scholarly journals Secondary organic aerosol formation from photooxidation of furan: effects of NO<sub><i>x</i></sub> and humidity

2019 ◽  
Vol 19 (21) ◽  
pp. 13591-13609 ◽  
Author(s):  
Xiaotong Jiang ◽  
Narcisse T. Tsona ◽  
Long Jia ◽  
Shijie Liu ◽  
Hailiang Zhang ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Experimental Conditions ◽  
Seed Particles ◽  
Significant Difference ◽  
Q Exactive ◽  
Orbitrap Ms

Abstract. Atmospheric furan is a primary and secondary pollutant in the atmosphere, and its emission contributes to the formation of ultrafine particles. We investigate the effects of NOx level and humidity on the formation of secondary organic aerosol (SOA) generated from the photooxidation of furan in the presence of NaCl seed particles. SOA mass concentration and yield were determined under different NOx and humidity levels. A significant difference is observed both in the variation of SOA mass concentration and SOA yield with the initial experimental conditions. Varying VOC (volatile organic compound) ∕ NOx ratios over the range 48.1 to 8.2 contributes to the effective formation of SOA in the presence of NaCl seed particles, with the SOA mass concentration and SOA yield ranging from 0.96 to 23.46 µg m−3 and from 0.04 % to 1.01 %, respectively. We found that there was a favourable relationship between the SOA yields and NOx concentration. In particular, the increase in SOA yield with increasing NOx concentration was continuously observed at high NOx levels owing to a corresponding increase in the amount of low-volatility hydroxyl nitrates and dihydroxyl dinitrates that can partition into the particle phase. In addition, varying relative humidity (RH) from 5 % to 88 % increased the SOA yield from 1.01 % to 5.03 %. The enhanced SOA formation from humid conditions may result from the high OH concentration, rapid furan decay rate, enhanced carbonyl-rich products condensation, and the aqueous-phase reactions. Using hybrid quadrupole-orbitrap mass spectrometer equipped with electrospray ionization (HESI-Q Exactive-Orbitrap MS), three carbonyl-rich products and three kinds of organonitrates were identified in the collected SOA. Based on the HESI-Q Exactive-Orbitrap MS analysis and Fourier transform infrared spectroscopy (FTIR), the reaction mechanism of furan photooxidation was proposed. This study demonstrates the effects of NOx and humidity on SOA formation during the furan–NOx–NaCl photooxidation and provides new insights into the oxidation regime and SOA composition in furan photooxidation. The results also illustrate the importance of studying SOA formation over a comprehensive range of environmental conditions. Only such evaluations can induce meaningful SOA mechanisms to be implemented in air quality models.

scholarly journals Secondary organic aerosol formation from photooxidation of furan: effects of NOx and humidity

2019 ◽  
Author(s):  
Xiaotong Jiang ◽  
Narcisse T. Tsona ◽  
Long Jia ◽  
Shijie Liu ◽  
Hailiang Zhang ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Ground Level ◽  
Organic Aerosol ◽  
Liquid Water Content ◽  
Aerosol Formation ◽  
Scanning Mobility Particle Sizer ◽  
Experimental Conditions ◽  
Significant Difference

Abstract. Atmospheric furan is a primary and secondary pollutant in the atmosphere, and its emission contributes to the formation of ultrafine particles and ground-level ozone. We investigate the effects of NOx level and humidity on the formation of secondary organic aerosol (SOA) generated from the photooxidation of furan in the presence of NaCl seed particles. The particle mass concentration and size distribution were determined with a scanning mobility particle sizer (SMPS). SOA mass concentration and yield were determined under different NOx and humidity levels. A significant difference is observed both in the SOA mass concentration and SOA yield variation with the initial experimental conditions. Six organic products were identified in the collected SOA by electrospray ionization exactive orbitrap mass spectrometry (ESI-Exactive-Orbitrap MS). The –COOH, –OH, –C=O and NO2 functional groups were assigned in the FTIR spectra and used as the indicator for the mechanism inference. In addition, O3 formation was also observed during the furan-NOx-NaCl photooxidation. Based on the MS analysis, the reaction mechanism was proposed to follow the RO2+NO pathway. A significant amount of carbonyl-rich products was detected in the SOA products from the photooxidation of furan. The SOA mass concentration and yield increase with increasing humidity, because higher aerosol liquid water content brings more aqueous phase reactions. The present study demonstrates the effect of NOx and humidity on SOA formation during the furan-NOx-NaCl photooxidation. Furthermore, the results illustrate the importance of studying SOA formation over a comprehensive range of environmental conditions. Only such evaluations can induce meaningful SOA mechanisms to be implemented in air quality models.

