# Presentation: 016842

## PM2.5 Chemical Speciation Network (CSN) Carbon Conversion

- Joann Rice

## PM2.5 Speciation Carbon Conversion

- PM2.5 Chemical Speciation Network (CSN):
- Speciation Trends Network (STN)
- 54 Trends sites: Largely static urban monitoring stations and protocols for sampling and analysis
- State and Local Air Monitoring Stations (SLAMS)
- Currently ~150 sites: monitors for state and local agency directed monitoring objectives
- Changes in the network to address inconsistencies in _carbon sampling and analysis_ procedures used in urban CSN and rural IMPROVE programs
- Field blank collection and subtraction also changing

## Carbon Data Comparability Issues

- A Brief History...
- Factor of 2 difference in Elemental Carbon (EC) highlighted by Chow et al., 2001*
- Data users comparing urban (speciation) and rural (IMPROVE) monitoring data for modeling, air quality data analyses, control strategy development, ...
- Question posed to CASAC on strengths and weaknesses of converting the network (December 2004)
- The CASAC subcommittee on monitoring strongly recommended changes to the network “to achieve fully _*comparable*_ data”
- EPA/OAQPS began communicating plans for changes to carbon in late 2004

- * Chow, J.C., Watson, J.G., Crow, D., Lowenthal, D.H., and Merrifield, T. (2001). Comparison of IMPROVE and NIOSH Carbon Measurements; Aerosol. Sci. and Tech. 34:23-34.

## A Brief History...
15 City CSN-to-IMPROVE comparison study
Preliminary data analysis from first 6 cities
ORD/OAQPS analysis of first year data in 2003 and OAQPS reassessment of full data set in 2005
Factor of 2 not observed for EC in urban locations; however, bigger differences found for EC in rural locations
Significant differences in OC observed due to filter face velocity/flow rate 
Results from additional 9 sites not yet evaluated

- 15 City CSN-to-IMPROVE comparison study
- Preliminary data analysis from first 6 cities
- ORD/OAQPS analysis of first year data in 2003 and OAQPS reassessment of full data set in 2005
- Factor of 2 not observed for EC in urban locations; however, bigger differences found for EC in rural locations
- Significant differences in OC observed due to filter face velocity/flow rate
- Results from additional 9 sites not yet evaluated

- Carbon Data Comparability Issues

## Organic Carbon Comparison

**  ****Sampler and filter-face velocity effects due to flow differences**
**  ****IMPROVE ~22 LPM;  and MetOne ~ 7 LPM**
**  ****IMPROVE OC un adjusted for blank**

## Elemental Carbon Comparison

**  ****EC compares better in urban areas, but large amount of scatter**
**  ****Rural EC at lower concentrations <0.3 ****μg/m3**

## Sampling and Analysis

- URG3000N Carbon Sampler
- Identical to the IMPROVE sampler _*except:*_
- Mass flow control
- Sampler operation and troubleshooting support provided by URG
- Modules loaded/provided by RTI
- Differs from CSN sampler
- 22.8 LPM flow rate
- 25-mm Pallflex Quartz filter
- Carbon Analysis
- IMPROVE_A TOR method
- Blank collection and subtraction

## PM2.5 Speciation Carbon Conversion

- EPA is using a contractor to procure, install and train operators on URG3000N sampler use
- The contractor coordinates installation with Region/State agencies
- Once installations are complete, new TOR analysis begins
- All sites move to TOR at once
- Concurrent CSN TOT and new sampling and TOR analysis done for about two months
- Sampling modules, cassettes, and analysis will continue to be supported and supplied by RTI
- Repeat process for rest of the network in batches of 50-60

## Project Status

- Phase I completed May 2007
- May 3rd start date
- Phase 2 site selection starting now
- Expect fall 2007 installation start date
- URG3000N web page created
- _[http://epa.gov/ttn/amtic/specurg3000.html](http://epa.gov/ttn/amtic/specurg3000.html)_
- Issues and Problems so far:
- Few sites not prepared for installation (space and power issues)
- Handful of sampler startup issues
- Some agencies without FTS to check 22 LPM
- Lead time on parts/supplies from vendor

## Questions