Yellow sand from China reduced visibility in many parts of the nation Saturday and will continue to drift over the archipelago through Sunday afternoon, the Meteorological Agency said.
Visibility was reduced to 5 km in Matsue, Shimane Prefecture, and in the city of Saga in the morning, and to 6 km in Nagasaki. The cities of Fukuoka, Kyoto, Osaka and Nagoya saw visibility drop to 8 km.
When visibility dips to less than 5 km, it begins to hinder transportation systems.
Meanwhile, Fukuoka warned Saturday that the average amount of PM2.5 particulate matter was likely to exceed environmental safety limits for a second consecutive day. The average amount of PM2.5, which measures less than 2.5 microns in diameter, was projected to reach 39.3 micrograms per cubic meter in the city. The government's maximum limit is 35 micrograms.
This is the fourth time the daily amount of PM2.5 has been projected to exceed the standard since Feb. 15, when local governments began issuing daily projections.
Fukuoka urged those with respiratory diseases to don masks and advised residents not to hang laundry outside.
The Yamaguchi Prefectural Government issued a similar warning Saturday after observing 89 micrograms of PM2.5 at an observatory in one hour before 10 a.m.