I was beyond halfway of a 3-hour flight when I suddenly started sneezing and getting a runny nose. I recovered overnight. However, on the trip back home, it happened again! This got me looking into how clean cabin air is.
Although 40 % of a cabin’s air gets filtered through the high-efficiency particulate air or HEPA system; the remaining 60 percent there are other things that you have to consider before you get duped into believing that the cabin air is really clean.