Thousands of billions of grass plants protect our earth and filter our ground water. In an average 10,000 square foot lawn, there are 8 million individual grass plants. These tightly growing grass leaves are responsible for the photosynthesis that makes the grass plant grow and in the process they exchange the carbon dioxide in the atmosphere for clean pure oxygen.
In addition, the tightly knit grass carpet traps urban air pollutants so that they are not recycled into the atmosphere. The worst of these include ozone, hydrogen fluoride, sulfur dioxide and peroxyacetyl nitrate. They are all absorbed, recycled, and made harmless by transformation of turfgrass. Science has no filter as efficient as grass.
Below ground grass roots are even more impressive. A single grass plant can generate millions of individual roots that weave miles of individual fibers. Multiplied by 8 million plants this forms a massive underground filter which traps and digests atmospheric pollutants.
This root mass is home to billions of micro organisms which work together to build up the humus and soil fertility and reduce carbon dioxide. This complex organic system transforms lawn fertilizers and herbicides into healthy plants and benign organic matter. It is grass that filters our ground water and regenerates the deep black soils so prized by gardeners. The deep black soils of the world are found in our prairies, not in our rain forests.
The rain that falls on the streets and parking lots of our cities quickly runs off to rivers and streams. This run off is not filtered by urban lawns, but carries with it vehicle and industrial residue. In the United States, there are some 30 million acres of turfgrass. Each acre captures an average of 600,000 gallons of ground water recharge every year. In modern urban design, if we want more clean water, we need more healthy green grass.