Characterisation of a mobile photoacoustic sensor for atmospheric black carbon monitoring

A mobile photoacoustic soot sensor (PASS), being a modified version of a pr evious set-up, has been improved and characterised in this work to enable o nline atmospheric black carbon (BC) monitoring. The sensitivity of this 19 inch instrument to BC was obtained by calibration with model soot and found to be 0.27 muV per mug m(-3) BC with a detection limit of similar to 200 n g m(-3) depending on the measurement time. The cross sensitivity to other a tmospheric components like light scattering particles, H2O and NO2 has been evaluated and taken into account. The time response of the system is in th e order of some seconds. An automated measurement cycle - optimised for imm ission measurements - has been programmed and is taking similar to5 minutes .