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Kisi, situated in the northern reaches of Oyo State, Nigeria, serves as a significant urban center within the expansive Guinea savanna belt. Positioned at coordinates 9.0833° N, 3.8500° E, the city is defined by a landscape of rolling hills and undulating plains, characteristic of the North-Central plateau transition. This elevated terrain, rising above the surrounding lowlands, plays a pivotal role in the local microclimate, influencing wind patterns that sweep across the vast agricultural hinterlands. The urban character of Kisi is deeply tied to its role as a regional trade hub for agricultural produce, including yam, cassava, and maize. Unlike the dense, industrial metropolitan areas of coastal Nigeria, Kisi maintains a distinct urban–rural gradient where human settlement integrates with scattered woodland and farmland. This proximity to expansive vegetation helps mitigate some localized heat island effects; however, the city's air quality is heavily influenced by regional environmental factors. During the dry season, the northeasterly trade winds, known as the Harmattan, transport significant quantities of Saharan dust across this northern landscape, drastically altering the atmospheric composition. Furthermore, the reliance on biomass fuels for domestic cooking and the presence of small-scale artisanal processing facilities contribute to localized particulate matter concentrations. As the city continues to expand, the interaction between its hilly topography and the regional dust transport remains the primary driver of its atmospheric profile, necessitating a nuanced understanding of how its inland position within the savanna influences the dispersion of pollutants across the local airshed.

Kisi experiences a classic tropical savanna climate, categorized by distinct wet and dry seasons that dictate the rhythm of air quality throughout the year. The dry season, typically spanning from November to March, represents the period of most significant atmospheric concern. During these months, the influx of the Harmattan wind brings dry, dusty air from the Sahara Desert, which elevates ambient particulate matter levels, often resulting in hazy skies and reduced visibility. The lack of precipitation during this window prevents the natural wet deposition of pollutants, meaning dust and smoke from agricultural clearing—a common practice in the surrounding hinterlands—remain suspended in the lower atmosphere for extended periods. Residents, particularly those with respiratory sensitivities, should prioritize indoor activities during peak dust events, typically occurring in January and February. Conversely, the wet season, which begins in April and peaks between June and October, offers a restorative phase for the local airshed. Frequent and often heavy rainfall effectively scrubs the air of suspended particles, providing a refreshing clarity to the atmosphere. During these months, the dense vegetation cover reduces wind-borne dust, making the wet season the most favorable time for outdoor exercise and community gatherings. However, moisture-rich conditions can lead to localized mold growth, which sensitive groups should monitor. By mid-October, as the rains subside, air quality begins to transition toward the dusty conditions of the Harmattan. Targeted health guidance suggests that vulnerable individuals should maintain consistent hydration and consider using air filtration systems during the peak dry season months.