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

Technical Note on Reporting PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5 continuous monitors and data from continuous methods capturing a total atmospheric measurement of PM_2.5. 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 PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5 concentration measurement data (from continuous monitors and speciation samplers) that still reasonably match the FRM, but are not to be used for NAAQS decisions.

To summarize, the following new procedures are to be used when submitting PM_2.5 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.

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.

2. 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 Robert Coats of EPA’s National Air Data Group (919) 541-5448, E-mail: coats.robert@epa.gov.

3. Agencies are expected to report the “acceptable” PM_2.5 continuous monitoring data to AQS. Raw data from PM_2.5 continuous monitors are strongly encouraged to also be reported to AQS so that assessments of the PM_2.5 data can be performed and a historical performance of the PM_2.5 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 Robert Coats of the OAQPS National Air Data group at (919) 541-5448, E-mail: coats.robert@epa.gov.

Other Reporting Notes:

AirNow:

1. Update PM_2.5 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 PM_2.5 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

3. 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 PM_2.5 continuous reporting data can now be reported to AQS.