointed out in the figure. In many cases, the LCD will list the available options for navigation.

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Figure 9. Controller connections and relays.

The controller program has 4 modes: Normal Mode, Diagnostic Mode, Changing Cartridge Mode, and Initializing Mode. The program is generally in Normal Mode whether the sampler is running or not. In the Normal Mode, the sampler may require a sample change or be ready to sample. Sections 9.2.1 through 9.2.4 detail the controller modes.

To move from the Normal Mode to the Changing Cartridge Mode, press the Filter Readings button from the Home Screen. This will switch the display from the Home Screen to the Filter Readings Mode. After completing the standard filter change, the program will automatically return to the Normal Mode. For other actions, press the Menu button and navigate through the different menu options. Certain menu options will take the controller into Diagnostic Mode, which is programmed to time out and return to Normal Mode after 8 hours. Initializing Mode is not relevant for operators and is only accessed while the controller is booting up.

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9.2.1 Normal Mode

When the sampler is in Normal Mode, the sampler may be ready to sample, currently sampling, or locked, which means a filter change is needed before it can sample again. The Home Screen display shows whether the sampler is sampling, ready to sample, or if a filter change is needed. In the figures below, several example displays are shown.

In the first example, Figure 10, the first line displays the current date and time.

For this example, the date is October 19, 2017. The time is 3:52 pm or 15:52. The second line indicates the 5-digit site code is ABCD9, it has been turned on for 1 hour, and the temperature is -1.00°C. The third line indicates which filter bag week number is currently installed. The fourth line indicates what the sampler is currently doing, which is running or sampling.

Figure 11 shows that the sampler is idle. It is not a sampling day, but it is ready to sample when the next sampling day begins.

The status screen in Figure 12 indicates that the sampler has collected all the samples for the week and will not sample until the operator changes the cartridges and collects the exposed and clean filter readings.

Figure 10. Current status, sampling is active.

Figure 11. Current status, idle screen.

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Figure 12. Current status, sampling complete, filter change required.

9.2.2 Changing Cartridge Mode

The Changing Cartridge mode is accessed by pushing the Start button after the Filter Readings option has been pressed from the Home Screen. Once in Changing Cartridge mode, filter readings should be completed before it returns to Normal Mode. This mode will time-out in 8 hours. Operators should not start the filter change procedure unless they are ready to install new filters. If the filter change procedure is exited less than halfway complete, the next week will not sample. This is because double sampling a filter will invalidate it and it is preferable for the controller to not sample rather than to double sample. Operator should always verify that the status when leaving site is either, “Sampling,” or, “Ready to Sample,” (Figure 10 and Figure 11).

9.2.3 Diagnostic Mode

Diagnostic mode is a mode mainly used for maintenance purposes. This mode is designed to interrupt normal sampling for purposes such as sampler maintenance, equipment replacement and testing, and other advanced purposes. This mode will automatically time out after a certain amount of time if it is entered.

9.2.4 Initializing Mode

Boot mode is the mode the controller must go through during the initial power up and software loading sequence. This mode is only accessed during controller restarts and power ups.

9.3 PM2.5 Sampling Modules

The inside of an IMPROVE aerosol sampler PM2.5 module is shown in Figure 13. The flow diagram for the IMPROVE PM2.5 module is shown in Figure 14. Approximate pressure readings in units of inches of mercury are listed in the figure.

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Figure 13. PM2.5 module from the IMPROVE aerosol sampler.

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Figure 14. Flow diagram for IMPROVE PM2.5 module.

9.3.1 PM2.5 Module Inlet and Cyclone

The ambient air enters through a screened inlet on top of the stack. The screen removes bugs, rain, and particles larger than approximately 15 µm. The air stream then passes through a cyclone that removes particles larger than 2.5 µm. The cyclone is located inside the module, as shown in Figure 13. The cyclone is 50% efficient at removing particles with aerodynamic diameters larger than 2.5 µm at the nominal flow rate of 22.8 L/min. A 5% decrease in flow rate, from 22.8 to

21.7 L/min, increases the cut point to 2.9 µm.

Module 2B (nylon) has a carbonate-coated annular denuder to remove nitric acid (HNO3) and sulfur dioxide (SO2). The denuder consists of four concentric 61-cm aluminum tubes. The calculated efficiency for removing HNO3 is greater than 99.7%. The denuder is located inside the inlet tube of module 2B.

