Popis: |
In this study, we estimate the background concentration of black carbon (BC) mass concentration measured at Gosan Climate Observatory from January 2008 to December 2011 by applying six methods: (1) Mean and Median (2) Trimmed mean method deployed in Inter- agency Monitoring of Protected Visual Environments (IMPROVE) network program (hereaf- ter, IMPROVE method), (3) Concentration-frequency distribution analysis method, (4) Advanced Global Atmospheric Gases Experiment (AGAGE) method (hereafter, AGAGE method), (5) Kaufman et al. (2001) method (hereafter, Kaufman method), and (6) Airmass sec- tor analysis. The background concentration of BC mass concentrations is estimated to be about 400~900 ng m −3 , but each method shows a large difference. The estimated background concen- tration, in general, is arranged in the order of: mean > IMPROVE method > median > Kaufman method > concentration-frequency distribution analysis method > AGAGE method. The back- ground concentration estimated by the airmass sector analysis is found to be about 550 ng m −3 which is lower than those estimated by other methods. When we apply the same analytical period (i.e., 4-day and 6-day) to both AGAGE and Kaufman methods, the estimated back- ground concentrations are quite similar. However, further researches on the development of sta- tistical method for estimating background concentration for various gas-phase and particulate pollutants under different environment are needed. |