AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Characterization of the Oxidation Chemistry of Secondary Aliphatic Amines Under Dry and Humid Conditions
DEREK PRICE, David R. Cocker III, University of California, Riverside
Abstract Number: 253 Working Group: Primary and Secondary Aerosols from Agricultural Operations
Abstract Secondary aliphatic amines are observed in the emissions from agricultural processes. It is important to understand the chemistry occurring from these emissions to improve atmospheric modelling in rural areas and in locations where rural and urban emissions may mix. A set of well characterized environmental chamber experiments were conducted on four secondary aliphatic amines (dimethylamine, diethylamine, dipropylamine, and dibutylamine). In these experiments, an amine was injected into the environmental chamber followed by an oxidant such as hydroxyl radical or nitrate radical. The experiments were repeated at 30% relative humidity. The chemical composition of the gas phase species was measured with a selected ion flow tube – mass spectrometer (SIFT-MS). A scanning mobility particle sizer (SMPS) was employed to measure the concentration and size distribution of the secondary organic aerosol produced. The chemical composition of the particle phase was measured with a high resolution – time of flight – aerosol mass spectrometer (HR-ToF-AMS) and a particle into liquid sampler – time of flight – mass spectrometer (PILS-ToF-MS). Differences were observed in the resultant aerosol properties (density, size, composition) among the secondary aliphatic amine precursors. The type of oxidant influenced the particulate matter and ozone concentration, as well as the reaction chemistry. For instance, the formation of carcinogenic nitramines was observed in the reactions with nitrate radical. Additionally, particulate matter concentration was greater with nitrate radical oxidation. The presence of water in the humid experiments provided alternate reaction pathways with select secondary aliphatic amine precursors.