Behavior of Airborne Particulate Secondary Pollutants in the Central Mountainous Area, Japan

• Published in: Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi Vol. 33; no. 5; pp. 284 - 296
• Main Authors: SATSUMABAYASHI, Hikaru, SASAKI, Kazutoshi, KATSUNO, Takao, SHIKANO, Masaaki, OHTA, Muneyasu, KURITA, Hidemi, MURANO, Kentaro, HATAKEYAMA, Shiro, KARASUDANI, Takashi, UEDA, Hiromasa
• Format: Journal Article
• Language: English
• Published: Japan Society for Atmospheric Environment 10.09.1998
• Subjects: aerosol; long-rang transport; mountainous area; photochemical reaction; sulfate
• ISSN: 1341-4178; 2185-4335
• DOI: 10.11298/taiki1995.33.5_284

The behavior of the chemical components of suspended particulate mater (SPM) in a mountainous area were investigated. A special attention was paid on the seaconal and diurnal variations of the secondary particulate. The sampling site was Happo at an altitude of 1850m, in the centratl mountainous region of Japan. Sulfate was the most abundant particulate and accounted for 20% of the SPM, followed by organic carbon (OC) (8%), NH4+ (5%) and elemental carbon (EC) (4%). The concentrations of SO42-were much higher from April to July than those from October to March, and these variations were similar to those of ozone, suggesting that almost all of the SO42-was produced by the photo-oxidation of SO2 and transported long distances. The ion balance between cations (NH4+, Na+, Mg2+ and Ca2+) and anions (SO42-, NO3-and Cl-) tended toward anion excess, and equivalent concentrations of SO42- were much higher than those of NH4+ These results suggest that a portion of the SO42-existed in the form of acidic aerosols such as HZSO4 and NH4HSO4. Backward trajectory analysis suggected that the air pollutants in this mountainous area were transported not only from other regions of Japan, but also from continental Asia. Seasonal variations of T-NO3 (total nitrate in gaseous and particulate matter), OC and oxalic acid concentrations were similar to those of ozone and SO42-and the correlation coefficients with SO42-were positive.These findings suggest that those components were produced by photochemical reactions. The secondary components, NH4+, SO42-, NO3-and a part of the OC, accounted for more than 23% of the SPM from April to August.