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Petrolândia, nestled in the heart of Pernambuco, Brazil, occupies a unique geographic position within the São Francisco River basin. Located at approximately -9.1828° latitude and -38.2689° longitude, the city’s terrain is characterized by a gently undulating landscape, transitioning from the riverine plains to slightly elevated plateaus. The São Francisco River, a vital artery of the Northeast region, forms a significant portion of Petrolândia's eastern boundary, influencing local climate and providing a crucial water source. The surrounding landscape is a mosaic of caatinga vegetation, a semi-arid biome adapted to harsh conditions, interspersed with areas of agricultural activity, primarily focused on livestock and subsistence farming. Petrolândia’s urban character is that of a relatively small, developing municipality, with a population of around 14,000. The urban–rural gradient is gradual, with agricultural lands extending relatively close to the city limits. There are no major industrial belts immediately adjacent to Petrolândia; however, the region experiences some agricultural processing activities, which can contribute to localized air emissions. The elevation is relatively low, averaging around 350 meters above sea level, which can influence the dispersion of pollutants, particularly during periods of atmospheric stability. The proximity to the São Francisco River, while beneficial for water resources, can also contribute to humidity and fog formation, potentially trapping pollutants under certain meteorological conditions. The caatinga biome, while generally sparse, can contribute to particulate matter through seasonal leaf shedding and occasional wildfires.

Petrolândia’s tropical climate dictates a distinct wet and dry season pattern, significantly impacting air quality dynamics. The dry season, typically spanning from May to September, is characterized by intense solar radiation, low humidity, and frequent dust events originating from the caatinga vegetation and agricultural lands. These events contribute to elevated particulate matter concentrations, particularly PM10 and PM2.5, which can irritate respiratory systems. Wind patterns during this period are often variable, sometimes leading to stagnant air conditions that exacerbate pollution accumulation. The wet season, from October to April, brings increased rainfall and higher humidity, generally leading to a reduction in particulate matter as precipitation washes pollutants from the atmosphere. However, periods of prolonged fog, common during the transition months (October-November and March-April), can trap pollutants near the ground, creating localized air quality concerns. Temperature inversions, though less frequent than in temperate climates, can occasionally occur, particularly during cooler nights, further hindering pollutant dispersion. Sensitive groups, including children, the elderly, and individuals with pre-existing respiratory conditions, should exercise caution during the dry season, limiting outdoor activities during peak dust events. During the wet season, while overall air quality improves, periods of dense fog necessitate similar precautions. Agricultural burning, though regulated, can occasionally occur during land clearing activities, contributing to short-term spikes in air pollution. The months of June, July, and August often experience the most persistent dust events, while February and March can be affected by fog-related pollution.