Smog smothers Japan, experts point to China

By Chisa Fujioka

TOKYO (Reuters) - Smog is menacing Japanese cities for the first time in 30 years and cropping up in rural areas for the first time ever, alarming the government and prompting experts to point the finger at neighbouring China.

Warnings for high levels of hazardous smog have been issued in a record 28 prefectures so far this year, from sparsely populated isles in southern Japan to Niigata, western Japan, where 350 people have suffered stinging eyes and throats.

While the government is cautious about placing blame, experts say much of the rise in pollution is coming from China, where air quality is a focus ahead of the Beijing Olympics next year.

The type of smog -- called "photochemical smog" because it is created when sunlight reacts with exhaust from cars and factories -- is made up of photochemical oxidant particles such as ozone. These particles can cause breathing difficulties and headaches.

"In terms of average levels of photochemical oxidants measured annually across Japan, there has been quite a rise since the 1990s," said Toshimasa Ohara, head of the National Institute of Environmental Studies' regional atmospheric modeling section. "We believe a substantial part of that rise has come from increasing emissions in China. We're looking into what percentage this factor has accounted for."

Smog adds to a string of environmental concerns that experts say originate in China, including acid rain and sandstorms that gain toxicity as they pass over its industrial regions.

But academics say Japan may find it hard to put pressure on China to cut emissions, with studies yet to show a precise figure on how much of Japan's smog is caused by cross-border pollution.

"If we are going to take action against other countries, we can't be vague," said Atsuko Mori, senior researcher at the Institute for Environmental Research and Public Health in Nagasaki, southern Japan. "There needs to be a thorough, scientific study into the causes."