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Dongzhang, nestled within Hebei Province, China, occupies a geographically complex position significantly influencing its air quality. Located at approximately 37.9350° N, 115.0839° E, the city sits on a gently sloping plain, part of the North China Plain, a vast alluvial landscape formed by the Yellow River. Its elevation is relatively low, averaging around 30 meters above sea level, contributing to atmospheric stability and potential for pollution accumulation. The surrounding landscape is predominantly agricultural, characterized by extensive fields of wheat, corn, and other crops, interspersed with smaller villages and rural settlements. To the west, the Taihang Mountains rise dramatically, acting as a partial barrier to prevailing winds but also creating conditions conducive to temperature inversions, particularly during the colder months. Dongzhang’s proximity to the Bohai Sea, roughly 150 kilometers to the east, introduces a maritime influence, though this is often overridden by regional weather patterns. The city is situated within the broader Beijing-Tianjin-Hebei economic region, a heavily industrialized belt. This proximity to industrial centers, including steel production and heavy manufacturing, is a primary driver of air pollution. The urban–rural gradient around Dongzhang is relatively sharp, with a noticeable transition from agricultural land to industrial zones and residential areas, further concentrating pollution sources. The flat terrain and limited natural ventilation exacerbate the challenges in dispersing pollutants, making Dongzhang particularly vulnerable to poor air quality episodes.

Dongzhang’s air quality follows a distinct seasonal pattern dictated by regional meteorology and human activity. Winter (November – February) consistently presents the most challenging period. Cold air masses dominate, leading to frequent temperature inversions where a layer of warm air traps cooler air near the ground, preventing vertical mixing and concentrating pollutants. Reduced sunlight hours also limit photochemical breakdown of pollutants. Agricultural burning, a common practice for clearing fields in the autumn, further compounds the problem. Spring (March – May) brings a gradual improvement as temperatures rise and winds increase, though dust storms originating from the Gobi Desert frequently impact air quality, carrying fine particulate matter. Summer (June – August) is generally the most favorable season, with increased rainfall and stronger winds aiding in pollutant dispersion. However, periods of stagnant weather can still lead to localized pollution episodes. Autumn (September – October) sees a return to more stable atmospheric conditions, with decreasing temperatures and increasing humidity, often resulting in fog and reduced visibility, which traps pollutants. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during winter and spring, limiting outdoor exposure and utilizing air purifiers when possible. During periods of heavy dust, wearing a high-quality mask is recommended. While summer offers respite, monitoring local conditions remains crucial, as sudden shifts in weather can quickly degrade air quality. Maintaining indoor air quality through ventilation and filtration is a year-round priority.