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Songjiang District, situated in southwestern Shanghai within China's East Asia region, occupies a strategic position in the Yangtze River Delta's vast alluvial plain. This urban district, with coordinates at 31.0058°N and 121.2333°E, lies approximately 40 kilometers from central Shanghai's core, creating a distinct urban-rural gradient where dense urban development transitions to suburban and agricultural zones. The terrain is predominantly flat, with elevations rarely exceeding 5 meters above sea level, characteristic of the delta's sedimentary formation. Songjiang's proximity to the Huangpu River and its tributaries, along with the nearby Dianshan Lake, creates a humid microclimate that influences pollution dispersion patterns. The district's location within Shanghai's broader industrial belt—particularly near manufacturing zones in neighboring districts—means it receives transported pollutants from regional industrial activities, while local sources include vehicular emissions from its growing population of nearly 2 million residents and construction from ongoing urban expansion. The surrounding landscape features a mix of urban infrastructure, agricultural plots growing vegetables and rice, and scattered green spaces like the Sheshan National Forest Park, which provides limited air purification benefits. This geographical setting, combined with its position downwind of Shanghai's industrial corridors during prevailing winds, makes Songjiang susceptible to accumulating particulate matter and ozone, especially when meteorological conditions inhibit dispersion across the flat terrain.

Songjiang's air quality follows a distinct seasonal pattern shaped by East Asian monsoons and local meteorological conditions. During winter (December-February), pollution typically peaks due to increased coal burning for heating, temperature inversions that trap pollutants near the ground, and reduced wind speeds from the northwest, creating hazy conditions that sensitive groups like children and the elderly should avoid prolonged outdoor exposure. Spring (March-May) brings variable air quality as increasing temperatures and occasional rainfall from the southeast monsoon help disperse pollutants, though dust storms from northern China can occasionally elevate particulate levels, making late spring generally more favorable for outdoor activities. Summer (June-August) sees improved air quality due to strong southerly monsoon winds from the Pacific Ocean that ventilate the region, along with frequent rainfall that washes pollutants from the atmosphere, though high temperatures can increase ozone formation on sunny days. Autumn (September-November) presents a transitional period where decreasing temperatures and shifting wind patterns sometimes lead to pollution accumulation, particularly in October and November when fog combines with pollutants to create reduced visibility conditions. Throughout the year, sensitive individuals should monitor daily forecasts and limit strenuous outdoor activities during periods of stagnant air, high humidity, or when regional agricultural burning occurs in surrounding areas.