A woman smokes an E-cigarette, an electronic substitute in the form of a rod, slightly longer than a normal cigarette, in Bordeaux, southwestern France, March 25, 2008. A changeable filter contains a liquid with nicotine and propylene glycol. When the user inhales as he would when smoking, air flow is detected by a sensor and a micro-processor activates an atomizer which injects tiny droplets of the liquid into the flowing air, producing a vapour. The E cigarette, which retails for 78 euros, is powered by a rechargeable battery. REUTERS/Regis Duvignau (FRANCE)