Loading effect correction for real-time aethalometer measurements of fresh diesel soot.
In this study, a correction was developed for the aethalometer to measure real-time black carbon (BC) concentrations in an environment dominated by fresh diesel soot. The relationship between the actual mass-specific absorption coefficient for BC and the BC-dependent attenuation coefficients was determined from experiments conducted in a diesel exposure chamber that provided constant concentrations of fine particulate matter (PM; PM(2.5); PM < 2.5 microm in aerodynamic diameter) from diesel exhaust. The aethalometer reported BC concentrations decreasing with time from 48.1 to 31.5 microg m(-3) when exposed to constant PM(2.5) concentrations of 55 +/- 1 microg m(-3) and b(scat) = 95 +/- 3 Mm(-1) from diesel exhaust. This apparent decrease in reported light-absorbing PM concentration was used to derive a correction K(ATN) for loading of strong light-absorbing particles onto or into the aethalometer filter tape, which was a function of attenuation of light at 880 nm by the embedded particles.
EULA-Chile, Environmental Sciences Center, University of Concepción, Concepción, Chile. jorgejimenez@udec.cl
Jorge
J
Jimenez
Candis
C
Claiborn
Timothy
T
Larson
Timothy
T
Gould
Thomas W
TW
Kirchstetter
Lara
L
Gundel
D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D000465:Algorithms; D004784:Environmental Monitoring / Q000295:instrumentation*; D008956:Models, Chemical; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry; D053260:Soot / Q000032:analysis / Q000737:chemistry; D001335:Vehicle Emissions / Q000032:analysis*
D000393:Air Pollutants; D052638:Particulate Matter; D053260:Soot; D001335:Vehicle Emissions