Nuclear magnetic resonance spectroscopy for determining the functional content of organic aerosols: A review

• Organic aerosol composition by 1H- and 13C-NMR spectroscopy.
• NMR fingerprints of specific sources, types and sizes of organic aerosol.
• Source reconciliation and apportionment using NMR spectroscopy.
• Research priorities towards understanding organic aerosol composition and origin.

The knowledge deficit of organic aerosol (OA) composition has been identified as the most important factor limiting our understanding of the atmospheric fate and implications of aerosol. The efforts to chemically characterize OA include the increasing utilization of nuclear magnetic resonance spectroscopy (NMR). Since 1998, the functional composition of different types, sizes and fractions of OA has been studied with one-dimensional, two-dimensional and solid state proton and carbon-13 NMR. This led to the use of functional group ratios to reconcile the most important sources of OA, including secondary organic aerosol and initial source apportionment using positive matrix factorization. Future research efforts may be directed towards the optimization of experimental parameters, detailed NMR experiments and analysis by pattern recognition methods to identify the chemical components, determination of the NMR fingerprints of OA sources and solid state NMR to study the content of OA as a whole.