A temperature probe is inserted in the inlet of one of the three PM2.5 modules (typically module 3C but it doesn’t matter). The temperature probe is situated in the air stream just prior to the cyclone. The temperature is measured every second and the average temperature is recorded on the SD memory card every 15 minutes.

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9.3.2 Critical Orifice Flow Control

A critical orifice located between the filter and the vacuum pump shields the flow system from pump fluctuations and resultant flow rate fluctuations. Critical flow will be maintained as long as the pressure behind the orifice is 53% or less of the pressure upstream of the orifice (behind the filter). A properly operating pump will maintain critical flow under most conditions. Critical flow will be lost when a pump begins to fail or, more commonly, when the filter loading is heavy (i.e., if the air is much polluted). Heavy filter loadings can cause large pressure drops across the filter, which result in the pressure in front of the critical orifice being too low to maintain critical flow.

A needle valve serves as the critical orifice in the IMPROVE PM2.5 aerosol samplers. The valve is adjusted by an authorized technician during each annual maintenance visit to achieve the desired nominal flowrate. A machined 0.062” ruby orifice serves as the critical orifice in the IMPROVE PM10 aerosol samplers, with the needle valve serving to fine tune the flow rate.

A constant volumetric flow rate of 22.8 L/min must be maintained to keep a 2.5 µm cut point. Two factors can cause the flow rate to vary from the nominal: a change in pressure drop across the filter or a change in ambient temperature. Both of these factors vary throughout the course of every sampling period; pressure drop due to gradual loading of the filter with particles and the temperature due to natural variability. Although flow rates vary by less than 1 L/min during a typical 24-hour period due to temperature fluctuations, they sometimes vary more, especially when a filter begins to clog. The critical orifice does not protect against these flow variations; its only purpose is to dampen pump fluctuations.

9.3.3 PM2.5 Module Flow Rate Measurement

The sample flow rate is monitored using pressure transducers. The controller will read and record the transducer measurements every second and record the averages every 1 minute. The transducer measurements are calibrated for flow rate using an orifice flow check device (transfer standard) that has been calibrated to a primary flow standard at UC Davis.

The flow rate determined by cyclone pressure drop is the primary measurement used for the air quality data and is referred to as the “CYC” flow rate. The “CYC” flow rate is related to the pressure drop of air as it passes through the cyclone. The two pressure transducer ports used to measure the pressure drop are placed in the inlet tee and immediately after the cyclone. The cyclone flow equation approximates a venturi-type meter. The flow rate equation is expressed in terms of parameters experimentally determined during the flow rate calibration at the site. The equation also includes a pressure function based on the elevation of the site, F(elev), and a temperature function based on the average ambient temperature during sample collection. The elevation factor is 1.00 for sites near

July 15, 2022 sea level and increases to 1.20 at 10,000 feet, as listed in Appendix I: Elevation factors of Section 12. The temperature function is equal to 1.00 at 20 °C and varies from 0.95 at -9 °C (17 °F) to 1.05 at 50 °C (122 °F). The equation for flow rate based on the first set of transducers is

273T)elev(FM10Q ba m where Qm = actual volumetric flow rate (L/min) from the “CYC” reading, M = “CYC” reading on the controller screen, F(elev) = the pressure function based on the elevation of the site (see Appendix I), T = average ambient temperature during sampling (°C), and a and b = universal calibration constants

The flow rate can also be determined by the orifice pressure and is referred to as the “ORI” flow. But “ORI” flow is not used for PM2.5 modules since the area of the valve is not constant making the flow measurement unreliable. This is not an issue with the ruby orifice in the PM10 module. The “ORI” flow rate is related to the air pressure immediately before the critical orifice. IMPROVE does not use the ORI flow rate equation for PM2.5. The equation for flow rate based on the second transducer is where

Qv = actual volumetric flow rate (L/min) from the “ORI” reading, V = “ORI” reading on the controller screen, F(elev) = the pressure function based on the elevation of the site, T = average ambient temperature during sampling (°C), and c and d = universal calibration constants.

