Combustion engine-powered leaf blowers and string trimmers are those powered by an internal combustion or rotary engine using gasoline, alcohol, or other liquid or gaseous liquid. These devices pose significant health hazards to both equipment operators and Oakland residents, including the discharge of particulate matter, carbon monoxide, unburned fuel, and ozone. They also contribute to climate change by emitting carbon dioxide, a greenhouse gas, and generate significant noise pollution, a paramount concern for Oakland residents.