Simulation chamber studies of the atmospheric degradation of naphthalene, 1-nitronaphthalene and phthaldialdehyde

Chen, Yang

Simulation chamber studies of the atmospheric degradation of naphthalene, 1-nitronaphthalene and phthaldialdehyde

dc.contributor.advisor	Wenger, John C.
dc.contributor.author	Chen, Yang
dc.contributor.funder	Environmental Protection Agency	en
dc.date.accessioned	2012-07-04T08:52:02Z
dc.date.available	2015-07-04T04:00:04Z
dc.date.issued	2012-04
dc.date.submitted	2012-06-25
dc.description.abstract	A detailed series of simulation chamber experiments has been performed on the atmospheric degradation pathways of the primary air pollutant naphthalene and two of its photooxidation products, phthaldialdehyde and 1-nitronaphthalene. The measured yields of secondary organic aerosol (SOA) arising from the photooxidation of naphthalene varied from 6-20%, depending on the concentrations of naphthalene and nitrogen oxides as well as relative humidity. A range of carbonyls, nitro-compounds, phenols and carboxylic acids were identified among the gas- and particle-phase products. On-line analysis of the chemical composition of naphthalene SOA was performed using aerosol time-of-flight mass spectrometry (ATOFMS) for the first time. The results indicate that enhanced formation of carboxylic acids may contribute to the observed increase in SOA yields at higher relative humidity. The photolysis of phthaldialdehyde and 1-nitronaphthalene was investigated using natural light at the European Photoreactor (EUPHORE) in Valencia, Spain. The photolysis rate coefficients were measured directly and used to confirm that photolysis is the major atmospheric loss process for these compounds. For phthaldialdehyde, the main gas-phase products were phthalide and phthalic anhydride. SOA yields in the range 2-11% were observed, with phthalic acid and dihydroxyphthalic acid identified among the particle phase products. The photolysis of 1-nitronaphthalene yielded nitric oxide and a naphthoxy radical which reacted to form several products. SOA yields in the range 57-71% were observed, with 1,4-naphthoquinone, 1-naphthol and 1,4-naphthalenediol identified in the particle phase. On-line analysis of the SOA generated in an indoor chamber using ATOFMS provided evidence for the formation of high-molecular-weight products. Further investigations revealed that these products are oxygenated polycyclic compounds most likely produced from the dimerization of naphthoxy radicals. These results of this work indicate that naphthalene is a potentially large source of SOA in urban areas and should be included in atmospheric models. The kinetic and mechanistic information could be combined with existing literature data to produce an overall degradation mechanism for naphthalene suitable for inclusion in photochemical models that are used to predict the effect of emissions on air quality.	en
dc.description.sponsorship	Environmental Protection Agency (STRIVE Doctoral Scholarships Programme (2008-PhD-AQ1))	en
dc.description.sponsorship	Environmental Protection Agency (STRIVE Doctoral Scholarships Programme (2008-PhD-AQ1)	en
dc.description.status	Not peer reviewed	en
dc.description.version	Accepted Version	en
dc.format.mimetype	application/pdf	en
dc.identifier.citation	Chen, Y, 2012. Simulation chamber studies of the atmospheric degradation of naphthalene, 1-nitronaphthalene and phthaldialdehyde. PhD Thesis, University College Cork.	en
dc.identifier.uri	https://hdl.handle.net/10468/622
dc.language.iso	en	en
dc.publisher	University College Cork	en
dc.rights	© 2012, Yang Chen	en
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/	en
dc.subject	Secondary organic aerosol	en
dc.subject	Photolysis	en
dc.subject.lcsh	Atmospheric chemistry	en
dc.subject.lcsh	Organic reaction mechanisms	en
dc.subject.lcsh	Naphthalene	en
dc.title	Simulation chamber studies of the atmospheric degradation of naphthalene, 1-nitronaphthalene and phthaldialdehyde	en
dc.type	Doctoral thesis	en
dc.type.qualificationlevel	Doctoral	en
dc.type.qualificationname	PhD (Chemistry)	en