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Dianké, nestled within the Tombouctou Region of Mali, occupies a precarious yet historically significant position on the edge of the Sahara Desert. Located at approximately 15.7258° N, 4.6428° W, the city’s geography is dominated by the Niger River and its surrounding floodplain, a vital lifeline in this arid landscape. The terrain is predominantly flat, characteristic of the Sahelian zone, with elevations rarely exceeding 150 meters above sea level. This flatness, while facilitating historical trade routes, contributes to air quality challenges. Dianké’s urban character is distinctly traditional, with mud-brick architecture defining the cityscape, reflecting the region’s building materials and climate adaptation strategies. The surrounding landscape is a mosaic of sparse vegetation, sand dunes, and seasonal wetlands, transitioning gradually into the vast expanse of the Sahara. The urban–rural gradient is sharp; the city is immediately bordered by sparsely populated agricultural zones reliant on flood recession farming along the Niger. There are no significant industrial belts nearby; economic activity is primarily centered on subsistence agriculture, fishing, and limited trade. The proximity to the Niger River, while providing water resources, can also exacerbate air quality issues during the wet season due to increased humidity and potential for stagnant water leading to biological emissions. The prevailing winds, often originating from the Sahara, carry dust and sand, significantly impacting particulate matter concentrations. The lack of topographic variation limits natural air circulation, trapping pollutants within the city’s confines.

Dianké’s air quality is inextricably linked to its distinct wet and dry seasons. The dry season, typically spanning November to May, presents the most significant air quality concerns. Characterized by intense solar radiation, low humidity, and frequent Harmattan winds blowing from the Sahara, this period sees a dramatic increase in particulate matter. These winds carry vast quantities of dust and sand, reducing visibility and impacting respiratory health. Temperature inversions, common during the cooler nights of the dry season, trap pollutants close to the ground, further worsening conditions. The months of January and February are particularly challenging, with prolonged periods of dust haze. Conversely, the wet season (June to October) brings a relative improvement in air quality, although not without its own issues. The monsoon rains wash away accumulated dust and particulate matter, and increased humidity can help to suppress dust lifting. However, the wet season also brings increased biological emissions from decaying vegetation and stagnant water, potentially impacting air quality locally. Fog, though infrequent, can also trap pollutants during cooler mornings. Sensitive groups, including children, the elderly, and individuals with pre-existing respiratory conditions, should exercise caution during the dry season, limiting outdoor activity during peak dust events. During the wet season, while generally better, vigilance regarding potential biological pollutants is advised, particularly near stagnant water sources. The intensity of the Harmattan wind and the duration of the dry season are key determinants of Dianké’s annual air quality profile.