理乐志

chihchao's blog

0%

文献阅读笔记：Liu-2017-AE

发表于 分类于

大气颗粒物（PM10）中有机胺的浓度、粒径分布和干沉降。

Information for the paper

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

Author: Liu, Fengxian

Year: 2017

Journal: Atmospheric Environment

URL: https://doi.org/10.1016/j.atmosenv.2017.10.016

The characteristics of amines associated with fine and coarse particles

  1. Approximately 94% of amines were found in the fine particles.
  2. MA, DMA and DBA were the dominant amines, which in total contributed approximately 85% and 78% to Ʃamines in fine and coarse particles, respectively.
  3. It is interesting to note that the concentration of MA was higher than other alkylamines in most areas.

Mass size distribution of amines

  1. For nine individual amines, more than 80% of amines were enriched in the first three segments (< 1.5 μm)
  2. The aerosol water content H2O was estimated from E-AIM (http://www.aim.env.uea.ac.uk/aim/aim.php). The estimation showed that 62% of H2O occurred in fine particles, with an average value of 238.4 nmol m−3, suggesting that direct dissolution may also play a role in the partitioning of amines into fine particles.
  3. nine individual amines and Ʃamines exhibited a bimodal distribution with a fine mode at 0.49–1.5 μm and a coarse mode at 7.2–10 μm.
  4. As shown in Fig. 3, nine individual amines and Ʃamines exhibited a bimodal distribution with a fine mode at 0.49–1.5 μm and a coarse mode at 7.2–10 μm. The results are consistent with previous reports that the maximum amount of amines occurs in the accumulation mode (0.1–2 μm). The minor peak in the coarse mode particles is likely from sea salts and crustal aerosols, suggesting that heterogeneous reactions with coarse particles, such as soil dust and sea-salt, are not insignificant sources of amines in Guangzhou.

The contribution of amines to WSOC and WSON

WSON: nitrogen derived from amines, amino acid, urea and other water-soluble nitrogen-containing organic compounds WSIN: nitrogen derived from ammonium, nitrate and nitrite

  1. More than 90% of WSOC occurred in fine particles.
  2. Based on the results, 66.0% of WSON occurred in fine particles.
  3. WSON accounted for 27.1% of the WSTN in fine particles
  4. The mean contributions of WSON to fine particles and coarse particles were approximately 3.0% and 5.4%, respectively.
  5. The ratios of amines to the PM mass, amines-C to WSOC and amines-N to WSON were 0.19%, 1.39% and 2.36% for fine particles and 0.05%, 1.19% and 0.23% for coarse particles, respectively.
  6. Amines-N accounted for less than 4% of WSON in each size segment, suggesting that other water-soluble nitrogenous organic compounds, such as organic nitrates (Day et al., 2010), amino acids (Barbaro et al., 2011; Mandalakis et al., 2011), urea (Mace et al., 2003a; Ho et al., 2016) and other unidentified ON, may constitute a large proportion of WSON.
  7. Due to thermodynamics processes, amines may be able to successfully out-compete NH3 in smaller sizes particles (e.g., clusters approximately 10 nm), and due to their higher relative ambient concentrations, NH3 may out-compete amines in larger size particles. (VandenBoer et al., 2011).

延伸阅读

  1. Ho, K.F., Ho, S.S.H., Huang, R.J., Chuang, H.C., Cao, J.J., Han, Y., Lui, K.H., Ning, Z., Chuang, K.J., Cheng, T.J., Lee, S.C., Hu, D., Wang, B., Zhang, R., 2016. Chemical composition and bioreactivity of PM2.5 during 2013 haze events in China. Atmos. Environ. 126, 162–170.
  2. Tao, Y., Ye, X.N., Jiang, S.Q., Yang, X., Chen, J.M., Xie, Y.Y., Wang, R.Y., 2016. Effects of amines on particle growth observed in new particle formation events. J. Geophys. Res. 121, 324–335.

What this article inspired me

  1. 细颗粒物中甲胺(MA)、二甲胺 (DMA)和二丁胺 (DBA) 约占 80% 的总胺。而且，在现有的离线研究中，甲胺都是浓度最多的一种胺。
  2. 胺类颗粒物呈双峰分布，细粒子模态 0.49–1.5 μm 和粗粒子模态 7.2–10 μm。80%的胺（包括二乙胺）都分布在1.5 μm 以下。粗粒子模态的颗粒物可能来自扬尘和海盐，通过多相化学反应与胺结合。