When we went over to the big island (after almost a week on Kaua'i), we were on the opposite side of the island from the volcano. The sky was ashen some of the time when we looked toward that side of the island (called 'Vog'), but when we drove up North, there was really no sign of the volcano activity that far away. One day we drove toward the volcano, stopped at Black Sand Beach along the way, and passed a few closed roads along the way beyond Volcano National Park area. That particular day, it was raining and visibility was really compromised with the Vog and the rain. When my husband spoke to one of the staff at the restaurant where we ate, he learned that had we come to that side of the island the day before, we would have seen red sky rather than the grey skies we saw that day. I was surprised my husband was actually trying to get close enough to see something of the volcano. That's not really like him at all.
Our friend who lives in the area has not had to evacuate, but does where a mask (like I had to wear when I was in the path of the California wildfires last October) when he goes outside.