Title: Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

Abstract

Abstract. The effect of relative humidity (RH) on the chemical composition of secondaryorganic aerosol (SOA) formed from low-NO_x toluene oxidation in theabsence of seed particles was investigated. SOA samples were prepared in anaerosol smog chamber at <2%RH and 75%RH, collected on Teflonfilters, and analyzed with nanospray desorption electrospray ionizationhigh-resolution mass spectrometry (nano-DESI–HRMS). Measurements revealed asignificant reduction in the fraction of oligomers present in the SOAgenerated at 75%RH compared to SOA generated under dry conditions. In aseparate set of experiments, the particle mass concentrations were measuredwith a scanning mobility particle sizer (SMPS) at RHs ranging from <2 to90%. It was found that the particle mass loading decreased bynearly an order of magnitude when RH increased from <2 to75–90% for low-NO_x toluene SOA. The volatility distributions of theSOA compounds, estimated from the distribution of molecular formulas usingthe “molecular corridor” approach, confirmed that low-NO_x toluene SOAbecame more volatile on average under high-RH conditions. In contrast, theeffect of RH on SOA mass loading was found to be much smaller forhigh-NO_x toluene SOA. The observed increase in the oligomer fraction andparticle mass loading under dry conditions were attributed to the enhancement ofcondensation reactions, which produce water and oligomers from smallercompounds in low-NO_x toluene SOA. The reduction in the fraction ofoligomericmore » compounds under humid conditions is predicted to partly counteractthe previously observed enhancement in the toluene SOA yield driven by theaerosol liquid water chemistry in deliquesced inorganic seed particles.« less

Authors:

Hinks, Mallory L. ^[1]; Montoya-Aguilera, Julia ^[1]; Ellison, Lucas ^[1]; Lin, Peng  ^[2];

• Search DOE PAGES for author "Lin, Peng"
• Search DOE PAGES for ORCID "0000-0002-3567-7017"

Laskin, Alexander  ^[2];

• Search DOE PAGES for author "Laskin, Alexander"
• Search DOE PAGES for ORCID "0000-0002-7836-8417"

Laskin, Julia ^[2]; Shiraiwa, Manabu ^[1]; Dabdub, Donald  ^[3];

• Search DOE PAGES for author "Dabdub, Donald"
• Search DOE PAGES for ORCID "0000-0002-5130-4122"

Nizkorodov, Sergey A.  ^[1]

• Search DOE PAGES for author "Nizkorodov, Sergey A."
• Search DOE PAGES for ORCID "0000-0003-0891-0052"

---

+ Show Author Affiliations

1. Univ. of California, Irvine, CA (United States). Dept. of Chemistry
2. Purdue Univ., West Lafayette, IN (United States). Dept. of Chemistry
3. Univ. of California, Irvine, CA (United States). Dept. of Mechanical and Aerospace Engineering

Publication Date:

Tue Feb 06 00:00:00 EST 2018

Research Org.:

Univ. of California, Irvine, CA (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USEPA; National Science Foundation (NSF)

OSTI Identifier:

1501910

Alternate Identifier(s):

OSTI ID: 1542076

Report Number(s):

PNNL-SA-124399
Journal ID: ISSN 1680-7324

Grant/Contract Number:  

SC0018349; AC06-76RL01830; 83588101; 1500284; AGS-1654104; MRI-0923323; AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Atmospheric Chemistry and Physics (Online)

Additional Journal Information:

Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 18; Journal Issue: 3; Journal ID: ISSN 1680-7324

Publisher:

European Geosciences Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY