Cloud condensation nuclei (CCN) activity of aliphatic amine secondary aerosol

Abstract

Abstract. Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g., hydroxyl radical and nitrate radical). The particle can contain both secondary organic aerosol (SOA) and inorganic salts. The ratio of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N 2 O 5 (source of nitrate radical, NO 3 ) contains less volatile compounds than the primary aliphatic amine (BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N 2 O 5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The humid BA + N 2 O 5 aerosol products were found to be very sensitive to the temperature at which the measurements were made within the streamwise continuous-flow thermal gradient CCN counter; κ ranges from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings. The variance of the measured aerosol κ values indicates that simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems' κ ranges within 0.2 < κ < 0.7. This work indicates that aerosols formed via nighttime reactions with amines are likely to produce hygroscopic and volatile aerosol, whereas photochemical reactions with OH produce secondary organic aerosol of lower CCN activity. The contributions of semivolatile secondary organic and inorganic material from aliphatic amines must be considered for accurate hygroscopicity and CCN predictions from aliphatic amine systems.

Size‐dependent hygroscopicity parameter (κ) and chemical composition of secondary organic cloud condensation nuclei

“…The evaporation of organics inside the CCN column, resulting in shrinking of aerosol particles at high temperature difference (higher SS), could also cause different κ at different supersaturations [ Asa‐Awuku et al ., ; Tang et al ., ]. However, this would cause a lower κ at higher supersaturation due to more efficient evaporation at higher temperature used at higher supersaturation, which is opposite to the finding in this study.…”

Characteristics and sources of aerosol aminiums over the eastern coast of China: insights from the integrated observations in a coastal city, adjacent island and surrounding marginal seas

“…Low molecular weight amines are commonly found in the atmosphere in both gas and particle phases (Ge et al, 2011a, b). Based on present theoretical calculations (Kurtén et al, 2008;Loukonen et al, 2010;Paasonen et al, 2012;Olenius et al, 2017), laboratory simulations (Wang et al, 2010a, b;Kurtén et al, 2014;Erupe et al, 2011;Almeida et al, 2013;Yu et al, 2012) and field observations (Smith et al, 2010;Kürten et al, 2016;Tao et al, 2016), amines in the atmosphere have been proved to play an important role in new particle formation and subsequent particle growth and thus affect both the number concentrations of aerosols and cloud condensation nuclei that are closely relevant to regional climate (Tang et al, 2014;Yao et al, 2018). For example, dimethylamine (DMA) was found to be a key species involved in new particle formation events in the urban area of Shanghai, and the nucleation mechanism was likely to be H 2 SO 4 -DMA-H 2 O ternary nucleation .…”

“…Zheng et al (2015) measured an average concentration 7.2 ppt of total amines in a suburban site of Nanjing during the summer of 2012, derived mainly from industrial emissions in adjacent areas. The aminiums in fine particles over Shanghai in the summer of 2013 were found to exhibit a high concentration (mean 86.4 ng m −3 ) and play an important role in the new particle formation events (Tao et al, 2016). Previous studies on aminiums over the marginal seas off the coast of China indicated that DMAH + and trimethylaminium (TMAH + ) were overwhelmingly from marine sources Yu et al, 2016;Xie et al, 2018).…”

“…Although the lifetime of gaseous amines in the atmosphere is only a few hours, it can be prolonged after amines partition into the particle phase, and thus they may be transported over a long range (Nielsen et al, 2012). Many studies have been done on the gas and/or particle phases of amines over eastern China and adjacent seas (Huang et al, 2012(Huang et al, , 2016Hu et al, 2015;Zheng et al, 2015;Tao et al, 2016;Yu et al, 2016;Shen et al, 2017;Xie et al, 2018;Yao et al, 2016Yao et al, , 2018. For example, C1 to C6 amines over Shanghai were measured during the summer of 2015, of which C1, C2 and C4 amines were the dominant species with average concentrations of 15.7, 40.0 and 15.4 ppt, respectively .…”

Effects of temperature on the formation of secondary organic aerosol from amine precursors

“…There have been a few previous atmospheric chamber studies investigating the oxidation of alkyl amines at room temperature (Malloy et al 2009a, Lee andWexler 2013;Price et al 2014;Tang et al 2014). These studies highlighted the presence and importance of salt formation, the formation of imines and carcinogenic nitramines, the formation of highly oxidized oligomers (trimethylamine experiments), and cloud condensation nuclei activity in secondary organic aerosol formation from alkyl amines.…”