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San Luis Potosí, capital of its namesake state in central Mexico, occupies a strategic position within the Mesa Central plateau at approximately 1,860 meters (6,100 feet) above sea level. This elevated basin, flanked by the Sierra Madre Oriental mountains to the east and the Sierra de San Miguelito to the west, creates a semi-enclosed topographic bowl that profoundly influences air quality dynamics. The city's urban core, home to over 770,000 residents, blends colonial architecture with modern industrial zones, particularly in its northern and eastern peripheries where manufacturing and automotive plants cluster. Surrounding the metropolitan area, the landscape transitions to arid scrubland and agricultural fields, primarily cultivating maize and beans, which contribute seasonal biomass burning emissions. The region lacks significant natural water bodies, with the city relying on underground aquifers, reducing any moderating maritime influence on pollution dispersion. This combination of high-altitude setting, industrial activity concentrated in specific corridors, and basin-like terrain fosters frequent temperature inversions, especially during cooler months, trapping vehicular exhaust, industrial emissions, and dust from unpaved rural roads. The urban–rural gradient sees cleaner air in southern residential districts near the Sierra de San Miguelito, while northern industrial belts experience higher particulate matter concentrations, exacerbated by prevailing northeasterly winds that channel pollutants across the basin.

In winter (December–February), San Luis Potosí experiences its most challenging air quality due to persistent temperature inversions that trap pollutants near the surface, compounded by increased residential wood and charcoal burning for heating. Cold, calm mornings often bring dense fog that mixes with emissions, creating hazy conditions until midday winds disperse some accumulation. Spring (March–May) sees gradual improvement as rising temperatures reduce inversion frequency, though sporadic dust storms from surrounding drylands and agricultural preparation fires can spike particulate levels, particularly in April. Summer (June–August) offers the cleanest air, with the North American monsoon bringing afternoon thunderstorms that scrub pollutants from the atmosphere, while stronger daytime winds enhance dispersion; however, ozone may briefly rise on hot, sunny days with low humidity. Autumn (September–November) marks a transition, with diminishing rains allowing pollutants to accumulate again, especially as agricultural burning resumes post-harvest and cooler nights reinstate inversion conditions by late November. Sensitive groups—such as asthmatics, children, and the elderly—should limit outdoor exertion on calm winter mornings and during spring dust events, favoring summer months for activities like hiking in the nearby sierras. Monitoring local air quality advisories is crucial, as industrial emissions and traffic patterns can cause unexpected daily variations.