Volatile organic compound emissions from switchgrass cultivars used as biofuel crops

Volatile organic compound (VOC) emission rates during the growth and simulated harvest phases were determined for switchgrass (Panicum virgatum) using laboratory chamber measurements. Switchgrass is a candidate for use in second-generation (cellulosic) biofuel production and the acreage dedicated to its growth in the USA has already increased during the past decade. We estimate that the yearly emissions from switchgrass plantations, including both the growth and harvest phases will be on the order of 3 kg C ha−1 methanol, 1 kg C ha−1 acetaldehyde, 1 kg C ha−1 acetone, 0.9 kg C ha−1 monoterpenes, 0.5 kg C ha−1 isoprene + another compound, most likely 1-penten-3-ol, 0.2 kg C ha−1 hexenals, and 0.1 kg C ha−1 hexenols. These emission rates are much lower than those expected from Eucalyptus or poplar plantations, which are other potential biofuel crops and have significantly higher VOC emissions, suggesting that the choice of species in the production of biofuels could have serious implications for regional air quality.