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Caririaçu, nestled in the interior of Ceará state, Brazil, occupies a geographically significant position within the broader Northeast region. Located at approximately -7.0419° latitude and -39.2839° longitude, the city sits on a gently undulating plateau, part of the Borborema Plateau, characterized by a predominantly semi-arid climate. The surrounding landscape is a mosaic of *caatinga* vegetation, a unique biome adapted to drought conditions, featuring thorny shrubs, cacti, and deciduous trees. This vegetation, while resilient, can contribute to particulate matter during the dry season when leaf litter accumulates. Caririaçu’s elevation, averaging around 450 meters above sea level, influences local wind patterns and temperature gradients. While not directly adjacent to major rivers, the city draws water from the São Francisco River basin, a vital resource for the region, impacting agricultural practices and potential dust generation from irrigation activities. The urban–rural gradient around Caririaçu is relatively sharp, transitioning quickly from the built environment to extensive agricultural lands, primarily dedicated to rain-fed farming and livestock grazing. The absence of large-scale industrial belts within immediate proximity is a mitigating factor for air pollution, though agricultural burning, a common practice for land clearing and pasture management, can significantly impact air quality during specific periods. The plateau's topography can trap pollutants, particularly during periods of low wind speed, exacerbating localized air quality issues. The city’s position inland, away from the coastal breezes, also limits natural air dispersal.

Caririaçu’s tropical climate dictates a distinct wet and dry seasonal cycle, profoundly influencing its air quality. The dry season, typically spanning from August to May, is characterized by intense solar radiation, high temperatures, and minimal rainfall. This period often witnesses a surge in particulate matter pollution, primarily due to agricultural burning practices employed to prepare land for planting and manage pastures. The lack of rainfall means dust from exposed soil is easily mobilized by even gentle winds, further contributing to the problem. Temperature inversions, common during the cooler nights of the dry season, trap pollutants near the ground, intensifying localized air quality degradation. Conversely, the wet season (May to August) brings relief, with frequent rainfall washing away accumulated pollutants and increased humidity suppressing dust generation. Stronger winds associated with occasional thunderstorms also aid in dispersing pollutants. During the transition months (April and September), air quality can be variable, influenced by the interplay of receding dry season conditions and the onset of rainfall. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, limiting outdoor activities during peak burning periods and avoiding areas with visible smoke. Maintaining indoor air quality through proper ventilation and air filtration can also be beneficial. The prevalence of dust storms, though not frequent, can significantly degrade air quality, requiring temporary restrictions on outdoor activities and heightened awareness of respiratory health.