Heterogeneous production of Cl2 from particulate chloride: Effects of composition and relative humidity |
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| Authors: | Cameron B Faxon Surya Venkatesh Dhulipala David T Allen Lea Hildebrandt Ruiz |
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| Affiliation: | McKetta Dept. of Chemical Engineering, The University of Texas at Austin, M/C 27100, 10100 Burnet Road, Austin, TX 78758 |
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| Abstract: | Reactions initiated by chlorine atoms can enhance the formation of ozone (O3) and secondary organic aerosol (SOA) in the troposphere. Environmental chamber experiments were conducted to quantify heterogeneous Cl2 production from NH4Cl and NaCl particles exposed to O3 and hydroxyl radicals (?OH). Observations are inconsistent with models of Cl2 production resulting solely from surface‐mediated reactions of ?OH and suggest that O3 plays a significant role. The production of Cl2 increased with relative humidity and decreased in the presence of SOA or nitric oxides (NOx). Heterogeneous reactive uptake coefficients for the production of Cl2 from O3 on pure NH4Cl (  ) averaged 1.4 ± 1.0 × 10?3. Cl2 production was six times more efficient on NH4Cl aerosol than on NaCl aerosol. Model calculations under atmospheric conditions suggest this heterogeneous Cl2 production could increase peak daily O3 concentrations by over 10%. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3151–3158, 2018 |
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| Keywords: | environmental chamber experiments particulate chloride reactive chlorine photochemistry heterogeneous chemistry |
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) averaged 1.4 ± 1.0 × 10?3. Cl2 production was six times more efficient on NH4Cl aerosol than on NaCl aerosol. Model calculations under atmospheric conditions suggest this heterogeneous Cl2 production could increase peak daily O3 concentrations by over 10%. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3151–3158, 2018