Data for Chromophores and chemical compositions of brown carbon aerosol before and after photooxidation of combustion emissions

To futher confirm the chromophore variation process during the photooxidation, links between chromophore and chemical composition were inverstigated. The HULIS chromophores were unsaturated and contained high fractions with 5 % –10 % of nitrogen containing molecules. In contrast, the PLS chromophores had low oxidation states and contained lower fraction (2 %) of nitrogen containing molecules.

After photooxidation, oxidation of PLS chromophores and volatile organic compounds in presence of NOx were converted into HULIS with the higher fraction of nitrogen containing and unsaturation chromophores. This study extends the current understanding of formation and photochemcial aging of brown carbon chromophorese e.g. PLS, HO-HULIS, and LO-HULIS from open fires including their molecular composition. This will facilitate modelling of brown carbon aerosol e.g. in trasport models.