Some of the numbers related to lawn in USA are really troubling. [source]
20 millions Acres of lawn in the U.S., — more land than any single crop takes up
3 Estimated pounds of pesticides per application for an acre of farmland
7 Estimated pounds of pesticides per application for an acre of lawn
100 miles a late model car would have to drive to produce as much pollution as a lawnmower emits in one hour
1984 Year that the U.S.’s use of synthetic fertilizer on lawns surpassed the amount used on all of India’s food crops
I have been mistaken to think that lawn can at least produce some Oxygen. I did not know that the pesticide used in lawn is linked to health adversely. In the part of world where I live, (Melbourne Australia) water is a scarce resource. I never water my lawn nor I put any fertiliser or pesticide on my lawn. But I will be converting my lawn to raised vegie beds. The above info just make me more absolute to do the conversion.