[1] This study reports the first high and low molecular weight measurements of dissolved organic nitrogen (DON) in size-fractionated atmospheric particles. The variations in concentration of nitrogen species corresponded to varying sources and weather conditions. The results indicate that continental, local, and marine origins are the key factors controlling the particle size distribution of inorganic and organic nitrogen species. For dissolved inorganic nitrogen and DON, relatively high concentrations and fine-mode particle (particle diameter <1 mm) enrichment were significantly affected by continental and locally derived sources, which were mainly attributable to anthropogenic activities. However, the coarse/fine ratios indicate that DON was derived from a coarse particle (particle diameter >1 mm) source that may be sea salt particles. To investigate the possible sources of DON, an ultrafiltration method was used to separate DON into high (HMW) and low (LMW) molecular weight categories. The results indicate that HMW-DON and LMW-DON contributed 57 ± 9% and 43 ± 9%, respectively, to the total DON concentration. Correlations and positive matrix factorization analysis of HMW-DON and LMW-DON levels with major and non-sea-salt ions indicated that HMW-DON and LMW-DON in coarse particles may be generated from continental soil dust and sea spray, respectively, whereas, in fine particles, DON may originate from aerosols derived from combustion processes. The annual fluxes of HMW-DON and LMW-DON were estimated to be 11.0 and 11.3 mmol m −2 yr −1 , respectively. Consequently, the inputs of HMW-DON and LMW-DON appear to make equal contributions to DON in aerosols over the studied coastal area.

[1] We analyzed 156 aerosol samples, including 10 dust storm samples, collected from January to December 2005 at a coastal site on the southern East China Sea at Keelung city, Taiwan, for water-soluble major ions, nitrogen, and phosphorus species. In addition, 4-d back trajectories of air masses arriving daily at the sampling site were calculated to determine the potential aerosol source regions. The obtained concentrations of major ions indicate that a continental source was dominant from January to May and from November to December, a local source during July, and an oceanic source from September to October. The measured atmospheric concentrations of nitrogen and phosphorus species show clear seasonal variations and correspond to the different sources and weather conditions. During the dust storm period, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) concentrations showed statistically significant linear relationships with the amount of aerosol particles, suggesting a continental source. The results of a factor analysis of combined major ions and DIN and DIP indicate that crustal sources, marine sources, and combustion sources are the three major controlling factors during the non-dust-storm period. Natural and anthropogenic land sources and marine sources are the most influential factors in terms of the distribution of aerosol during the dust storm period. A strong correlation was also found between DIN and DIP, indicating similar sources and transportation mechanisms. The results of flux calculations indicate that aerosols derived from dust storms and biomass burning provide 12 ± 8% and 46 ± 36% of total DIN and 16 ± 10% and 46 ± 38% of total DIP, respectively. Consequently, the inputs of aerosol derived from biomass burning may be an important source of nitrogen and phosphorus in aerosols over the East China Sea.

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Azaarenes belong to the newly identified classes of anthropogenic pollutants. To our knowledge, this study presents the first result of pollution history of azaarenes and their controlling factors in estuary. To understand the transport mechanisms, surface sediment samples were collected from 18 sites of the Danshuei River during the summer and the winter of 2005. The highest concentrations of azaarene, 21.9 ng g 21 for 2-ring, 9.89 ng g 21 for 3-ring, and 9.17 ng g 21 for 4-ring, were observed in midstream surface sediments near the Shi-Zi-Tou waste water pumping station. Therefore, this waste water pumping station not only provides a good sediment accumulation environment but also discharges small particle size sediments, which contain mass amounts of azaarenes into the Danshuei River. This research also finds highly significant covariations among 3-ring and 4-ring azaarenes, which suggests similar source strengths and transport mechanisms for these compounds. Additionally, core samples were collected from two sites of the Danshuei River and analyzed to determine the pollution history. Values found in the core sediments correspond to pollution events in recent history. Contaminant inputs via in situ burning of dumping field and wastewater discharge for the periods of 1975-1985 and 2004-2005

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