| Title: | Insights into the Formation and Evolution of Individual Compounds in the Particulate Phase during Aromatic Photo-Oxidation |
| Author(s): | Pereira KL; Hamilton JF; Rickard AR; Bloss WJ; Alam MS; Camredon M; Ward MW; Wyche KP; Munoz A; Vera T; Vazquez M; Borras E; Rodenas M; |
| Address: | "Wolfson Atmospheric Chemistry Laboratory, Department of Chemistry, University of York , York, YO10 5DD, United Kingdom. National Centre for Atmospheric Science, University of York , York, YO10 5DD, United Kingdom. School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham, B15 2TT, United Kingdom. LISA, UMR CNRS/INSU 7583, University of Paris-Est Creteil and Paris Diderot , Creteil, 94010, France. Air Environment Research, School Environment and Technology, University of Brighton , Brighton, BN2 4AT, United Kingdom. CEAM-UMH, EUPHORE, Valencia, 46980, Spain" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Secondary organic aerosol (SOA) is well-known to have adverse effects on air quality and human health. However, the dynamic mechanisms occurring during SOA formation and evolution are poorly understood. The time-resolved SOA composition formed during the photo-oxidation of three aromatic compounds, methyl chavicol, toluene and 4-methyl catechol, were investigated at the European Photoreactor. SOA was collected using a particle into liquid sampler and analyzed offline using state-of-the-art mass spectrometry to produce temporal profiles of individual photo-oxidation products. In the photo-oxidation of methyl chavicol, 70 individual compounds were characterized and three distinctive temporal profile shapes were observed. The calculated mass fraction (Ci,aer/COA) of the individual SOA compounds showed either a linear trend (increasing/decreasing) or exponential decay with time. Substituted nitrophenols showed an exponential decay, with the nitro-group on the aromatic ring found to control the formation and loss of these species in the aerosol phase. Nitrophenols from both methyl chavicol and toluene photo-oxidation experiments showed a strong relationship with the NO2/NO (ppbv/ppbv) ratio and were observed during initial SOA growth. The location of the nitrophenol aromatic substitutions was found to be critically important, with the nitrophenol in the photo-oxidation of 4-methyl catechol not partitioning into the aerosol phase until irradiation had stopped; highlighting the importance of studying SOA formation and evolution at a molecular level" |
| Keywords: | "Allylbenzene Derivatives Anisoles/chemistry Atmosphere/chemistry Humidity Hydrocarbons, Aromatic/*chemistry *Light Nitrophenols/analysis Oxidants/chemistry Oxidation-Reduction/radiation effects Particulate Matter/*analysis Temperature Time Factors Toluene;" |
| Notes: | "MedlinePereira, Kelly L Hamilton, Jacqueline F Rickard, Andrew R Bloss, William J Alam, Mohammed S Camredon, Marie Ward, Martyn W Wyche, Kevin P Munoz, Amalia Vera, Teresa Vazquez, Monica Borras, Esther Rodenas, Milagros eng Research Support, Non-U.S. Gov't 2015/10/17 Environ Sci Technol. 2015 Nov 17; 49(22):13168-78. doi: 10.1021/acs.est.5b03377. Epub 2015 Oct 28" |
