Diré, a town in the Tombouctou Region of Mali, sits precariously on the southern edge of the Sahara Desert, at coordinates 16.2667° N, -3.4000° W. Its location is fundamentally shaped by the Niger River, which, while not immediately adjacent, exerts a significant influence on the surrounding landscape and microclimate. The terrain is largely flat, characteristic of the inland Niger Delta, with a gradual rise towards the desert’s dunes further north. The town’s elevation is relatively low, contributing to limited atmospheric dispersion of pollutants. Diré’s urban character is defined by its traditional mud-brick architecture, reflecting the available building materials and the need for thermal regulation in the harsh climate. Surrounding the town are expanses of savannah and agricultural lands, primarily subsistence farming, with limited industrial activity within Diré itself. However, regional dust storms originating from the Sahara are a major factor. The urban-rural gradient is sharp; beyond the town limits, the landscape quickly transitions to sparsely populated rural areas. This proximity to both agricultural practices (potential for seasonal burning) and the vast Sahara creates a unique air quality challenge, with dust and biomass smoke being the dominant concerns. The lack of paved roads also contributes to significant particulate matter from vehicle and foot traffic.

Diré experiences a pronounced wet and dry season, dictating the rhythm of air quality. The dry season, roughly November to June, is characterized by consistently poor air quality. Harmattan winds, laden with Saharan dust, dominate, reducing visibility and increasing particulate matter concentrations. January to March are particularly challenging months, as these winds are strongest. Temperature inversions, common during the cooler nights of the dry season, trap pollutants near the ground, exacerbating the problem. The wet season, from July to October, brings temporary relief. Rainfall washes away dust and suppresses windblown particles. However, increased humidity can also promote the growth of mold and allergens. Agricultural burning, following the harvest, becomes a significant source of smoke pollution in October, just before the rains fully subside. Sensitive groups – children, the elderly, and those with respiratory conditions – should limit outdoor activity during the peak of the dry season (January-March) and avoid exposure to smoke from agricultural fires in October. The relatively cooler temperatures and cleaner air of August and September offer the most favourable conditions for outdoor activities, though vigilance regarding allergens remains important.