Some good info here
Atlanta has received an Air Quality Score of F for three years in a row for ground-level ozone. Small engines are unregulated super-polluters. If we modernized the landscaping industry with trade-in programs for clean electric equipment, we could clean up our air.
Don’t doubt the toxic exhaust from these machines, just read more here: https://www.kcet.org/shows/socal-connected/california-throttles-down-pollution-from-small-engines
And here: https://www.arb.ca.gov/msprog/offroad/sm_en_fs.pdf
And here: https://www.npr.org/templates/story/story.php?storyId=5400950