&EPA
United States
Environmental Protection
Agency
MET ONE 831
Citizen Science
Operating Procedure
Office of Research and Development
National Exposure Research Laboratory
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EPA/600/R-15/114 | May 2015 | www.epa.gov/ord
Met One 831
Citizen Science Operating Procedure
Ron Williams
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC, USA 27711
Amanda Kaufman
ORISE Participant
Oak Ridge Institute for Science and Education
Oak Ridge, TN, USA 37831
Sam Garvey
Alion Science and Technology
Research Triangle Park, NC 27709
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CITIZEN SCIENCE
Contents
Met One 831 1
What Is PM? 1
What You Will Need 1
I mportant Considerations 2
Preparing the Device 2
Charging the Battery 2
Installing the Software 3
Setting the 831 Internal Clock 5
Routine Data Collection 6
Verifying Proper Operation 6
Collecting Data 8
Processing Data 10
Maintenance 12
Checking the Flow Rate (Optional) 13
Performing a Zero Count Test (Optional) 15
For Additional Help 16
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Met One 831
The Met One 831 sensor measures participate matter (PM) by counting and
sizing individual particles using scattered laser light. The unit then converts the
count data to mass measurements in micrograms per cubic meter (ug/m3). The
Met One 831 counts particles in four different PM size ranges simultaneously
(PMi, PM2.5, PM4, and PMio). Each of these represents a maximum particle
size.
Thus, PMio measures all particles 10 micrometers (urn) in diameter or less and
PMi measures all particles 1 urn in diameter or less. This handheld device was
designed for use in applications such as remote sampling, indoor air quality
monitoring, and industrial and occupational hygiene. It has an internal battery pack that provides
8 hours of continuous operation, and it can store up to 2,500 data points that can be either
viewed on the Met One 831 display or exported to a computer using a USB cable. This
operating procedure explains what you need to do to collect quality data using the Met One 831
for your monitoring project.
What Is PM?
PM pollution is a mixture of particles of various sizes such as soot, smoke, dirt, and dust. Many
pollutant particles that make their way indoors are generated and released into the air from
outdoor sources such as power plants, industrial processes, and automobiles. Living near a
major roadway, for instance, can significantly increase PM exposure. Other particles are
generated within the home from activities such as cooking or burning wood in fireplaces. Small
particles also include mold and bacteria and larger particles include pollen and dust mite
casings. PM can have both short- and long-term health effects, with the smallest particles
posing the greatest health risk. Effects of PM pollution exposure include increased respiratory
(breathing) symptoms such as coughing and difficulty breathing as well as aggravated asthma
or other existing respiratory and cardiovascular conditions. For more information on particle
pollution, visit the U.S. Environmental Protection Agency's Web site
at http://www.epa.qov/airqualitv/particlepollution/index.html.
What You Will Need
»:» Met One Model 831 PM sensor
»> USB (Universal Serial Bus) cable (part no. 500787)
*:* Battery charger (part no. 390031)
<» Comet Communications utility software (part no. 80248)
<* Computer with Windows operating system
»;» Zero filter kit (part no. 80846), optional
»;» Flow meter kit (part no. 80530), optional
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Important Considerations
The Met One 831 must be calibrated annually by the manufacturer as described in the
User's Manual, and calibration should not be performed by the user.
• The Met One 831 has no user-repairable parts. It must be returned to the manufacturer
when repairs are required.
• If using more than one Met One 831, place the devices at least 18 inches away from each
other and ensure they have access to ambient air.
Preparing the Device
Before collecting data with the Met One 831, you must charge the battery and install the
software. This section also explains how to set the device's internal clock. The following
procedures will guide you through preparing your device for data collection.
Charging the Battery
The battery must be charged before initial operation. To
charge the battery, simply connect the battery charger AC
power cord to an AC power outlet, and connect the battery
charger DC plug to the socket on the left side of the Met One
831. The light on the charger will turn from red to green and
the 831 will display the message "BATTERY = 100%" (Figure
1) when the battery is fully charged. A completely discharged
(drained) battery takes approximately 2.5 hours to charge
fully.
