I assume you mean "improve the quality of people who visit us". You likely would not say "tourists' qualities" but rather "the quality of tourists". First, you likely would say "quality" rather than "qualities" because you are probably not speaking about each individual quality, but rather the overall improvement of the tourists. You could even say "tourist" instead of "tourists", but it really makes no difference here. Second, if you don't use the possessive (instead using "of") it implies more importance on the "quality" aspect rather than who you're talking about, because likely you don't care exactly who it is, you just want them to be better.

The last part is fine, but what do you mean by "tourists' qualities"? That's very vague.