scholarly journals Characteristics and Sources of Environmentally Persistent Free Radicals in PM2.5 in Dalian: Important Role of Polycyclic Aromatic Hydrocarbons

2021 ◽  
Author(s):  
Zhansheng Li ◽  
Hongxia Zhao ◽  
Xintong Li ◽  
Tadiyose Girma Bekele
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Free Radicals ◽  
Aromatic Hydrocarbons ◽  
Airborne Particulate Matter ◽  
Mean Value ◽  
Biomass Combustion ◽  
Atmospheric Conditions ◽  
Secondary Sources ◽  
Polycyclic Aromatic

Abstract Environmentally persistent free radicals (EPFRs) are an emerging class of environmental hazardous contaminants that extensively, stably exist in airborne particulate matter and pose harmful effects on human health. However, there was little research about the sources of EPFRs in actual atmospheric conditions. This study reported the occurrence, characteristics and sources of EPFRs and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Dalian, China. The concentrations of PM2.5-bound EPFRs ranged from 1.13×1013 to 8.97×1015 spins/m3 (mean value: 1.14×1015 spins/m3). Carbon-centered radicals and carbon-centered radicals with adjacent oxygen atoms were detected. The concentration of ∑PAHs ranged from 1.09 to 76.24 ng/m3 and PAHs with high molecular weight (HMW) were predominant species in PM2.5. The correlation analysis and PMF result showed that coal and biomass combustion are the top contributors to EPFR, followed by vehicle emission. The secondary sources to EFPRs was negligible. The finding of present study provides an important evidence for further study on the formation mechanism of EPFRs in actual atmospheric to control the air pollution.

Role of alterations in ca2+‐associated signaling pathways in the immunotoxicity of polycyclic aromatic hydrocarbons

1995 ◽  
Vol 45 (2) ◽  
pp. 101-126 ◽  
Author(s):  
Donna R. Davila ◽  
DeAnn P. Davis ◽  
Kerry Campbell ◽  
John C. Cambier ◽  
Letitia A. Zigmond ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Signaling Pathways ◽  
Aromatic Hydrocarbons ◽  
Polycyclic Aromatic

9,10-Dinaphthylphenanthrene: Synthese, Rotationsisomerie und Photocyclisierung zu polycyclischen aromatischen Kohlenwasserstoffen9,10-Dinaphthylphenanthrenes: Synthesis, Rotational Isomers and Photocyclization to Polycyclic Aromatic Hydrocarbons

1992 ◽  
Vol 47 (12) ◽  
pp. 1764-1774 ◽  
Author(s):  
Karl-Dietrich Gundermann ◽  
Elke Romahn ◽  
Maximilian Zander
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Energy Transfer ◽  
Nmr Spectroscopy ◽  
Aromatic Hydrocarbons ◽  
Trans Isomers ◽  
Preparative Scale ◽  
Rotational Isomers ◽  
Polycyclic Aromatic

9,10-Di(1-naphthyl)phenanthrene (5 a) and 9,10-di(2-naphthyl)phenanthrene (5 b) have been synthesized. It is shown that 5 a and 5b both form two stable rotational (cis/trans) isomers with the naphthalene molecular planes perpendicular to the phenanthrene plane. In the case of 5 a the mixture of the two isomers has been separated in a preparative scale and each isomer characterized by e. g., NMR spectroscopy. Photocyclization of 5a leads to benzo[e]phenanthro[1,2,3,4-ghi]perylene (9) while 5 b yields phenanthro[9,10-i]pentahelicene (14); both hydrocarbons have not been previously described in the literature. The observed selectivities of photocyclization are explained on the basis of the structures and stabilities of the initially formed photoproducts (dihydro structures 15 and 14 a). The role of intramolecular non-radiative singlet-singlet energy transfer (naphthalene → phenanthrene) as competing with photocyclization is discussed in detail.

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