Particle location with respect to the plasma volume and the focal volume of the collection optics is identified as an important source of uncertainty in single-aerosol laser-induced breakdown spectroscopy (LIBS) measurements. Two sets of optics were used to image different regions of a LIBS plasma and simultaneously collect spectra from single particles. Strong variation and lack of correlation between the two measurement channels suggest that emission from a single particle is localized within the plasma. Measurement precision and detection efficiency were improved by imaging a larger plasma region, thus integrating the spatially distributed signal. (c) 2005 American Institute of Physics.