4. Results of aerosol observation by using airplane over the Goto Islands

Hitoshi MUKAI (National Institute for Environmental Studies)

Vertical distribution of aerosol composition was observed by using a tape-type high volume aerosol sampler equipped on airplane.

A tape filter was made of Tefron filter (AF07P, Sumitomo Elec. Co., Japan).The sampling area of the filter was 11 cm in diameter.Sampling was done for 15-30 min at each altitude with a flow rate of 150 l/min.

The sampled filter was cut in half and one piece was put into PP test tube with 6ml deionized water.Extraction was done by both ultrasonic cleaner (over 15 min) and a shaker (over 30 min).The extract solution was analyzed by ion chromatography (Model Quick, Dionex Co.)


Observation results in January ('97) , December ('97) and February ('99) were summarized in Tables 1-3 and Figures 1-8.

  1. Jan 1997 (Table 1, Fig. 1,2)
  2. We observed very high concentration of NSS-sulfate (over 10 ug/m3) on Jan 11 even at high altitude, suggesting that polluted air mass came over the Goto islands.We also detected relatively high concentrations in sea salt components at high altitude.It may be due to contamination from clouds.On Jan 13, sulfate concentration became low.

  3. December 1997 (Table 2, Fig. 3-5)
  4. On December 9, nitrate concentration was relatively high compared to NSS-sulfate.Some contamination by cloud or a sampler was admitted in first sample on this day.

    On December 11, only Nitrate and sulfate concentration were slightly high.

    On December 13, concentrations of aerosol components were low.

  5. February 1999 (Table 3, Fig. 6-8)

On Feb 2, high concentration of sulfate and nitrate were observed at both low and high altitude.

On Feb 4, sea salts component and K were high in low altitude.

On Feb 6, sulfate, nitrate and Ca had high concentrations in mixing layer.