Recently, Anderson et al. (2012,
https://doi.org/10.1126/science.1222978, 2017, https://doi.
org/10.1073/pnas.1619318114) and Anderson and Clapp (2018,
https://doi.org/10.1039/C7CP08331A) proposed that summertime
convectively injected water vapor over North America could lead to
stratospheric ozone depletion through halogenic catalytic reactions.
Such ozone loss would reduce the ozone column and increase erythemal
daily dose (EDD). Using 10 years of observations over the North American
monsoon region from the Aura Ozone Monitoring Instrument, we find that
the column ozone and EDD has a ~0.8–0.9 spatial
correlation with lower stratospheric water vapor measured by the Aura
Microwave Limb Sounder. We show that this correlation appears to be due
to the elevation of the monsoonal tropopause and associated monsoonal
convection. The increase in tropopause altitude reduces the ozone column
and increases EDD. We see no apparent evidence of substantial
heterogeneous chemical ozone loss in lower stratospheric ozone
coincident with the stratospheric monsoonal water vapor enhancement.