The radiocarbon composition of tree rings as a tracer of local fossil fuel emissions in the Los Angeles basin: 1980-2008

摘要: [1] Quantifying local fossil fuel CO2 emissions in urban areas is challenging due to the heterogeneity and atmospheric mixing ratios of CO2. Measurements radiocarbon content tree rings are an alternative large networks CO2monitoring stations. In this study, we calculated 3-year averages from combustion 1980 2008 using sampled at six sites within Los Angeles basin adjacent mountains. We observed up 23 μmol·mol−1 inland ∼5–10 μmol·mol−1at coastal sites. Although expected see increasing trends fuel-derived CO2over time, not all showed a significant increase. Analysis correlations between CO2and socioeconomic variables revealed that followed census tract and/or city population or vehicle statistics most also CO/CO2combustion ring nearby measurements CO ratios. widespread declines ratio support increases efficiency automobile fleet over past few decades. This study demonstrates utility for quantifying temporal spatial patterns areas.