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Massaguet, nestled within the Hadjer-Lamis region of Chad (coordinates 12.4742° N, 15.4428° E), occupies a geographically significant position on the southern edge of the Chari-Bahr escarpment. The city’s terrain is characterized by undulating plains gradually rising towards the escarpment, resulting in an average elevation of approximately 450 meters above sea level. This location influences local air circulation patterns, often trapping pollutants during periods of low wind. Massaguet is situated relatively far from major rivers, though seasonal watercourses drain from the escarpment, contributing to localized humidity. The surrounding landscape is predominantly Sahelian savanna, a mosaic of grasslands, scattered acacia trees, and sparse shrubland. This agricultural zone, vital for regional food security, contributes to air quality through dust emissions from cultivation and livestock activities. The urban–rural gradient around Massaguet is gradual, with small villages and nomadic pastoralism defining the immediate periphery. Further afield, the landscape transitions into more arid desert conditions. While Massaguet lacks significant industrial zones within its immediate vicinity, it serves as a regional trading hub, with vehicular traffic contributing to localized pollution. The escarpment to the north acts as a partial barrier, influencing wind patterns and potentially concentrating pollutants within the valley where the city resides. The prevailing winds, generally from the northeast, can carry dust and pollutants from distant agricultural areas, impacting air quality.

Massaguet’s air quality is inextricably linked to its distinct wet and dry seasons, a characteristic of the Sahelian climate. The dry season, typically spanning from November to May, presents the most significant air quality challenges. Characterized by minimal rainfall and consistently high temperatures, this period is prone to intense dust storms originating from the surrounding savanna and desert regions. These storms, often exacerbated by strong Harmattan winds blowing from the Sahara, dramatically reduce visibility and elevate particulate matter concentrations. Temperature inversions, common during the cooler nights of the dry season, can trap pollutants close to the ground, further worsening air quality. The months of February and March are particularly concerning, often experiencing prolonged periods of hazy conditions. Conversely, the wet season (June to October) brings a degree of respite. Rainfall helps to wash pollutants from the atmosphere, and increased humidity can suppress dust lifting. However, agricultural activities during this period, including burning of crop residues, can introduce localized sources of smoke and particulate matter. Fog, though infrequent, can occur during cooler mornings, trapping pollutants and reducing air quality. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, limiting outdoor activities during peak dust storm periods and avoiding strenuous exertion. During the wet season, while overall air quality improves, awareness of potential smoke pollution from agricultural practices remains important.