Increase of High Molecular Weight Organosulfate With Intensifying Urban Air Pollution in the Megacity Beijing

Abstract Organosulfates (OSs), a key component of secondary organic aerosols (SOA), account for up to one third of organic matter in the atmosphere. However, high molecular weight (HMW, 500–800 Da) OSs in ambient aerosols are poorly characterized at a molecular level, due to experimental difficulties. With Fourier transform‐ion cyclotron resonance mass spectrometry (FT‐ICRMS), we are able to identify more than 8,000 OSs in wintertime aerosols …