The SAE International has published Aerospace Information Report (AIR) 6241 which outlined
the design and operation of a standardized measurement system for measuring non-volatile
particulate matter (nvPM) mass and number emissions from commercial aircraft engines. Prior
to this research, evaluation of this system by various investigators revealed differences in nvPM mass emissions measurement on the order of 15–30% both within a single sampling system and
between two systems operating in parallel and measuring nvPM mass emissions from the same
source. To investigate this issue, the U. S. Environmental Protection Agency in collaboration with
the U. S. Air Force’s Arnold Engineering Development Complex initiated the VAriable Response In
Aircraft nvPM Testing (VARIAnT) research program to compare nvPM measurements within and
between AIR-compliant sampling systems used for measuring combustion aerosols generated both
by a 5201 Mini-CAST soot generator and a J85-GE-5 turbojet engine burning multiple fuels. The
VARIAnT research program has conducted four test campaigns to date. The first campaign
(VARIAnT 1) compared two essentially identical commercial versions of the sampling system
while the second campaign (VARIAnT 2) compared a commercial system to the custom-designed
Missouri University of Science and Technology’s North American Reference System (NARS) built
to the same specifications. Comparisons of nvPM particle mass (i.e., black carbon), number, and
size were conducted in both campaigns. Additionally, the sensitivity to variation in system
operational parameters was evaluated in VARIAnT 1. Results from both campaigns revealed
agreement of about 12% between the two sampling systems, irrespective of manufacturer, in all
aspects except for black carbon determination. The major source of measurement differences
(20–70%) was due to low BC mass measurements made by the Artium Technologies LII-300 as
compared to the AVL 483 Micro-Soot Sensor, the Aerodyne Cavity Attenuated Phase Shift (CAPS
PMSSA) monitor, and the thermal-optical reference method for elemental carbon (EC) determination, which was used as the BC reference. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.