# Presentation: 462040

##  Why continuous PM2.5 FEMIII data may not be appropriate for attainment demonstrations  

- Dirk Felton
- National Air Quality Conference
- Portland, OR
- April 6-9, 2008

## Recent versions of both the MetOne BAM and the FDMS TEOM have been 	evaluated and compared to a routine daily FRM in New York City.       

- Recent versions of both the MetOne BAM and the FDMS TEOM have been 	evaluated and compared to a routine daily FRM in New York City.
- Both the FDMS and the BAM measure significantly more mass than the FRM.
- 	The difference is greater in the summer months.
-     (FDMS TEOM Version B&C)                  (BAM with Smart Heater set at 45%)

**Notes:**
This is the urban comparison between the FDMS and the BAM.

The FDMS and the BAM both measure significantly more mass than the FRM.

The data from the BAM is slightly more scattered with a larger y-intercept 	than the FDMS.

## Why doesn't the vendor data match S&L Data?The candidate FEMs compare more favorably to the FRMs operated by the vendors than to the FRMs operated by the S & L Agencies.

- Primarily because the vendor’s triplicate PM2.5 FRMs are not operated the way instruments are operated by S&L Agencies.
-  	    “there is no requirement that the daily measurements start at    	any particular time of day, as long as they meet the 22 to 	25 hour duration requirement of §53.35”
- The specifications for operating FRMs in the FEM Test Protocols bias the data high when compared to data from FRMs operated in a S&L Agency network.

## 1405 DF TEOM

- NY Hosted Class III FEM
- Equivalency evaluation
- for the TEOM 1405 last
- summer.

## Slide 5

## The first thing to notice is that the vendor data is higher than the S&L Agency data on high days.  In urban areas, the proportion of volatile mass is often higher on days with high PM2.5 concentration.

- Vendor: ThermoFisher

## In this example, the S & L Agency is different, the vendor    is different but the results are the same.  

- In this example, the S & L Agency is different, the vendor    is different but the results are the same.
- The FEM test protocols produce “FRM” data that is not comparable enough to routine FRM data to provide a basis for determining how a candidate Class III FEM will operate in a real world application.
- Vendor: MetOne

## Reason #2: 

- The sample collection interval also effects the FRM’s ability to retain volatile mass:
- Collecting the sample from midnight to midnight exposes the sample to the highest evaporative losses in the hottest part of the day when the sample is at relatively high loading.
- Collecting the sample from 9:00 to 9:00 or 11:00 to 11:00 am exposes the sample to the highest ambient temperatures before much of the mass has been collected.

- (Summer test site actual average diurnal temperatures: Ave 740 F)

## What will NY do with Class III FEM Data?

- We do not plan to use Method code 88101.
- Method code 88500 is more appropriate for these instruments.

- Figure 1: EPA Technical Note: June 1, 2006

## Conclusions

- The Bias is most significant on high concentration days in urban 	areas in warm months (This is very important for data used 	for comparisons to the 24-hr std) (Org Carbon & Nitrate)
- The availability of FEMs provides greater flexibility for 	monitoring Agencies (Can reduce filter based network)
- There is value in producing more accurate, hourly PM2.5 data 	(Health Research, Atmospheric Science Studies)
- The current FEM tests should not be viewed as predictors of 	results in S&L Agency networks
- NAAQS comparison issues should be discussed with the 	Regional EPA office before the decision is made to operate 	and where to operate a Class III FEM

## How do we resolve this situation?

- 	 MetOne BAMs and FDMS TEOMs work as designed and provide data 	that includes a higher proportion of the volatile mass
- 	  It’s the FRM that is flawed.  The “Gold Standard” is tarnished   	and in need of an overhaul.  This is not new information.
- The FRM design should include a chiller to keep the filters cold 	and a drier to prevent condensation at the end of the sample 	period.
- This design change should be implemented in time for the next 	review of the PM2.5 NAAQS (2010)
- The result will be a PM2.5 dataset that is more consistent and 	responsive to the needs of health researchers.
- 		(After all we should try to measure what we are breathing)