Cytotoxic Free Radicals on Air-Borne Soot Particles...

Research studies on wood smoke and other air pollution.

Cytotoxic Free Radicals on Air-Borne Soot Particles...

Postby Wilberforce » Sun Mar 08, 2020 7:45 pm

RESEARCH
https://pubs.acs.org/doi/10.1021/acs.est.9b06395
Cytotoxic Free Radicals on Air-Borne Soot Particles Generated by Burning Wood or Low-Maturity Coals
Hanzhong JiaShuaishuai LiLan WuShiqing LiVirender K. SharmaBing Yan*

Cite this: Environ. Sci. Technol. 2020, XXXX, XXX, XXX-XXX
Publication Date:February 21, 2020
https://doi.org/10.1021/acs.est.9b06395
Copyright © 2020 American Chemical Society

Abstract
The traditional cook stove is a major contributor to combustion-derived soot particles, which contain various chemical species that may cause a significant impact to human health and ecosystems. However, properties and toxicity associated with environmentally persistent free radicals (EPFRs) in such emissions are not well known. This paper investigated the characteristics and cytotoxicity of soot-associated EPFRs discharged from Chinese household stoves. Our results showed that the concentrations of EPFRs were related to fuel types, and they were higher in wood-burning soot (8.9–10.5 × 1016 spins/g) than in coal-burning soot (3.9–9.7 × 1016 spins/g). Meanwhile, EPFR concentrations in soot decreased with an increase of coal maturity. The soot EPFRs, especially reactive fractions, readily induced the generation of reactive oxygen species (ROS). Potential health effects of soot EPFRs were also examined using normal human bronchial epithelial cell line 16HBE as a model. Soot particles were internalized by 16HBE cells inducing cytotoxicity. The main toxicity inducers were identified to be reactive EPFR species, which generated ROS inside human cells. Our findings provided valuable insights into potential contributions of soot EPFRs associated with different types of fuel to health problems. This information will support regulations to end or limit current stove usage in numerous households.

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Re: Cytotoxic Free Radicals on Air-Borne Soot Particles...

Postby Wilberforce » Sun Mar 15, 2020 2:11 pm

https://www.ncbi.nlm.nih.gov/pubmed/25942056
Combustion Processes as a Source of High Levels of Indoor Hydroxyl Radicals through the Photolysis of Nitrous Acid.
Bartolomei V1, Gomez Alvarez E1, Wittmer J2, Tlili S1, Strekowski R1, Temime-Rouss
Environ Sci Technol. 2015 Jun 2;49(11):6599-607. doi: 10.1021/acs.est.5b01905. Epub 2015 May 15.
https://doi.org/10.1021/acs.est.5b01905

Environ Sci Technol. 2015 Jun 2;49(11):6599-607. doi: 10.1021/acs.est.5b01905. Epub 2015 May 15.
Combustion Processes as a Source of High Levels of Indoor Hydroxyl Radicals through the Photolysis of Nitrous Acid.
Bartolomei V1, Gomez Alvarez E1, Wittmer J2, Tlili S1, Strekowski R1, Temime-Roussel B1, Quivet E1, Wortham H1, Zetzsch C2, Kleffmann J3, Gligorovski S1.
Abstract

Hydroxyl radicals (OH) are known to control the oxidative capacity of the atmosphere but their influence on reactivity within indoor environments is believed to be of little importance. Atmospheric direct sources of OH include the photolysis of ozone and nitrous acid (HONO) and the ozonolysis of alkenes. It has been argued that the ultraviolet light fraction of the solar spectrum is largely attenuated within indoor environments, thus, limiting the extent of photolytic OH sources. Conversely, the ozonolysis of alkenes has been suggested as the main pathway of OH formation within indoor settings. According to this hypothesis the indoor OH radical concentrations span in the range of only 10(4) to 10(5) cm(-3). However, recent direct OH radical measurements within a school classroom yielded OH radical peak values at moderate light intensity measured at evenings of 1.8 × 10(6) cm(-3) that were attributed to the photolysis of HONO. In this work, we report results from chamber experiments irradiated with varying light intensities in order to mimic realistic indoor lighting conditions. The exhaust of a burning candle was introduced in the chamber as a typical indoor source causing a sharp peak of HONO, but also of nitrogen oxides (NOx). The photolysis of HONO yields peak OH concentration values, that for the range of indoors lightning conditions were estimated in the range 5.7 ×· 10(6) to 1.6 × 10(7) cm(-3). Excellent agreement exists between OH levels determined by a chemical clock and those calculated by a simple PSS model. These findings suggest that significant OH reactivity takes place at our dwellings and the consequences of this reactivity-that is, formation of secondary oxidants-ought to be studied hereafter.


PMID:25942056
DOI:10.1021/acs.est.5b01905
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https://www.hindawi.com/journals/omcl/2011/809696/
Hydroxyl Radical and Its Scavengers in Health and Disease
Review Article | Open Access
Volume 2011 |Article ID 809696 | 9 pages
https://doi.org/10.1155/2011/809696

It is generally believed that diseases caused by oxidative stress should be treated with antioxidants. However, clinical trials with such antioxidants as ascorbic acid and vitamin E, failed to produce the expected beneficial results. On the other hand, important biomolecules can be modified by the introduction of oxygen atoms by means of non-oxidative hydroxyl radicals. In addition, hydroxyl radicals can reduce disulfide bonds in proteins, specifically fibrinogen, resulting in their unfolding and scrambled refolding into abnormal spatial configurations. Consequences of this reaction are observed in many diseases such as atherosclerosis, cancer and neurological disorders, and can be prevented by the action of non-reducing substances. Moreover, many therapeutic substances, traditionally classified as antioxidants, accept electrons and thus are effective oxidants. It is described in this paper that hydroxyl radicals can be generated by ferric ions without any oxidizing agent. In view of the well-known damaging effect of poorly chelated iron in the human body, numerous natural products containing iron binding agents can be essential in the maintenance of human health. However, beneficial effects of the great number of phytochemicals that are endowed with hydroxyl radical scavenging and/or iron chelating activities should not be considered as a proof for oxidative stress.

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Related
Hydroxyl Ion versus Hydroxyl Radical
https://www.lifeionizers.com/blog/hydro ... l-radical/
• The Surgeon General has determined that there is no safe level of exposure to ambient smoke!

• If you smell even a subtle odor of smoke, you are being exposed to poisonous and carcinogenic chemical compounds!

• Even a brief exposure to smoke raises blood pressure, (no matter what your state of health) and can cause blood clotting, stroke, or heart attack in vulnerable people. Even children experience elevated blood pressure when exposed to smoke!

• Since smoke drastically weakens the lungs' immune system, avoiding smoke is one of the best ways to prevent colds, flu, bronchitis, or risk of an even more serious respiratory illness, such as pneumonia or tuberculosis! Does your child have the flu? Chances are they have been exposed to ambient smoke!
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