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Ulan-Ude, the capital of Russia's Buryatia Republic, occupies a distinctive geographic position in southeastern Siberia, nestled within the Uda River valley at an elevation of approximately 500 meters above sea level. Situated at the confluence of the Uda and Selenga rivers, the city lies about 100 kilometers southeast of Lake Baikal, the world's deepest freshwater lake, which exerts a moderating influence on the local climate. The urban area is surrounded by the forested Khamar-Daban and Ulan-Burgasy mountain ranges, creating a basin-like topography that significantly impacts air quality through frequent temperature inversions, particularly during winter months. This terrain traps pollutants from general urban sources like vehicle emissions, residential heating, and small-scale industries within the valley. The city serves as a major transportation hub along the Trans-Siberian Railway, with industrial zones concentrated in its eastern and southern peripheries, while agricultural lands and rural settlements extend into the surrounding steppe and forest-steppe zones. The urban-rural gradient shows decreasing pollution levels toward the mountainous outskirts, but the basin effect means even moderate emissions can accumulate to concerning concentrations under stagnant atmospheric conditions.

Ulan-Ude's air quality follows a pronounced seasonal pattern shaped by its continental climate and topographic constraints. Winter, from November through February, brings the worst pollution episodes as intense cold spells trigger persistent temperature inversions that trap emissions from coal-fired heating systems and vehicles near the ground, often exacerbated by low wind speeds and frequent fog. Sensitive groups like children, elderly residents, and those with respiratory conditions should limit outdoor activities during these months, especially in calm morning hours. Spring, from March to May, sees gradual improvement as increasing solar radiation breaks up inversions and occasional winds disperse pollutants, though March can still experience poor air quality from lingering winter patterns. Summer, from June to August, offers the cleanest air with warmer temperatures reducing heating emissions, more vigorous atmospheric mixing, and occasional rainfall helping to wash pollutants from the air—making this the ideal season for outdoor recreation. Autumn, from September to October, marks a transition as cooling temperatures and reduced mixing height begin to allow pollutant accumulation again, particularly in October when heating systems restart. Throughout the year, wind direction plays a crucial role, with northerly winds typically bringing cleaner air from forested areas while southerly flows may transport occasional dust from the steppe regions.