An improved design of a resonant photoacoustic spectrophone is reported for aerosol absorption measurements by using a near‐infrared laser diode (&lgr;=802 nm;P=450 mW) in combination with a double‐pass configuration for excitation of azimuthal modes and right‐angle mounting of two electret microphones for signal detection. As a result of the new spectrophone setup a small‐sized portable sensor system for real‐timeinsituelemental carbon monitoring is presented. The detection limit is estimated to 4.5×10−8cm−1or 1.5 &mgr;g elemental carbon per m3. ©1995 American Institute of Physics.