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Licheng, situated in Jiangsu Province's Changzhou prefecture-level city, occupies a strategic position within the Yangtze River Delta region, approximately 150 kilometers west of Shanghai. This urban district lies in the heart of China's most economically dynamic area, characterized by flat alluvial plains with an average elevation of just 5-10 meters above sea level. The terrain is dominated by the Yangtze River to the north and the Grand Canal running through the area, creating a network of waterways that influence local microclimates. Licheng's location places it within the expansive Taihu Lake basin, surrounded by intensive agricultural zones transitioning to dense urban development. This urban-rural gradient creates complex pollution dynamics as agricultural emissions from surrounding farmlands mix with urban pollutants. The district's position in the Yangtze River Delta industrial belt means it's downwind of major industrial clusters, particularly during prevailing northeasterly winds. Proximity to the Yangtze River provides some natural ventilation but also contributes to humidity that can trap pollutants. The flat topography prevents natural dispersion of emissions, while the dense network of rivers and canals creates moisture-rich conditions that facilitate secondary aerosol formation. Urban expansion has created heat island effects that alter local atmospheric circulation patterns, further complicating air quality management in this rapidly developing district.

Licheng experiences distinct seasonal air quality patterns shaped by East Asian monsoon circulation. During winter (December-February), cold, dry northerly winds transport industrial pollutants from northern China while temperature inversions trap emissions near the surface, creating persistent haze episodes—particularly severe in January when heating demands peak. Sensitive groups should limit outdoor exposure during morning hours when inversions are strongest. Spring (March-May) brings transitional conditions with increasing rainfall that helps cleanse the atmosphere, though March can still experience dust events from northern regions. This season offers the most favorable conditions for outdoor activities, especially in April-May when prevailing southeasterly winds bring cleaner marine air. Summer (June-August) features the East Asian summer monsoon with abundant rainfall that significantly reduces particulate pollution, though high temperatures and sunlight intensity can elevate ozone levels during afternoon hours. Vulnerable populations should avoid strenuous outdoor activities during midday heat. Autumn (September-November) sees gradually deteriorating conditions as monsoon retreats and atmospheric stability increases, with October-November often experiencing the year's worst visibility due to agricultural burning emissions mixing with urban pollution. The seasonal shift creates complex pollution layers that require residents to monitor daily forecasts and adjust activities accordingly throughout the year.