Science Daily March 24, 2021
Cloud processing is potentially important for secondary organic aerosol (SOA) formation, a major aerosol component: however, laboratory experiments fail to mimic this process under atmospherically relevant conditions. An international team of researchers (Switzerland, UK, USA – Carnegie Mellon University, industry) developed a wetted-wall flow reactor to simulate aqueous-phase processing of isoprene oxidation products (iOP) in cloud droplets. They found that 50 to 70% (in moles) of iOP partition into the aqueous cloud phase, where they rapidly react with OH radicals, producing SOA. Integrating their experimental results into a global model, they showed that clouds effectively boost the amount of SOA. They concluded that, on a global scale, cloud processing of iOP produces approximately 20% of the total biogenic SOA burden and is the main source of SOA in the mid-troposphere. The experimental setup opens the possibility of investigating aerosol formation in clouds under near-atmospheric conditions so that these processes can ultimately be included in climate models…read more. Open Access TECHNICAL ARTICLEÂ
Time series of isoprene oxidation products measured by mass spectrometry for a case study of type A and solubility-dependent uptake ratio. Credit: Science Advances 24 Mar 2021: Vol. 7, no. 13, eabe2952