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Changchun, the capital of Jilin Province in Northeast China, occupies a strategic position on the Songliao Plain, approximately 200 kilometers south of the provincial border with Heilongjiang. Situated at an average elevation of 200 meters above sea level, the city lies within a gently undulating terrain characterized by fertile black soil that supports extensive agricultural zones, particularly to the west and south. This urban center is part of the broader Northeast China industrial belt, historically significant for heavy manufacturing, though it has diversified into automotive production and technology. Changchun's geography significantly influences its air quality through several mechanisms: its inland location, far from major bodies of water like the Yellow Sea to the southeast, limits natural ventilation and pollutant dispersion. The city is surrounded by agricultural lands that contribute seasonal biomass burning and dust, while urban expansion has created a sharp urban–rural gradient with concentrated emissions from transportation, heating, and industry. The lack of significant topographic barriers, such as mountains, allows pollutants to accumulate under stable atmospheric conditions, particularly during cold months when temperature inversions are common. Additionally, its position in a region with continental climate extremes exacerbates pollution episodes, as stagnant air masses trap emissions from coal-based heating systems and vehicular traffic, making geographic context a key determinant of air quality challenges in this major northeastern metropolis.

Changchun's air quality follows a distinct seasonal pattern shaped by its continental monsoon climate, with pollution levels fluctuating dramatically throughout the year. In winter, from December to February, air quality deteriorates significantly due to coal combustion for heating, combined with frequent temperature inversions that trap pollutants near the surface. Cold, stagnant air and low wind speeds exacerbate this, making these months particularly hazardous for outdoor activities, especially for sensitive groups like children, the elderly, and those with respiratory conditions who should limit exposure and use air purifiers indoors. Spring, from March to May, sees some improvement as temperatures rise and winds increase, dispersing pollutants, though dust storms from surrounding agricultural areas can cause temporary spikes in particulate matter. Summer, from June to August, offers the best air quality due to higher precipitation, active monsoon patterns that bring cleansing rains, and stronger winds that ventilate the urban area; this is the ideal time for outdoor pursuits. Autumn, from September to November, marks a transition as heating systems restart and atmospheric stability returns, leading to a gradual buildup of pollutants, with October and November often experiencing worsening conditions. Throughout the year, fog and haze can occur, particularly in late autumn and winter, reducing visibility and compounding health risks. Residents and visitors are advised to monitor local air quality reports and plan activities accordingly, with winter being the peak pollution season to avoid for prolonged outdoor exertion.