Midea's ad 120- 15c Why is the outlet of evaporative cooling fan only the upper part and the lower part sealed?

It should be the five advantages of health guards: effective sterilization: water can effectively kill bacteria in water and keep it sterile for a long time. Avoid bacterial growth and prevent water from changing water quality, such as yellowing, turbidity and peculiar smell: effectively modify calcium and magnesium ions and suspended substances in water, so that they are not easy to be enriched in places with fast water flow, and effectively prevent water from scaling in the pump.