Recently TV news reported pollutant aerosols around mainland Japan from China. Of course Okinawa island also have as well.
Here is web site for the Pollutant aerosols forecast,created by Kyusyu University as reference.
Based on this information, you can decide you go to the park with kids during weekend or not. you hang your clothes for dry or your futon outside or not.
Information includes level of aerosols for each region and movie.
for example, this figure is aerosols concentration around 9am on Feb 7th
English site
Japanese site