I found a CARB report[1] that addresses this. TL;DR: nobody's directly measured the particulates ("fugitive dust") kicked up, but the estimates made from back-calculating measurements of dust present on road services suggest that the majority of PM10 and PM2.5 from a leaf blower are due to fugitive dust, and therefore will still be present in electric leaf blowers.
There isn't a lot of data on how much the chemical makeup of particulates affects health, nor on what the makeup of particulates likely to be kicked up by a leaf-blower are. At least some of the particulates from two-stroke engine emissions are known to be really bad (e.g. partially combusted lubricants). So the jury is out on if the particulate related health risks are dominated by the engine or the dust. If you think "all PM2.5 is bad" then it's almost certainly dominated by the dust though.
That makes sense. I am curious as to how big the difference the power source makes for a machine that’s purpose-made to kick up particulate matter up into the air from the ground.
I believe that! I am curious as to how big the difference the power source makes for a machine that’s purpose-made to kick up particulate matter up into the air from the ground though.
Compare Table 3 to Table 5. PM emissions from exhaust are on the order of 1 gram per hour. Whereas fugitive dust emissions, depending on the surface, are 100s or 1000s of grams per hour.