It is not easy being green: Exploring the linkages between biofuel crops, biogenic emissions, and regional air quality in the Pacific Northwest

Land-use and long-term climate changes are likely to significantly affect emissions of biogenic volatile organic compounds (BVOCs), which play an important role in tropospheric chemistry. Here the impacts of converting low isoprene-emitting agricultural land for biofuel production in the Pacific Northwest were studied using the regional chemical transport model WRF-Chem coupled with the biogenic emissions model MEGAN. Default isoprene emissions and leaf area index (LAI) were modified to represent the increased emissions and LAI of one proposed crop, Arundo donax. The responses of the default and modified isoprene emissions to current and future CO ₂ levels also were considered. Changes in modeled BVOC emissions were compared, as well as the subsequent changes in modeled hydroxyl radical and criteria air pollutant (ozone, nitrogen oxides, fine particulate matter) concentrations. The results of this work are important for understanding linkages between BVOCs and criteria pollutants and specifically, the potential impacts of biofuel crop emissions on air quality.