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AQS Memos - Technical Note on Reporting PM2.5 Continuous Monitoring and Speciation Data to the Air Quality System (AQS)

Technical Note on Reporting PM2.5 Continuous Monitoring and Speciation

Data to the Air Quality System (AQS)

6/01/2006

Since 2003 EPA with its partners at State, local and Tribal Monitoring Agencies has been successfully reporting PM2.5 continuous monitoring data to the public on AIRNow

(http://www.airnow.gov). In many cases the State, local and Tribal agencies are also reporting on their own web sites and through other media to the public. While the near real-time data are posted on these web sites, the EPA’s repository of validated ambient air data continues to be the Air Quality System (AQS). Storage in AQS provides for a permanent archive of the validated data for further analysis including comparison to pollutant data not available in near real-time such as filter-based Federal Reference Method (FRM) and speciation data.

While reporting of PM2.5 continuous monitoring data in AQS appears to be at a high level (522 monitors reporting data as of April 2005), it is often difficult to understand the quality of the data. In many cases the PM2.5 continuous monitors are directly producing data that reasonably estimate what an FRM would provide and agencies are reporting those data. In other cases where the continuous monitor does not approximate the FRM, but they are correlated, State, local or Tribal agencies are statistically correcting the data. For submitting data to AQS there has not been a standard protocol for whether raw data or statistically corrected data should be submitted. This severely limits analysts from utilizing the data as they may be unsure of its quality and also may potentially confuse or mislead the general public regarding PM2.5 air quality status. To resolve this issue a workgroup of EPA, State, and local agencies identified several options for coding data in AQS. EPA considered this input and at the 2005 National Air Quality and AQS Conferences announced new parameter codes to accommodate raw data from PM2.5 continuous monitors and data from continuous methods capturing a total atmospheric measurement of PM2.5. At this time several State and local agencies are utilizing these two new parameter codes.

The addition of these two new parameter codes brought to light a need to better distinguish PM2.5 data that are used in NAAQS decision making from data usable only for other monitoring objectives, and not just to distinguish those data that reasonably match the FRM from those that do not. For instance, there may be a point in the future where a PM2.5 continuous method is approved for NAAQS decisions in one geographical area, but not another. In this example, there would need to be a clear understanding of which data are to be used for the NAAQS decisions. Although method code does provide one way to indicate which methods are reference and equivalent, we have decided to make the AQS data even more transparent by allowing parameter code 88101 (PM2.5 at local conditions) to only be used for PM2.5 data obtained with methods eligible for use in the NAAQS decision making process for the applicable geographical area. Therefore, a new and different parameter code has been created to store all other PM2.5 concentration measurement data (from continuous monitors and speciation samplers) that still reasonably match the FRM, but are not to be used for NAAQS decisions.

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To summarize, the following new procedures are to be used when submitting PM2.5 continuous monitor data or mass data from speciation samplers to AQS:         

  Summary

1.)

For the AQS parameter code 88101 – PM2.5 at local conditions, only report those data validated from Federal Reference Methods, Federal Equivalent Methods, or other methods that are to be used in making NAAQS decisions. For instance, Approved Regional Methods may become part of a future PM2.5 monitoring network to meet multiple monitoring objectives, including NAAQS decisions. Note: at this time only filter-based FRM and FEMs will use parameter code 88101.

2.)

Report to S/L/T web sites, AIRNow, and AQS uncorrected or statistically corrected hourly continuous data that is seasonally or yearly within 10 percent bias1and has a correlation of at least 0.92 (squared correlation of at least 0.81) with the FRM. When reporting to AQS, use parameter code 88502 – Acceptable PM2.5 AQI and Speciation Mass. This parameter code is also expected to be utilized for mass concentration data produced from the speciation networks. Use the most appropriate method code in AQS that clearly indicates the operation of the monitor when submitting data. For PM2.5 continuous methods that have been statistically corrected, use method codes that indicate the use of external correction factors as applicable.

3.)

