Atmospheric amines and ammonia measured with a chemical ionization mass spectrometer (CIMS)

Abstract

Abstract. We report measurements of ambient amines and ammonia with a fast response chemical ionization mass spectrometer (CIMS) in a southeastern US forest and a moderately polluted midwestern site during the summer. At the forest site, mostly C3-amines (from pptv to tens of pptv) and ammonia (up to 2 ppbv) were detected, and they both showed temperature dependencies. Aerosol-phase amines measured thermal-desorption chemical ionization mass spectrometer (TDCIMS) showed a higher mass fraction in the evening with cooler temperatures and lower in the afternoon with warmer temperatures, a trend opposite to the gas-phase amines. Concentrations of aerosol-phase primary amines measured with Fourier transform infrared spectroscopy (FTIR) from micron and submicron particles were 2 orders of magnitude higher than the gas-phase amines. These results indicate that gas to particle conversion is one of the major processes that control the ambient amine concentrations at this forest site. Temperature dependencies of C3-amines and ammonia also imply reversible processes of evaporation of these nitrogen-containing compounds from soil surfaces in daytime and deposition to soil surfaces at nighttime. During the transported biomass burning plume events, various amines (C1–C6) appeared at the pptv level, indicating that biomass burning is a substantial source of amines in the southeastern US. At the moderately polluted Kent site, there were higher concentrations of C1- to C6-amines (pptv to tens of pptv) and ammonia (up to 6 ppbv). C1- to C3-amines and ammonia were well correlated with the ambient temperature. C4- to C6-amines showed frequent spikes during the nighttime, suggesting that they were emitted from local sources. These abundant amines and ammonia may in part explain the frequent new particle formation events reported from Kent. Higher amine concentrations measured at the polluted site than at the rural forested site highlight the importance of constraining anthropogenic emission sources of amines.

Inconsistency of ammonium–sulfate aerosol ratios with thermodynamic models in the eastern US: a possible role of organic aerosol

“…Nitrate at the ensemble of Southeast sites averages 0.25 ± 0.08 µg m −3 in summer 2013, representing less than 4 % of PM 2.5 mass. Aerosol amines are present in low concentrations in the Southeast (You et al, 2014) and concentrations of alkaline cations other than ammonium (e.g., Ca 2+ , Mg 2+ ) are also too low to significantly affect the charge balance, as previously shown by Kim et al (2015). Concentrations of these other alkaline cations are reported at the CSN sites, and we find for the ensemble of CSN sites in Fig.…”

“…Here and elsewhere, mean ratios are calculated as the ratios of the mean quantities. ammonia concentrations at Southeast sites (You et al, 2014;Guo et al, 2015;Saylor et al, 2015;Weber et al, 2016).…”

Constraining the sensitivity of iodide adduct chemical ionization mass spectrometry to multifunctional organic molecules using the collision limit and thermodynamic stability of iodide ion adducts

“…Determination of the identities of these organics, and their abundance in the atmosphere, has remained an analytical challenge because of the inherent complexity of the chemical system, which involves a multitude of precursors and significantly more oxidation products (Bertram et al, 2009;Goldstein and Galbally, 2007). Chemical ionization mass spectrometry (CIMS) has become increasingly utilized for the measurement of these types of compounds (Bertram et al, 2011;Brophy and Farmer, 2015;Fortner et al, 2004;Hearn and Smith, 2004;Holzinger et al, 2010;Huey et al, 1995;Jokinen et al, 2012;Jordan et al, 2009;Lee et al, 2014;Lopez-Hilfiker et al, 2014;Slusher, 2004;Veres et al, 2008Veres et al, , 2010Yatavelli et al, 2012;You et al, 2014;Yu and Lee, 2012). Typically, a specific reagent ion is generated using a radioactive ion source, X-rays, or corona discharge, and then mixed with ambient air for a fixed time.…”

New particle formation in the sulfuric acid–dimethylamine–water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

“…Despite the strong evidence that sulfuric acid-amine nucleation is very efficient, it has rarely been observed in the atmosphere. Only one study has so far reported sulfuric acid-amine nucleation (Zhao et al, 2011) despite amine mixing ratios of up to tens of parts per trillion volume at some sites (Yu and Lee, 2012;You et al, 2014;Freshour et al, 2014;Yao et al, 2016). A global modeling study of sulfuric acid-amine nucleation has been carried out so far (Bergman et al, 2015), applying a nucleation parametrization based on the measurements of Almeida et al (2013) and Glasoe et al (2015).…”