scholarly journals Secondary organic aerosol formation from photooxidation of furan: effects of NO<sub>x</sub> level and humidity

2018 ◽  
Author(s):  
Xiaotong Jiang ◽  
Narcisse T. Tsona ◽  
Long Jia ◽  
Shijie Liu ◽  
Yongfu Xu ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Ground Level ◽  
Organic Aerosol ◽  
Organic Nitrate ◽  
Aerosol Formation ◽  
Scanning Mobility Particle Sizer ◽  
Seed Particles ◽  
Significant Difference

Abstract. Atmospheric furan is both primary and secondary pollutants in the atmosphere, and their emission contributes to the formation of ultrafine particles and ground-level ozone. We investigate the effects of NOx level and humidity on the formation of secondary organic aerosol (SOA) generated from the photooxidation of furan in the presence of NaCl seed particles. The particle mass concentration and size distribution were determined with a scanning mobility particle sizer (SMPS). SOA mass concentration and yield were determined under different NOx and humidity levels. Owing to condensation and coagulation, the particle number concentration decreases with increasing particle size. A significant difference is observed both in the SOA mass concentration and SOA yield variation with the initial experiment conditions. A relatively high NOx level, ranging from 16.8 to 97.5 ppb, contributes to effective formation of SOA in the presence of NaCl seed particles, with the mass concentration of SOA and SOA yield ranging from 0.96 μg m−3 to 23.46 μg m−3 and from 0.04 % to 1.01 %, respectively. Likewise, the SOA mass concentration and yield increase with increasing humidity, because the increasing RH increases the aerosol liquid water content, which contributes to the liquid phase reactions. Nine organic nitrate species were detected by electrospray ionization exactive orbitrap mass spectrometry (ESI-Exactive-Orbitrap MS). The -COOH，-OH，-C = O and NO2 functional groups were assigned in the FTIR spectra and used as the indicator for the mechanism inference. The present study directly addresses NOx effects and reinforces the implication of humidity on SOA formation during the furan-NOx-NaCl photooxidation. Furthermore, the results illustrate the importance of studying SOA formation over a comprehensive range of environmental conditions. Only such evaluations can induce meaningful SOA mechanisms to be implemented in air quality models.

scholarly journals Gaseous products and secondary organic aerosol formation during long term oxidation of isoprene and methacrolein

2015 ◽  
Vol 15 (6) ◽  
pp. 2953-2968 ◽  
Author(s):  
L. Brégonzio-Rozier ◽  
F. Siekmann ◽  
C. Giorio ◽  
E. Pangui ◽  
S. B. Morales ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Solar Spectrum ◽  
Organic Aerosol ◽  
Product Distribution ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Experimental Conditions ◽  
Gaseous Products ◽  
Oxidation Rates

Abstract. First- and higher order-generation products formed from the oxidation of isoprene and methacrolein with OH radicals in the presence of NOx have been studied in a simulation chamber. Significant oxidation rates have been maintained for up to 7 h, allowing the study of highly oxidized products. Gas-phase product distribution and yields were obtained, and show good agreement with previous studies. Secondary organic aerosol (SOA) formation has also been investigated. SOA mass yields from previous studies show large discrepancies. The mass yields obtained here were consistent with the lowest values found in the literature, and more specifically in agreement with studies carried out with natural light or artificial lamps with emission similar to the solar spectrum. Differences in light source are therefore proposed to explain partially the discrepancies observed between different studies in the literature for both isoprene- and methacrolein-SOA mass yields. There is a high degree of similarity between the SOA mass spectra from isoprene and methacrolein photooxidation, thus strengthening the importance of the role of methacrolein in SOA formation from isoprene photooxidation under our experimental conditions (i.e., presence of NOx and long term oxidation). According to our results, SOA mass yields from both isoprene and methacrolein in the atmosphere could be lower than suggested by most of the current chamber studies.

scholarly journals Enhancement of Secondary Organic Aerosol Formation and its Oxidation State by SO<sub>2</sub> during Photooxidation of 2-Methoxyphenol

