Model on anti-smoking bus shelter ad coughs when smokers walk by

If you walk past this bus shelter ad in Stockholm while smoking, the model on the screen starts to cough. Next, the display shows smoking cessation products sold by pharmacy chain Apotek Hjartat, the sponsor of the ad. From CNN:

Akestam Holst, the agency behind the campaign, created the effect by attaching smoke detectors to the digital advertising screen. They chose a location where people often smoke -- Stockholm's Odenplan square -- and let the coughing begin.

The agency filmed the reactions of smokers -- some express surprise, others react with laughter.