Downward transport of stratospheric air significantly modifies the chemical and radiation budget of the Earth's atmosphere.The Tibetan Plateau including the Himalayas is the largest and highest plateau on Earth and one of the most climatically important, sensitive, and complex regions in the world.Its topography and thermal heating affect the evolution of the Asian monsoon system via its uplift, leading to complex stratospheric-tropospheric interactions that play an important role in the global mass budget [1].In addition, the plateau is impacted by both naturally and anthropogenically sourced chemicals and is the source area of many major Asian rivers providing a sustainable water supply and food security for billions of people [2].Constraining the intensity and integrated flux of stratosphere-to-troposphere transport and potential influences on atmospheric chemistry and deposition at the Tibetan Plateau and surrounding regions is therefore central to quantification of their consequences for the hydrosphere and cryosphere near term and in the future.