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Ati, situated in the Batha Pounama region of Chad (coordinates 13.2133° N, 18.3381° E), occupies a geographically significant position within the Sahelian belt. The city’s terrain is predominantly characterized by undulating sandy plains, typical of the region’s semi-arid climate. Elevation is relatively low, averaging around 450 meters above sea level, contributing to a stable atmospheric layer that can, under certain conditions, trap pollutants. Ati lies near the Wour River, a vital water source for the region, though its influence on local air quality is limited due to the river's generally shallow and intermittent flow. The surrounding landscape is a mosaic of sparse vegetation, including acacia trees and grasses, interspersed with agricultural fields practicing subsistence farming, primarily sorghum and millet cultivation. This agricultural activity, while crucial for local livelihoods, can contribute to particulate matter through seasonal burning practices. The urban–rural gradient around Ati is gradual, with small villages and nomadic pastoralism defining the immediate periphery. Further afield, the landscape transitions into the expansive Sahara Desert. There are no major industrial belts directly adjacent to Ati; however, the city serves as a regional market town, experiencing periodic influxes of vehicles and associated emissions. The prevailing winds, generally from the north during the dry season, play a crucial role in dispersing or concentrating pollutants, often influenced by the topography of the surrounding plains. The lack of significant topographical barriers means that pollutants can travel relatively long distances, impacting air quality beyond the city limits.

Ati’s air quality follows a distinct seasonal pattern dictated by its tropical savanna climate. The dry season, spanning roughly from November to May, is typically characterized by lower humidity and increased wind speeds, which generally aids in pollutant dispersion. However, this period also sees a surge in agricultural burning as farmers clear fields for planting, leading to elevated levels of particulate matter, particularly in February and March. Temperature inversions, though less frequent than in colder climates, can occasionally occur during the cooler nights of December and January, trapping pollutants close to the ground. The onset of the rainy season (June to October) brings a noticeable improvement in air quality. Rainfall effectively ‘washes’ pollutants from the atmosphere, and increased vegetation growth helps absorb some gaseous pollutants. However, the rainy season isn't entirely benign; heavy downpours can stir up dust and contribute to temporary spikes in particulate matter. Fog, though infrequent, can form during periods of calm weather and high humidity, particularly in the transitional months of May and November, exacerbating localized air quality issues. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, particularly when agricultural burning is prevalent. Limiting outdoor exertion during periods of visible smoke is advisable. The transitional months of May and November, with their potential for fog, also warrant increased vigilance. Maintaining good hydration and avoiding prolonged exposure to dusty conditions are general recommendations for all residents.