Japanese authorities issued health warnings as the suffocating smog that engulfed China last week apparently blew over the ocean towards Japan, sending air pollution to hazardous levels in some places.

Air quality in western Japan plummeted recently with concentration levels of PM 2.5, exceeding government standards up to 42%.

Readings in northern Kyushu island reached 50 micrograms per cubic meter of air over recent days, according to AFP. The government safe limit is 35 micrograms.

“We can’t deny there is an impact from pollution in China,” officials said, citing last week’s off-the-scale toxic haze that shrouded eastern China.

The Ministry of Environment forecast more of the thick smog from its Asian neighbor would arrive in Japan on Tuesday and skies will start to clear by Wednesday.

Japanese officials and scientists dismissed fears over the pollution, saying the smog was not as bad as it was in 2011, but warned people with respiratory illnesses and small children to take precautionary measures.

Atushi Shimizu of the National Institute for Environmental Studies (NIES) told AFP that there are a lot Japan can do to address its neighbor’s air pollution such as encouraging China to use pollutant-filtering equipment in factories.