The universal battery charger that comes with the Met One
831 works with power line voltages of 100 to 240 volts, at
50/60 Hz. When fully charged, the battery will power the 831
for approximately 8 hours of continuous sampling. For
extended operation, you can operate the unit with the battery
charger attached.
Caution
Use only the charger and adapter that
came with your Met One 831. Using
others might damage the device.
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Installing the Software
The Comet communications utility software must be installed on a computer in order to retrieve
data from the 831. It can be installed from the CD included with the sensor as outlined in the
following procedure.
Procedure: Install Software from CD
1. Insert CD and click 'Run AutoRun.exe'.
2. Click Install Comet'.
3. Click 'Next' to continue.
AutoPlay
DVD/CD-RW Drive (D:) Comet
I I Always do this for software and games:
Dm vcur media
Open folder to view files
| using Windows Explorer
View more AutcPla;. ccticnE in Control Panel
Welcome to the Comet Setup Wizard
WARNING This computer program is protected by copyright law and international treaties.
UrtaiHho(izeddupll£=.ur a iJnTLudun ul lln; pruyijn. i:r any puiti'.Bi .i A may lesult in severe civil
r>rrrirri!r.sl pen.ahe;, and will be prosecuted to the mammum r-,+---rt pflsi^e under the law.
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4. Click the "I Agree" radio button to accept the
terms of the license and then click 'Next'.
License Agreement
This is a legal agreement between you and Met One Instruments
(hereinafter "LICENSOR') covering the downloading and or installation
of Comet. By downloading and or installing, copying, or otherwise using
Comet on any computer or device, you agree to be bound by the terms
of this End User License Agreement (EULA). Be sure to read the
following agreement before using the PROGRAM(S).
5. Use the 'Browse' button to choose the folder
where you want to install the software and
press 'Next'.
Select Installation Folder
The installer will insKsl Con^i h:, fix- following folder.
To install in this folder, click "Next". To install n -i oVt;snt folder enter it below 01 dick "Browse".
C '•.Rf.:gi3rii'ile-;l,M?M:'^.Corner'.
Install Comet for yourself, orfor anyone who uses Ihis computer
•a Everyone
C Just me
6. Press 'Next' to confirm the installation.
Contirm Installation
TheinslaHer is ready tr ir, ;K;ill r on-if-i on your computer.
Click "Next" to start the installation.
7. Click 'Close' when the installation is complete.
Installation Complete
Cornel has been successfully installed.
Click "Close" to exit.
Please use Windows Update to check tor any -:-.hr.-J updates to the .NET Framework
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Setting the 831 Internal Clock
The internal clock of the Met One 831 can be set using the Comet Communications utility
software included with the sensor.
Procedure: Set Device Clock
1. Ensure the time is accurate on the computer your device is connected to.
2. Open the Comet software and select the 'SetUp' tab (Figure 2).
3. Click the 'Synchronize Device's Clock' checkbox to synchronize the 831's internal
clock with the computer.
4. Press the 'Set' button to send these instructions to the 831.
Si Comet
IHJ
File Station Help
IJ]o-a ry
Station Ho
Product MODEL 831
in-
version:
Connection Wo
Port: COM5
Baud: 38400
Data Options
Retrieve Cum*
Open Previous
dear Memory
Figure 2
Data | Direct Conrej{[s«'-'Pa^
Location 1 4- Serial Number
PM1 PM2.5 PM4 PM10
| 1.00 g)l 1.00 til 1.00 ti «• ti
f^ Synchronize Devices Dock
** | •£ ^^
^^^•^^^^
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Routine Data Collection
With a charged battery and installed software, you are now ready to collect data. The following
procedures will guide you through data collection, retrieval, and processing. Note that if
anything goes wrong with the sensor during data collection, the Met One 831 will display an
error message. Possible error messages include the following:
<» "LOW BATTERY!" - Indicates that approximately 15 minutes of operation left before sampling
stops.
<» "Sensor Noise" or "Sensor Error" - the Met One 831 detects a problem in the particle sensor.
