Highly Elevated Levels and Particle-Size Distributions of Environmentally Persistent Free Radicals in Haze-Associated Atmosphere

Yang, Lili; Liu, Guorui; Jin, Rui-Bo; Zhu, Qingqing; Zhao, Yuyang; Wu, Xinke; Xu, Yang

doi:10.1021/acs.est.7b01929

Cited by 121 publications

(100 citation statements)

References 55 publications

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“…Thus far, we have reported data of EPFRs in airborne PM in six countries, i.e., China, Germany, Greece, India, Saudi Arabia and the USA. As listed in Table 1, there are various forms of sampling media for airborne PM, including a glass fiber filter (GFF) [21,31], quartz fiber filter (QFF) [32][33][34][35], Teflon membrane filter (TMF) [24,36,37], polytetrafluoroethylene (PTFE) [35,38,39], polycarbonate filter (PCF) [40], and even a leaf [41].…”

Section: Samplingmentioning

confidence: 99%

Environmentally persistent free radicals in PM2.5: a review

Tang

et al. 2019

Waste Dispos. Sustain. Energy

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Environmentally persistent free radicals (EPFRs) are a new class of pollutants that are long-lived in fine particles (PM 2.5), i.e., their 1/e lifetime ranges from days to months (or even infinite). They are capable of producing harmful reactive oxygen species such as hydroxyl radicals. The redox cycling of EPFRs is considered as an important pathway for PM 2.5 to induce oxidative stress inside the humans, causing adverse health effects such as respiratory and cardiovascular diseases. Consequently, research regarding their toxicity, formation and environmental occurrences in PM 2.5 has attracted increasing attentions globally during the past two decades. However, literature data in this field remain quite limited and discrete. Hence, an extensive review is urgently needed to summarize the current understanding of this topic. In this work, we systematically reviewed the analytical methods and environmental occurrences, e.g., types, concentrations, and decay behaviors, as well as possible sources of EPFRs in PM 2.5. The types of pretreatment methods, g-values of common EPFRs and categories of decay processes were discussed in detail. Moreover, great efforts were made to revisit the original data of the published works of EPFRs in airborne particulate matter and provided additional useful information for comparison where possible, e.g., their mean and standard deviation of g-values, line widths (∆H p-p), and concentrations. Finally, possible research opportunities were highlighted to further advance our knowledge of this emerging issue.

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Section: Samplingmentioning

confidence: 99%

Environmentally persistent free radicals in PM2.5: a review

Tang

et al. 2019

Waste Dispos. Sustain. Energy

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“…This speculation supplements our previous study on the sources of EPFRs in the atmospheric PM. In that they arise not only from human activities, such as coal burning, automobile exhaust, biomass burning, and thermal processes, 39 but also from the transformation of organic pollutants with catalysis by metal oxide- containing particles, and especially metal oxide nanoparticles. The synergic toxicity of the metal oxide nanoparticles and EPFRs should be investigated further.…”

Section: 38mentioning

confidence: 99%

Pivotal Roles of Metal Oxides in the Formation of Environmentally Persistent Free Radicals

Yang

Liu

Jin

et al. 2017

Environ. Sci. Technol.

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105

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Environmentally persistent free radicals (EPFRs) are emerging pollutants that can adversely affect human health. Although the pivotal roles of metal oxides in EPFR formation have been identified, few studies have investigated the influence of the metal oxide species, size, or concentration on the formation of EPFRs. In this study, EPFR formation from a polyaromatic hydrocarbon with chlorine and hydroxyl substituents (2,4-dichloro-1-naphthol) was investigated using electron paramagnetic resonance spectroscopy. The effect of the metal oxide on the EPFR species and its lifetime and yield were evaluated. The spectra obtained with catalysis by CuO, Al 2 O 3 , ZnO, and NiO were obviously different, indicating that different EPFRs formed. The abilities of the metal oxides to promote EPFR formation were in the order Al 2 O 3 > ZnO > CuO > NiO, which were in accordance with the oxidizing strengths of the metal cations. A decay study showed that the generated radicals were persistent, with a maximum 1/e lifetime of 108 days on the surface of Al 2 O 3 . The radical yields were dependent on the concentration and particle size of the metal oxide. Metal oxide nanoparticles increased the EPFR concentrations more than micrometer-sized particles.

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“…This particulate matter is related to combustion, which indicates that coal combustion in winter may provide an important contribution to EPFRs. The EPFR concentration in the fine PM of Linfen reported above is equivalent to that in the fine PM of Xi'an, but it is ten times smaller than that in the fine PM of Beijing (Yang et al, 2017;Chen et al, 2019b). Although the particle size distribution characteristics of EPFRs in winter and summer are different, their concentration levels are similar, which indicates that the EPFR concentration is not related to the PM concentration, but is determined by the source characteristics.…”

Section: Concentrations and Types Of Epfrsmentioning

confidence: 73%

Size-resolved exposure risk of persistent free radicals (PFRs) in atmospheric aerosols and their potential sources

Chen¹,

Sun²,

Song³

et al. 2020

Preprint

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<p><strong>Abstract.</strong> Environmentally persistent free radicals (EPFRs) are a new type of substance with potential health risks. EPFRs are widely present in atmospheric particulates, but there is a limited understanding of the size-resolved health risks of these radicals. This study first reported the exposure risks and source of EPFRs in atmospheric particulate matter (PM) of different particle sizes (<&#8201;10&#8201;&#956;m) in Linfen, a typical coal-burning city in China. The type of EPFRs in fine particles (<&#8201;2.1&#8201;&#956;m) is different from that in coarse particles (2.1&#8211;10&#8201;&#956;m) in both winter and summer. However, the EPFR concentration is higher in coarse particles than in fine particles in summer, and the opposite trend is found in winter. In both seasons, combustion sources are the main sources of EPFRs with coal combustion as the major contributor in winter, while biomass combustion is the major source in summer. Dust contributes part of the EPFRs and it is mainly present in coarse particles in winter and the opposite in summer. The upper respiratory tract was found to be the area with the highest risk of exposure to EPFRs of the studied aerosols, with an exposure equivalent to that of approximately 21 cigarettes per person per day. Alveolar exposure to EPFRs is equivalent to 8 cigarettes per person per day, with combustion sources contributing the most to EPFRs in the alveoli. This study helps us to better understand the potential health risks of atmospheric PM with different particle sizes.</p>

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Highly Elevated Levels and Particle-Size Distributions of Environmentally Persistent Free Radicals in Haze-Associated Atmosphere

Cited by 121 publications

References 55 publications

Environmentally persistent free radicals in PM2.5: a review

Environmentally persistent free radicals in PM2.5: a review

Pivotal Roles of Metal Oxides in the Formation of Environmentally Persistent Free Radicals

Size-resolved exposure risk of persistent free radicals (PFRs) in atmospheric aerosols and their potential sources

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