9.3.4 PM2.5 Module Filter Cassettes and Cartridges

The filter cassettes and cartridges are manufactured specifically for the IMPROVE sampler. They are made of acetal homopolymer with stainless steel screens. The two halves of the cassette snap together and are sealed with an o-ring. A special tool is required to separate and assemble the two halves. This process is only done at the UC Davis central laboratory when the filters are unloaded and reloaded. The individual cassettes are always installed in cartridges, with four cassettes per cartridge. Most cassettes are secured in the cartridges by a

July 15, 2022 snap ring and cannot be removed easily. Some cassettes are to be moved from one cartridge and to a second cartridge in the field; these cassettes are held in by an o-ring and can be removed and inserted relatively easily. Each cartridge has a center hole and a small alignment hole. When the cartridge is placed on the cyclone manifold, alignment pins on the manifold prevent the cartridge from being rotated a quarter or half turn. Each cassette is labeled with the site, module, and the sample collection date. When the cartridges are loaded into the PM2.5 modules, the labels on the cartridges will always be oriented facing upward.

9.4 PM10 Sampling Module

An IMPROVE PM10 module is shown in Figure 15. Note that the PM10 module manifold is oriented in the opposite direction as the PM2.5 module manifold.

Figure 15. PM10 module from the IMPROVE sampler.

9.4.1 PM10 Module Inlet and Cyclone

The ambient air enters through an inlet on top of the stack. Two different inlets have been used in the IMPROVE network. The first inlet was manufactured by Wedding TP10 and uses cyclonic flow to eliminate particles larger than 10 µm from the sample stream. The Wedding inlet requires a flow rate of 19 LPM. The second inlet is manufactured by Sierra-Anderson and uses impaction to eliminate particles larger than 10 µm from the sample stream. The Sierra-Anderson inlet is

July 15, 2022 the only inlet currently used in the IMPROVE network for PM10 modules. The Sierra-Anderson inlet requires a flow rate of 16.9 LPM. Both inlets are 50% efficient at removing particles with aerodynamic diameters larger than 10 µm at the respective nominal flow rates.

9.4.2 PM10 Module Flow Rate Measurement

The sample flow rate is monitored using orifice pressure transducers. The controller will read and record the transducer measurements every minute and record the averages every 15 minutes. The transducer measurements are calibrated for flow rate using an orifice flow check device that has been calibrated to a primary flow standard at UC Davis. One flow measurement is made in the PM10 module.

The flow rate is referred to as the “ORI” measurement. The “ORI” flow rate is related to the pressure before the orifice. The flow rate equation is expressed in terms of parameters determined during the flow rate calibration at the site. The equation also includes a pressure function based on the elevation of the site, F(elev), and a temperature function based on the average ambient temperature during sample collection, as described in Section 9.3.3. The equation for flow rate based on the second set of transducers is where

Qv = actual volumetric flow rate (L/min) from the “ORI” reading, V = “ORI” reading on the controller screen, F(elev) = the pressure function based on the elevation of the site (see Appendix I), T = average ambient temperature during sampling (°C), and c and d = universal calibration constants.

9.4.3 PM10 Module Filter Cassettes and Cartridges

The same cassettes and cartridges are used in the PM10 module as the PM2.5 modules, which were described in Section 9.3.4. The only difference is that they are inserted in an opposite direction compared to those in the PM2.5. For the PM10 module (4D), the labels and blue dot on the cartridge will be oriented facing down when they are installed in the sampler.