If you see the "Sensor Noise" error, perform the zero count test described in the Maintenance
section. Contact the Met One Service Center if you receive the "Sensor Error" message. For
other troubleshooting guidance, consult the Model 831 Manual.
Verifying Proper Operation
Before collecting data, ensure that your setup is correct and that your Met One 831 is collecting
data properly.
Procedure: Verify Proper Operation
1. Press the 'Power' button (^) for at least half a second to turn on the power (Figure 3).
A startup screen (Figure 4) will display for 3 seconds and then the sampling screen will
be displayed (Figure 5).
2. Press the 'Start/Stop' button (•) to begin sampling. One data point will be taken per
minute.
3. After at least 1 minute has passed, stop the device with the 'Start/Stop' button.
4. Check the mass values on the display, and rotate the 'Select' dial (Figure 6) to view
additional PM ranges (PMi, PM4, and PMio).
If no error messages are displayed, the unit is ready for use.
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Collecting Data
After you have verified that your device is working properly, you can begin collecting data. While
the Met One 831 can store approximately 41 hours of data internally, using the Direct Connect
feature allows data to be stored directly on the computer's hard drive instead. The following
procedure will guide you through collecting data using the Direct Connect feature.
Procedure: Collect Data
1. Connect the 831 to a computer using a USB cable
(Figure 7).
2. Open the Comet communications
utility software by clicking the icon
that was created on the desktop
during installation.
3. Select an existing station or create a new one in the
Startup dialog box as shown in Figure 8. The station
is the name of the file where you want the
downloaded data to be stored. Once you have
specified a station, the Data, Chart, Direct Connect,
and §ej;.y.p tabs become available as shown in
Figure 9.
File Station Help
--?*y v
Station Wo
Ham:
ID;
ttrten:
Put:
but
Startup
New Station
Figure 8
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4. View or change the data storage directory for your station under File > Settings (Figure
9).
File Station Help
Station Info
Name: Testl
Product: MODEL 831
ID: 001
Vereion: VI .1.0
Connection Info
Port: COM23
Baud: 38400
Data Options
Figure 9
5. Click the 'Direct Connect' tab (Figure 10) for continuous monitoring, and click the
'Connect' button to connect the computer to the 831.
File Stition Help
Ju-id IV
SUtonlnfo
Name MM One
Product MODEL 831
ID: 001
Poll: COM5
Baud 38400
Data Options
RetneveCunrt
OpenPmioui
Figure 10
Data
331. 80B6S-1, VI. 1.0
-ss
SS B1567E
•ID 1
ID 001
•SKI 1
SKI 1.00
•SKJ 1
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•ni somojaasssis
Tin*: 10-29-13 09:63:16
•29/OCT/2Q13 10:00:30,001,0-2.0-5.0.6,0.7,000,*225*
29/OCI/2013 10:01:30.001,0.3,0.5,0.«,0.7,000,-2256
2S/OCI/2013 10:02:30.001.0.2,0.4,0.5,0.7.000.-2254
29/OCT/2013 10:04:30.001,0.3,0.5,0.6,0.7,000,*225S
2S/OCT/2013 10:05:30.001.0.2,0.4,0.5,0.7.000,-2257
• ASCII Ho
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6. Press the 'Start/Stop' button (fj) on the Met One 831 to begin measurements. The
'Direct Connect' tab window will be appended with a new line of data each minute.
7. At the end of each sampling period, click the 'Capture' button on the 'Direct Connect'
tab (Figure 11) to save the data as a text file. It is recommended that data be
downloaded from the unit at the end of each day.
File Station Help
Du-id &
Station Ho
Name Met One
Product MODa831
ID 001
Venon
Port COH5
Baud 38400
Data Options
Return Curenl
(fcen Pnsviciut
Figure 11
•av
831. 8086S-1. VI.1.0
-SS
SS P1S67«
•ID 1
ID 001
•SKI I
SKI 1.00
SKI 1
SK2 1.00
SK3 1
SX3 1.00
-5K4 1
SX4 1.00
•BT 2013102909S916
'29/OCT/2Q13 10:00:3Q,OQ1,0.2,Q.S,Q.€,Q
29/OCT/2013 10:01:30,001,0.3,0.6,0.6,0.
