Any recommendations for air purifier / humidifier for baby ?

Honeywell has a great range of air purifiers. My parents have one at their place and they love it. They had it for years and it's still working great. It's a bit pricey, retailing at around 700sgd but it's worth the price they say. You can get it at most electrical appliance stores like Best Denki. Here's an article that can be useful if you want to invest in an air purifier. http://sg.theasianparent.com/buying-an-air-purifier-choosing-the-right-one-for-your-home/

I would recommend the BioCair, it works as a humidifier, air purifier, and even as a disinfectant. It is definitely worth its price. There are also health benefits which is good for you and your family. I have friends who are using it and has been giving good feedbacks. Check out Mothercare or even roadshows, you can get it with a more affordable price. http://biocair.com.sg