MEASUREMENT OF PM2.5 SEMI-VOLATILE MATERIAL WITH THE FDMS TEOM MONITOR Brett D. Grover, Michael Kleinman, Norman L. Eatough and Delbert J. Eatough, Brigham Young University Philip K. Hopke and Prasanna Venkatachari, Clarkson University Judy Chow and John Watson, Desert Research Institute William E. Wilson, William McClenny and Russell Long, U.S. Environmental Protection Agency Jeff Ambs and Michael Meyer, R&P Co. Inc. Robert A. Cary, Sunset Laboratory Inc. Hans Grimm and Bill Roe, GRIMM Technologies, Inc.

Semi-continuous Mass Monitors The RAMS monitor developed by BYU has been shown to measure semi-volatile nitrate and organic material, but not water. R&P has developed two samplers which are thought to also measure semi-volatile PM2.5 mass. These methods were compared in studies during January in Lindon Ut; July in Rubidoux CA & December in Fresno CA PC-BOSS and other semi-continuous compositional data obtained to help explain any differences observed.

Real-time Ambient Mass Sampler Particle Concentrator Denuders (NO2) and Dryer (H2O) Real-time Ambient Mass Sampler Blank Filter BOSS Denuder (VOC, SO2, O3, HNO3) and Dryer (H2O) “Sandwich” Filter, Quartz & CIG

R&P FDMS TEOM Monitor

Self-Referencing Differential TEOM Monitor For time interval t(n), Particle-laden air stream (ESP off) : MAeff = Mpnv + Mpv - Mpv ± Mfilt artifacts ± Minst effects For time interval t(n+1),, Particle-free air stream (ESP on) : MBeff = - Mpv ± Mfilt artifacts ± Minst effects Therefore: MAeff - MBeff = Mpnv+Mpv Ideally, switching time interval t  0 (or switching time small compared to rate constant for volatilization process)

Lindon Study RAMS FDMS TEOM 50C TEOM PC-BOSS Data obtained in January and February, 2003 during winter inversion conditions. Lindon is a residential community just north of Provo Emissions included mobile sources and woodsmoke RAMS FDMS TEOM 50C TEOM PC-BOSS

Lindon RAMS and FDMS TEOM data agreed The ±3 µg/m3 uncertainty in the RAMS data is evident in the results

Comparison with 3-h PC-BOSS Constructed Mass

Rubidoux Study RAMS FDMS TEOM Differential TEOM 50C TEOM GRIMMS Data obtained in July 2003 during LA Basin inversion conditions. Rubidoux is a residential community on the west side of the Basin (by Riverside) PM2.5 composition included ammonium sulfate and secondary semi-volatile organic material RAMS FDMS TEOM Differential TEOM 50C TEOM GRIMMS R&P Nitrate Sunset Lab C (SVOC) PC-BOSS

TEOM Monitor biased low

Determination of SVOC Lost from Particles with Modified Sunset Monitor Determination of Quartz Filter Carbonaceous Material with Conventional Sunset Monitor Determination of SVOC Lost from Particles with Modified Sunset Monitor

Total Measured Semi-volatile Material (Nitrate plus SVOM) Accounts for the Difference Seen.

The FDMS and PC-BOSS PM2.5 Results Agreed

The GRIMM monitor results appear to include particle bound water The difference is high when the RH is high at night

Modeling PM2.5 Water Content Accounts for the Higher GRIMM Measurement Results

The Semi-Volatile Material Measured by the FDMS is not Accurately Determined with the PM2.5 FRM

Fresno Study Data obtained in December 2003 during San Jauquin Valley winter inversion conditions. Fresno is a residential community in the central valley area PM2.5 composition included ammonium sulfate and secondary semi-volatile organic material RAMS FDMS TEOM Differential TEOM 50C TEOM GRIMMS R&P Nitrate & Sulfate Dionex Sulfate & Nitrate Sunset Lab C (SVOC) PC-BOSS

FDMS and Differential TEOM Agreed. Heated TEOM is Substantially Lower

Mass Constructed from Supersite Continuous Monitor Data Sulfate from R&P monitor, present as ammonium sulfate Nitrate from R&P monitor, present as ammonium nitrate C from R&P monitor, OC to OM factor = 1.6

Concentrations Increase in the Order Heated TEOM<Constructed<FDMS

Semi-volatile nitrate and organic material is included in the mass measured with the RAMS, FDMS TEOM and Differential TEOM These three measurement methods appear to be equivalent The GRIMM monitor also appears to respond to fine particulate water content The Heated TEOM and FRM single filter sampler both give results which are low

The United States Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here under contract or assistance agreement number BC-R044-NAEX to Brigham Young University.  It has been subjected to Agency review and approved for presentation.  Mention of trade names or commercial products do not constitute endorsement or recommendation for use.