Anthropogenic iron oxide aerosols enhance atmospheric heating.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28508863.
- Also identified by DOI 10.1038/ncomms15329 and PMC identifier 5440854.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Combustion-induced carbonaceous aerosols, particularly black carbon (BC) and brown carbon (BrC), have been largely considered as the only significant anthropogenic contributors to shortwave atmospheric heating. Natural iron oxide (FeO<sub>x</sub>) has been recognized as an important contributor, but the potential contribution of anthropogenic FeO<sub>x</sub> is unknown. In this study, we quantify the abundance of FeO<sub>x</sub> over East Asia through aircraft measurements using a modified single-particle soot photometer. The majority of airborne FeO<sub>x</sub> particles in the continental outflows are of anthropogenic origin in the form of aggregated magnetite nanoparticles. The shortwave absorbing powers (P<sub>abs</sub>) attributable to FeO<sub>x</sub> and to BC are calculated on the basis of their size-resolved mass concentrations and the mean P<sub>abs</sub>(FeO<sub>x</sub>)/P<sub>abs</sub>(BC) ratio in the continental outflows is estimated to be at least 4-7%. We demonstrate that in addition to carbonaceous aerosols the aggregate of magnetite nanoparticles is a significant anthropogenic contributor to shortwave atmospheric heating.