Airborne total bromine (Br^tot) and tracer measurements suggest Br^tot-rich air masses persistently protruded into the lower stratosphere (LS), creating a high Br^tot region over the North Atlantic in fall 2017. The main source is via isentropic transport by the Asian monsoon and to a lesser extent transport across the extratropical tropopause as quantified by a Lagrange model. The transport of Br^tot via Central American hurricanes is also observed. Lastly, the impact of Br^tot on LS O₃ is assessed.