Biochar could save ‘millions’ of dollars per year in health care costs

New research from Rice University claims biochar from recycled waste boosts crop growth and reduces health costs by helping clean the air of pollutants.

Scientists from the university have concluded that widespread use of biochar in agriculture could significantly reduce health care costs, particularly for those living in urban areas close to farmland.

The research was led by Ghasideh Pourashem, from Rice’s Baker Institute for Public Policy, and has been published in the American Chemical Society’s Environmental Science and Technology journal.

Biochar is charcoal produced from plant matter, such as waste wood, manure and leaves, via pyrolysis. It is currently being investigated as a means for carbon sequestration to mitigate climate change. Previous research has shown that when biochar is added to soil it boosts crop yields, lessens the need for fertiliser and reduces pollutants by capturing nitrogen that would otherwise be released into the atmosphere.

Pourashem and colleague’s research shows that urban dwellers in the US Midwest and Southwest would stand to gain the greatest benefits in air quality and health from greater use of biochar. 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 are the areas standing to save the most in health care costs through reduced smog, according to the researchers.

"Our model projections show health care cost savings could be on the order of millions of dollars per year for some urban counties next to farmland," Pourhashem said. "These results are now ready to be tested by measuring changes in air pollutants from specific agricultural regions."

A key measurement in the study was the rate of soil emission of nitric oxide (NO), which is a smog precursor and contributor to acid rain, after biochar had been applied to a field.

"We know that biochar impacts the soil nitrogen cycle, and that's how it reduces nitrous oxide," said Masiello, a professor of Earth, environmental and planetary science. "It likely reduces NO in the same way. We think the local impact of biochar-driven NO reductions could be very important."

Data from three studies of NO emissions from soil in Indonesia, Zambia, Europe and China were used in the Rice team’s research. The data revealed a wide range of NO emission curtailment -- from 0 percent to 67 percent -- depending on soil type, meteorological conditions and the chemical properties of biochar used.

Basing their calculations on the highest figure from the three studies, the Rice team determined that a 67% reduction in NO emissions in the United States could reduce annual health impacts of agricultural air pollution by up to $660 million. Savings through the reduction of airborne particulate matter -- to which NO contributes -- could be 10 times larger than those from ozone reduction, they wrote.

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