Air purifiers have become one of the most popular home gadgets in recent years and you can spend hundreds of pounds on the top-end models. They promise to remove harmful pollutants in the air, reduce the symptoms of allergies and help you breathe more easily in a more healthy environment. But what's the evidence around how effective they are?

Listener Laura, a respiratory doctor, got in touch wanting to know whether they work and even if they could help some of her patients in their daily lives.

Greg Foot investigates the science behind the product, speaking to experts to find out just how many pollutants are being pulled from thin air, the effective range of air purifiers and whether there are any downsides to how they work.

This series, we’re testing your suggested wonder-products. If you’ve seen an ad, trend or fad and wonder if there's any evidence to back up a claim drop us an email to sliced.bread@bbc.co.uk or you can send us a voice note to our new WhatsApp number: 07543 306807

PRESENTER: Greg Foot PRODUCERS: Kate Holdsworth and Julian Paszkiewicz