This clever billboard coughs at people who smoke nearby

Most smokers are used to hearing complaints about their habit, but few of those complaints are lodged in the form of a coughing billboard.

As part of a new anti-smoking awareness campaign in Sweden, the ad agency Akestam Holst has installed a kiosk in Stockholm's busy Odenplan square.

Whenever a person lights up near the billboard, which is outfitted with a smoke detector, a virtual man will produce a nasty, barking cough on-screen.

In the video introducing the billboard, smokers react with a mixture of delight, surprise, and mild disdain for the digital secondhand smoker.

After a few seconds, the screen then displays an ad for various cessation products from Apotek Hjartat - hopefully within enough time to catch the smoker mid-puff.

Ida Persson, a spokeswoman for the agency, says the billboard is meant to help people make good on a common New Year's resolution: quit smoking.