气候变化领域集成服务门户(CCPortal): Effects of the sample matrix on the photobleaching and photodegradation of toluene-derived secondary organic aerosol compounds

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DOI	10.5194/acp-22-10155-2022
	Effects of the sample matrix on the photobleaching and photodegradation of toluene-derived secondary organic aerosol compounds
	Klodt, Alexandra L.; Adamek, Marley; Dibley, Monica; Nizkorodov, Sergey A.; O'Brien, Rachel E.
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	10155
结束页码	10171
卷号	22 期号:15 页码:17
英文摘要	Secondary organic aerosol (SOA) generated from the photooxidation of aromatic compounds in the presence of oxides of nitrogen (NOx) is known to efficiently absorb ultraviolet and visible radiation. With exposure to sunlight, the photodegradation of chromophoric compounds in the SOA causes this type of SOA to slowly photobleach. These photodegradation reactions may occur in cloud droplets, which are characterized by low concentrations of solutes, or in aerosol particles, which can have highly viscous organic phases and aqueous phases with high concentrations of inorganic salts. To investigate the effects of the surrounding matrix on the rates and mechanisms of photodegradation of SOA compounds, SOA was prepared in a smog chamber by photooxidation of toluene in the presence of NOx. The collected SOA was photolyzed for up to 24 h using near-UV radiation (300-400 nm) from a xenon arc lamp under different conditions: directly on the filter, dissolved in pure water, and dissolved in 1 M ammonium sulfate. The SOA mass absorption coefficient was measured as a function of irradiation time to determine photobleaching rates. Electrospray ionization high-resolution mass spectrometry coupled to liquid chromatography separation was used to observe changes in SOA composition resulting from the irradiation. The rate of decrease in SOA mass absorption coefficient due to photobleaching was the fastest in water, with the presence of 1 M ammonium sulfate modestly slowing down the photobleaching. By contrast, photobleaching directly on the filter was slower. The high-resolution mass spectrometry analysis revealed an efficient photodegradation of nitrophenol compounds on the filter but not in the aqueous phases, with relatively little change observed in the composition of the SOA irradiated in water or 1 M ammonium sulfate despite faster photobleaching than in the on-filter samples. This suggests that photodegradation of nitrophenols contributes much more significantly to photobleaching in the organic phase than in the aqueous phase. We conclude that the SOA absorption coefficient lifetime with respect to photobleaching and lifetimes of individual chromophores in SOA with respect to photodegradation will depend strongly on the sample matrix in which SOA compounds are exposed to sunlight.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000837634000001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273254
作者单位	University of California System; University of California Irvine
推荐引用方式 GB/T 7714	Klodt, Alexandra L.,Adamek, Marley,Dibley, Monica,et al. Effects of the sample matrix on the photobleaching and photodegradation of toluene-derived secondary organic aerosol compounds[J],2022,22(15):17.
APA	Klodt, Alexandra L.,Adamek, Marley,Dibley, Monica,Nizkorodov, Sergey A.,&O'Brien, Rachel E..(2022).Effects of the sample matrix on the photobleaching and photodegradation of toluene-derived secondary organic aerosol compounds.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(15),17.
MLA	Klodt, Alexandra L.,et al."Effects of the sample matrix on the photobleaching and photodegradation of toluene-derived secondary organic aerosol compounds".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.15(2022):17.