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156861 
Book/Book Chapter 
Thermal-optical-transmittance analysis for organic, elemental, carbonate, total carbon, and OCX2 in PM2.5 by the EPA/NIOSH method 
Peterson, MR; Richards, MH 
2002 
Pittsburgh 
Research Triangle Institute (RTI) performs thermal-optical-transmittance (TOT) analyses for
carbon species in PM2.5 collected on quartz fiber filters in support of several Federal and State
ambient air monitoring programs and human exposure studies. U.S. National Institute for
Occupational Safety and Health (NIOSH) Method 5040, an evolved gas TOT method, was
chosen for measurement of organic carbon (OC), elemental carbon (EC), carbonate carbon (CC),
total carbon (TC), and OCX2 (the most refractory component of OC) in PM2.5 samples collected
in the U.S. Environmental Protection Agency's (EPA's) nationwide chemical speciation program.
Primary instrumentation in RTI's OC/EC Laboratory includes three Sunset Laboratory
Thermal/Optical Carbon Analyzers and a muffle furnace used to pre-clean quartz filters.
This paper presents: an overview of the EPA/NIOSH TOT analysis method, sometimes called
the Speciation Trends Network (STN) method; observations on the challenges posed by using
multiple instruments for an analysis in which the analytes are defined by the conditions of the
analysis; a comparison of the conditions used for the EPA/NIOSH method with the conditions
used for other thermal-optical analysis methods and how these differences affect measurement
results; and the dependence of the OC-EC analysis split time, which is used to determine the
proportions of OC and EC in a sample, on sampling location. 
Symposium on Air Quality Measurement Methods and Technology 
Pittsburgh