Measurements of peroxyacetyl nitrate (PAN) and NO2 at the South Pacific Ocean

Abstract:

We measured peroxyacetyl nitrate (PAN) and NO₂ in remote marine boundary area during the SHIPPO (Shipborne Pole to Pole Observation). The measurements were made on the R/V Araon from Christ church, New Zealand to Gwangyang, South Korea along the western Pacific Ocean from March 30th to April 25th, 2014. Both PAN and NO₂ were analyzed every 2 minute by a fast chromatograph with luminol-based chemiluminescence detection. In order to improve their detection limits, random noise from PMT has been successfully reduced by ensembled chromatograms with every 30 samples. Additionally, we replaced Nylon membrane surface with reflective aluminum surface and applied the new Luminol solution, which enhanced the signals significantly with detection limits of 6 pptv and 40 ppbv for PAN and NO₂, respectively.

Average concentrations of PAN and NO₂ were 8 pptv for PAN and 80 pptv for NO₂ during the experiment. The back trajectory analysis showed that the directly influenced air masses from anthropogenic activities were rare except the latitudes higher than 20°N. Relatively good correlations between PAN and NO₂ were consistently observed, while PAN and O₃ were not clearly correlated except in the air masses recently originated from land masses.