High levels of yellow sand and particle-laden smog known as PM2.5 are now being registered in some parts of the nation, creating misery for allergy sufferers and posing a potential hazard from prolonged exposure.

The first clouds of yellow sand were observed in Kyushu and Yamaguchi Prefecture on Sunday and Monday. On Tuesday, the Meteorological Agency reported that a westerly wind from China was bringing the sand to much of western Japan.

At times, visibility in the cities of Kobe, Matsuyama, Fukui and Tottori was reduced to between 5 and 10 km, while Kyoto and Osaka were also affected. Earlier in the week, visibility in the city of Nagasaki was reduced to about 6 km at one point because of the sand, the agency said.