|Lee, Su Anne|
|Silva, Philip - Phil|
|Cocker Iii, David|
Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2013
Publication Date: 6/1/2013
Publication URL: http://handle.nal.usda.gov/10113/57138
Citation: Tang, X., Price, D., Praske, E.J., Lee, S., Shattuck, M.A., Purvis-Roberts, K., Silva, P.J., Asa-Awuku, A., Cocker III, D.R. 2013. NO3 and OH initiated secondary aerosol formation from aliphatic amines - salt formation and effect of water vapor. Atmospheric Environment. 72:105-112. Interpretive Summary: Amines are a class of volatile organic compounds emitted from waste management methods; they are carbon-containing analogues to ammonia that can participate in atmospheric chemistry to produce aerosols. There is significant uncertainty about the emissions of amines, the chemistry of amines in the atmosphere, and the properties of aerosols produced by atmospheric reactions. In this study, atmospheric reactions of several representative amines were studied to determine their aerosol production potential and properties of the aerosol. Atmospheric reactions of amines form significant aerosol some products of which result in organic compounds and others in the production of salt. Because of the complexity of the aerosol products, further studies are needed to understand the effects of amines on climate as some of these compounds are potential players as cloud condensation.
Technical Abstract: Aliphatic amines enter the atmosphere from a variety of sources, and have been detected existing in gas and particle phases in the atmosphere. Similar to ammonia, amines can form inorganic salt through acid-base reactions. However, the atmospheric behavior of amines with atmospheric oxidants (e.g. nitrate radicals, hydroxyl radicals, O3) is still poorly understood. In this study, trimethylamine (TMA), diethylamine (DEA) and butylamine (BA) were chosen as representatives of tertiary, secondary and primary amine, respectively. Chamber experiments were conducted to explore the reaction between amines and O3/ nitrate radical (NO3)/ hydroxyl radical (OH). Humidity in the real ambient environment was also taken into account, so we conducted experiments under different relative humidity conditions. Results show that all three amines have high potential of secondary aerosol formation in reactions with NO3 radicals, which is affected by the presence of water vapor. PILS-IC and SMPS were used to identify and quantify the formation of inorganic salts. DEA and BA are capable of forming significant amount of stable inorganic salt at atmospheric-relevant concentrations, while TMA tends to form mostly non-salt secondary organic aerosol under dry conditions. On the other hand, OH photooxidation of amines has much lower secondary aerosol yield and is independent of relative humidity. Formed aerosol from OH radical oxidation was composed of organic components only, due to the lack of acid source. This study demonstrated that night time chemistry of aliphatic amines can produce secondary aerosol which is a mixture of organic and inorganic compounds, suggesting that aliphatic amines are important aerosol contributor and potential cloud condensation nuclei.