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Capim Grosso, nestled in the heart of Bahia, Brazil, occupies a geographically significant position within the semi-arid Sertão region. Located at approximately -11.3808° latitude and -40.0128° longitude, the city’s terrain is predominantly undulating, characterized by gently sloping plains and occasional low hills, typical of the Brazilian Northeast. The surrounding landscape is a mosaic of *caatinga* vegetation, a unique biome adapted to drought conditions, interspersed with agricultural lands and scattered settlements. Elevation ranges modestly, generally between 400 and 600 meters above sea level, influencing local wind patterns and temperature distribution. While Capim Grosso lacks direct proximity to major rivers or large bodies of water, it benefits from the Rio de Contas basin, a crucial watershed for the region, though water scarcity remains a persistent challenge. The urban–rural gradient transitions relatively quickly, with agricultural activities, primarily focusing on cassava, corn, and beans, dominating the immediate periphery. The city’s regional position places it within a developing agricultural belt, with increasing mechanization and fertilizer use potentially impacting local air quality. The *caatinga* biome, while naturally resilient, can be susceptible to deforestation and unsustainable land management practices, contributing to dust and particulate matter. The relatively flat topography can exacerbate the accumulation of pollutants, particularly during periods of stagnant air. The climate, classified as semi-arid, with a distinct dry season, further influences the dispersal of airborne contaminants, often leading to localized air quality concerns.

Capim Grosso’s tropical climate dictates a seasonal narrative heavily influenced by the wet and dry seasons. The dry season, typically spanning from April to September, is characterized by minimal rainfall and consistently high temperatures. This period often witnesses a noticeable increase in particulate matter concentrations, primarily due to windblown dust from agricultural fields and the *caatinga* vegetation. The lack of rainfall reduces atmospheric cleansing, allowing pollutants to persist for longer durations. Temperature inversions, common during the cooler months (June-August), can trap pollutants near the ground, further degrading air quality. Conversely, the wet season (October to March) brings frequent rainfall, effectively washing away pollutants and significantly improving air quality. The increased humidity also reduces dust generation. However, intense rainfall events can occasionally lead to flooding and the release of contaminants from soil and agricultural runoff. During the transition months (March/April and September/October), fluctuating wind patterns and variable humidity levels can result in unpredictable air quality. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during the dry season, particularly during periods of high wind or stagnant air. Outdoor activities are generally more favorable during the wet season, although vigilance regarding potential flooding is advised. Agricultural burning, a practice sometimes employed for land clearing, can significantly impact air quality during the dry season’s transition, creating localized pollution hotspots. Maintaining awareness of regional weather forecasts and minimizing exposure during periods of elevated dust or stagnant air is crucial for protecting respiratory health.