Instrumentation study demonstrates real-time chemical characterization of black carbon aerosols, indicating improved sensitivity for atmospheric particle monitoring.
Key Points
To develop, calibrate, and validate the Soot Particle Aerosol Mass Spectrometer for measuring the chemical and physical properties of particles containing refractory black carbon.
Integrated a 1064 nm intracavity laser vaporizer from a Single Particle Soot Photometer into an Aerodyne Aerosol Mass Spectrometer alongside a standard resistively heated tungsten vaporizer.
Operated the instrument in three configurations: laser vaporizer alone, tungsten vaporizer alone, and dual-vaporizer mode with laser modulation to distinguish absorbing refractory material from total nonrefractory particulate matter.
Performed calibration procedures to quantify sensitivity, mass-specific ionization efficiency relative to nitrate, and detection limits as a function of laser-particle beam overlap.
Achieved an instrument sensitivity exceeding 140 carbon ions detected per picogram of refractory black carbon mass sampled.
Determined a 3σ detection limit below 0.1 μg·m−3 for a 60-second averaging period.
Measured a mass-specific ionization efficiency relative to particulate nitrate of 0.2 ± 0.1, with variations dependent on laser-particle beam overlap.