2018 ◽  
Author(s):  
Changgeng Liu ◽  
Tianzeng Chen ◽  
Yongchun Liu ◽  
Jun Liu ◽  
Hong He ◽  
...  
Keyword(s):  
Oxidation State ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Wood Smoke ◽  
Organic Nitrates ◽  
Carbon Oxidation ◽  
Formation Processes ◽  
Aerosol Formation ◽  
Product Model ◽  
Seed Particles

Abstract. 2-Methoxyphenol (guaiacol) is derived from the lignin pyrolysis and taken as a potential tracer for wood smoke emissions. In this work, the effect of SO2 at atmospheric levels (0–56 ppb) on secondary organic aerosol (SOA) formation and its oxidation state during guaiacol photooxidation was investigated in the presence of various inorganic seed particles (NaCl and (NH4)2SO4). Without SO2 and seed particles, SOA yields (9.46–26.37 %) obtained at different guaiacol concentration (138.83–2197.36 μg m−3) could be well expressed by a one-product model. The presence of SO2 resulted in enhancing SOA yield by 14.05–23.66 %. With (NH4)2SO4 and NaCl seed particles, SOA yield was enhanced by 23.06 % and 29.57 %, respectively, which further increased significantly to 29.78–53.47 % in the presence of SO2, suggesting that SO2 and seed particles have a synergetic contribution to SOA formation. It should be noted that SO2 was found to be in favor of increasing the carbon oxidation state (OSC) of SOA, indicating that the functionalization reaction should be more dominant than oligomerization reaction. In addition, the average N/C ratio of SOA was 0.037, which revealed that NOx participated in the photooxidation process, consequently leading to the formation of organic nitrates. The experimental results demonstrate the importance of SO2 on the formation processes of SOA and organosulfates, and also are helpful to further understand SOA formation from the atmospheric photooxidation of guaiacol and its subsequent impacts on air quality and climate.

scholarly journals Secondary organic aerosol formation from isoprene photooxidation during cloud condensation–evaporation cycles

2016 ◽  
Vol 16 (3) ◽  
pp. 1747-1760 ◽  
Author(s):  
L. Brégonzio-Rozier ◽  
C. Giorio ◽  
F. Siekmann ◽  
E. Pangui ◽  
S. B. Morales ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Multiphase Systems ◽  
Dry Conditions ◽  
Water Cloud ◽  
The Impact

Abstract. The impact of cloud events on isoprene secondary organic aerosol (SOA) formation has been studied from an isoprene ∕ NOx ∕ light system in an atmospheric simulation chamber. It was shown that the presence of a liquid water cloud leads to a faster and higher SOA formation than under dry conditions. When a cloud is generated early in the photooxidation reaction, before any SOA formation has occurred, a fast SOA formation is observed with mass yields ranging from 0.002 to 0.004. These yields are 2 and 4 times higher than those observed under dry conditions. When the cloud is generated at a later photooxidation stage, after isoprene SOA is stabilized at its maximum mass concentration, a rapid increase (by a factor of 2 or higher) of the SOA mass concentration is observed. The SOA chemical composition is influenced by cloud generation: the additional SOA formed during cloud events is composed of both organics and nitrate containing species. This SOA formation can be linked to the dissolution of water soluble volatile organic compounds (VOCs) in the aqueous phase and to further aqueous phase reactions. Cloud-induced SOA formation is experimentally demonstrated in this study, thus highlighting the importance of aqueous multiphase systems in atmospheric SOA formation estimations.

scholarly journals Gaseous products and Secondary Organic Aerosol formation during long term oxidation of isoprene and methacrolein

2014 ◽  
Vol 14 (16) ◽  
pp. 22507-22545 ◽  
Author(s):  
L. Brégonzio-Rozier ◽  
F. Siekmann ◽  
C. Giorio ◽  
E. Pangui ◽  
S. B. Morales ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Experimental Conditions ◽  
Gaseous Products ◽  
Oxidation Rates ◽  
Chamber Studies ◽  
High Degree

