I wouldn't say dangerous, but it does affect different people differently by: David
The Big Island Vog Blog has all the most current comments. Those pictures are from it. It has 2 years of posts.
I personally am not affected by the vog, but others are.
I do have to say that people have been breathing volcanic fumes since there were people. At the same time peoples health and welfare have suffered at times from volcanoes.
I think is all what health you are in, and how sensitive you are to it.
The pics above show all conditions from the so2 satellite images. They tell a pretty good story.