Black carbon transport from the Santiago Metropolitan Area, Chile, up to the adjacent Andes Cordillera and its glaciers is of major concern. Its deposition accelerates the melting of the snowpack, which could lead to stress on water supply in addition to climate feedback. A proposed pathway for this transport is the channelling through the network of canyons that connect the urban basin to the elevated summits, as suggested by modelling studies, although no observations have validated this hypothesis so far. In this work, atmospheric measurements from a dedicated field campaign conducted in winter 2015, under severe urban pollution conditions, in Santiago and the Maipo canyon, southeast of Santiago, are analysed. Wind (speed and direction) and particulate matter concentrations measured at the surface and along vertical profiles, demonstrate intrusions of thick layers (up to 600 m above ground) of urban black carbon deep into the canyon on several occasions. Transport of PM down-valley occurs mostly through shallow layers at the surface except in connection with deep valley intrusions, when a secondary layer in altitude with return flow (down-valley) at night is observed. The transported particulate matter is mostly from the vicinity of the entrance to the canyon and uncorrelated to concentrations observed in downtown Santiago. Reanalyses data show that for 10% of the wintertime days, deep intrusions into the Maipo canyon are prevented by easterly winds advecting air pollutants away from the Andes. Also, in 23% of the cases, intrusions proceed towards a secondary north-eastward branch of the Maipo canyon, leaving 67% of the cases with favourable conditions for deep penetrations into the main Maipo canyon. Reanalyses show that the wind directions associated to the 33% anomalous cases are related to thick cloud cover and/or the development of coastal lows.

从智利圣地亚哥大都市区到邻近的安第斯山脉及其冰川的黑碳运输是主要问题。它的沉积加速了积雪的融化，除了气候反馈之外，这还可能导致供水压力。正如建模研究所建议的那样，建议的这种运输途径是通过将城市盆地连接到高架山峰的峡谷网络，尽管到目前为止还没有观察结果证实了这一假设。在这项工作中，分析了 2015 年冬季在严重城市污染条件下在圣地亚哥和圣地亚哥东南部的迈波峡谷进行的专门实地活动的大气测量值。在地表和沿垂直剖面测量的风（速度和方向）和颗粒物浓度，展示了城市黑碳的厚层（高达地面以上 600 m）多次侵入峡谷深处。PM 向下山谷的传输主要发生在地表的浅层，除非与深谷侵入有关，当观察到夜间回流的高海拔次生层（向下山谷）时。输送的颗粒物主要来自峡谷入口附近，与圣地亚哥市中心观察到的浓度无关。再分析数据显示，在冬季有 10% 的时间里，东风将空气污染物从安第斯山脉平流带走，从而阻止了对迈波峡谷的深度入侵。此外，在 23% 的情况下，入侵会朝着迈坡峡谷的第二个东北分支进行，留下 67% 的案例具有深入渗透到主要迈坡峡谷的有利条件。再分析表明，与 33% 异常情况相关的风向与厚云层和/或沿海低气压的形成有关。