Abstract. First- and higher-generation products from the oxidation of isoprene and methacrolein with OH radicals in the presence of NOx have been studied in a simulation chamber: (1) significant oxidation rates have been maintained for up to 7 h allowing the study of highly oxidized products, (2) gas-phase products distribution and yields are provided, and show good agreement with previous studies. Secondary organic aerosol (SOA) formation resulting from these experiments has also been investigated. Among the general dispersion exhibited by SOA mass yields from previous studies, the mass yields obtained here were consistent with the lowest values found in the literature, and more specifically in agreement with studies carried out with natural light or artificial lamps with emission spectrum similar to the solar one. An effect of light source is hence proposed to explain, at least in part, the discrepancies observed between different studies in the literature for both isoprene- and methacrolein-SOA mass yields. A high degree of similarity is shown in the comparison of SOA mass spectra from isoprene and methacrolein photooxidation, thus strengthening the importance of the role of methacrolein in SOA formation from isoprene photooxidation under our experimental conditions (i.e. presence of NOx and long term oxidation). Overall, if these results are further confirmed, SOA mass yields from both isoprene and methacrolein in the atmosphere could be lower than suggested by most of the current chamber studies.

scholarly journals Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

2018 ◽  
Vol 18 (8) ◽  
pp. 5677-5689 ◽  
Author(s):  
Tengyu Liu ◽  
Dan Dan Huang ◽  
Zijun Li ◽  
Qianyun Liu ◽  
ManNin Chan ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Functional Groups ◽  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Seed Particles ◽  
The Difference ◽  
Wet Particles

Abstract. The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm−3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm−3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m ∕ z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS), indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory experiments conducted with a wide variety of SOA precursors and inorganic seeds under different NOx and RH conditions are warranted.

scholarly journals In-cloud processes of methacrolein under simulated conditions – Part 2: Formation of secondary organic aerosol

2009 ◽  
Vol 9 (14) ◽  
pp. 5107-5117 ◽  
Author(s):  
I. El Haddad ◽  
L. Nieto-Gligorovski ◽  
V. Michaud ◽  
B. Temime-Roussel ◽  
E. Quivet ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Aqueous Phase ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Esi Ms ◽  
Aerosol Mass Concentration

Abstract. The fate of methacrolein in cloud evapo-condensation cycles was experimentally investigated. To this end, aqueous-phase reactions of methacrolein with OH radicals were performed (as described in Liu et al., 2009), and the obtained solutions were then nebulized and dried into a mixing chamber. ESI-MS and ESI-MS/MS analyses of the aqueous phase composition denoted the formation of high molecular weight multifunctional products containing hydroxyl, carbonyl and carboxylic acid moieties. The time profiles of these products suggest that their formation can imply radical pathways. These high molecular weight organic products are certainly responsible for the formation of secondary organic aerosol (SOA) observed during the nebulization experiments. The size, number and mass concentration of these particles increased significantly with the reaction time: after 22 h of reaction, the aerosol mass concentration was about three orders of magnitude higher than the initial aerosol quantity. The evaluated SOA yield ranged from 2 to 12%. These yields were confirmed by another estimation method based on the hygroscopic and volatility properties of the obtained SOA measured and reported by Michaud et al. (2009). These results provide, for the first time to our knowledge, strong experimental evidence that cloud processes can act, through photooxidation reactions, as important contributors to secondary organic aerosol formation in the troposphere.

scholarly journals Secondary Organic Aerosol formation from isoprene photooxidation during cloud condensation–evaporation cycles

2015 ◽  
Vol 15 (14) ◽  
pp. 20561-20596 ◽  
Author(s):  
L. Brégonzio-Rozier ◽  
C. Giorio ◽  
F. Siekmann ◽  
E. Pangui ◽  
S. B. Morales ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Mass Concentration ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Multiphase Systems ◽  
Dry Conditions ◽  
Water Cloud ◽  
The Impact

Abstract. The impact of cloud events on isoprene secondary organic aerosol (SOA) formation has been studied from an isoprene/NOx/light system in an atmospheric simulation chamber. It was shown that the presence of a liquid water cloud leads to a faster and higher SOA formation than under dry conditions. When a cloud is generated early in the photooxidation reaction, before any SOA formation has occurred, a fast SOA formation is observed with mass yields ranging from 0.002 to 0.004. These yields are two and four times higher than those observed under dry conditions. When the cloud is generated at a later photooxidation stage, after isoprene SOA is stabilized at its maximum mass concentration, a rapid increase (by a factor of two or higher) of the SOA mass concentration is observed. The SOA chemical composition is influenced by cloud generation: the additional SOA formed during cloud events is composed of both organics and nitrate containing species. This SOA formation can be linked to water soluble volatile organic compounds (VOCs) dissolution in the aqueous phase and to further aqueous phase reactions. Cloud-induced SOA formation is experimentally demonstrated in this study, thus highlighting the importance of aqueous multiphase systems in atmospheric SOA formation estimations.

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