Air Quality Study in Urban Centers: Case Study of Ouagadougou, Burkina Faso

Abstract

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).