Articles | Volume 16, issue 7
Technical note
11 Apr 2016
Technical note |  | 11 Apr 2016

Technical Note: Development of chemoinformatic tools to enumerate functional groups in molecules for organic aerosol characterization

Giulia Ruggeri and Satoshi Takahama

Abstract. Functional groups (FGs) can be used as a reduced representation of organic aerosol composition in both ambient and controlled chamber studies, as they retain a certain chemical specificity. Furthermore, FG composition has been informative for source apportionment, and various models based on a group contribution framework have been developed to calculate physicochemical properties of organic compounds. In this work, we provide a set of validated chemoinformatic patterns that correspond to (1) a complete set of functional groups that can entirely describe the molecules comprised in the α-pinene and 1,3,5-trimethylbenzene MCMv3.2 oxidation schemes, (2) FGs that are measurable by Fourier transform infrared spectroscopy (FTIR), (3) groups incorporated in the SIMPOL.1 vapor pressure estimation model, and (4) bonds necessary for the calculation of carbon oxidation state. We also provide example applications for this set of patterns. We compare available aerosol composition reported by chemical speciation measurements and FTIR for different emission sources, and calculate the FG contribution to the O : C ratio of simulated gas-phase composition generated from α-pinene photooxidation (using the MCMv3.2 oxidation scheme).

Short summary
We present a set of tools for mapping molecular information to functional group composition. This allows us to reduce the complexity of representing the organic aerosol composition, as it consists of hundreds of thousands of different compounds. We describe the tools and methods for validation, and demonstrate several applications in which this tool can facilitate measurement intercomparisons and chemical modeling of aerosol chemistry.
Final-revised paper