Problem: In Lhasa (0.65 atm and 25 degree C), ozone was observed at 70 ppb. In Hong Kong (1 atm and 25 degree C), ozone was observed at 65 ppb. The ratio of the ozone concentrations is 0.93 (65 ppbv/70 ppbv). Then, what would be the ratio of the number of ozone molecules in a same volume (e.g. molecules/cm3) between Lhasa and Hong Kong (hint: # of total air molecules in 1 cm3 is 2.5 x 1019 molecules at 25 degree C and 1 atm).