Impact of traffic emissions on air quality in Cabo Verde

Air quality degradation due to road traffic emissions is one of the topics of major interest for the scientific community and urban planners worldwide. Cabo Verde does not have regulations for traffic emission control or air quality guidelines, although the number of road vehicles has grown steadily over the past decade. Moreover, studies focusing on the impact of road transport on air quality in this archipelago are sparse. In this study, we present a first detailed air pollutant inventory of road traffic emissions through a bottom-up methodology, along with snapshots of the state of air quality on the islands of Santiago, São Vicente, and Sal. For the year 2017, emission estimates for the main island (Santiago) are 654 tons of CO, 35 tons of PM₁₀, 562 tons of NO_x, and 84 tons of NMVOCs. The air quality assessment was carried out using the TAPM model for a period of 6 months from January to July 2017. The results showed that the mean concentration values for Sao Vicente, Sal, and Santiago Islands ranged between 2.0 and 18 μg m^-3 for NO₂ and 3.8 and 5.6 μg m^-3 for PM₁₀. NO₂ concentrations show an increasing trend from January to July in Santiago and Sal, and no clear trend in São Vicente Island. The simulated PM₁₀ concentrations showed values in the same range over the year, even though they appeared slightly higher in July than in January. It was observed that both NO₂ and PM₁₀ average concentrations have been consistently above healthful levels, according to air quality guidelines fixed by the WHO.