We use radiocarbon measurements to apportion organic carbon (OC) aerosols in the atmosphere to non-fossil sources (such as natural plant emissions or biomass burning) and fossil sources (like coal combustion or traffic). These investigations showed for European cities in winter that OC originates from fossil-fuel usage only to a minor extent (e.g. 25% for Zurich).
A recent study pointed out larger fossil emissions for China during winter (i.e. 61% for Beijing) with a substantial contribution from coal combustion. However, the still considerable extent of non-fossil OC aerosols (39%) remains surprising for such a mega-city as Beijing. They are mainly attributed to biomass-burning emissions.

This work was carried out in the group of PD Dr. Sönke Szidat in collaboration with Prof. Yanlin Zhang from the Nanjing University of Information Science and Technology.

References:

• Y. Zhang, H. Ren, Y. Sun, F. Cao, Y. Chang, S. Liu, X. Lee, K. Agrios, K. Kawamura, D. Liu, L. Ren, W. Du, Z. Wang, A.S.H. Prevot, S. Szidat, P.Q. Fu;
  "High Contribution of Nonfossil Sources to Submicrometer Organic Aerosols in Beijing, China"
  Environ. Sci. Technol., 2017, 51(14), 7842-7852; doi:10.1021/acs.est.7b01517.