The University of Arkansas notes that artificial grass is much hotter during the summer than natural grass. A temperature survey showed Bermudagrass temperature to be 104 degrees Fahrenheit while synthetic turf was 165 degrees.
Natural grass can clean and renew itself in ways artificial grass can't, according to TreeHugger. Although some artificial turf is treated with antimicrobial compounds, football players' higher-than-usual incidence of antibiotic-resistant staff infection is attributed to an increased risk of abrasions from synthetic turf and the risk of contracting an infection from bacteria on the turf.
Real grass and artificial are about even from an environmental standpoint. Artificial grass eventually winds up in landfills, where it remains intact. Grass decomposes, but chemicals that treat grass and the emissions from the machinery that maintains it have environmental consequences.