Overview of CSN Data Relevant to OC/EC Artifact Adjustments
Download
1 / 19

overview of csn data relevant to oc - PowerPoint PPT Presentation


  • 179 Views
  • Uploaded on

Overview of CSN Data Relevant to OC/EC Artifact Adjustments presented by James Flanagan RTI International Davis, CA January 22-23, 2008. Assignment: “Review of current artifact adjustment approach for CSN, including sampler-specific variations”.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'overview of csn data relevant to oc' - Albert_Lan


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Slide1 l.jpg
Overview of CSN Data Relevant to OC/EC Artifact Adjustmentspresented byJames FlanaganRTI InternationalDavis, CAJanuary 22-23, 2008


Slide2 l.jpg
Assignment: “Review of current artifact adjustment approach for CSN, including sampler-specific variations”

  • There is no artifact adjusted data currently being posted to AQS for any CSN species, therefore this presentation will focus on:

    • Blank data available that could be used for artifact adjustments:

      • Original CSN samplers and analysis

      • New 3000N samplers and analysis

    • CSN program timeline

    • CSN sampler types

    • Blank level differences between sampler types

    • Lab blanks and other QC data


Csn timeline l.jpg

CSN Timeline approach for CSN, including sampler-specific variations”

2/9/2000 – 7/7/2003

OC, EC analyses done by RTI International Laboratory using Sunset Labs Instruments

No OC or EC fractions (“peaks”) reported

“OCX” or “OCX2” were reported during this period

7/8/2003 – present

OC, EC analyses for CSN samplers done by RTI International Laboratory.

4 OC fractions (plus Pyrolysis C) are reported; no OCX or OCX2.

no EC fractions reported.

-- Initial Set of 55 3000N Samplers Added to CSN in May, 2007 --

5/2007 – present

3000N filters are being analyzed by Desert Research Inst. (DRI).

3000N samplers are collocated with the existing CSN samplers at each site, and are run collocated for 2 months

4 OC, Pyrolysis C, and 3 EC fractions, plus OC and EC by TOT and TOR are being uploaded to AQS without artifact correction.


Csn stn tot analysis method l.jpg
CSN: “STN” TOT Analysis Method approach for CSN, including sampler-specific variations”

  • Filter: 47mm Whatman quartz w/ 5% borosilicate binder

  • Filters pre-fired at 900oC in air

  • Sunset Lab Carbon Aerosol Analyzers

  • Protocol: NIOSH 5040, optimized for PM2.5

  • Time-driven analysis (12 min total)

  • Thermal-Optical Transmittance (TOT)


Csn sampler types l.jpg
CSN Sampler Types approach for CSN, including sampler-specific variations”

  • URG MASS – Wins Impactor; Teflon module

  • Andersen RAAS - cyclone; Teflon coated module

  • MetOne SASS – mini-cyclone; alloy module

  • other types:

    • R&P 2300 – internal greased impactor; alloy module

    • R&P sequential FRM


Csn sampler module types l.jpg
CSN Sampler Module Types approach for CSN, including sampler-specific variations”

URG MASS

Andersen RAAS

Cassette used for IMPROVE and 3000N Samplers

MetOne SASS

R&P 2300


Csn field and trip blanks reported to aqs l.jpg
CSN: Field and Trip Blanks approach for CSN, including sampler-specific variations”(reported to AQS)

  • Field Blanks are collected at 10% of routine frequency (monthly or bimonthly at each site) – filter modules mounted for a short period of time and removed.

  • Trip Blanks are collected at 3% of rout. freq. – filter modules not removed from shipping bag.

  • Field and Trip Blank results are very similar.

  • Field/Trip Blank levels differ significantly between sampler types.


Csn field trip blank averages original oc ec analyses l.jpg
CSN: Field/Trip Blank Averages approach for CSN, including sampler-specific variations”(Original OC/EC Analyses)

Trip and Field Blank averages 2000 – 2006, ug/filter

*

* R&P module contains silicone impactor grease, which may appear as EC.

  • 47 mm Whatman filter with borosilicate binder.

  • CSN (STN) analysis protocol.

  • Each number is 100’s or 1000’s of measurements.

Source: Max R. Peterson, James B. Flanagan, Larry C. Michael, and R.K.M. Jayanty. 2007.

Analysis of PM2.5 Speciation Network Carbon Blank Data. AAAR 26th Annual Conference,

Reno, NV, September 24-28.


Csn laboratory qc data for original oc ec analyses not reported to aqs l.jpg
CSN: Laboratory QC Data for Original OC/EC Analyses approach for CSN, including sampler-specific variations”(not reported to AQS)

  • Analyses are performed by RTI International’s OC/EC Laboratory in North Carolina using Sunset Labs Instruments.

  • Acceptance Blanks — full STN analysis of the larger of 2 or 2% of pre-fired filters.

  • Instrument Blanks — full STN analysis using a clean filter punch, usually from the preceding analysis.

