... (the ultrasound frequency 1.7Mhz) to produce the mist that helps to add the indoor humidity. ii. No any chemicals or ... . iv. The mist contains a large number of anion that helps to freshen the air, precipitate the dust and moisten the ... . If put some fragrance or disinfectant into the water, it helps to cure the modern air-condition ill, the dermatopathy, asthma ...