Abstract
The cloud condensation nucleus (CCN) activity of organic‐sulfate particles was investigated using a steady‐state environmental chamber. The organic component consisted of secondary organic aerosol (SOA) generated in the dark from 24 ± 2 ppb α‐pinene for conditions of 300 ± 5 ppb ozone, 40 ± 2% relative humidity, and 25 ± 1°C, with the organic mass loading in the chamber ranging from 23 to 37 μg m−3. CCN analysis was performed for 80‐ to 150‐nm particles having variable organic‐sulfate volume fractions, which were estimated from the diameter of the organic‐sulfate particle relative to that of the seed as well as independently from mass spectra. Critical supersaturation, which increased for greater SOA volume fraction and smaller particle diameter, was well predicted by a Köhler model having two components, one for ammonium sulfate and another for SOA. The entire data set could be successfully modeled by a single suite of effective chemical parameters for SOA. The results suggest that the effects of limited organic solubility in mixed SOA‐sulfate particles may be reliably omitted in the treatment of cloud droplet formation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
