Biochar from recycled waste may both enhance crop growth and save health costs by helping clear the air of pollutants, according to Rice University researchers.

Rice researchers in Earth science, economics and environmental engineering have determined that widespread use of biochar in agriculture could reduce health care costs, especially for those who live in urban areas close to farmland.

Biochar is ground charcoal produced from waste wood, manure or leaves. Added to soil, the porous carbon has been shown to boost crop yields, lessen the need for fertilizer and reduce pollutants by storing nitrogen that would otherwise be released to the atmosphere.

The study led by Ghasideh Pourhashem, a postdoctoral fellow at Rice’s Baker Institute for Public Policy, appears in the American Chemical Society journal Environmental Science and Technology.

Pourhashem worked with environmental engineering graduate student Quazi Rasool and postdoc Rui Zhang, Rice Earth scientist Caroline Masiello, energy economist Ken Medlock and environmental scientist Daniel Cohan to show that urban dwellers in the American Midwest and Southwest would gain the greatest benefits in air quality and health from greater use of biochar.

They said the U.S. counties that would stand to save the most in health care costs from reduced smog are Will, La Salle and Livingston counties in Illinois; San Joaquin, San Diego, Fresno and Riverside counties in California; Weld County in Colorado; Maricopa County in Arizona; and Fort Bend County in Texas.