An aerosol-into-liquid collector (ALC) for collecting gas-borne particles from a large volume of gas such as air into a small volume of liquid is described. The ALC uses a linear quadrupole to concentrate particles flowing in a gas and to help direct these concentrated particles toward a small volume of collection liquid so that these particles tend to combine with a small volume of collection liquid that can then be drawn from the ACL for further analysis. The particles in the gas are typically given a charge that is opposite to that of the charge imparted to the volume of collection liquid so that electrostatic forces help draw particles from the flowing gas into the small volume of liquid. The linear quadrupole focuses toward it axis particles that have the charge, mass and mobility to be stable in the linear quadrupole.