Altos sits in the heart of Piauí, acting as a vital link within the metropolitan influence of Teresina. The landscape is defined by the transition between the semi-arid Sertão and the more humid tropical zones, characterized by undulating plains and low-lying plateaus. This mid-elevation positioning influences local wind patterns, which are crucial for atmospheric dispersion. The urban fabric of Altos is a compact settlement surrounded by an extensive agricultural periphery, where land use is dominated by small-scale farming and seasonal clearing. This urban-rural gradient creates a specific pollution profile; while the city center experiences concentrated vehicular emissions from local transit, the surrounding landscape introduces significant particulate matter through biomass burning and dust. The lack of dense forest cover in the immediate vicinity means there is little natural filtration for airborne pollutants. Furthermore, the city’s proximity to the Parnaíba river basin affects local humidity levels, which in turn dictates how aerosols settle or remain suspended. As the region experiences shifts in moisture, the interaction between the dry soil and the seasonal winds becomes a primary driver of air quality. The geographic layout, while conducive to regional trade, facilitates the movement of smoke from distant agricultural fires directly into the urban core, making the city's atmospheric health deeply tied to the land management practices of the surrounding Piauí hinterlands and the broader climatic shifts occurring across the entire Brazilian Northeast region today. This makes monitoring vital for all residents who live near the growing urban and agricultural zones within this unique area.

In Altos, air quality is dictated by the dramatic interplay between the wet and dry seasons characteristic of the Piauí climate. The wet season, typically spanning from January to May, offers the highest air quality. During these months, frequent rainfall acts as a natural scrubber, washing particulate matter and aerosols from the atmosphere. Increased humidity and cloud cover help disperse pollutants, making this the ideal period for outdoor physical activities and reducing respiratory stress. Conversely, the dry season, which dominates from June to December, presents the most significant challenges. As the rains cease, the landscape dries out, and the prevalence of biomass burning for agricultural land clearing reaches its peak. During these months, particularly from August to November, the air often becomes heavy with smoke and fine particulate matter. This is exacerbated by temperature inversions, where cooler air is trapped near the ground by a layer of warmer air above, preventing the vertical dispersion of urban and agricultural smoke. Residents, especially sensitive groups such as children, the elderly, and those with pre-existing asthma or COPD, should monitor local conditions closely during the late dry season. It is advisable to limit strenuous outdoor exercise during the midday heat or when smoke is visible on the horizon. Utilizing air purifiers indoors and keeping windows closed during peak burning periods can mitigate exposure. Favoring early morning activities when the air is relatively stable can also be beneficial before the daily thermal mixing occurs. Stay informed via local weather reports to ensure personal safety.