29/OCT/2013 10:03:30,001,0.2,0.4,0.6.0.
29/OCT/2013 10:03:30.001.0.2,0.4,0.6,0,
SS/OCT/2013 10:04:30,001.0.3,0.8,0.6.0.
29/OCI/2013 10:05:30,001,0.2.0.4,0.6,0.
7,000,-2254
,003.-2:s«
.000,-2254
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» .ASCII Ho
Connect
8. Press the 'Start/Stop' button again to end measurements.
9. Press the 'Power' button (,) to turn the unit off.
Processing Data
Data should be downloaded at the end of each collection day. All generated data are saved in
the current Direct Connect session as a text file (*.txt). The name of the text file is automatically
derived from the time and date when the Capture button was clicked, as described in the data
collection procedure. In this text file (Figure 12), all values are separated, or 'delimited', by
commas. The order of the columns in the text files generated by the Met One 831 are as
follows: timestamp (includes both date and time), location code (default = 001), PMi, PM2.5,
PM4, and PMio. The last two columns contain error codes and diagnostic data (these are not of
concern to the user but can help the manufacturer with troubleshooting the device if necessary).
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™| MetOnel31203_140104Jerm.txt -
File Edit Format View Help
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02 /DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02 /DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02 /DEC/2013
02 /DEC/201 3
02 /DEC/201 3
02 /DEC/2013
02 /DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02 /DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02 /DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
02/DEC/2013
14
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To process the collected data, use the following procedure to transfer the text file created by the
Met One 831 to spreadsheet software such as Microsoft Excel. Most spreadsheet programs are
able to read data from a text file in a delimited format. Microsoft Excel 2013 is used here to
illustrate the data transfer, but the relative locations of import options are similar in earlier versions
of Microsoft Excel (dating back to 2003).
Procedure: Process Data
1. Open a new Microsoft Excel spreadsheet and select Data > Get External Data > From
Text.
2. When prompted, use Windows Explorer to navigate to the folder containing the text file
previously specified in the 'Configure Data Destination' window.
3. When prompted, in the next screens select 'Delimited' and 'Comma-delimited'.
4. Press 'Finish' to display the data in columns in the Excel spreadsheet (Figure 13).
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m a *>-
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12/2/2013 14:36 1 0.5 1.7 3.1 4.9 0 *2247
12/2/2013 14:37 1 0.5 1.6 2.9 4.7 0 *2252
12/2/2013 14:38 1 0.5 1.7 3.2 5.2 0 *2244
12/2/2013 14:39 1 0.5 1.6 3.1 5.6 0 "2247
12/2/2013 14:40 1 0.5 1.7 3.2 5.1 0 *2236
12/2/2013 14:41 1 0.5 1.8 3.2 6.2 0 "2240
12/2/2013 14:42 1 0.5 1.8 3.1 4.3 0 *2239
12/2/2013 14:43 1 0.5 1.9 3.1 4.7 0 *2245
12/2/2013 14:44 1 0.5 1.5 3.1 4.9 0 *2244
12/2/2013 14:45 1 0.5 1.7 3.4 6.6 0 *2249
12/2/2013 14:46 1 0.5 1.8 3.4 5.4 0 *224S
12/2/2013 14:47 1 0.5 1.9 3.7 6.8 0 *2258
12/2/2013 14:48 1 0.5 1.9 3.7 6.3 0 *2254
12/2/2013 14:49 1 0.5 1.9 3.5 6.3 0 *2253
12/2/2013 14:50 1 0.5 1.5 1 3 6.4 0 *2237
12/2/2013 14:51 1 0.5 1.9 3.4 6.4 0 *2246
12/2/2013 14:52 1 0.5 1.9 3.5 6.6 0 "2250
12/2/2013 14:53 1 0.5 1.7 3.1 5.7 0 *2245
12/2/2013 14:54 1 0.5 1.5 3.3 5.S 0 *2247
12/2/2013 14:55 1 0.5 1.8 3.5 5.7 0 *2252
12/2/2013 14:56 1 0.5 2 3.6 6.9 0 *225O
12/2/2013 14:57 1 0.4 1.6 3.3 5.7 0 *2249
12/2/2013 14:58 1 0.4 1.6 3.2 6.5 0 *2248
12/2/2013 14:59 1 0.4 1.4 3.1 6 0 *2241
12/2/2013 15:00 1 0.4 1.6 3.2 6.2 0 *2233
12/2/2013 15:01 1 0.4 1.5 3.1 6.9 0 *2239
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Maintenance
The manufacturer recommends that a couple of procedures be performed regularly to keep the
Met One 831 generating reliable data:
<» A monthly check of the flow rate
<» An optional zero count test weekly
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Checking the Flow Rate [Optional]
The sample flow rate is factory set to 0.1 cubic feet per minute (cfm), or 2.83 liters per minute
(Ipm). Continued use and variations in ambient temperature and pressure might cause minor
changes in the flow that can reduce measurement accuracy. The following steps guide you
through checking the flow rate and adjusting it if necessary.
