NMR spectroscopic applications to atmospheric organic aerosol analysis – Part 2: A review of existing methodologies and perspectives

In the last decade, the considerable technological progress achieved in parallel science disciplines provides a potential for a breakthrough in NMR atmospheric applications. Improvements in probe sensitivity and in the NMR devices, like innovative tubes with a better filling factor, enable to improve the signal-to-noise ratios of an order of magnitude with respect to the earlier techniques. This already allows for the development of NMR techniques in experimental setups, like laboratory simulation chambers, where the limited sampling volumes and aerosol loads have hampered full application in the past. In parallel, the development of techniques for high-performance data analysis, including metabolomics, and multivariate statistical techniques applied to complex spectral datasets greatly expand the potential of NMR-based aerosol characterization techniques for individual compound identification and source apportionment. To achieve this goal, a more systematic NMR characterization of atmospheric tracers and relevant sources is required.