Japan Geoscience Union Meeting 2014

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Oral

Symbol A (Atmospheric, Ocean, and Environmental Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS22_1PM2] Atmospheric Chemistry

Thu. May 1, 2014 4:15 PM - 6:00 PM 511 (5F)

Convener:*Nobuyuki Takegawa(Research Center for Advanced Science and Technology, University of Tokyo), Yousuke Sawa(Geochemical Research Department, Meteorological Research Institute), Yugo Kanaya(Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology), Kenshi Takahashi(Research Institute for Sustainable Humanosphere, Kyoto University), Hiroshi Tanimoto(National Institute for Environmental Studies), Chair:Nobuyuki Takegawa(Research Center for Advanced Science and Technology, University of Tokyo)

4:15 PM - 4:30 PM

[AAS22-P18_PG] Seasonal variations of peroxyacyl nitrates and alkyl nitrates concentration at Suzu, the Noto Peninsula

3-min talk in an oral session

*Ayana ISHIYAMA1, Ryo TAKAJI1, Yasuhiro SADANAGA1, Atsushi MATSUKI2, Keiichi SATO3, Kazuo OSADA4, Hiroshi BANDOW1 (1.Osaka Prefecture University, 2.Kanazawa University, 3.Asia Center for Air Pollution Research, 4.Nagoya University)

Keywords:peroxyacyl nitrates and alkyl nitrates, long-range transport, seasonal variation

NOx emissions have been increasing in East Asia with recent remarkable economic progress. NOx has relatively short lifetime and NOx concentrations are governed by local NOx emissions. On the other hand, descendant photochemical products of NOx such as T.NO3 (the sum of gaseous nitric acid and particulate nitrates), PANs (peroxyacyl nitrates) and ANs (alkyl nitrates) have longer lifetime than NOx, so that they can be transported over a long-distance. In order to understand influences of the cross-border pollution, it is important to clarify the long-range transport of T.NO3, PANs, and ANs. We have been continuously observing several pollutants at NOTOGRO (Noto Ground-based Research Observatory) supersite in Suzu, the Noto Peninsula. NOTOGRO is located at 37.45N and 137.36E. NOx were determined by an LED photolytic converter / NO-O3 chemiluminescence method. NOy and T.NO3 were observed by a scrubber difference / NO-O3 chemiluminescence method. CO was monitored by a non-dispersive infrared photometer. PANs and ANs were measured by a thermal dissociation / cavity attenuated phase shift spectroscopy method.In this presentation, observational results and discussion from December, 2012 to July, 2013 are described, focusing on seasonal variations of PANs and ANs. The air mass origins arriving at Suzu were classified into the following four groups, Russia and North China (RC), Korea and Middle China (KC) and Japan (JP) and Sea (S) using backward trajectory analyses. From winter to spring, both PANs and ANs concentrations from KC were higher than those from the other air mass origins. From spring to summer, their concentrations were independent of air mass origins.From winter to spring, the lifetimes of PANs and ANs are long because of low temperature and weak solar radiation. In addition, their in-situ photochemical generation rates are low, so that PANs and ANs concentrations in this season are governed by long-range transport. From spring to summer, the lifetimes of PANs and ANs become shorter and their photochemical production rates become higher, that is, local photochemical productions of PANs and ANs are relatively important. Diurnal variations of PANs and ANs also support these concentration variation factors. From winter to spring, no diurnal variations were observed. Meanwhile, PANs and ANs concentrations began to be higher and lower in the daytime and nighttime, respectively, from spring to summer.