Procedure: Check Flow Rate
1. Remove the silver-colored inlet screen from the
inlet nozzle cover. The screen pulls off easily.
2. Use the small Allen wrench provided in the flow
meter kit to remove the two hex set screws
securing the inlet cover.
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3. Gently lift the cover off the inlet nozzle.
4.
5.
6.
Connect a flow meter (not included) to the inlet
nozzle, and start both the 831 and the flow
meter.
Begin sampling and check the flow meter
reading after approximately 30 seconds. The
flow rate should be 0.1 cfm (2.83 Ipm) ± 5%. If
the flow is not within the acceptable range
(0.095-0.105 cfm or 2.69-2.97 Ipm), proceed
to the next step.
Adjust the flow by using a small flathead
screwdriver to turn the trimmer potentiometer,
or trim pot (a miniature adjustable electrical
component set at the factory), located in the
access hole in the side of the unit: Turn the
trim pot clockwise to increase flow and
counterclockwise to decrease flow. Repeat
Step 5 to determine flow rate and ensure it is
within the acceptable range.
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Performing a Zero Count Test [Optional]
In addition to the flow rate test, the manufacturer recommends that a zero filter test be
performed weekly and as needed in response to a "Sensor Noise" error.
Procedure: Perform Zero Count Test
1. Remove the screen and inlet cover as done for
the flow rate test (steps 1-3).
2. Attach the zero filter included with the unit
(Figure 14).
3. Allow the unit to flow for 5 minutes with the zero
filter attached.
4. Take at least one measurement with the unit to
confirm that it reads zero.
Contact the manufacturer if you are unable to obtain a
zero reading.
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CITIZEN SCIENCE
For Additional Help
Model 831 Manual, 831-9800 Rev D1.doc, Met One Instruments, Inc., 1600 Washington Blvd.
Grants Pass, OR 97526, http://www.metone.com/docs/831 operationmanual.pdf, last accessed
May 13, 2015.
U.S. Environmental Protection Agency, Particulate Matter
(PM), http://www.epa.gov/airquality/particlepollution/index.html, last accessed May 13, 2015.
The purpose of this document is to provide general operating guidelines, and
the U.S. Environmental Protection Agency (EPA) does not assume any liability
regarding any aspect of its use. Reference herein to any specific commercial
products, process, or service by trade name, trademark, manufacturer, or
otherwise does not necessarily constitute or imply its endorsement,
recommendation, or favoring by EPA. The views and opinions of authors
expressed herein do not necessarily state or reflect those of EPA and shall not
be used for advertising or product endorsement purposes. EPA assumes no
liability associated with any errors in the suggested procedures, errors
potentially made by the instrument in question, user misuse of the instruments
or data collected, or costs due to any damage the instrument might experience
under any circumstance or use. This user guide is specific to the make'model
and version number of the instrument identified in the document and is not
generalizable to any other sensor. The users should understand that they
should develop operating guidelines specific to their own research needs, and
any general document of this nature would be limited in meeting their full need.
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