The only reason Hilo, HI is even ON that list is because of the ACTIVE Volcano just down the road. Sometimes you can smell it, but it’s Mother Nature, NOT human-Caused.
Yup. Kilauea Volcano, and today and yesterday have been oppressive, but only several days per year in Hilo proper. If they are considering the southern and southwestern parts of the island, the vog has been regular for quite a while. It could stop at any moment, or run for eternity