Report valid raw data (uncorrected) to AQS that is not within 10% bias and/or does not have a correlation of at least 0.9 of the FRM with the new parameter code: “PM2.5 Raw Data” (parameter code 88501). In fact, we recommend that agencies report all raw PM2.5 concentration data to AQS even if statistically adjusted data is also being reported. This parameter code would not be readily available for public review on web sites such as AirData (http://www.epa.gov/air/data/), but would be available in AQS for historical review of method performance. This parameter code is expected to only apply to continuous PM2.5 methods.

4.)

Report Filter Dynamic Measurement System (FDMS) data to AQS associated with the parameter code: “Total Atmospheric PM2.5” (parameter code 88500). This should be the total concentration of the monitor including both base and reference channels. This will allow for more insightful interpretation of data when reviewing events that may contain aerosols not normally retained on the FRM during warmer seasons.

5.)

Report the reference channel data of the FDMS to AQS with the new parameter code:

“PM2.5 Volatile Channel” (parameter code 88503). This should be the reference channel of the FDMS as reported from the instrument. For instance, the calculation of the FDMS reference mass may report a loss of 3.2 micrograms per cubic meter in a one hour time period as -3.2 and this would be reported to AQS as -3.2.

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Table 1, PM2.5 Parameter Codes

Parameter Name

Parameter Code

Purpose

Notes

PM2.5 LOCAL CONDITIONS

88101

Appropriate code for all FRM/FEM/ARMs

Original code for PM2.5 at local conditions

PM2.5 TOTAL ATMOSPHERIC

88500

Valid data from methods measuring total PM2.5 aerosols in the atmosphere, including those that can be volatilized from the FRM

Introduced in 2005

PM2.5 RAW DATA

88501

Valid uncorrected data that does not reasonably match the FRM

Introduced in 2005

ACCEPTABLE PM2.5 AQI & SPECIATION MASS1

88502

Valid data that does reasonably match the FRM

with or without correction, but not to be used in NAAQS decisions

Introduced in 2006

PM2.5 VOLATILE CHANNEL1

88503

Store important related data such as the FDMS reference channel

Introduced in 2006

1 –We anticipate it will take several months to align all reporting agencies with these new codes.

REPORTING NOTES:

  1. These procedures may be implemented in 2006, but without exception should be applied to all data collected on or after January 1, 2007.

  1. Agencies are encouraged to apply the procedures retrospectively and update AQS. EPA has created and tested an automated script to facilitate migrating monitor records with the new parameter codes. This script will be used by EPA to re-code the speciation data in the coming weeks. Agencies wishing EPA to migrate their monitor records to the new parameter codes should contact Jonathon Miller of EPA’s National Air Data Group (919) 541-7738, E-mail: miller.jonathan@epa.gov.

  1. Agencies are expected to report the “acceptable” PM2.5 continuous monitoring data to AQS. Raw data from PM2.5 continuous monitors are strongly encouraged to also be reported to AQS so that assessments of the PM2.5 data can be performed and a historical performance of the PM2.5 method can be determined. The latter includes independent assessments of the data adjustments.

If you have any monitoring questions on these procedures feel free to contact Tim Hanley of the OAQPS Ambient Air Monitoring Group (919) 541-4417, E-mail:

hanley.tim@epa.gov. For questions on AQS please contact Jake Summers of the OAQPS National Air Data group at (919) 541-5695, E-mail: summers.jake@epa.gov.

Other Reporting Notes: AIRNow:

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  1. Update PM2.5 site information table to describe site, method, and statistical correction, if applicable.

  2. Access to AIRNowTech – where the site information table exists for each agency – can now be requested by any member of the ambient air monitoring community. See the webs site: http://www.airnowtech.org/index.cfm?page=login

  3. AIRNow may in the future be backfilled with validated AQS data for parameter code 88502 (Acceptable PM2.5 AQI and Speciation Mass) so that invalid PM2.5 continuous data are not used from AIRNow. This will provide consistency between AQS and AIRNow so that the appropriate number of days are calculated for the AQI in each area, using either data set.

AQS:
  1. For new parameter codes continue to use POCs 3 and 4 for continuous monitors and POCs 5 and 6 for speciation samplers since there is a nice record of these POCs with parameter code 88101.

