[en] Full text: Pollutants due to vehicular emission is a major source of human health deterioration in many countries. This is especially so in Nigeria where substantial number of old vehicles, which no longer meet environmental standards set in developed countries, are being imported. In an urban city like Lagos, hundreds of thousands of hawkers that spend the whole day along motorways are victims of pollution from vehicular emission. Ambient air along major motorways in an urban setting in Lagos and Ile Ife in southwest Nigeria was sample for eight hours at each location selected. Locations were selected to reflect variations in traffic volume and corresponding number of those exposed. Sampling was done using both a twin-flow air sampler for total suspended particulate matter and a stacked 'Gent' PM₁₀ sampler to determine the inhalable fraction. Volume of traffic at each location was also measured. Whatman 41 filters used for the TSPM and Nuclepore filters used for the PM₁₀ samplers were digested using ultra-pure acids and then analysed using a total reflection X ray fluorescence spectrometer donated by the IAEA. Ga was used as internal standard. Concentrations of the pollutants were determined using the QXAS software. Source apportionment was carried out to determine the contribution to the pollutants from vehicular emission. (author)