Unfortunately, there is no answer. With carcinogens, ANY exposure has the POTENTIAL to give you cancer. Most believe there is very, very little risk from single low exposures. We just don’t understand enough to know how it works at that level. Everyone is exposed to asbestos since it occurs naturally in the air. Just digging in the garden exposes you. Most regulations are based on an “average” person and are for measurable exposures.

Now to the level. If you had been wearing a monitoring device, it probably would not even have registered asbestos above background. To get to a measurable amount you have to have small clouds of material around you and to get to a regulated amount, you have to be grinding, sanding, etc for a single exposure like you had.

Not to worry. Your driving is a million times (at least) more likely to kill you than this asbestos exposure.