  2. The following table provides the method codes associated with the new parameter codes available in AQS:

Table 2, PM2.5 Method Codes

Parameter Code

Parameter

Name /

Methodology

Code

Recording Mode

Sample Collection Description

Sample Analysis Description

88500

PM2.5 Total Atmospheric

88500

760

CONTINUOUS

PM2.5 SCC

FDMS-Gravimetric

88500

761

CONTINUOUS

PM2.5 VSCC

FDMS-Gravimetric

88501

PM2.5 Raw Data

88501

701

CONTINUOUS

PM2.5 SCC w/No Correction Factor

TEOM Gravimetric 50 deg C

88501

703

CONTINUOUS

PM2.5 SCC w/No Correction Factor

TEOM Gravimetric 30 deg C

88501

706

CONTINUOUS

PM2.5 SCC w/No Correction Factor

TEOM Gravimetric 40 deg C

88501

711

CONTINUOUS

PM2.5 SSI w/No Correction Factor

TEOM Gravimetric 50 deg C

88501

715

CONTINUOUS

PM2.5 VSCC w/No Correction Factor

TEOM Gravimetric 30 deg C

88501

716

CONTINUOUS

PM2.5 VSCC w/No Correction Factor

TEOM Gravimetric 50 deg C

88501

721

CONTINUOUS

PM2.5 WINS w/No Correction Factor

TEOM Gravimetric 50 deg C

88501

723

CONTINUOUS

PM2.5 WINS w/No Correction Factor

TEOM Gravimetric 30 deg C

88501

731

CONTINUOUS

Met-One BAM W/PM2.5 SCC

Beta Attenuation

88501

732

CONTINUOUS

Met-One BAM W/PM2.5 WINS

Beta Attenuation

88501

750

CONTINUOUS

Andersen BAM w/PM2.5 SCC

Beta Attenuation

88501

751

CONTINUOUS

Andersen BAM w/PM2.5 SSI

Beta Attenuation

88501

752

CONTINUOUS

Andersen BAM w/PM2.5 WINS

Beta Attenuation

Parameter Code

Parameter

Name /

Methodology

Code

Recording Mode Sample Collection Description Sample Analysis Description

88501

753

CONTINUOUS

Andersen BAM w/PM2.5 VSCC

Beta Attenuation

88502

Acceptable

PM2.5 AQI &

Speciation Mass

88502

701

CONTINUOUS

PM2.5 SCC w/No Correction Factor

TEOM Gravimetric 50 deg C

88502

702

CONTINUOUS

PM2.5 SCC w/Correction Factor

TEOM Gravimetric 50 deg C

88502

703

CONTINUOUS

PM2.5 SCC w/No Correction Factor

TEOM Gravimetric 30 deg C

88502

704

CONTINUOUS

PM2.5 SCC w/Correction Factor

TEOM Gravimetric 30 deg C

88502

705

CONTINUOUS

PM2.5 SCC w/Correction Factor

TEOM Gravimetric 40 deg C

88502

706

CONTINUOUS

PM2.5 SCC w/No Correction Factor

TEOM Gravimetric 40 deg C

88502

707

INTERMITTENT

IMPROVE Module A with Cyclone

Inlet-Teflon Filter, 2.2 sq. cm.

