Total run time and emitted particulate matters, do you actually have reason to believe the total output of lawn equipment is comparable to vehicle output?
Same with the ICE snowblower that I bought back when I was young and dumb seeing all my neighbors with one, so I bought one - what a maintenance nightmare. I use snow shovels now which are way better for the environment and my health.
If you are going to ban one thing, why not just ban lawns ;-p
Although to support your point, “Quantification of the environmental and economic benefits of the electrification of lawn mowers on the US residential market”[1] abstract says “Gasoline-powered lawn mowers and garden equipment [in the USA are] accounting for a quarter of all non-road gasoline emissions.”.
[1] https://link.springer.com/article/10.1007/s11367-021-01917-x
I inherited a large lawn mower which I use for the overgrown uneven driveway. I could replace the mower with a weed whacker, however that would then take many hours longer (for a chore I really hate doing and do as little as possible!) I hate the noise but it works. An equivalent electric mower would be completely unaffordable for me.
I thought the majority of PM2.5 emissions was due to two-stroke engines?
The only two-stroke device I own is a chainsaw. I wanted to get a battery powered chainsaw, but they are at least 3 times the price. I also own a mains powered electric chainsaw, but an extension cord is frustrating, and only reasonable to use within tens of metres from a house.
Stones can be difficult if they're tall enough and everywhere. Otherwise you'd just make sure to keep the blade higher than the stones.