Ionisers

Can somebody give me the straight dope on ionisers (probably ioniZers to those of you in the US) - those little air purification devices that you see advertised alongside air filtration and air conditioning equipment.

They supposedly release ‘a stream of negative ions’, but my question(s):

Do they really work?

Why would negative ions be beneficial?

When you create negative ions, doesn’t this result in a corresponding number of positive ions? - if so, where do they go?

Well, Ionizers (at least, the ones I’m familiar with) are supposed to get rid of dust and such in the air.

You can take my testimony on that. Our house used to be dusty as hell. Now it’s very, very dust free.

The way it was explained to me, they supposedly make dust particles attract each other (or something), making them into too big of clumps to stay airborne. So they fall to the ground. Make sure you have your Pledge handy.

See above.

Note: I don’t know how scientifically accurate this is… this is just how the process was explained to me, and I know that there’s been a huge reduction in the amount of dust floating around our house.

That makes sense, thanks.

Are they quiet in operation?

Here is a previous thread on ionizers from 2 monthes ago.

http://boards.straightdope.com/sdmb/showthread.php?threadid=66614

I believe most of the effects are just because it’s a Placebo.

Oops! now you know it’s a placebo… It won’t work. Sorry.

PerfectDark

Thanks.

Hahahaha, the placebo effect; you don’t actually believe in that do you?

BTW, The OP is because my dear wife suffers very badly from some sort of allergy, similar to hay fever, but it hits her at about three in the morning, anti histamines help sometimes, but it doesn’t seem like a good idea to be popping pills all the time.

She doesn’t get the attacks if we keep the windows closed at night, so I figure it must be airborne (genius eh?), but if we keep them closed, the room gets too hot and stuffy - I am planning to buy an air purifier (filter type) and I see that you can get them with the ioniser built-in, I’ll probably get this type anyway as there isn’t a great deal of difference in the price.