9.5 Sampler Installation

Prior to the installation of an IMPROVE sampler, the local support agency must establish power and erect a shelter at the site to prepare for installation of the sampler. UC Davis will provide the power requirements and shelter dimensions. UC Davis will ship the

July 15, 2022 sampler to the site. A field technician from UC Davis will install the sampler. The installation consists of:

• Placing the controller and filter modules on a wall of the shelter and cutting holes in the ceiling for the inlets

• Installing the module inlets

• Connecting the cables between the controller, filter modules, and pumps

• Connecting the vacuum hoses between the modules and the pumps

• Selecting the sampling parameters

• Adjusting the flow rates of the sample modules

• Attaching the sample changing instructions to the inside of the controller door

• Training the site operators

• Installing the initial set of sample cartridges with the site operators

9.6 Tuesday Sample Changes

The sample cartridges should be changed every Tuesday. Alternative days for sample changes are shown on the IMPROVE calendar and vary each week. It takes approximately fifteen minutes to change the sample cartridges every Tuesday. Care must be taken during the change to protect the samples from contamination by rain or snow.

9.6.1 Preparation

The Blue Box should be received 5 calendar days before the first sample-change day. If the appropriate box is not present the Thursday before the sample-change date, the operator should contact the UCD laboratory (530-752-1123).

Before going to the site, the operator must check the dates on the Blue Box(es).

The operator needs the Blue Box(es) with the bags for both the current install date and the previous install date. For example, if the first date on the new Blue Box is today’s date, the operator should bring both this Blue Box and the previous Blue Box. The used samples are returned to the previous Blue Box, and the new samples are installed from the new Blue Box.

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Figure 16. Field logsheet for sample cartridges with three cassettes (i.e., three sampling days).

Two of the three logsheets in every Blue Box will have three sampling days listed, while one of the three logsheets will only have two sampling days listed.

9.6.2 Sample Change Procedures

The basic steps in the sample change procedures are: 1) collect the exposed (final) filter flow rate readings for each used cassette; 2) remove the exposed filter cartridges; 3) install the clean cartridges; 4) collect the clean (initial) filter flow rate readings for each new cassette. This procedure must be repeated for all four sampling modules: 1A, 2B, 3C, and 4D.

For two of every three Tuesday sample changes, the modules will not be actively collecting samples. For one of every three Tuesday sample changes, the modules will be actively collecting samples, and the sampling will have to be interrupted to change the filter cartridges. The procedures required to change the cartridges on sampling days are slightly more complicated than on the non-sampling days.

On the active sampling days, the operator will have to transfer the cassettes in position 3, which are in the midst of sampling, from the old to the new cartridges.

This transfer must be done for each of the four modules because all four modules

July 15, 2022 are sampling simultaneously. The position 3 cassettes have a black O-ring around them and are the only ones that can be removed without a special tool. Figure 17 shows the removal of the position 3 cassette from a cartridge. This cassette must be loaded into the open hole in position 3 of the new cartridge. After the cassette is transferred to the new cartridge, the new cartridge is installed in the sampler.

After the initial readings are taken, the sampler will resume collection on the filters in position 3. If the roof does not provide adequate protection from the elements, you should remove all four of the exposed cartridges, move to a protected location, switch the position 3 cassettes from the old cartridges to the new, and then return to the sampler to install the new cartridges.

Figure 17. Photos illustrating the removal of position 3 cassette (note black o-ring on removable cassette) from the cartridge.

The sample change procedures are detailed below. There will be a series of informational screens providing detail about what is happening throughout this procedure when the pumps are turned on or when the readings are being recorded on the memory card. The display will automatically switch to the next screen after several seconds.

1. Open the controller module door.

2. Fill in your initials, the date, and the time on the logsheet (Figure 16).

3. Make sure that the date and time on the controller module are correct. If they are off by more than 5 minutes, note the problem on the logsheet and refer to Section 6.3 to enter the correct date and time. If this is a sampling day, do not change the time and wait until the following week to correct the time.

4. Also, note any unusual activities that occurred during sampling days on the logsheet (e.g., fires, road paving, power outage, etc.)

5. Initiate the sample change sequence by pressing the Filter Readings button (Figure 18).

6. Press the set of initials corresponding to the operator performing the filter readings. If the operator’s initials are not displayed, enter the initials by pressing the Add Initials button, then use the ↑ and ↓ to toggle value and the ← and → buttons to toggle position. Press Save to save and exit Add Initials screen (Figure 19).

