Air Conditioning use in public places and public transport may be the cause of COVID19 high case count in Western world where AC is very affordable. When it started in China virus spread through their AC system like through water.

Airlines like Spirit claim they have filtration system which eliminates 99.99% of the viruses. The same is needed for all cruise ships.

https://www.purdue.edu/newsroom/releases/2020/Q1/cruise-ship-ac-systems-could-promote-rapid-coronavirus-spread,-prof-says.html