A helium-enabled Niton X-ray analyser (HHpXRF) study of 296 lava stepping stones from ancient Pompeii showed that their surfaces were contaminated with superficial deposits of Zn and Pb. Recent research has shown that concentrations of these elements are highest in urban areas, where they were attributed to tyre dust and leaded petrol, respectively. The distribution of these elements on the stepping stones is represented on maps of the site. Zn pollution is most abundant in areas visited by tourists and is attributed mostly to wear from their rubber-soled footwear. Pb pollution is attributed to the movement of onsite vehicles using leaded petrol.