Publication: Secondary organic aerosol from chlorine-initiated oxidation of isoprene

Publication - Secondary organic aerosol from chlorine-initiated oxidation of isoprene

Title: Secondary organic aerosol from chlorine-initiated oxidation of isoprene
DOI: 10.5194/acp-17-13491-2017
Publication Year: 2017
Author list: Wang, D. S., Hildebrandt Ruiz, L.
Journal Short Name: ACPD
Publisher: Copernicus

Abstract
Recent studies have found concentrations of reactive chlorine species to be higher than expected, suggesting that atmospheric chlorine chemistry is more extensive than previously thought. Chlorine radicals can interact with hydroperoxy (HOx) radicals and nitrogen oxides (NOx) to alter the oxidative capacity of the atmosphere. They are known to rapidly oxidize a wide range of volatile organic compounds (VOCs) found in the atmosphere, yet little is known about secondary organic aerosol (SOA) formation from chlorine-initiated photooxidation and its atmospheric implications. Environmental chamber experiments were carried out under low-NOx conditions with isoprene and chlorine as primary VOC and oxidant sources. Upon complete isoprene consumption, observed SOA yields ranged from 7 to 36 %, decreasing with extended photooxidation and SOA aging. Formation of particulate organochloride was observed. A high-resolution time-of-flight chemical ionization mass spectrometer was used to determine the molecular composition of gas-phase species using iodide–water and hydronium–water cluster ionization. Multi-generational chemistry was observed, including ions consistent with hydroperoxides, chloroalkyl hydroperoxides, isoprene-derived epoxydiol (IEPOX), and hypochlorous acid (HOCl), evident of secondary OH production and resulting chemistry from Cl-initiated reactions. This is the first reported study of SOA formation from chlorine-initiated oxidation of isoprene. Results suggest that tropospheric chlorine chemistry could contribute significantly to organic aerosol loading.

Additional Notes



Experiments (14)

ID Name Start date Experiment Category Reaction Type Reactant(s) Oxidant Name Temperature Humidity Type of Seed RO2 Main Fate Data Sets (count) Actions
376 Hildebrandt Ruiz Lab_20150707_ISOPRENE_Chlorine radical_Ammonium sulfate_A2_neutral seed 2015-07-07 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 2 Download
377 Hildebrandt Ruiz Lab_20150714_ISOPRENE_Chlorine radical_Ammonium sulfate_A3_neutral seed 2015-07-14 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 1 Download
378 Hildebrandt Ruiz Lab_20150717_ISOPRENE_Chlorine radical_Ammonium sulfate_A4_neutral seed 2015-07-17 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 2 Download
379 Hildebrandt Ruiz Lab_20150908_ISOPRENE_Chlorine radical_Ammonium sulfate_A5_neutral seed 2015-09-08 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 0 Download
380 Hildebrandt Ruiz Lab_20170611_ISOPRENE_Chlorine radical_Ammonium sulfate + Sulfuric acid_A6_acidic seed 2017-06-11 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate + Sulfuric acid Not Sure 2 Download
381 Hildebrandt Ruiz Lab_20170617_ISOPRENE_Chlorine radical_Ammonium sulfate + Sulfuric acid_A7_acidic seed 2017-06-17 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate + Sulfuric acid Not Sure 2 Download
382 Hildebrandt Ruiz Lab_20140203_ISOPRENE_Chlorine radical_Ammonium sulfate_A8_neutral seed 2014-02-03 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 0 Download
383 Hildebrandt Ruiz Lab_20150706_ISOPRENE_Chlorine radical_Ammonium sulfate_C1_continuous Cl injection_neutral seed 2015-07-06 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 1 Download
384 Hildebrandt Ruiz Lab_20150630_ISOPRENE_Chlorine radical_Ammonium sulfate_C2_continuous Cl injection_neutral seed 2015-06-30 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 1 Download
385 Hildebrandt Ruiz Lab_20150703_ISOPRENE_Chlorine radical_Ammonium sulfate_C3_continuous Cl injection_neutral seed 2015-07-03 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 1 Download
386 Hildebrandt Ruiz Lab_20150803_ISOPRENE_Chlorine radical_Ammonium sulfate_C4_continuous Cl injection_neutral seed 2015-08-03 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 1 Download
387 Hildebrandt Ruiz Lab_20151231_ISOPRENE_Chlorine radical_Ammonium sulfate_C5_continuous Cl injection_neutral seed 2015-12-31 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate Not Sure 1 Download
388 Hildebrandt Ruiz Lab_20170704_ISOPRENE_Chlorine radical_Ammonium sulfate + Sulfuric acid_C6_continuous Cl injection_acidic seed 2017-07-04 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate + Sulfuric acid Not Sure 2 Download
389 Hildebrandt Ruiz Lab_20170708_ISOPRENE_Chlorine radical_Ammonium sulfate + Sulfuric acid_C7_continuous Cl injection_acidic seed 2017-07-08 Gas phase chemical reaction, Volatility and partitioning, Aerosol formation Photooxidation ISOPRENE Chlorine radical 25 0 Ammonium sulfate + Sulfuric acid Not Sure 2 Download