which thickness of ordinary air can block every intensity of Vacuum UV
(10~200 nm)? (with method of calculating and reference for furmulas
and constants used)

My guess is a rare photon of 200 nanometers wave length makes it all
the way to Sealevel. The thickness of Earth's atmosphere is about 100
miles = 170 kilometers, but somewhat more is occasionally quoted, and
a few would argue as thick a 1000 kilometers, as there are still
thousands of particles per cubic meter at an altitude of 1000
kilometers. The thickness increases when CMEs = coronal mass ejections
hit Earth.  Neil