GRAVIMETRIC

88502

711

CONTINUOUS

PM2.5 SSI w/No Correction Factor

TEOM Gravimetric 50 deg C

88502

712

CONTINUOUS

PM2.5 SSI w/Correction Factor

TEOM Gravimetric 50 deg C

88502

713

CONTINUOUS

PM2.5 SSI w/Correction Factor

TEOM Gravimetric 30 deg C

88502

715

CONTINUOUS

PM2.5 VSCC w/No Correction Factor

TEOM Gravimetric 30 deg C

88502

716

CONTINUOUS

PM2.5 VSCC w/No Correction Factor

TEOM Gravimetric 50 deg C

88502

717

CONTINUOUS

PM2.5 VSCC w/Correction Factor

TEOM Gravimetric 50 deg C

88502

721

CONTINUOUS

PM2.5 WINS w/No Correction Factor

TEOM Gravimetric 50 deg C

88502

722

CONTINUOUS

PM2.5 WINS w/Correction Factor

TEOM Gravimetric 50 deg C

88502

723

CONTINUOUS

PM2.5 WINS w/No Correction Factor

TEOM Gravimetric 30 deg C

88502

724

CONTINUOUS

PM2.5 WINS w/Correction Factor

TEOM Gravimetric 30 deg C

88502

731

CONTINUOUS

Met-One BAM W/PM2.5 SCC

Beta Attenuation

88502

732

CONTINUOUS

Met-One BAM W/PM2.5 WINS

Beta Attenuation

88502

740

CONTINUOUS

PM2.5 SCC

CAMMS Mass pressure drop

88502

741

CONTINUOUS

PM2.5 WINS

CAMMS Mass pressure drop

88502

750

CONTINUOUS

Andersen BAM w/PM2.5 SCC

Beta Attenuation

88502

751

CONTINUOUS

Andersen BAM w/PM2.5 SSI

Beta Attenuation

88502

752

CONTINUOUS

Andersen BAM w/PM2.5 WINS

Beta Attenuation

88502

753

CONTINUOUS

Andersen BAM w/PM2.5 VSCC

Beta Attenuation

88502

760

CONTINUOUS

PM2.5 SCC

FDMS-Gravimetric

88502

761

CONTINUOUS

PM2.5 VSCC

FDMS-Gravimetric

88502

771

CONTINUOUS

Correlated Radiance Research M903

Nephelometry

88502

781

INTERMITTENT

SINGLE-FILTR WINS 2.5UM IMPACT

GRAVIMETRIC

88502

783

INTERMITTENT

SEQUENT SAMPLR WINS 2.5UM IMP

GRAVIMETRIC

88502

785

INTERMITTENT

DICHOTOMOUS APPROVED PM10 REFR

GRAVIMETRIC

88502

787

CONTINUOUS

AUTOMATED WINS 2.5UM IMPACTOR

BETA GUAGE

88502

789

CONTINUOUS

AUTOMATED WINS 2.5UM IMPACTOR

TEOM-GRAVIMETRIC

88502

791

CONTINUOUS

OTHR AUTOMATD 2.5 MASS CONCENT

SURROGATE MEASURE

88502

793

INTERMITTENT

OTHR 24HR FILTER BASED SAMPLER

GRAVIMETRIC

88502

810

INTERMITTENT

Met One SASS Teflon

Gravimetric

88502

820

INTERMITTENT

Andersen RAAS Teflon

Gravimetric

88502

830

INTERMITTENT

URG MASS400 Teflon WINS

Gravimetric

88502

850

INTERMITTENT

R&P MDL2300 PM2.5 SEQ SPEC

GRAVIMETRIC

88502

870

INTERMITTENT

URG MASS400 Teflon VSCC

Gravimetric

88502

899

INTERMITTENT

No Method-None

None

88503

PM2.5 Volatile Channel

88503

760

CONTINUOUS

PM2.5 SCC

FDMS-Gravimetric

88503

761

CONTINUOUS

PM2.5 VSCC

FDMS-Gravimetric

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  1. If additional method codes are necessary, reporting agencies should contact EPA.

Data Quality:

1.) There may on occasion be cases where one or a couple of days are well outside of the goal for control of bias of +/-10 % as compared to a FRM. In these cases the data should still be used, so long as there is no apparent reason to otherwise invalidate the data and the general control of bias for the season or year is still acceptable.

2.) In many cases monitoring agencies are correcting their data prospectively. For example, Agencies use a previous year’s worth of collocated FRM and raw continuous monitoring data with statistical linear regression to report corrected continuous monitoring data in the current year. In most cases this prediction will be sufficient for archiving in AQS. In a few cases it may be more appropriate to rerun the statistical linear regression using the current year’s FRM and continuous monitoring data to determine the current year’s corrected data.

3.) It may be unreasonable to expect continuous monitoring technologies with different conditioning and measurement techniques to provide closely matched results with collocated FRM’s. However, within a reasonable margin of error (10 percent bias and a correlation of at least 0.92 compared to a collocated FRM) many existing continuous monitoring technologies can provide useful results for public reporting purposes and other monitoring objectives.

4.) As pointed out earlier, ultimately agencies must decide for themselves whether the data quality of the methods they are operating are sufficient to be reported to their own web sites and AIRNow. However, regardless of data quality – as compared to collocated FRM’s – all valid PM2.5 continuous reporting data can now be reported to AQS.

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