This is interesting to me because I've visited the Big Island pretty often, probably more than ten times. We usually spend a day driving down to Volcano NP and on one occasion we had access to a current lava flow and could get quite close, well, inside 6 feet it started to get really hot.
Our last trip we stayed 2 nights on the Hilo side of the island fairly near the current activity zone. At some point some developer laid out quite a few grids for residential development much of which never happened, but some did. You can see those grids laid out over square miles with nary a house in some places, and in others there are sporadic houses. All of this is in the "zone" on the side of Kilauea, which has been erupting since 1984 continuously at one spot or another. The lava flow had been restricted to a vent on the side of the mountain called "Pu'u", and you can't get there by foot, or shouldn't anyway even then. We climbed one "dead" vent about 5 miles away and could see Pu'u erupting, and we've taken helo tours to see the vents.
Anyway, the island is roughly 100 miles by 100 miles, so most of the island is unaffected except for some "vog" in the air. The Kona side is fine to visit, and is where we usually stay. Folks living southwest of Hilo are in the impacted area right not, but this could get worse of course and affect Hilo itself. You might wonder why anyone would live there on the side of an active volcano, but I think humans see all the trees and whatnot and figure things will remain calm, so they build on cheaper land and enjoy the climate (which can be pretty rainy around Hilo).
The crater inside the main crater in the national park has been venting SO2 for years now and the road that went around the crater has been closed for years, we drove it last in about 2008. And the crater inside that crater has been venting and has active lava at its surface which you can't see from the area you are allowed to visit (the whole thing is closed now).
Anyway, it's a neat place to visit and relax, a lot less touristy than Oahu with cattle farms and regular people, and with ever changing volcanoes.
