Formation of secondary organic aerosols from the ozonolysis of dihydrofurans

Yolanda Diaz-de-Mera, Alfonso Aranda, Larisa Bracco, Diana Rodriguez, Ana Rodriguez
2017 Atmospheric Chemistry and Physics  
<p><strong>Abstract.</strong> In this work we report the study of the ozonolysis of 2,5-dihydrofuran and 2,3-dihydrofuran and the reaction conditions leading to the formation of secondary organic aerosols. The reactions have been carried out in a Teflon chamber filled with synthetic air mixtures at atmospheric pressure and room temperature. The ozonolysis only produced particles in the presence of SO<sub>2</sub>. Rising relative humidity from 0 to 40<span class="thinspace"></span>% had no
more » ... span>% had no effect on the production of secondary organic aerosol in the case of 2,5-dihydrofuran, while it reduced the particle number and particle mass concentrations from the 2,3-dihydrofuran ozonolysis. The water-to-SO<sub>2</sub> rate constant ratio for the 2,3-dihydrofuran Criegee intermediate was derived from the secondary organic aerosol (SOA) yields in experiments with different relative humidity values, <i>k</i><sub>H<sub>2</sub>O</sub>/<i>k</i><sub>SO<sub>2</sub></sub> = <span class="thinspace"></span>(9.8<span class="thinspace"></span>±<span class="thinspace"></span>3.7)<span class="thinspace"></span>× 10<sup>−5</sup>. <br><br> The experimental results show that SO<sub>3</sub> may not be the only intermediate involved in the formation or growth of new particles in contrast to the data reported for other Criegee intermediate–SO<sub>2</sub> reactions. For the studied reactions, SO<sub>2</sub> concentrations remained constant during the experiments, behaving as a catalyst in the production of condensable products. <br><br> Computational calculations also show that the stabilised Criegee intermediates from the ozonolysis reaction of both 2,5-dihydrofuran and 2,3-dihydrofuran may react with SO<sub>2</sub>, resulting in the regeneration of SO<sub>2</sub> and the formation of low-volatility organic acids.</p>
doi:10.5194/acp-17-2347-2017 fatcat:qhavdcrjr5caxch2yme3gybtti