Bikou, nestled within the rugged landscapes of Gansu Province, China, occupies a geographically significant position at approximately 32.75°N, 105.24°E. The city’s location within the Qilian Mountains foothills dictates a challenging terrain characterized by steep slopes and varying elevations, influencing both its urban development and air quality dynamics. Bikou sits at an elevation of roughly 1,700 meters (5,577 feet), contributing to cooler temperatures and a propensity for temperature inversions, particularly during the colder months. The surrounding landscape is dominated by semi-arid steppe and sparse vegetation, typical of the Loess Plateau region. While Bikou itself is a relatively small town with a population of around 16,247, it lies within a broader agricultural zone, with surrounding areas dedicated to wheat and corn cultivation. This agricultural activity, alongside potential localized livestock farming, can contribute to particulate matter emissions. The city’s proximity to the Gobi Desert, though not immediately adjacent, means that dust storms originating from that region can significantly impact air quality, especially during spring. The urban–rural gradient is relatively sharp, with the town itself exhibiting a compact layout, while the surrounding areas remain largely rural. Industrial activity is limited within Bikou itself, but the broader Gansu province hosts several mining and energy-related industries, and their emissions can be transported via prevailing winds, impacting Bikou's air quality. The lack of significant surface water bodies nearby further limits natural air purification processes.

Bikou’s air quality experiences a distinct seasonal cycle heavily influenced by its climate and regional weather patterns. Winters (November – February) are typically the most challenging, marked by frequent temperature inversions where cold air becomes trapped near the ground, preventing the dispersion of pollutants. This, combined with reduced sunlight hours and a drier atmosphere, leads to a build-up of particulate matter and other emissions. Spring (March – May) brings the risk of dust storms originating from the Gobi Desert, dramatically degrading air quality and increasing PM10 and PM2.5 concentrations. These events are often unpredictable and can persist for several days. Summers (June – August) generally see improved air quality due to increased rainfall and stronger winds, which help to disperse pollutants. However, occasional periods of stagnant air can still occur. Autumn (September – October) offers a transitional period, with generally moderate air quality, though the potential for dust events remains. The monsoon season, though less pronounced than in southern China, still contributes to increased humidity and occasional rainfall during the summer months, aiding in pollutant removal. Sensitive groups, including children, the elderly, and individuals with respiratory conditions, should exercise caution during winter and spring, limiting outdoor activity on days with visible haze or dust. During the dust storm season, wearing a high-quality mask is strongly recommended. Even during the relatively cleaner summer months, monitoring local conditions and avoiding strenuous outdoor activity during periods of stagnant air is advisable.