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    基于PI-SWERL模拟实验的东北黑土区非铺装田间道路粉尘释放特征

    Dust emission characteristics of unpaved field roads in the black soil region of Northeast China based on PI-SWERL experiments

    • 摘要: 非铺装道路扬尘是大气颗粒物的重要来源之一。东北黑土区是我国重要的粮食生产基地,广泛分布的非铺装道路产生的风蚀扬尘对该区农业生产和公共健康具有显著影响。此外,东北黑土区受多种侵蚀营力的综合作用,非铺装道路上的风蚀同时影响融雪和水力侵蚀,因此亟需进行研究和防控。利用便携式原位风蚀实验室(PI-SWERL)量化了东北黑土区不同类型非铺装田间道路的粉尘(以PM10表征)释放通量,明确其动态释放特征。结果表明,裸土道路的粉尘释放潜力最高,在摩阻风速为0.56m∙s-1时,裸土道路的粉尘释放通量为0.43-9.51mg∙m-2·s-1,相较于摩阻风速为0.86m∙s-1时砾石道路的粉尘释放通量(0.04-1.54mg∙m-2·s-1)高出1-2个数量级;东北黑土区非铺装道路的粉尘释放主要受跃移颗粒冲击和空气直接抬升的影响;经过平整和固化处理的砾石道路粉尘释放通量最低(0.09-0.18mg∙m-2∙s-1),说明硬化措施能有效减少粉尘释放。研究解决了传统方法难以准确量化粉尘释放潜力的问题,揭示了东北黑土区非铺装道路粉尘释放的差异,对非铺装道路粉尘释放的防治具有重要意义。

       

      Abstract: Background Unpaved road dust represents a significant source of atmospheric particulate matter. The black soil region of Northeast China is a crucial grain production base. Unpaved roads are subjected to compounded erosion forces, leading to severe soil degradation and ecological risks. Wind-induced dust emissions from widespread unpaved roads not only threaten agricultural production and public health but also amplify surface erosion through synergistic interactions with seasonal processes, so thorough research and control measures are urgently needed. However, quantifying dust emission potential under dynamic field conditions remains challenging due to limitations in conventional sampling methods. Methods This study employed a Portable In-Situ Wind ERosion Lab (PI-SWERL) to systematically quantify real-time PM10 emission fluxes from typical unpaved roads in the black soil region of Northeast China. Field experiments target three road types: the bare soil road, gravel roads and the hardened gravel road which is subjected to leveling and solidification. Dust emissions are measured under controlled friction velocities, simulating natural wind shear stresses. Statistical analyses differentiated emission mechanisms (saltation and aerodynamic entrainment). Results The PM10 emission flux demonstrate a positive correlation with friction velocity, and there exist highly significant disparities in the dust emission fluxes measured under varying wind speeds. It is suggested that the bare soil road exhibits the highest potential for dust emission among the types investigated. Specifically, at a friction velocity of 0.56 m·s-1, the dust emission flux of the bare soil road is measured to be in the range of 0.43 to 9.51 mg·m-2·s-1. In contrast, when a higher friction velocity reaches 0.86 m·s-1, the dust emission flux of gravel roads is determined to be between 0.04 and 1.54 mg·m-2·s-1. The dust emission flux of the bare soil road at a lower friction velocity exceeds that of gravel roads at a higher friction velocity by 1-2 orders of magnitude. The dust emission types of unpaved roads within the study region can be categorized into four distinct types, based on comprehensive analysis of PM10 concentration and saltation particle variation trend, and dust emissions in this region primarily result from particle saltation and aerodynamic entrainment. Notably, the hardened gravel road exhibits the lowest emission fluxes ranging 0.09-0.18 mg∙m-2∙s-1, indicating that hardening measures effectively reduce dust emissions and play a critical role of road hardening in dust suppression. Conclusions This research quantifies the dust emission potential of unpaved roads in the black soil region of Northeast China and elucidates the dynamic processes and characteristic differences in dust emission across different road surface types. These findings provide a theoretical basis for optimizing wind erosion control technologies targeting unpaved agricultural roads in erosion-prone black soil ecosystems.

       

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