Traditional lawn Gas-powered push mowers produce 11 times more air pollution per hour than a car, though push-reel mowers are blame-free. Pesticide and herbicide runoff seriously affects plant and animal life in waterways.
Synthetic lawn Made from petrochemical plastics. They’re non-biodegradable, provide no air-clearing photosynthesis, and some environmentalists are concerned they leach heavy metals from "tire crumb" substrates into soil.
Native grasses None.
New drought-tolerant blends None ― but only if you forgo mowing and let the grasses grow as a meadow.