A21H-0256
Top-Down Evaluation of Nitrous Oxide Emissions in Los Angeles Basin

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Toshihiro Kuwayama, California Air Resources Board, Sacramento, CA, United States
Abstract:
Nitrous oxide (N2O) is a potent long-lived greenhouse gas (GHG) that accounted for 3% of California’s GHG emissions in 20131, 2. It has been postulated that anthropogenic N2O emissions may be larger than previously estimated. To evaluate this hypothesis, long-term measurements of N2O and carbon monoxide (CO) concentrations were obtained at Mt. Wilson Monitoring Site between 2012 and 2015. This site provided a suitable location to study the regionally well-mixed urban emissions from the Los Angeles Basin. The resulting dataset was analyzed to investigate the monthly N2O trends and seasonal variability of urban N2O emissions in the region. N2O:CO orthogonal regression slopes, integrated with regional CO emissions data3 (as an urban pollution surrogate), were used to estimate the top-down N2O emissions from the Los Angeles Basin. The results from this top-down analysis were also analyzed to evaluate the various source sectors in the Los Angeles Basin.