Renovation taking a toll - Solution ? Buy Air purifier

We just moved 3 weeks ago and renovation works are still ongoing due to delay during the Chinese New Year holidays.
The dust and chemicals are taking a toll on the baby and all of us. We've been rotating sore throat, cough and runny noses amongst us in the last 2 weeks.
Our good friend and neighbour Valerie who went through moving into a newly renovated house just 19 months ago advised us to get a air purifier. We borrowed her mega air purifier cum super vacuum from Rainbow and I think it helped.
We have just went out this weekend and evaluated several models. These were the key features we looked for.

1. Filter granularity - There is HEPA (which is most common ) and ULPA. ULPA are apparently finer at 0.03 microns.
2. UV light
3. Charcoal Filter
4. Photocatalytic filters
5. Negative Ioniser
6. Capacity to filter 500 Sq Feet.

We saw Air Purifier and Ionisers from Sharp which claim to kill flu virus, Osim iLife which looked like the Ipod and VGO (from Korea) which is a new entrant.
In the end we got the VGO as it had everything and was well priced at $400 for its features.

Been using it for the last two days at night and daytime when reno is still going on.

Anyone knows effects of prolonged use of Ioniser? You can post comments below.
Think I may research a little more on this.