In this work, a study on air quality in the city of Ouagadougou (Burkina Faso) was carried out. The concentration levels of NO2, SO2, BTEX and PM10 in the city have been quantified. The results show that NO2 concentrations (range from 22 to 27 µg m -3 on average) in the city remain below the limit set by the WHO standard, except for downtown where values often exceed this standard. The average concentrations of SO2 (range from 0.5 to 10.5 µg m -3 ) remain low in general throughout the city. The concentrations of BTEX (e.g. benzene: 27.9 µg m -3 ) are high in the city. PM10 concentrations are very high in the city in general; they exceed the limit set by the WHO standard by a factor of 3 to 4. These PM10 are mostly composed of dust from the desert and the re-suspension of dust particles related to vehicles traffic on unpaved roads. Two daily peaks for PM10 are observed at heavy traffic hours. Finally, the study showed that the values of PM10 concentrations observed are in the same order of magnitude of those generally observed in the Sahelian region (range from 119 to 227µg m -3 ).