By Terril Yue Jones BEIJING, Jan 30 (Reuters) - China's foulest fortnight for air pollution in memory has rekindled a tongue-in-cheek campaign by a multimillionaire with a streak of showmanship who is selling canned fresh air. Chen Guangbiao, who made his fortune in the recycling business and is a high-profile philanthropist, on Wednesday handed out soda pop-sized cans of air, purportedly from far-flung, pristine regions of China such as Xinjiang in the northwest to Taiwan, the southeast coast.