The personal aeroallergen sampler (PAAS) with a structure resembling a gimbal to enable a particle collection surface continuously directed upward regardless of inclination of the sampler was developed. To evaluate the particle size-dependent collection characteristics by the PAAS, the particle size distributions obtained by the PAAS were compared with those by an existing reference active sampler for sampling durations of 5 h to 6 days. The results showed good correlations between the two methods, suggesting usability of the PAAS for long-term personal monitoring of airborne coarse particles such as aeroallergens. The effective particle deposition velocities experimentally obtained for the personal samplings by the PAAS were 0.17, 0.35, 0.66 and 1.6 cm s(-1) for particles with projected area diameters of 10-20, 20-30, 30-50 and 50-100 mu m, respectively. Unlike existing active samplers, the PAAS is convenient for personal air sampling because of simplicity of handling. It can be easily used for epidemiological studies to investigate relationships between aeroallergen exposures and allergic airway diseases. (C) 2006 Elsevier Ltd. All rights reserved.