Raman detection of single airborne aerosol particles of isovanillin

Single airborne aerosol particle of isovanillin were detected using a compact Raman spectroscopy system. The Raman system consisted of a 10 W, 532-nm cw laser, a 50x aerosol concentrator, an aerosol flow cell, an f/1.0 single-sided collection optics, an f/1.8 Raman spectrometer with a spectral range of 400-1400 cm-1, and a low-noise CCD camera (1340 x 400 pixels; 20 x 20 μm/pixel). The combined collection and detection efficiency of the Raman system was 1.0%. The diameters of eleven particles were determined to be 3.4, 3.1, 3.5, 3.4, 2.3, 3.1, 2.5, 2.6, 2.5, 3.0, and 3.1μm based on the fundamental Raman equation. The accuracy of the particle diameter is estimated to be ±0.1 μm using measured concentration of the atmospheric CO2.