Japan looks west, holds its breath as mainland pollution heads its way
The choking pollution that has shrouded large parts of the mainland is moving east to Japan, threatening to push levels of health-threatening PM2.5 particles there beyond World Health Organisation health standards.
Japanese computer simulations show the fine air particulates could reach 40 micrograms per cubic metre today or tomorrow and cause smog in parts of western Japan such as Nagasaki.
Dr Toshimasa Ohara, head of the National Institute of Environmental Studies' Centre for Regional Environmental Research, conceded this figure was very low by Chinese standards, as cities such as Beijing often measure PM2.5 levels in the hundreds. But 40 was twice the level generally seen in Japanese cities this time of year and higher than the 25 micrograms level set by the WHO.