Chemical composition and bioreactivity of PM2.5 during 2013 haze events in China

Ho, Kin Fai; Ho, Steven Sai Hang; Huang, Ru; Chuang, Hsiao Chi; Cao, Jun; Han, Yongming; Lui, Ka Hei; Ning, Zhi; Chuang, Kai Jen; Cheng, Tsun Jen; Lee, Shuncheng; Hu, Di; Wang, Bei; Zhang, Renjian

doi:10.1016/j.atmosenv.2015.11.055

Cited by 80 publications

(26 citation statements)

References 70 publications

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“…The average mass concentrations of PM2.5 and aerosol-phase SO4 2− were 39.21 g m −3 and 2.20 g m −3 , respectively. The mass concentration ratio of SO4 2− to PM2.5 was 6 % in this study, which 340 was lower than previous studies (Ho et al, 2016;Shao et al, 2018). The discrepancy may be accounted by the decreased ratio of SO4 2− to PM2.5 due to SO2 emissions control in recent years, as shown in the Supplement.…”

Section: Andcontrasting

confidence: 79%

Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

Xuan¹,

Chen²,

Gong³

et al. 2020

Preprint

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Abstract. Hydrogen peroxide (H2O2) is a vital oxidant in the atmosphere and plays critical roles in the oxidation chemistry of both liquid and aerosol phases. The partitioning of H2O2 between the gas and liquid phase or the aerosol phase could affect its abundance in these condensed phases and eventually the formation of secondary components. However, the partitioning processes of H2O2 in gas-liquid and gas-aerosol phases are still unclear, especially in the ambient atmosphere. In this study, field observations of gas-, liquid-, and aerosol-phase H2O2 were carried out in the urban atmosphere of Beijing during the summer and winter of 2018. The effective field-derived mean value of Henry's law constant (HAm, 2.1&#8201;&#215;&#8201;105&#8201;M&#8201;atm&#8722;1) was 2.5 times that of the theoretical value in pure water (HAt, 8.4&#8201;&#215;&#8201;104&#8201;M&#8201;atm&#8722;1) at 298&#8201;&#177;&#8201;2&#8201;K. The effective derived gas-aerosol partitioning coefficient (KPm, 3.8&#8201;&#215;&#8201;10&#8722;3&#8201;m3&#8201;&#956;g&#8722;1) was four orders of magnitude higher on average than the theoretical value (KPt, 2.8&#8201;&#215;&#8201;10&#8722;7&#8201;M&#8201;atm&#8722;1) at 270&#8201;&#177;&#8201;4&#8201;K. The partitioning of H2O2 in the gas-liquid and gas-aerosol phases in the ambient atmosphere does not only obey Henry's law or Pankow's absorptive partitioning theory but is also influenced by certain physical and chemical reactions. The average concentration of liquid-phase H2O2 in rainwater during summer was 44.12&#8201;&#177;&#8201;26.49&#8201;&#956;M. In three-quarters of the collected rain samples, the measured H2O2 was greater than the predicted value in pure water calculated by Henry's law. In these samples, 46&#8201;% of the measured H2O2 was from gas-phase partitioning, and most of the rest may have come from residual H2O2 in raindrops. In winter, the level of aerosol-phase H2O2 was 0.093&#8201;&#177;&#8201;0.085&#8201;ng&#8201;&#956;g&#8722;1, which was much higher than the predicted value based on Pankow's absorptive partitioning theory. Almost all aerosol-phase H2O2 was not from the partitioning of the gas phase. The decomposition/hydrolysis of aerosol-phase organic peroxides could be responsible for 32&#8201;% of aerosol-phase H2O2 formation at the maximum rate of 3.65&#8201;ng&#8201;&#956;g&#8722;1. Furthermore, the heterogeneous uptake of H2O2 on aerosols contributed to less than 0.5&#8201;%.

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Section: Andcontrasting

confidence: 79%

Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

Xuan¹,

Chen²,

Gong³

et al. 2020

Preprint

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show abstract

“…Besides, ROS generation is mediated through activation of MAPKs signals (ERK1/2, p38, and JNK), phosphorylation transcription factors (NF-κB and activator protein-1), and upregulation of the expression of pro-inflammation mRNA (MMPs, COX-2, and collagen types I and III) [44,45]. In addition, the overexpression of inflammatory cytokines (TNF-α, IFN-γ, IL-6, IL-8, IL-1α, and IL-1β) also plays a key role in PM-inducing oxidative stress that results in lipid peroxidation and DNA damage [46][47][48]. Another major mechanism entails endoplasmic reticulum stress, autophagy, and mitochondrial swelling caused by PM exposure, which increases the expression of pro-apoptotic markers (caspase-3/-9 and cytochrome c) and leads, thereby, to apoptosis that manifests as skin damage [49,50].…”

Section: Discussionmentioning

confidence: 99%

Effects of Microwave-Assisted Opuntia humifusa Extract in Inhibiting the Impacts of Particulate Matter on Human Keratinocyte Skin Cell

et al. 2020

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Particulate matter (PM) is one of the most important factors causing serious skin diseases, due to its generation of reactive oxygen species (ROS) over the course of long-term exposure. As a source of natural antioxidants, Opuntia humifusa (O. humifusa) is a potential candidate for the design of advanced formulations to prevent PM’s harmful effects. Unfortunately, its high viscosity does not allow it to be utilized in these formulations. In this present study, a new approach to the extract of O. humifusa using high-power microwave treatment, namely microwave-assisted O. humifusa extract (MA-OHE), was investigated. The results indicated that MA-OHE not only is a reasonable viscosity extract, but also enhances O. humifusa’s antioxidant properties. Additionally, this study also found that MA-OHE exhibited outstanding antioxidant and anti-inflammatory activities in eliminating PM’s effects, due to suppression of AhR degradation, ROS production, and COX-2 and MMP-9 expression in HaCaT keratinocytes. It is believed that MA-OHE is a potential cosmeceutical ingredient that could be utilized to prevent PM-induced skin oxidative stress and inflammation.

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“…In this study, the ratio of mass concentration of SO4 2− to PM2.5 was 6 %, which was lower than that in previous studies. The ratio in Beijing was 19 % in 2013 (Ho et al, 2016), and decreased to around 10 % in 2016−2017 (Shao et al, 2018;Xu et al, 2019).…”

Section: S4mentioning

confidence: 97%

Supplementary material to "Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases"

Xuan¹,

Chen²,

Gong³

et al. 2020

Preprint

View full text Add to dashboard Cite

Chemical composition and bioreactivity of PM2.5 during 2013 haze events in China

Cited by 80 publications

References 70 publications

Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

Effects of Microwave-Assisted Opuntia humifusa Extract in Inhibiting the Impacts of Particulate Matter on Human Keratinocyte Skin Cell

Supplementary material to "Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases"

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Chemical composition and bioreactivity of PM2.5 during 2013 haze events in China

Cited by 80 publications

References 70 publications

Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases

Effects of Microwave-Assisted Opuntia humifusa Extract in Inhibiting the Impacts of Particulate Matter on Human Keratinocyte Skin Cell

Supplementary material to &quot;Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases&quot;

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Supplementary material to "Partitioning of hydrogen peroxide in gas-liquid and gas-aerosol phases"