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Lagoa Grande, nestled in the arid heart of Pernambuco, Brazil, presents a unique geographic profile significantly influencing its air quality. Situated at -8.9969° latitude and -40.2719° longitude, the city lies within the *Sertão* region, a semi-arid expanse characterized by sparse vegetation and limited water resources. Its elevation, relatively low at approximately 420 meters above sea level, contributes to a tendency for stagnant air conditions, particularly during drier periods. The surrounding landscape is dominated by *caatinga* vegetation, a thorny scrubland adapted to extreme drought, offering minimal natural air filtration. Lagoa Grande’s proximity to the São Francisco River, though not directly adjacent, is crucial; the river’s presence moderates temperatures slightly and can influence regional wind patterns. The urban fabric is compact, reflecting the city’s relatively small population of 24,088. The urban–rural gradient is sharp, transitioning quickly from the built environment to extensive agricultural lands, primarily focused on subsistence farming and livestock grazing. While not a major industrial hub, Lagoa Grande experiences some agricultural processing and small-scale manufacturing, potentially contributing localized pollution. The regional position, far from major industrial belts along the coast, generally shields the city from widespread industrial emissions, but dust storms originating from the *Sertão* are a recurring environmental challenge, directly impacting air quality and visibility. The terrain, undulating and punctuated by occasional rocky outcrops, further complicates air circulation patterns, potentially trapping pollutants within the valley-like depressions.

Lagoa Grande’s tropical climate dictates a distinct wet and dry season cycle, profoundly impacting air quality. The dry season, typically spanning from April to September, is characterized by intense heat, minimal rainfall, and consistently low humidity. This period often witnesses a significant increase in particulate matter pollution, primarily due to wind-driven dust storms originating from the surrounding *caatinga* and agricultural lands. The lack of rainfall prevents the natural cleansing effect of precipitation, allowing dust and other pollutants to accumulate. Temperature inversions, common during the cooler nights of the dry season, trap pollutants near the ground, exacerbating the problem. Conversely, the wet season (October to March) brings relief. Frequent rainfall effectively washes pollutants from the atmosphere, significantly improving air quality. Increased humidity also helps to settle dust particles. However, periods of intense rainfall can lead to localized flooding and the release of organic compounds from saturated soils, potentially contributing to temporary odour issues. The months of August and September are generally the most challenging for air quality, with peak dust events. Individuals with respiratory conditions, such as asthma, and the elderly should exercise caution during these periods, limiting outdoor activity and ensuring adequate ventilation. During the wet season, while overall air quality improves, those with allergies may experience increased pollen exposure. Maintaining indoor air quality through proper ventilation and air filtration is advisable year-round, particularly during the dry season’s dust events.