Vehicle exhaust (VE) particles represent the emissions from vehicle engines, excluding secondary inorganic species. It explains the 43% of the total variation of TC.This factor also includes S, Fe,Cu, Sn.The occurrence of K in this factor may also reveal a small contribution from biomass burning, but in very small proportion.While no marked differences were found between the profile concentrations of the PMF2 and ME-2 solutions, the contributions in PMF2 were 15% lower in PM10, 23% in PM2.5 and only 17% in PM1
respect to ME-2.Both solutions showed the same time evolution pattern of this factor, with maxima in winter and minima in summer in PM2.5 and PM1, but this seasonality is less clear in PM10 (probably because of the absence of several samples during winters of 2004 and 2005).