沙尘天气在干旱及半干旱地区日趋频繁，已对生态环境与居民健康造成严重威胁。沙尘对人口的危害不仅取决于气候变化，还与人口规模和沙尘空间分布密切相关。目前仍缺少对于沙尘人口暴露的长时序和系统性的评估。依据环境相似性理论，整合沙尘站点数据与9种环境因子数据，运用随机森林方法构建沙尘强度模拟模型，结合人口数据建立沙尘人口暴露风险指数系统评估2000—2020年中国北方沙尘强度及人口暴露风险的时空演变规律。结果表明：①沙尘强度模型决定系数均大于0.6（p<0.01），对模型贡献度最高的3个因子分别为干旱指数、风速和归一化植被指数。②中国北方沙尘强度呈现显著空间异质性。极高、高和较高强度的沙尘主要集中于西北地区，而华北和东北地区以极低、低和较低强度为主。研究期内沙尘强度总体降低53%，累计有1.9×10⁶ km²的极高、高和较高强度的沙尘区域转化为极低、低和较低强度的沙尘区域。③中国北方3.5亿人口遭受沙尘威胁，沙尘人口暴露高风险区集中于人口密集的京津冀、陕晋南部以及沙尘强度高的新疆南部地区。研究区沙尘人口暴露风险显著下降，暴露于极高、高和较高强度的沙尘人数减少0.73亿人。上述结论揭示了中国北方地区沙尘人口暴露风险的时空分布特征，为地方政府制定针对性的沙尘防治和应对措施提供了科学依据。

The frequent occurrence of sand and dust causes serious harm to the ecological environment and public health in arid and semiarid regions. The risk of population exposure depends not only on climate change but also on the population size and spatial distribution of sand and dust. However, systematic evaluations of long-term exposure to dust are still insufficient. Based on the theory of environmental similarity, this study integrated data from sand and dust monitoring stations and nine environmental variables. Using the random forest method to construct a simulation model of sand and dust intensity, combined with population data to establish a sand and dust population exposure risk index system, and evaluated the spatiotemporal evolution of sand and dust intensity and population exposure risk in northern China from 2000 to 2020. The results showed that \mathrm{①} the coefficients of determination of the dust intensity model were all greater than 0.6 (p<0.01). The three most influential factor with the highest contribution to the model were the drought index, wind speed, and NDVI. \mathrm{②} Sand and dust intensities in the study area showed significant spatial heterogeneity. The extremely high, high, and high intensities of sand and dust were mainly concentrated in Northwest China, while the extremely low, low, and low intensities of sand and dust were mainly concentrated in North and Northeast China. During the study period, the sand and dust intensity decreased by 53%, and the extremely high- , high- , and high-intensity sand and dust areas of 1.9×10⁶ km² were transformed into very low, low, and low sand and dust areas. \mathrm{③} In northern China, 350 million people are exposed to dust and sand, and high-risk areas of dust exposure are concentrated in the Beijing-Tianjin-Hebei region, southern Shaanxi and Shanxi provinces with high population density, and southern Xinjiang with high dust intensity. The overall risk of exposure to sand and dust in the study area decreased significantly, with 73 million people exposed to extremely high, high, and high-intensity sand and dust. The findings reveal the spatial and temporal distribution characteristics of sand and dust exposure risk in northern China and provide a scientific basis for local governments to formulate targeted sand and dust prevention and control measures.