AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Measurements of Atmospheric Amines and Ammonia with a Chemical Ionization Mass Spectrometer (CIMS)
SHANHU LEE, Yi You, Roxana Sierra-Hernández, Joost de Gouw, Abigail Koss, Karsten Baumann, Eric Edgerton, Kent State University
Abstract Number: 380 Working Group: Air Quality and Climate in the Southeast US: Insights from Recent Measurement Campaigns
Abstract Amines and ammonia play critical roles in new particle formation, via acid-base reactions at the initial stage of aerosol nucleation. Nitrogen-containing base compounds also contribute to the SOA formation, by forming salts or via condensation of amine photo-oxidation reactions. However, atmospheric measurements of amines with fast response detection methods are very limited. Here, we report ambient concentrations of amines and ammonia measured with a chemical ionization mass spectrometer (CIMS) in an Alabama forest and a moderately polluted Midwestern site (Kent). In the Alabama forest, mostly C3-amines (pptv and tens pptv) and ammonia (up to 2 ppbv) were detected at the daily base, but other amines were usually within the CIMS detection limits. C3-amines and ammonia showed similar diurnal trends and similar temperature and wind direction dependences, and they were not associated with the transported CO and SO2 plumes. These results indicate these base compounds were emitted likely from the same natural sources (such soils and trees) at this forest site and they were also affected by the theromodynamic equilibrium between the gas and aerosol phases. When there were transported biomass burning plumes, various amines (C1-C6) were measured at the pptv level, indicating that biomass burning can be a substantial source of amines even in the Southeast U.S. In the moderately polluted Kent site, higher concentrations of amines (C1-C6 at pptv and tens pptv) and ammonia (up to 6 ppbv) were detected. Diurnal variations of C1- to C3-amines and ammonia closely followed the ambient temperature. But C4- to C6-amines showed frequent and abrupt rises during the nighttime, suggesting that they were emitted from some local sources. These abundant amines and NH3 may in part explain the high frequency of new particle formation events reported from Kent.