Secondary organic aerosol reduced by mixture of atmospheric vapours
Authors: Gordon McFiggans, Thomas Mentel, Jürgen Wildt, Iida Pullinen, Sungah Kang, Einhard Kleist, Sebastian Schmitt, Monika Springer, Ralf Tillmann, Cheng Wu, Defeng Zhao, Mattisa Hallquist, Cameron Faxon, Michael Le Breton, Åsa Hallquist, David Simpson, Robert Bergström, Michael E Jenkin, Mikael Ehn, Joel A Thornton, M Rami Alfarra, Thomas J Bannan, Carl J Percival, Michael Priestley, David Topping, Astrid Kiendler-Scharr
Publication Date: 30 January, 2019
Department of: Earth and Environmental Sciences
Less particulate matter made when air pollutants are mixed
Secondary organic aerosol (SOA) particles are extremely small and are made from natural and man-made emissions by interactions of sunlight with VOC from trees, plants, cars or industry. Fine particles damage human health, being the major factor in the annual premature death of around 5.5 million people globally, and their influence is the major uncertainty in manmade effects on radiation balance affecting climate.
Researchers from the University of Manchester, along with collaborators from Jülich and Gothenburg, showed that highly reactive volatile organic compounds (VOC) present in the atmosphere that form a modest amount of aerosol may not increase, and may decrease, SOA. Biogenic VOC such as highly reactive terpenes emitted from plants are important SOA particle precursors. Isoprene dominates terpene emissions globally but its oxidation generally forms a modest mass of particles.
Using a simulation chamber, isoprene, carbon monoxide and methane were each shown to suppress particle mass yield from monoterpenes in their mixtures. Each ‘scavenged’ hydroxyl radicals, preventing monoterpene oxidation, with the resulting peroxy radicals scavenging highly oxygenated low-volatility monoterpene products that would form SOA. Global modelling demonstrated that this could happen effectively in the real atmosphere, showing the need to account for interactions between such molecules, as done for ozone modelling.
- We have identified new links between natural emissions and with manmade pollutants to help quantify what controls formation of atmospheric particulate matter
- Our finding can help inform stronger and more evidence-based clean air and climate-related legislation
- We identify the need to know the make-up of the mixture of manmade and natural trace compounds in the real atmosphere in order to quantify particulate pollution
- Phys.org: Unexpected link between air pollutants from plants and manmade emissions
- Nature Korea: Reduction of secondary organic aerosols through the mixing of atmospheric vapors
- My Newsdesk; IVL Swedish Environmental Research Institute: Discovery sheds new light on how air pollution is transformed into the atmosphere
- Forskning.se: New light on how air pollution is transformed into the atmosphere