Concentration, size distribution and dry deposition of amines in atmospheric particles of urban Guangzhou, China

Size-segregated PM10 samples were collected in Guangzhou, China during autumn of 2014. Nine amines, including seven aliphatic amines and two heterocyclic amines, were detected using a gas chromatography-mass spectrometer after derivatization by benzenesulfonyl chloride. The total concentration of the nine amines (amines) was 79.6-140.9 ng m(-3) in PM10. The most abundant species was methylamine (MA), which had a concentration of 29.2-70.1 ng m(-3). MA, dimethylamine (DMA), diethylamine (DEA) and dibutylamine (DBA) were the predominant amines in the samples and accounted for approximately 80% of amines in each size segment. Two heterocyclic amines, pyrrolidine (PYR) and morpholine (MOR), were detected in all samples and had average concentrations of 1.14 +/- 0.37 and 1.89 +/- 0.64 ng m(-3), respectively, in particles with aerodynamic diameters < 3 mu m. More than 80% of Eamines were found in particles with diameters < 1.5 mu m, indicating that amines are mainly enriched in fine particles. All amines exhibited a bimodal distribution with a fine mode at 0.49-1.5 pm and a coarse mode at 7.2-10 mu m. The maximum contributions of amines to particles (0.21%) and amines-N to water-soluble organic nitrogen (WSON) (3.1%) were found at the sizes < 0.49 mu m. The maximum contribution of amines-C to water-soluble organic carbon (WSOC) was 1.6% over the size range of 0.95-1.5 mu m. The molar ratio of amines to ammonium ranged from 0.0068 to 0.0107 in particles with diameters < 1.5 mu m, and the maximum ratio occurred in the smallest particles (diameter < 0.49 mu m). The average dry deposition flux and velocity of Eamines in PM10 were 7.9 1.6 mu g m(-2) d(-1) and 0.084 +/- 0.0021 cm s(-1), respectively. The results of this study provide essential information on the contribution of amines to secondary organic aerosols and dry removal mechanisms in urban areas