Almost　all　previous　studies　on　atmospheric　corrosion　of　metals　focused　on　anions　such　as　Cl−　and　CO3　2−,　ignoring　the　effects　of　cations　such　as　Na+　in　the　atmosphere.　Recent　studies　have　shown　that　Na+　corrosion　products　such　as　NaAlCO3(OH)2　play　an　important　role　in　the　corrosion　process　of　metals.　However,　detecting　Na　or　its　corrosion　products　remains　a　challenging　task.　In　this　work,　Na　depth　profiling　in　Al　corrosion　samples　was　studied　using　single-shot　laser-induced　breakdown　spectroscopy　and　3D　topography　measurements.　We　found　that　the　concentration　of　Na+　satisfies　a　power　law,　and　it　originates　from　atmospheric　corrosion.　An　electrochemical　corrosion　model　was　established　to　interpret　the　invasion　of　Na+　into　the　Al　matrix,　and　we　employed　COMSOL　to　simulate　the　corrosion　process,　by　considering　the　controlling　role　of　NaAlCO3(OH)2　on　the　atmospheric　corrosion　rate.　Simulation　results　are　consistent　with　the　experimental　data　in　different　atmospheric　environments.　©　2019　Elsevier　B.V.