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7. Press start to begin recording filter readings (Figure 20). A status bar will explain what is happening during the procedure. Operators should listen for any pumps that fail to start, start slowly, or sound different from the other pumps. High pitched screeching; loud, hammer-like knocking; or electrical buzzing may indicate a serious problem and should be reported as soon as possible. If you encounter any of these issues, press Yes for troubleshooting. Otherwise, press No to continue to the readings.

Figure 18. Home screen with filter readings button.

Figure 19. Select operator initials screen.

Figure 20. Start Exposed Filter Readings screen.

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8. Record the Exposed (Final) Readings (Pres/Ori, Flow/Cyc, and ET) for each used cassette. Figure 20 shows the flow and pressure readings (Pres/Ori & Flow/Cyc) and elapsed time (ET) for the first cassette (FIL

1) in Module 1A.

9. Press the → key to go to the next module (and the ← key to move to the previous module). A standard sampler will have 8 or 12 filters (2 or 3 per module, depending on the week).

10. When all the Exposed (Final) Readings are collected, check that all blank fields on the log sheet are filled in.

11. Note any problems or mistakes made during the sample change procedures (e.g., dropped cartridge or cassette, touched filter with finger, etc.).

12. Also note any unusual events that occurred near the site (e.g., fires, construction, painting, power outages, lightning strikes, fireworks, high traffic, etc.).

13. If all the readings are acceptable, press the Continue button (Figure 22).

To review any of the readings, navigate back using the arrow buttons.

14. Put the completed logsheet in its original re-sealable bag (i.e., the re-sealable bag and the top of the logsheet should be labeled with the same date).

15. Get out the new bag of filters labeled with the “USE WEEK” date displayed on the controller. Figure 23 shows that the bag label for the week is 11/27/18. For newer and backup operators, the Instructions button will walk through the procedure with written instructions and pictures.

16. Press the Filter Change Completed when you have removed the exposed filters and installed the appropriate bag of clean filters (Figure 23).

Figure 21. Flow rate and pressure readings screen.

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Figure 22. Continue screen.

17. Start with Module 1A, which is color-coded red.

If this is not a sampling Tuesday, the sampler should not be running when you arrive at the site.

a1. Figure 23 shows the screen that will be displayed on a non-sampling Tuesday.

b1. Remove the cartridge of used cassettes from the module by raising the sampling manifold using the stainless-steel toggle switch and pulling out the cartridge.

c1. Put the red caps on the cassettes and return the used cartridge to its original re-sealable bag.

d1. Remove the red caps from the new cassettes and install the new cartridge in the module. Align the new cartridge in the lower manifold with the pins through the holes in the cartridge.

e1. Lower the manifold using the stainless-steel toggle switch (stop pressing the toggle switch when the motor starts to strain).

f1. For the PM2.5 modules (1A, 2B, and 3C), the labels and the red, yellow, or green dot will be facing up (Figure 5-9). For the PM10 module (4D), the labels and the blue dot will be facing down (Figure 5-10).

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Figure 23. Change filter screen.

Figure 24. PM2.5 cassette orientation. Figure 25. PM10 cassette orientation.

---------------------------- OR ----------------------------

If this is a sampling Tuesday, the sampler should be running when you arrive at the site.

a2. Figure 26 shows the screen that will be displayed on a sampling Tuesday. Note the comment informing of “Movable Filter Week.”

b2. The old cartridge will have a black O-ring around the cassette in position 3, and the new cartridge will have an empty space in position 3.

c2. Remove the used cartridge from the sampler by raising the sampling manifold using the stainless-steel toggle switch and pulling out the cartridge.

d2. Move the position 3 cassette of the used cartridge to the empty position in the new cartridge. (Do not move the cassette label from the old cartridge to the new cartridge.)

red ring red ring

July 15, 2022 e2. Install the new cartridge in the module align the new cartridge in the lower manifold with the pins through the holes in the cartridge, and lower the manifold using the toggle switch.

f2. Put the red caps on the used cassettes, and return the cartridge to its original re-sealable bag.

g2. For the PM2.5 modules (1A, 2B, and 3C), the stickers and the red, yellow, or green dot will be oriented upwards. For the PM10 module (4D), the labels and the blue dot will be facing down (Figure 5-10).

