Flask samples from two sites in East Asia, Tae-Ahn Peninsula, Korea (TAP), and Shangdianzi, China (SDZ), were measured for trace gases including CO2, CO and fossil fuel CO2(CO(2)ff, derived from Delta(CO2)-C-14 observations). The five-year TAP record shows high CO(2)ff when local air comes from the Korean Peninsula. Most samples, however, reflect air masses from Northeastern China with lower CO(2)ff. Our small set of SDZ samples from winter 2009/2010 have strongly elevated CO(2)ff. Biospheric CO2 contributes substantially to total CO2 variability at both sites, even in winter when non-fossil CO2 sources (including photosynthesis, respiration, biomass burning and biofuel use) contribute 20-30% of the total CO2 enhancement. Carbon monoxide (CO) correlates strongly with CO(2)ff. The SDZ and TAP far-field (China influenced) samples have CO: CO(2)ff ratios (R-CO:CO2ff) of 47 +/- 2 and 44 +/- 3 ppb/ppm respectively, consistent with recent bottom-up inventory estimates and other observational studies. Locally influenced TAP samples fall into two distinct data sets, ascribed to air sourced from South Korea and North Korea. The South Korea samples have low R-CO:CO2ff of 13 +/- 3 ppb/ppm, slightly higher than bottom-up inventories, but consistent with emission ratios for other developed nations. We compare our CO(2)ff observations with modeled CO(2)ff using the FLEXPART Lagrangian particle dispersion model convolved with a bottom-up CO(2)ff emission inventories. The modeled annual mean CO(2)ff mole fractions are consistent with our observations when the model inventory includes the reported 63% increase in Chinese emissions from 2004 to 2010, whereas a model version which holds Chinese emissions flat is unable to replicate the observations.