[Contribution of water soluble organic nitrogen to total nitrogen in atmospheric aerosols in Qingdao].

Organic nitrogen (ON) is a quantitatively important component of reactive nitrogen in atmospheric aerosols. Deposition of ON in seawater from atmosphere could enhance primary productivity, as well as with the changes in the phytoplankton community composition. 64 total suspended particles (TSP) samples collected at Qingdao from January to December in 2008 were applied to analyze the concentrations of water soluble organic nitrogen in aerosols. Concentrations of ON in Qingdao aerosols ranged from 30 to 2073 nmol x m(-3) (100-12 157 micromol x g(-1)), with the highest values occurring in December, followed in March and April and the lowest values in June to September. ON mean concentration in TSP in 2008 was 430 nmol x m(-3) (2 323 micromol x g(-1)). The contribution of ON to total nitrogen (TN) was (37.5 +/- 21.6)%, with the maximum presenting in December and the minimum in September. The distribution of organic nitrogen in aerosols was significantly affected by the weather conditions. During haze and fog episodes, the concentrations of ON in the aerosols were 789 nmol x m(-3) and 412 nmol x m(-3), respectively, 4 times and twice higher than that during clear episodes. However, the particle mass concentrations in haze and fog days were comparable with that in clear days. During dust episodes, the concentration of particles was 5 times higher than that during clear episodes while ON concentration slightly enhanced 0.4 times. The ON concentration in aerosols after raining was 57 nmol x m(-3), decreased 80% than that before raining due to the efficient wet scavenging.

[Distribution of atmospheric particulate inorganic nitrogen in different weather conditions in the heating period in Qingdao].

The atmospheric aerosol samples were collected before and in the heating period during October 2007-April 2008 in Qingdao coastal region, and inorganic nitrogen components were analyzed using IC (Ion Chromatography). The results showed that the concentration of aerosol particles and particulate inorganic nitrogen components (NH4+, NO3-) were increased from 137.41 microg/m3, 2.48 microg/m3, 6.95 microg/m3 before to 250.34 microg/m3, 4.43 microg/m3, 10.28 microg/m3 in the heating period respectively. The concentrations of TSP (total suspended particles) and inorganic nitrogen in Qingdao were influenced by different weather conditions. The average concentration of TSP was 181.34 microg/m3 in sunny days during heating period, increased by 32.0% than before. But the nitrate and ammonium showed a value of 5.56 and 1.86 microg/m3 in sunny days, lower than that before heating, which mainly came from secondary aerosols. The average concentrations of TSP, nitrate and ammonium increased were 1-2 times higher in foggy days in heating period due to lower temperature, high humidity and accumulation of pollutants. The concentrations of TSP, nitrate and ammonium decreased in strong winds and temperature drop weather. The size distribution of aerosol particles and inorganic nitrogen, were influenced clearly by heating soot and ash. The size distribution of nitrate showed double peaks with a higher peak in accumulation mode (0.43-0.65 microm) and a lower one in coarse mode (3.3-4.7 microm) before heating, and the peak in the 'accumulation mode' shifted to 0.65-1.1 microm during heating period. NH4(+) -N, a major inorganic nitrogen component in the particulate matter, showed single peak in the "accumulation mode".

[Distributions of dissolved and particulate amino compounds in atmospheric aerosols at Qingdao].

Amino compounds is one class of organic nitrogen compounds that has been measured extensively in aerosols and rainwater. These compounds in atmospheric deposition might have a potential role in marine ecosystem since it can be directly utilizable sources of nitrogen for microorganisms and plants. 66 total suspended particles samples were collected at Qingdao from January to December in 2008. Concentrations of dissolved amino compounds (DAC) and particulate amino compounds (PAC) were analyzed using precolumn fluorescence derivatization with o-phthaldialdehyde and N-isobutyryl-L-cysteine, combined with reverse-phase high performance liquid chromatography. Concentrations of DAC in Qingdao aerosols ranged from 2.4 to 40.9 nmol x m(-3), with highest values occurring in spring, followed in summer and lowest values in autumn and winter. PAC concentration were from 0.7 to 76.1 nmol x m(-3), presenting the seasonal trend of spring > winter > autumn > summer. Compositions of amino compounds in aerosols varied seasonally. By classifying air mass back trajectories during each sampling period, the aerosol samples in Qingdao were mainly influenced by northerly continental source, southerly continental source and marine source. Concentrations of DAC and PAC were found highest in the samples influenced by southerly continental source, followed by northerly continental source and lowest in the samples by marine source. Compositions of amino compounds were also influenced by the sources. Contributions of protein-type to total amino compounds were highest in the aerosols from marine source and lowest in the aerosols from southerly continental source.