We studied the suspended particulate matter (SPM) collected in Akita Prefecture, Japan from April 2008 to January 2009 for inorganic ion composition and nitrogen isotopic ratio (δ15N) of NH4+ and NO3-. The results showed an average SPM concentration of 15.6μgm-3. The seasonal trend for SPM was higher values in the spring, lower in the winter. The major cations were Na+, NH4+, Ca2+ and major anions were SO42-, NO3-, Cl-. The annual correlation coefficient of ions indicates a very high value with NH4+ and SO42- (R=0.93), NO3- and K+ (R=0.65), NO3- and Ca2+ (R=0.62). The high springtime values are the apparent result of the dust stream from Asia. Average δ15N-NH4+ and δ15N-NO3- were 16.1‰ and -0.69‰, respectively. δ15N-NH4+ increased slightly in summer, and δ15N-NO3- increased considerably in winter. The trends indicated conversely. The heavy δ15N-NH4+ in summer appears to be from agricultural sources such as animal waste and fertilizer. In addition, according to the difference in isotopes of NOx sources as the precursor of NO3-, the dominant origin of heavy δ15N-NO3- in winter could be NOx emitted from fossil fuel combustion at low temperature. Moreover, the average δ15N-NO3- seemed to be made to baseline (approximately 0%) by vehicle emissions at high temperature. These results are considered to be very reasonable. © 2011 Elsevier Ltd.
CITATION STYLE
Kawashima, H., & Kurahashi, T. (2011). Inorganic ion and nitrogen isotopic compositions of atmospheric aerosols at Yurihonjo, Japan: Implications for nitrogen sources. Atmospheric Environment, 45(35), 6309–6316. https://doi.org/10.1016/j.atmosenv.2011.08.057
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