Long-term Air Quality and Health Effects of Dairy Digesters in the Future San Joaquin Valley
Jia Jiang, Ali Akherati, Hamed El-Mashad, Frank Mitloehner, MICHAEL KLEEMAN,
University of California, Davis Abstract Number: 437
Working Group: Health-Related Aerosols
AbstractCalifornia, as the nation's leader in milk production, has more than 1.5M cows that emit large quantities of methane (a potent greenhouse gas). Reducing these methane emissions is a priority for dairy farms as California works towards an 80% greenhouse gas reduction by the year 2050. Widespread adoption of anaerobic digesters that capture methane from animal manure provides one option for reduced methane emissions. Carbon dioxide is a less potent greenhouse gas than methane, and so the power produced from burning digester gas has a net climate benefit. Many farms in the San Joaquin Valley (SJV) have already adopted some form of this digester technology, but a rigorous evaluation of the air quality impacts remains to be completed.
Here we use a regional chemical transport model to predict pollutant concentrations under multiple future scenarios to better understand and quantify the long-term air quality effects of widespread digester adoption in the SJV. A Business as Usual (BAU) scenario is contrasted with a complete digester adoption scenario and a perfect alternative manure management scenario that eliminates dairy VOC emissions without the use of digesters. All scenarios are evaluated across 32 randomly selected weeks over a 10-year period from the year 2046 to 2055 to establish a long-term average impact in the presence of ENSO variability. All scenarios are evaluated over a range of background atmospheres to explore the effects of changing chemical regimes. The impact of widespread dairy digester adoption O
3 and PM
2.5 concentrations in the future SJV atmosphere will be reported. The health co-benefits under each scenario will also be calculated using the Environmental Benefits Mapping and Analysis Program-Community Edition (BenMap-CE), with the goal of providing additional insight into race/ethnicity disparities in future air pollution exposure in different practices.