QUOTE(misspinky @ Jun 9 2017, 10:04 AM)
Thanks for clarification.

my house no aircond even in room also no aircond. Only the fan, from what i can see dehumidifier have a storage behind it, is it water will fill automatically when use it? so, the water in that thing is contamination?
Dehumidifier is to
reduce the humidity in your environment like you feel your room or
house very humid (潮湿) , means
water vapour is high in the air thn u need the dehumidifier. Dehumidifier does not have storage behind i think, that is humidifier as it need to humidity the room so may have a small water storage behind or inside. The water in that thing is not contaminants.
Contaminants (污染源)is means that those dust or dirty things that we are
unable to see by using our eyes . It may contain in our air or environment. Like pets' fur, dust, cigerette smoke, dust of haze an so on that some ppl will feel uncomfortable on it and may be will cause health problem. So that,
air purifier (空气净化器)is another use to absorb those contaminants and reduce the dust or those thing in the air, to let us have more fresh air.