Figure 26. Active sampling Tuesday sample change.

18. Repeat Step 17 for modules 2B (yellow), 3C (green), and 4D (blue), making sure to install the appropriately colored cartridge in each module.

19. Press the Filter Change Completed button when all the new cartridges are installed. A reminder screen will ask the operator to verify that the movable position has been transferred from the old cartridge to the new one (Figure 27). Double check that four filters are present in each module and press Continue.

Figure 27. Verify movable filter position is installed.

20. The screen shown in Figure 28 shows the Clean (Initial) Readings for the new filters for all three filter cassette positions in Module 1A.

21. Record the Initial Readings (MxOri, Pres/Ori, and Flow/Cyc) for each new cassette on the new logsheet. Note that only one MxOri reading is necessary for each module, and only one space is provided on the logsheet for each module. Several error screens may be encountered during the initial readings.

Error Screen 1: If the flow pressure reading is significantly less than the nominal pressure, the message shown in Figure 29 will appear. The most common cause of this issue is that the filters were installed orientation. If this is the case correct this issue, then press the Retest button. If you see the screen shown in Figure 30, the problem may not have been corrected.

If the installation appears to be correct, you will need to override this check and proceed with the sample change by pressing the Force full test button. Please call UC Davis at (530) 752-1123 for assistance in the event of this error as it indicated possible sensor errors.

Figure 28. Clean (Initial) filter readings screen.

Figure 29. Low flow through cyclone warning.

Figure 30. Problem still detected.

Error Screen 2: If there is a problem during filter readings causing a lack of connection for more than 6 seconds, the screen shown in Figure 31 will be shown.

This may indicate a problem with the controller connector board, module cable, or Ebox during filter readings. Inspect all connections looking for improperly seated module cable connections, and along each module cable looking for fraying, nicks, or rodent damage. If the problem has been solved, press the Retry button to retake Filter Readings. If no connection problem is obvious, inspect the LEDs on the face of the Ebox. A blinking green LED indicates proper functioning. A blinking red LED may indicate a restart is necessary. Troubleshooting can be done by unplugging the Ebox from either the Ebox side or controller side first. If this doesn’t fix the problem, press the Restart button, then go through the Filter Readings procedure again.

Error Screen 3: If the software running in the background crashes at any point the error screen shown in Figure 32 will be displayed. The controller will most likely reset itself within a minute. If it does not reset, pull the gray power cord

July 15, 2022 from underneath the controller. Wait until the blue LED lights on the front panel of the controller stop blinking, then plug the gray power cable back in. If this problem persists, please call UC Davis at (530) 752-1123 for assistance.

Figure 31. Lost Ebox connection error screen.

Figure 32. Software connection error screen.

22. The screen shown in Figure 33 will be displayed after Initial Readings are completed. Compare the filled out logsheet to the sample logsheet posted near the controller. Usually this sample logsheet will be on the outside of the 3C module door, though its location is site dependent. If the readings are out of the tolerances displayed on the sample logsheet, press Yes for troubleshooting options and the opportunity to retake Filter Readings.

23. If today’s bag is the first in a new Blue Box, the controller will prompt the operator to change the SD memory card (Figure 34). Otherwise, skip to step 24.

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a. Remove the memory card from the controller by pressing it down and removing finger, then pulling it out of the controller. Press the Card Removed button.

b. Place the memory card in the small plastic case in the old Blue Box.

c. Remove the SD memory card from the new Blue Box and place it in the controller. It will only fit in one way, with the 45° notch on the lower side of the card, and the electrical pins facing left. (If there is no memory card in the new box, reinsert the old one in the controller and write a note in the old logsheet.)

d. Press the Card Inserted button.

Note: If the warning shown in Figure 35 appears when a memory card is installed in the controller, try removing the SD card, and reinstalling it.

Then press the Back button. If the warning is still displayed, reinstall the old memory card and note the problem on the logsheet or call UC Davis

(530) 752-1123. Then press the Skip button.

Figure 33. Check sample logsheet values.

Figure 34. Replace memory card screens.

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Figure 35. Memory card warning.

24. The information for the Filter Readings will…