The study of mole ratio variation of nitrogen to phosphorus among different atmospheric particle-size in the coastal area of the northern Taiwan

• Main Authors: Chia-Chun, Liu, 劉珈均
• Other Authors: Hung-Yu, Chen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/68732522236968012125

碩士 === 國立臺灣海洋大學 === 海洋環境資訊學系 === 101 === This study analyzed 98 aerosol samples collected from January 2008 to April 2010 at a coastal site at Keelung city, Northern Taiwan, for water-soluble nitrogen species (WSIN) and dissolved inorganic phosphorus (DIP). The atmospheric particles were fractionated into seven stages ( <0.4μm、0.4~0.67μm、0.67~1.28μm、1.28~1.97μm、1.97~3.9μm、3.9~9.3μm、>9.3μm). In this study, we defined the particle size greater and smaller than 1.97μm as coarse and fine mode, respectively. In addition, 3-day back trajectories of air masses arriving daily at the sampling site were calculated to determine the potential aerosol source regions. The result indicates that mass concentration, nitrogen and phosphorus species concentration is mainly affected by the air masses source and the seasonal wind shifts in the study area. The concentration of mass concentration during winter, spring and autumn time is higher than summer when the air mass is mainly land-derived; while it is the lowest during summer when the air mass is mainly sea-borne and S.E region. The results of size distribution show that ammonium and phosphorus were enriched in fine mode particle with any seasonal variation. Nitrate was enriched in coarse mode particle and varied with different origin source. The results show that concentrations in fine mode particle of ammonium and nitrate were respectively 80.33 nmol m-3 and 14.08 nmol m-3; concentrations in coarse mode particle of ammonium and nitrate were respectively 5.00 nmol m-3 and 30.31 nmol m-3. Strong relationships were found between WSIN and DIP, but N/P values varied with different sources. The N/P ratio in atmospheric particles during winter and autumn is higher than summer and spring. The average N/P ratio of the year was 166.44. In this region, phosphorus is limiting factor for organism. .The deposition fluxes calculated of ammonium, nitrate, WSIN and phosphate were respectively 5.48 mmol m-2 yr-1, 19.38 mmol m-2 yr-1, WSIN 25.32 mmol m-2 yr-1 and 0.33 mmol m-2 yr-1. According to the above result, the deposition of the N/P ratio was 76.72.