Inorganic components were measured in the aged ambient aerosols from Cape Hedo, Okinawa, an outflow region of East Asia, using online quadrupole Aerodyne aerosol mass spectrometer (Q-AMS) and offline ion chromatography (IC) and Sunset Lab carbon analyzer. Here, we performed an inter-comparison study on nitrate (NO3−), ammonium (NH4+) and sulfate (SO42−) that were measured by IC and AMS. Sulfate and ammonium showed a good agreement between two instruments. However, abundances of NO3− by AMS are on average twice overestimated compared to nitrate obtained by IC. We also found that a significant amount of organic nitrogen (ON) was detected in the filter samples from Okinawa. The online measurement (Q-AMS) data and offline filter based-NO3− data need to be carefully evaluated when ON is abundantly present in aerosols. The OM/OC ratios derived from AMS are consistent with the bulk OMAMS/OCSunset ratios (2.1). This study demonstrates that the OM/OC of 2.1 is the reasonable criteria for more aged aerosols.