Association among the concentrations of carbonaceous aerosols using different methods. Sunset EC and Sunset OC are the 24-hr averaged concentrations, HI EC and HI OC were measured over a 24-hr period at the supersite, STN EC and STN OC were measured over 24 hr at a nearby STN site, Aeth BC is the 24-hr averaged concentration, Aeth S/N 280 was used for routine measurement, and the Aeth S/N 314 was used for collocating measurement. Regression between (a) HI EC and Sunset ThEC concentrations, (b) STN EC and Sunset OptEC concentrations, (c) HI OC and Sunset OptOC concentrations, (d) HI TC and Sunset TC concentrations, (e) Sunset OptEC and Aeth BC concentrations, and (f) S/N 280 and S/N 314 Aeth BC concentrations.