An important pathway for ozonolysis of alpha-pinene and beta-pinene in aqueous phase and its atmospheric implications

Zhang, Xuan; Chen, Zhongming; Wang, Hongli; He, Shuzhong; Huang, Da

doi:10.1016/j.atmosenv.2009.06.028

Cited by 47 publications

(42 citation statements)

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“…The fraction of H 2 O 2 undergoing the aqueous reaction with SO 2 was calculated to be negligible when there was no rain or fog. We suggest that the oxidation of S(IV) initiated by H 2 O 2 on the surface of aqueous aerosols may provide evidence to explain this inverse correlation, because the surface reaction may be more important and more ubiquitous than the reaction in the bulk of wet aerosols, especially for the rapid reactions Zhang et al, 2009). The elevated H 2 O 2 at night can be probably ascribed to its particular sources.…”

Section: Paa-h 2 O 2 −Mhp Relationshipmentioning

confidence: 89%

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO<sub>x</sub> cycle and implication on radical chemistry

Zhang

Chen

et al. 2010

Atmos. Chem. Phys.

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Abstract. Peroxyacetic acid (PAA) is one of the most important atmospheric organic peroxides, which have received increasing attention for their potential contribution to the oxidation capacity of the troposphere and the formation of secondary aerosols. We report here, for the first time, a series of data for atmospheric PAA concentrations at urban and rural sites, from five field campaigns carried out in China in summer 2006, 2007 and 2008. For these five measurements, daytime mean (08:00-20:00 LT) PAA concentrations on sunlit days were 21.4-148.0 pptv with a maximum level of ∼1 ppbv. The various meteorological and chemical parameters influencing PAA concentrations were examined using Principal Factor Analysis. This statistical analysis shows that the local photochemical production was the major source of PAA, and its concentration increased with increasing temperature, solar radiation and ozone but decreased with increasing NO x (NO and NO 2 ), CO, SO 2 , and relative humidity. Based on the dataset, several issues are highlighted in this study: (i) Because PAA is a product from the photochemical oxidation of some specific volatile organic compounds (VOCs) that lead to acetyl peroxy radicals, the importance of various VOCs with respect to the PAA formation is therefore ranked using the incremental reactivity method. (ii) The contribution of PAN thermal degradation to PAA formation under conditions of different NO x concentrations is estimated based on the chemical kinetics analysis. The result shows that PAN seems to play an important role in the formation of PAA when the NO/NO 2 concentration ratio was less than 0.2 and PAA would correspondingly have feedback on the PAN-NO x cycle. (iii) PAA and other peroxides, such as methyl Correspondence to: Z. M. Chen (zmchen@pku.edu.cn) hydroperoxide (MHP) and H 2 O 2 , usually exhibited a similar asymmetric shape typically shifted to the afternoon. However, under some conditions, H 2 O 2 diurnal cycle was out of phase with MHP and PAA. The combination of linear regression and kinetics analysis indicate that the formation and removal processes of H 2 O 2 may be different from those of MHP and PAA. (iv) Considering that PAA is the reservior of free radicals, its fate is expected to have an effect on the free radical budget in the atmosphere. A box model based on the CBM-IV mechanism has been performed to access its influence on the radical budget. We suggest that the detailed information on PAA in the atmosphere is of importance to better understand the free radical chemistry.

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Section: Paa-h 2 O 2 −Mhp Relationshipmentioning

confidence: 89%

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO<sub>x</sub> cycle and implication on radical chemistry

Zhang

Chen

et al. 2010

Atmos. Chem. Phys.

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“…Nighttime is usually more humid than daytime, increasing the significance of aqueous-phase and heterogeneous reactions. Recent laboratory studies have suggested that H 2 O 2 and ROOH could also be produced during aqueous-phase reactions and heterogeneous reactions on particles [Chen et al, 2008a[Chen et al, , 2008bZhang et al, 2009]. On 25 July concentrations of C 2 -C 11 alkenes decreased from 4.5 to 3.3 ppbv during 1800-2000, which is when the peroxides accumulated.…”

Section: Nighttime Production Of Peroxidesmentioning

confidence: 99%

“…[39] In fact, several previous works point to the heterogeneous formation of H 2 O 2 in aerosol and cloud water [de Reus et al, 2005;Chen et al, 2008b;Zhang et al, 2009]. The aerosol and cloud water may act as both source and sink for H 2 O 2 .…”

