I've gotta chime in that the other posts are glossing over certain realities. Vog is ever-present on Big Island, including Kona area. (I live in Captain Cook 45 minutes south) It is very common for people to complain year around about allergy like symptoms, and associate it with the vog. (This includes friends who live right in Kona) It's much like smog on the mainland.. we infrequently have an excessive amount (except for now, of course... you definitely want a vog mask now!), but we definitely get enough that it can effect people with respiratory issues.
Vogmasks, assuming you're referring to the brand, include a carbon filter layer, and are tested/rated for PM 2.5. You will get incredibly hot if you want to walk around wearing one all day, however, it will definitely help you with your respiration issues regardless of whether we currently have 30,000 ft tall ash plumes or not.
It would not help with actual direct sulfur dioxide inhalation, however, that is rarely concentrated enough to be a concern unless you are near a lava flow. It will help with the sulfur dioxide which bonded with water vapor to be inhaled as rain/humidity, however, which is a significant factor Kona side.
On Big Island we don't wear masks because it's hot, and no one else does. It's not because of our vast wisdom in avoiding respiratory issues.