Atmospheric nitrogen input into the North Sea: organic nutrient detection

The levels of gaseous organic nitrogen compounds (alkyl nitrates - ANs) together with identification of the possible sources of these compounds in the air were studied. Seasonal trends were investigated by conducting the sampling campaigns during the spring, summer and winter time. The air-mass backward trajectories (BWTs) were calculated for the sampling periods by Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model (Draxler and Rolph, 2003). These BWTs were considered for the determination of the influence of the Atlantic Ocean, the North Sea and the continent as possible sources of ANs. An adapted set-up for low and high volume samplings, extraction and minimized clean-up, identification and quantification capabilities resulting from the complementary use of GC-ECD and GC-MS methods is reported. The AN levels were found to be in the range of a few to 7400 pg.m-3 in the air. The AN fraction consisted of primarily the 2C4, C5 and C6 isomers, which contribute largely to the total AN level. The N-fluxes by ANs were more pronounced for the summer periods than for the winter/spring months, organic nitrates were the most abundant in the Atlantic/Channel/UK air-masses

Low-pressure gas chromatography ion trap mass spectrometry for the fast determination of polycyclic aromatic hydrocarbons in air samples

Peer reviewe

Fast chromatographic determination of polycyclic aromatic hydrocarbons in aerosol samples from sugar cane burning

Peer reviewe

Atmospheric nitrogen fluxes at the Belgian coast: 2004-2006

Daily and seasonal variations in dry and wet atmospheric nitrogen fluxes have been studied during four campaigns between 2004 and 2006 at a coastal site of the Southern North Sea at De Haan (Belgium) located at coordinates of 51.1723° N and 3.0369°; E. Concentrations of inorganic N-compounds were determined in the gaseous phase, size-segregated aerosol (coarse, medium, and fine), and rainwater samples. Dissolved organic nitrogen (DON) was quantified in rainwater. The daily variations in N-fluxes of compounds were evaluated with air-mass backward trajectories, classified into the main air-masses arriving at the sampling site (i.e., continental, North Sea, and Atlantic/UK/Channel).The three, non-episodic campaigns showed broadly consistent fluxes, but during the late summer campaign exceptionally high episodic N-deposition was observed. The average dry and wet fluxes for non-episodic campaigns amounted to 2.6 and4.0mg N m-2 d-1, respectively, whereas during the episodic late summer period these fluxes were as high as 5.2 and 6.2mg N m-2 d-1, respectively. Non-episodic seasons/campaigns experienced average aerosol fluxes of 0.9-1.4 mg N m d-1. Generally, the contribution of aerosol NH4+ was more significant in the medium and fine particulate fractions than that of aerosol NO3-, whereas the latter contributed more in the coarse fraction, especially in continental air-masses. During the dry mid-summer campaign, the DON contributed considerably (~15%) to the total N-budget.Exceptionally high episodic aerosol-N inputs have been observed for the late summer campaign, with especially high deposition rates of 3.6 and 2.9 mg N m-2 d-1 for Atlantic/UK/Channel and North Sea-continental (mixed) air-masses, respectively. During this pollution episode, the flux of NH4+ was dominating in each aerosol fraction/air-mass, except for coarse continental aerosols. High deposition of gaseous-N was also observed in this campaign with an average total N-flux of 2-2.5-times higher than in other campaigns

Atmospheric nitrogen input into the North Sea: inorganic and organic nutrient fluxes. Final report EV/39

The North Sea is threatened by eutrophication. Excess supply of nutrients, especially nitrogen compounds, causes proliferation of algae, leading to pernicious oxygen depletion. The nitrogen supply is not only due to rivers, but to the atmosphere as well. Especially in summer, when nutrients are scarce and the river supply is reduced, the atmospheric contribution can become predominant. The relevant atmospheric nitrogen is emitted as nitrogen oxides (by traffic and industry) and as ammonia (by agriculture). Organic nitrogen compounds might be important but their deposition fluxes are unknown.Measurements of the concentrations of the various inorganic and organic nitrogen components and of their deposition, with rain and in the dry phase, will allow evaluating the contribution of the atmosphere to eutrophication processes, using adequate mathematical models