1. Time-Integrated Sampling
Advances in the Measurement of Organic Molecular Markers in Urban Particulate Matter
Presenter
Monica Mazurek Civil & Environmental Engineering Department
Rutgers University
Session 2
Time-Integrated Sampling
European Monitoring and Evaluation Program (EMEP) Workshop on Particulate Matter Measurement & Modeling, United Nations Economic Commission for Europe, New Orleans, LA April 19-23, 2004
Supported by NSF ATM, NESCAUM, EPRI, NYSERDA, American Chem. Council, U.S. EPA

2. Major Analytical Challenges
Given the low ambient concentrations, how can individual marker compounds be measured precisely and accurately?
How do sample collection, pretreatment and methods of detection impact identification and quantitation of individual marker in PM extract complex mixtures?
Since identification and quantitation of known and new molecular tracers will be improved through better MS standards, community-based MS databases, additional source emission tests, how can this common use resource base be developed?

3. Carbon Chemical Mass Balance
West Los Angeles (1982 annual average)
Accounts for various forms of organic carbon
Multiple analytical measurements
Monitor variations in fine aerosol composition from bulk C to molecular organic C

4. Estimating Source Contribution
Total C (EC+OC) : Organic Matter (1.4 X OC) : Elutable Organic Matter : Molecular Tracer
Mass Emission Ratios
hopane concentration ng/m3
OC concentration g/ m3
= ratio of source emission rates
Rogge et al., 1993 vehicle exhaust = 2.7X10-3
Relative Source Contribution to Modeled OC Compounds Ambient Concentrations
Diesel vehicles = 60% Gasoline Vehicles = 30%
Paved road dust = 10%
Schauer et al., 1996

5. Molecular Tracers in Ambient Fine PM
West Los Angeles, CA April
Molecular Tracers in Ambient Fine PM
Sub parts-per-billion
Collection, sample workup, analytical measurement system
Time-integrated collection
Composites or large air volumes needed, no sample replicate
Mass quantitation
MS based, requires authentic standards, MS reference spectra
West Los Angeles, CA October

6. Tailoring Mass Spectrometer Instrumentation to Analyte Chemistry
100,000
10,000
1000
Nonpolar
Very Polar
GC/MS
APCI
API-Electrospray
From Hewlett Packard/Agilent poster: “Fundamentals of Electrospray and Atmospheric Pressure Chemical Ionization LC/MS” 1997

7. Thank you

8. End of Presentation