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Alcântaras, a municipality nestled within the state of Ceará in northeastern Brazil, presents a unique geographic context influencing its air quality. Located at -3.5889 latitude and -40.5458 longitude, the city sits relatively close to the Atlantic coastline, approximately 25km inland. The terrain is generally flat, characteristic of the coastal plain, with elevations rarely exceeding 50 meters. This flatness contributes to limited natural dispersion of pollutants. Surrounding Alcântaras is a landscape dominated by *caatinga* scrubland, a semi-arid biome, interspersed with areas of small-scale agriculture, primarily subsistence farming focused on crops like cassava and beans. The urban area of Alcântaras, with a population of around 11,369, is compact, exhibiting a typical Brazilian small-city structure. While not a major industrial hub, the region experiences some activity related to cashew processing and fishing, both potential localised sources of particulate matter. The proximity to the coast introduces the influence of sea breezes, which can both dilute and transport pollutants. The urban-rural gradient is relatively sharp, with agricultural lands bordering the city limits. This proximity means agricultural burning, a common practice for land clearing, can significantly impact local air quality, particularly during drier periods. The lack of significant topographical features hinders natural ventilation, exacerbating pollution episodes.

Alcântaras experiences a distinct wet and dry season, rather than traditional four seasons. Air quality in Alcântaras is most compromised during the dry season, typically from August to December. This period sees reduced rainfall, leading to increased dust resuspension from the *caatinga* vegetation and agricultural lands. Lower humidity also means pollutants have less chance of being washed out of the atmosphere. The Harmattan winds, blowing from the Sahara Desert, can occasionally transport significant amounts of dust across the Atlantic, further degrading air quality. Temperature inversions, common during the cooler nights of the dry season, trap pollutants near the ground. The wet season, from January to July, generally brings improved air quality due to rainfall cleansing the atmosphere. However, even during the wet season, localised pollution from cashew processing and vehicle emissions remains a concern. February and March, during peak rainfall, are generally the most favourable months for outdoor activity. Sensitive groups – children, the elderly, and those with respiratory conditions – should limit strenuous outdoor exertion during the dry season, particularly in September and October when dust levels are highest. Monitoring local weather patterns and avoiding activity near agricultural burning is crucial for protecting health.