From trustworthy wikipedia: "A 2011 study found that the amount of NMHC pollutants emitted by a leaf blower operated for 30 minutes is comparable to the amount emitted by a Ford F-150 pickup truck driving from Texas to Alaska. The two-stroke engines used in most leaf blowers operate by mixing gasoline with oil, and a third of this mixture is not burned, but is emitted as an aerosol exhaust. These pollutants have been linked to cancer, heart disease, and asthma," cited with https://www.edmunds.com/car-reviews/features/emissions-test-... and https://www.wsj.com/articles/leaf-blowers-are-loud-ugly-and-...