Effects of amines on formation of sub‐3 nm particles and their subsequent growth

Abstract

[1] Field observations and quantum chemical calculations suggest that amines can be important for formation of nanometer size particles. Amines and ammonia often have common atmospheric emission sources and the similar chemical and physical properties. While the effects of ammonia on aerosol nucleation have been previously investigated, laboratory studies of homogeneous nucleation involving amines are lacking. We have made kinetics studies of multicomponent nucleation (MCN) with sulfuric acid, water, ammonia and amines under conditions relevant to the atmosphere. Low concentrations of aerosol precursors were measured with chemical ionization mass spectrometers (CIMS) to provide constrained precursor concentrations needed for nucleation. Particle sizes larger than $2 nm were measured with a nanodifferential mobility analyzer (nano-DMA), and number concentrations of particles larger than $1 nm were measured with a particle size magnifier (PSM). Our observations provide the laboratory evidence that amines indeed can participate in aerosol nucleation and growth at the molecular cluster level. The enhancement of particle number concentrations due to several atmospherically relevant amine compounds and ammonia were related to the basicity of these compounds, indicating that acid-base reactions may contribute to the formation of sub-3 nm particles. Citation: Yu, H., R. McGraw, and S.-H. Lee (2012), Effects of amines on formation of sub-3 nm particles and their subsequent growth, Geophys.

New particle formation and growth from methanesulfonic acid, trimethylamine and water

“…Water vapor has also been reported to play a role in particle formation from H 2 SO 4 and amines. 22,26,27,66,67 The reaction order of 2 with respect to H 2 O does not imply an elementary reaction involving two water molecules nor the number of water molecules in a critical cluster, but rather the involvement of water in the rate-determining step(s). 68 The second order dependence is captured by the individual steps in the kinetics model as discussed below, and is attributed to the involvement of water in forming the reactive MSA hydrates and/or in subsequent rate-determining step(s).…”

“…33,40,41 Results from quantum chemical calculations show that amines are much more strongly bound to H 2 SO 4 than NH 3 , 25 and laboratory experiments have demonstrated higher efficiencies of amines in particle formation compared to NH 3 . 22,[26][27][28] In addition, amines have been shown to displace NH 3 in sulfate particles and clusters. [42][43][44][45] Based on these results, small particles are more likely to be aminium salts even if ammonium salts are initially formed.…”

Ozonolysis of Trimethylamine Exchanged with Typical Ammonium Salts in the Particle Phase

“…2,7−9 It has been suggested that amines may contribute up to 10−20% of the organic content of ambient particles, and frequently over one hundred different amine species containing 1−4 N atoms and ranging in MW from 59−302 Da have been observed in the particle phase. 2,10 Amines play an important role in new particle formation (NPF) for the H 2 SO 4 −H 2 O-amines ternary system and their subsequent growth, 11 in particular, in areas of where anthropogenic emission of amines are strong. For example, aliphatic amines contributed 23% to the NPF events at a remote forested site in Hyytiala, Finland in March, 2006 and 47% to that at an urban site in Tecamac, Mexico in April, 2007.…”

Ideas and perspectives: on the emission of amines from terrestrial vegetation in the context of new atmospheric particle formation

“…The importance of amines for NPF has recently been established by field (Angelino et al, 2001;Makela et al, 2001;Smith et al, 2010;Zhao et al, 2011) and laboratory experiments (Murphy et al, 2007;Berndt et al, 2010;Erupe et al, 2011;Bzdek et al, 2010;Zhao et al, 2011;Yu et al, 2012;Zollner et al, 2012;Almeida et al, 2013;Jen et al, 2014;Kurten et al, 2014), as well as from modelling studies (Kurten et al, 2008;Barsanti et al, 2009;Bzdek et al, 2010;Ortega et al, 2012;Loukonen et al, 2010;Nadykto et al, 2011;Paasonen et al, 2012;Almeida et al, 2013;DePalma et al, 2014). On a molecular level, Kurten et al (2014) observed how DMA stabilises SA, increasing the stable cluster concentration by up to 6 orders of magnitude.…”