Seasonal variation of aliphatic amines in marine sub-micrometer particles at the Cape Verde islands

Abstract

Abstract. Monomethylamine (MA), dimethylamine (DMA) and diethylamine (DEA) were detected at non-negligible concentrations in sub-micrometer particles at the Cap Verde Atmospheric Observatory (CVAO) located on the island of São Vicente in Cape Verde during algal blooms in 2007. The concentrations of these amines in five stage impactor samples ranged from 0 to 30 pg m−3 for MA, 130 to 360 pg m−3 for DMA and 5 to 110 pg m−3 for DEA during the spring bloom in May 2007 and 2 to 520 pg m−3 for MA, 100 to 1400 pg m−3 for DMA, 90 to 760 pg m−3 for DEA during an unexpected winter algal bloom in December 2007. Anomalously high Saharan dust deposition and intensive ocean layer deepening were found at the Atmospheric Observatory and the associated Ocean Observatory during algal bloom periods. The highest amine concentrations in fine particles (impactor stage 2, 0.14–0.42 μm) indicates that amines are likely taken up from the gas phase into the acidic sub-micrometer particles. The contribution of amines to the organic carbon (OC) content ranged from 0.2 to 2.5%C in the winter months, indicating the importance of this class of compounds to the carbon cycle in the marine environment. Furthermore, aliphatic amines originating from marine biological sources likely contribute significantly to the organic nitrogen in the marine atmosphere. The average contribution of the amines to the total detected nitrogen content in submicron particles can be non-negligible, especially in the winter months (0.1% N to 1.5% N in the sum of nitrate, ammonium and amines). This indicates that these smaller aliphatic amines can be important for the carbon and the nitrogen cycles in the remote marine environment.

Large Increases in Primary Trimethylaminium and Secondary Dimethylaminium in Atmospheric Particles Associated With Cyclonic Eddies in the Northwest Pacific Ocean

“…Higher concentrations of aminium salts in marine atmospheric particles cooccur with higher concentrations of chlorophyll‐ a in coastal waters and the open ocean (Facchini et al, ; Gibb, Mantoura, Liss, & Barlow, ; Hu et al, ; Müller et al, ). Using chlorophyll‐ a as a proxy, Myriokefalitakis et al () estimated that approximately 0.8 Tg of amines are ejected into the atmosphere from the oceans every year.…”

“…Many studies have demonstrated that marine aminium aerosol particles are derived from secondary processes and are mainly formed by gas‐particle conversion (Facchini et al, ; Gibb, Mantoura, & Liss, ; Hu et al, ; Köllner et al, ; Müller et al, ; Myriokefalitakis et al, ; Yu et al, ); that is, they are unlikely to be produced by bubble bursting (Facchini et al, ). In contrast, some studies hypothesized that the aminium salts detected in marine particles are emitted from surface waters to the atmosphere by bubble bursting (Gorzelska & Galloway, ; Milne & Zika, ; Mopper & Zika, ).…”

Heterogeneous uptake of ammonia and dimethylamine into sulfuric and oxalic acid particles

“…We performed additional experiments with H2C2O4 to further elucidate the influence of phase state on the co-uptake process. H2C2O4 is a model organic acid frequently detected in ambient aerosols (Kawamura and Ikushima, 1993;Decesari et al, 15 2000;Yao et al, 2003;Yu et al, 2005;Müller et al, 2009) . Efflorescence of aqueous supermicron H2C2O4 particles occurs at 51.8%-56.7% RH, forming anhydrous solids .…”

“…The results also reveal the influence of the extent of neutralization and the change in phase state on the uptake behavior of both gases. DMA was chosen as the model R3N due to its atmospheric abundance (Müller et al, 2009;Rehbein et al, 2011;Hu et al, 2015;10 Youn et al, 2015) and unique characteristics, such as forming a non-crystallizing DMAS droplet even at low RH (Chan and Chan, 2013) and its higher hygroscopicity than that of (NH4)2SO4.…”

“…the time of phase change was as low as 0.05 (Table 2, tpc), hence even if the concentration of DMA species was low compared to the amount of NH3 species present in the particle. Since R3NH/NH4 ratios in ambient samples near emission sites can be up to 0.23 (Sorooshian et al 2008), and with DMAH + as the most frequently detected aminium ion in aerosols (Müller et al, 2009;Rehbein et al, 2011;Hu et al, 2015;Youn et al, 2015) DMAH/NH4 ratios in aerosols can possibly reach ≥ 0.05 and thus could change the crystallization behavior of NH4-H-SO4-salts in atmospheric particles. 5…”