Japan logged a huge surge in air purifier sales last month, as Tokyo warned that smog was blowing into its territory from China, which is grappling with an air pollution crisis. Acrid haze blanketing swathes of China has sparked health risk warnings in Japan while complicating already strained ties between Tokyo and Beijing, which are embroiled in a tense territorial row over islands in the East China Sea. The Japanese foreign ministry has proposed a meeting over the issue with Beijing, which has promised action as it faces rising public anger over the persistent problem.