Other countries doing the same thing, spraying inside the plane as quarantine measures. They even have thermal gadget to monitor the body temperature of each passenger. I hope these safety measures will really help.
This is for control of insects, not any flu

HKG has had thermal scanners active ever since SARS and never removed or stopped using then, i seem to remember they were always also at PVG or NRT (cant remember shich, one i visit often but i not paying attention) but not always used.