Organic Nitrogen of Atmospheric Aerosols in the Coastal Area of Seto Inland Sea

ABSTRACT Chemical compositions and particle number densities of atmospheric aerosols were measured in the coastal area of Seto Inland Sea during the spring of 2015. The mean concentrations of NH4+, NO3–, and water-soluble organic nitrogen (ONws) in the total (fine and coarse) particles were 1.6, 0.85, and 0.28 µg N m–3, respectively. Although NO3– existed in fine and coarse particles, while NH4+ and ONws existed primarily in fine particles. The contribution of ONws to the total nitrogen was approximately 10%, however, these fractions are comparable to the contribution of fine NO3– and coarse NH4+. The dry deposition fluxes of particulate NH4, NO3–, and ONws were 280, 660 and 83 µg N m–2 day–1, respectively. The dry deposition flux of NO3– was more effective than any other nitrogen compounds, since the deposition rate depends upon the size distribution. The dry deposition flux of ONws was approximately 8.1% of nitrogen compounds, however, it is found that ONws should be considered in evaluating the effects of nitrogen compounds on marine ecosystems.