There are many advantages to living in Kagoshima City (鹿児島市): ferries to take you to any number of islands south of Kyushu; onsen far and wide; beautiful beaches practically within your grasp; ohhh, and the food... c'est magnifique.
However, the landmark that dominates the skyline over Kagoshima City is the source of both the greatest onsen in the city and the showers of ash.
Sakurajima (桜島) is still quite the active volcano, but it has not had a serious eruption in over fifty years. Nevertheless, small eruptions, resulting in earthquakes and more often than not, ash showers, occur quite often. So often in fact that residents of the prefecture capital city are given yellow garbage bags with which to dispose of the ash on their property.
During the summer months of June and July, the prevailing winds usually shift the ash towards Kagoshima City and the western coastal areas. In the fall, the direction reverses to rain upon Miyazaki and eastern Kyushu.
June 5th, 2007... a day that will soon enough be forgotten. I'm emerging from an internet cafe while NTT assesses whether my apartment is a candidate for a fiber optic line. The sky is grey, the crowds around Tenmonkan dense. It takes me a few seconds to realize that the light drizzle I'm feeling around my face and neck isn't wet. Soon enough my black shirt looks like a few tiny birds had a field day.
In the distance, I can see a huge cloud over Sakurajima slowly dispersing, guiding its way towards our fair city. People just put up with it, and so did I; it's too big to inhale, so I doubt there's much risk to your health. If you're wearing a suit I can see where some frustration might go down, but other than that... just treat it like rain and cast up your umbrella.
Another unique experience in Kyushu. The days are just packed.