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Nagqu, situated at 31.4760°N, 92.0510°E in the Tibet Autonomous Region of China, occupies a strategic position on the northern Tibetan Plateau, approximately 450 kilometers north of Lhasa. Perched at an average elevation of 4,500 meters above sea level, it is one of the highest cities in the world, earning it the nickname 'Roof of the World.' The urban area lies within the Nagqu River valley, surrounded by vast, rolling grasslands and distant snow-capped peaks of the Tanggula Mountains to the north. This high-altitude, semi-arid landscape significantly influences air quality: the thin atmosphere at this elevation reduces pollutant dispersion, while the lack of major industrial belts or dense agricultural zones means pollution sources are primarily localised. Nagqu functions as a regional administrative and transportation hub, with an urban-rural gradient characterised by sparse settlement patterns blending into nomadic pastoral lands. Proximity to the Nagqu River provides minimal moderating effects on air quality due to the river's seasonal flow. The city's isolation from China's eastern industrial heartlands means it avoids transboundary pollution, but local factors like vehicle emissions from the Qinghai-Tibet Highway, residential heating using biomass or coal during cold months, and occasional dust from unpaved roads contribute to particulate matter levels. The surrounding open grasslands allow for some wind-driven ventilation, yet temperature inversions in the valley can trap pollutants, particularly in winter, creating episodic air quality challenges unique to this high-altitude setting.

Nagqu's air quality narrative is shaped by its high-altitude continental climate, with distinct seasonal variations driven by temperature, wind patterns, and precipitation. In winter (December to February), cold, stable conditions prevail, with temperatures often plummeting below -20°C. Temperature inversions are common in the valley, trapping pollutants from heating sources and vehicle emissions, leading to periodic peaks in particulate matter; this season is least favourable for outdoor activities, especially for sensitive groups like those with respiratory or cardiovascular conditions, who should limit exposure during calm, cold spells. Spring (March to May) brings gradual warming and increased windiness, which helps disperse pollutants, though dust from dry grasslands and roads can elevate particulate levels during windy days; outdoor activities are generally more favourable, but monitoring for dust events is advised. Summer (June to August) sees the mildest conditions, with temperatures rarely exceeding 15°C, and the Indian monsoon brings increased rainfall, which scrubs pollutants from the air, resulting in the cleanest air of the year; this is the optimal time for outdoor pursuits, with minimal health risks. Autumn (September to November) transitions to cooler, drier weather, with decreasing winds and occasional fog, which can lead to pollutant accumulation; sensitive individuals should be cautious as heating season resumes. Year-round, the high elevation means lower oxygen levels, exacerbating health impacts from poor air quality, so visitors and residents with pre-existing conditions should acclimatise and avoid strenuous activities during pollution episodes.