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Ihosy serves as a critical crossroads in the Ihorombe region of Madagascar, positioned strategically along the National Route 7. The city occupies a transitional geographic space where the rugged central highlands descend into the vast, undulating plains of the south. This unique positioning creates an urban character defined by its role as a transit hub, surrounded by an expansive landscape of savannah grasslands and occasional rocky outcrops. The elevation contributes to a moderate climate, yet the open terrain allows wind to sweep across the plateau, which typically helps disperse pollutants. However, the urban–rural gradient is porous, with agricultural activities and livestock grazing extending directly into the city's periphery. The proximity to the Matitanana River provides a vital water source, but the surrounding arid scrubland becomes a source of airborne particulate matter during the dry periods. Unlike the dense industrial belts of Antananarivo, Ihosy’s pollution profile is dominated by domestic biomass combustion and the heavy transit of trucks transporting goods between the south and the national capital. The lack of significant forest cover around the immediate urban core means there are fewer natural biological filters to trap dust and smoke. Consequently, the air quality is heavily influenced by the interplay between the wind-swept plains and the concentrated emissions from the roadside corridors. This combination of open-air exposure and localized combustion creates a specific atmospheric dynamic where dust and smoke often linger in the lower boundary layer.

In Ihosy, air quality follows a distinct binary rhythm dictated by the tropical savannah climate's wet and dry cycles. During the dry season, stretching from May to October, the atmosphere becomes significantly more burdened. This period is characterized by increased wind speeds that lift fine mineral dust from the parched plains, combined with a surge in biomass burning for heating and cooking during the cooler winter months. Temperature inversions are common during these clear, cold nights, trapping smoke and particulate matter close to the ground, which can lead to degraded air quality in the early mornings. Conversely, the wet season from November to April brings heavy precipitation that effectively scrubs the atmosphere of suspended particulates, leading to the cleanest air of the year. However, increased humidity can occasionally trap local pollutants in a denser layer of fog. For sensitive groups, including children and the elderly, the mid-winter months of July and August are the most challenging, as respiratory irritants peak. It is advisable to limit strenuous outdoor activities during the early morning hours when inversions are most pronounced. Health guidance suggests utilizing cleaner cooking alternatives to reduce indoor smoke, which compounds outdoor pollution. By favoring the rainy season for outdoor excursions and implementing dust-mitigation strategies during the winter, residents can better manage their exposure. The interplay of monsoon-driven rains and plateau winds ensures a seasonal flushing of the air, maintaining a general atmospheric equilibrium.