  • Duplicate Analyses —10% of filter samples reanalyzed on the same analyzer to test uniformity of filter deposit.

  • Replicate Analyses — a group of filters analyzed on 3 or more analyzers to assess between-analyzer variability and to establish measurement uncertainties.


Csn laboratory qc data received for oc ec 3000n not reported to aqs l.jpg
CSN: Laboratory QC Data Received for OC/EC 3000N approach for CSN, including sampler-specific variations”(not reported to AQS)

  • Analyses are being done by Desert Research Institute (DRI) in Reno, NV.

  • System Blanks — Full IMPROVE_A analysis without a filter punch.

  • Replicate Analyses — Analysis of a second punch from 10% of filter samples on a randomly-chosen (different or same) analyzer used to evaluate between-analyzer variability.

  • DRI performs additional QC not reported to RTI.


Csn available blank types with 3000n sampler protocol blank data reported to aqs l.jpg
CSN: Available Blank Types with 3000N Sampler Protocol approach for CSN, including sampler-specific variations”(blank data reported to AQS)

  • Afterfilters – identical to IMPROVE NEW to CSN

  • IMPROVE-type “field blanks” (passive blank in 4th position of cassette) NEW to CSN

  • Field Blanks (like existing CSN Trip and Field Blanks)


Afterfilters frequency and availability of data for statistics l.jpg
Afterfilters – Frequency and Availability of Data for Statistics

  • Since May, 2007, CSN runs afterfilters at all sites equipped with 3000N at a rate of 10%

  • Sufficient afterfilter data are available to calculate reliable statistics on a monthly basis

    • Median

    • Standard Deviation

    • other?


Tot afterfilter vs ambient levels with 3000n module l.jpg
TOT Afterfilter vs. Ambient Levels Statisticswith 3000N Module

Original CSN field and trip blanks are generally poorly correlated to season or site location; however, afterfilters from 3000N show some correlation with ambient levels.

  • Data from 3000N:

  • X-axis = front filter

  • Y-axis = afterfilter

  • N = 820, R2=0.2378

  • 55 sites nationwide

  • 5/2007 – 12/2007


Slide14 l.jpg

CSN: Temporal Variability Statistics

in Trip and Field Blank Levels

Average Total Carbon Blank by Year, ug/m3 (subset of sites with long-term data)

  • Between 2002 and 2005, STN field and trip blank annual averages for Met One (SASS) and Anderson (RAAS) samplers decreased 33% and averages for URG (MASS) samplers increased 25%.

From “Carbon Measurements and Adjustments “, presented by Neil Frank at Air Quality Data in Health Effects Research conference, Nov 30 – Dec 1, 2006


Slide15 l.jpg

From “Carbon Measurements and Adjustments “, presented by Neil Frank at Air Quality Data in Health Effects Research conference, Nov 30 – Dec 1, 2006


Slide16 l.jpg

CSN: Temporal Variability by Neil Frank at Air Quality Data in Health Effects Research conference, Nov 30 – Dec 1, 2006

in Trip and Field Blank Levels

MetOne Sampler

Total Carbon Field and Trip Blanks, μg/m3

From “Carbon Measurements and Adjustments “, presented by Neil Frank at Air Quality Data in Health Effects Research conference, Nov 30 – Dec 1, 2006


Lab blank variability l.jpg
Lab Blank Variability by Neil Frank at Air Quality Data in Health Effects Research conference, Nov 30 – Dec 1, 2006

“Second”

“Third”

  • Instrument blanks are typically less than 10% of trip and field blanks when expressed in the same units

  • Between-instrument variability and the effect of a software upgrade are visible

  • One of the lab analyzers appears to be more sensitive to the software change than the other.

Source: Max R. Peterson, James B. Flanagan, Larry C. Michael, and R.K.M. Jayanty. 2007. Analysis of PM2.5 Speciation Network Carbon Blank Data. AAAR 26th Annual Conference, Reno, NV, September 24-28.


Notable differences between original csn method and improve 3000n l.jpg
Notable Differences Between Original CSN Method and IMPROVE/3000N

  • Face velocity and deposit density are potentially up to 10x greater for IMPROVE/3000N relative to MetOne due to flow rate and filter size.

  • Different filter materials.

  • Different flow control technology (IMPROVE)

  • Different analysis protocols:

    • temperature steps

    • timebase

    • TOT vs. TOR


Slide19 l.jpg
Summary Slide: Pros and Cons IMPROVE/3000Nfor the use of existing field and trip blank data for artifact correction of original CSN data

  • Pro: Lots of existing data 2000 - present

  • Pro: Probably closer to truth than lab blanks

  • Con: May not represent “true” artifact

  • Con: Questionable relevance to IMPROVE data

  • Con: Unlike afterfilters, the existing CSN trip and field blanks are not sensitive to seasonal or geographic variations


ad