Section: Physical Factors 331 Meteorological Factors Influencing Tmentioning

confidence: 99%

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

He¹,

Chen²,

Zhang³

et al. 2010

J. Geophys. Res.

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[1] For the 2008 Beijing Olympic Games full-scale control (FSC) of atmospheric pollution was implemented to improve the air quality from 20 July to 20 September 2008, resulting in a significant decrease in the emission of pollutants in urban Beijing, especially vehicular emissions. The combination of reduced emissions and weather condition changes provided us with a unique opportunity to investigate urban atmospheric chemistry. Hydrogen peroxide (H 2 O 2 ) and organic peroxides play significant roles in atmospheric processes, such as the cycling of HO x radicals and the formation of secondary sulfate aerosols and secondary organic aerosols. We measured atmospheric H 2 O 2 and organic peroxides in urban Beijing, at the Peking University campus, from 12 July to 30 September, before and during the FSC. The major peroxides observed were H 2 O 2 , methyl hydroperoxide (MHP), and peroxyacetic acid (PAA), having maximal mixing ratios of 2.34, 0.95, and 0.17 ppbv (parts per billion by volume), respectively. Other organic peroxides were detected occasionally, such as bis-hydroxymethyl hydroperoxide, hydroxymethyl hydroperoxide, ethyl hydroperoxide, and 1-hydroxyethyl hydroperoxide. On sunny days the concentrations of H 2 O 2 , MHP, and PAA exhibited pronounced diurnal variations, with a peak in the afternoon (1500-1900) and, occasionally, a second peak in the evening (2000-0200). The night peaks can be attributed to local night production from the ozonolysis of alkenes, coupled with the reaction between NO 3 radicals and organic compounds. Sunny-day weather dominated during 16-26 July, and we found that the concentrations of H 2 O 2 , MHP, and PAA increased strikingly on 22-26 July, compared with the concentrations during 16-19 July. This effect was mainly attributed to the NO x (NO and NO 2 ) decline because of the FSC, due to (i) the suppressing effect of NO and NO 2 on the production of peroxides and (ii) the indirect effect of reduced NO x on the concentration of peroxides via O 3 production in the volatile organic compound-sensitive area. Although the time period from 29 July to 15 August fell within the FSC, the concentrations of H 2 O 2 , MHP, and PAA decreased significantly. This can be explained by a combination of chemical and physical factors during this period, when rainy-and cloudy-day weather dominated. Weaker irradiation and lower temperatures resulted in a lower photochemical production of peroxides; the higher humidity resulted in their greater loss through their aqueous-phase oxidation of S(IV) and through heterogeneous removal, and lower temperatures and higher nighttime humidity resulted in a quicker surface deposition of peroxides. Furthermore, our observations seem to imply that the heterogeneous removal of H 2 O 2 is faster than that of MHP, as indicated by the strong negative correlation between the H 2 O 2 -to-MHP ratio and the aerosol surface area.

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“…However, it remains difficult to quantify the reaction products. Alternatively, a series of recent laboratory experiments on the aqueous oxidation of psVOCs in bulk water in the absence of gas phase interference were performed to quantitatively determine the effect of condensed water on the distribution of products that formed in the aqueous reaction of several psVOCs Zhang et al, 2009Zhang et al, , 2010Huang et al, 2011;EI Haddad et al, 2009;Liu et al, 2012). Interestingly, those studies revealed that the production of carbonyls, organic acids, and peroxides in the aqueous ozonolysis of α-pinene, β-pinene, methacrolein (MAC), and methyl vinyl ketone (MVK), and the aqueous OH radical-initiated oxidation of isoprene, MAC, and MVK significantly differed from those observed in the corresponding gas phase reaction.…”

Section: Introductionmentioning

confidence: 99%

Understanding the aqueous phase ozonolysis of isoprene: distinct product distribution and mechanism from the gas phase reaction

et al. 2012

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Abstract. The aqueous phase reaction of volatile organic compounds (VOCs) has not been considered in most analyses of atmospheric chemical processes. However, some experimental evidence has shown that, compared to the corresponding gas phase reaction, the aqueous chemical processes of VOCs in the bulk solutions and surfaces of ambient wet particles (cloud, fog, and wet aerosols) may potentially contribute to the products and formation of secondary organic aerosol (SOA). In the present study, we performed a laboratory experiment of the aqueous ozonolysis of isoprene at different pHs (3-7) and temperatures (4-25 • C). We detected three important kinds of products, including carbonyl compounds, peroxide compounds, and organic acids. Our results showed that the molar yields of these products were nearly independent of the investigated pHs and temperatures, those were (1) carbonyls: 56.7 ± 3.7 % formaldehyde, 42.8 ± 2.5 % methacrolein (MAC), and 57.7 ± 3.4 % methyl vinyl ketone (MVK); (2) peroxides: 53.4 ± 4.1 % hydrogen peroxide (H 2 O 2 ) and 15.1 ± 3.1 % hydroxylmethyl hydroperoxide (HMHP); and (3) organic acids: undetectable (<1 % estimated by the detection limit). Based on the amounts of products formed and the isoprene consumed, the total carbon yield was estimated to be 94.8 ± 4.1 %. This implied that most of the products in the reaction system were detected. The combined yields of both MAC + MVK and H 2 O 2 + HMHP in the aqueous isoprene ozonolysis were much higher than those observed in the corresponding gas phase reaction. We suggest that these unexpected high yields of carbonyls and peroxides are related to the greater capability of condensed water, compared to water vapor, to stabilize energy-rich Criegee radicals. This aqueous ozonolysis of isoprene (and possibly other biogenic VOCs) could potentially occur on the surfaces of ambient wet particles and plants. Moreover, the high-yield carbonyl and peroxide products might provide a considerable source of aqueous phase oxidants and SOA precursors.

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An important pathway for ozonolysis of alpha-pinene and beta-pinene in aqueous phase and its atmospheric implications

Cited by 47 publications

References 42 publications

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO<sub>x</sub> cycle and implication on radical chemistry

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO<sub>x</sub> cycle and implication on radical chemistry

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

Understanding the aqueous phase ozonolysis of isoprene: distinct product distribution and mechanism from the gas phase reaction

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An important pathway for ozonolysis of alpha-pinene and beta-pinene in aqueous phase and its atmospheric implications

Cited by 47 publications

References 42 publications

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO&lt;sub&gt;x&lt;/sub&gt; cycle and implication on radical chemistry

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO&lt;sub&gt;x&lt;/sub&gt; cycle and implication on radical chemistry

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

Understanding the aqueous phase ozonolysis of isoprene: distinct product distribution and mechanism from the gas phase reaction

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Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO<sub>x</sub> cycle and implication on radical chemistry

Peroxyacetic acid in urban and rural atmosphere: concentration, feedback on PAN-NO<sub>x</sub> cycle and implication on radical chemistry