TY - JOUR
T1 - The additivity and stability of carbon signatures obtained by evolved gas analysis
AU - Turner, J. R.
AU - Hering, S. V.
PY - 1994/1/1
Y1 - 1994/1/1
N2 - Evolved Gas Analysis (EGA) profiles are evaluated as a tool to classify carbonaceous aerosols for source apportionment studies. EGA is a method of characterizing carbonaceous aerosols according to their volatility. In this study the stability and additivity of EGA profiles were examined explicitly for the purpose of determining the applicability of EGA characterization to chemical mass balance techniques. Samples collected in a vehicle tunnel were subsequently exposed to particle-free (filtered) and particle-laden ambient air. The EGA profile did not change for tunnel samples exposed to filtered ambient air. By contrast, for tunnel samples exposed to particle-laden (unfiltered) ambient air, the resultant EGA profile was not the direct sum of the ambient and tunnel profiles. Specifically, the low-volatility carbon peak evolved at a lower temperature than the same peak in the unexposed tunnel samples. The change in evolution temperature was independent of carbon mass loading. Although evolution temperatures of characteristic peaks shifted, both the ambient and the tunnel profiles could be classified into three characteristic peaks, corresponding to high-, intermediate-, and low-volatility carbon. Additivity of ambient samples yielded an uncertainty of 13% within a given peak. Additivity of the tunnel samples subsequently loaded with ambient aerosol yielded an uncertainty of 19% within a given peak.
AB - Evolved Gas Analysis (EGA) profiles are evaluated as a tool to classify carbonaceous aerosols for source apportionment studies. EGA is a method of characterizing carbonaceous aerosols according to their volatility. In this study the stability and additivity of EGA profiles were examined explicitly for the purpose of determining the applicability of EGA characterization to chemical mass balance techniques. Samples collected in a vehicle tunnel were subsequently exposed to particle-free (filtered) and particle-laden ambient air. The EGA profile did not change for tunnel samples exposed to filtered ambient air. By contrast, for tunnel samples exposed to particle-laden (unfiltered) ambient air, the resultant EGA profile was not the direct sum of the ambient and tunnel profiles. Specifically, the low-volatility carbon peak evolved at a lower temperature than the same peak in the unexposed tunnel samples. The change in evolution temperature was independent of carbon mass loading. Although evolution temperatures of characteristic peaks shifted, both the ambient and the tunnel profiles could be classified into three characteristic peaks, corresponding to high-, intermediate-, and low-volatility carbon. Additivity of ambient samples yielded an uncertainty of 13% within a given peak. Additivity of the tunnel samples subsequently loaded with ambient aerosol yielded an uncertainty of 19% within a given peak.
UR - https://www.scopus.com/pages/publications/0028534061
U2 - 10.1080/02786829408959717
DO - 10.1080/02786829408959717
M3 - Article
AN - SCOPUS:0028534061
SN - 0278-6826
VL - 21
SP - 294
EP - 305
JO - Aerosol Science and Technology
JF - Aerosol Science and Technology
IS - 4
ER -