There are also piston powered diesels that burn either jet-A or regular automotive diesel, neither of which have lead. They are becoming more common. Leaded av

There are also piston powered diesels that burn either jet-A or regular automotive diesel, neither of which have lead. They are becoming more common. Leaded avgas is for older gasoline piston aircraft. There’s still many around but overall it’s not that significant and is slowly on its way out. The exhaust is mostly released high in altitude where there is ample time for extreme dilution. The concern is mostly for people who work at small airports, live near them, or work with these aircraft as mechanics etc. I think there’s an unleaded 100 octane formulation in testing that will probably replace leaded gas but the general aviation industry is small and slow moving.