Valuing the Air Quality Effects of Biochar Reductions on Soil NO Emissions

While it is clear that biochar can alter soil N 2 O emissions, data on NO impacts are scarce. Reports range from 0 to 67% soil NO emission reductions postbiochar amendment. We use regional air quality and health cost models to assess how these soil NO reductions could influence U.S. air quality and health costs. We find that at 67% soil NO reduction, widespread application of biochar to fertilized agricultural soils could reduce O 3 by up to 2.4 ppb and PM 2.5 by up to 0.15 μg/m 3 in some regions. Modeled biochar-mediated health benefits are up to $4.3 million/county in 2011, with impacts focused in the Midwest and Southwest. These potential air quality and health cobenefits of biochar use highlight the need for an improved understanding of biochar’s impacts on soil NO emissions. The benefits reported here should be included with estimates of other biochar benefits, such as crop yield increase, soil water management, and N 2 O reductions.