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Free Radicals in Wood Smoke Emissions

PostPosted: Sat Mar 28, 2009 12:43 am
by Wilberforce

Carbon-Centered Free Radicals in Particulate Matter Emissions from Wood and Coal Combustion
Tian, et al

"Table 1 shows a comparison of the free radicals in PM emissions from different fuels. The average radical
intensities in PM emissions from Fatwood, pine wood, bituminous coal, and anthracite are 1.2 × 10ˆ18,
9.1 × 10ˆ17, 4.4 × 10ˆ17, and 2.3 × 10ˆ17 spins/gram, respectively. For comparison, the radical intensity
was reported to be 3 × 10ˆ16 spins/gram in cigarette tar and 1.3 × 10ˆ16 to 1.5 × 10ˆ17 spins/gram in
airborne PM2.5"


From the data, the various type of combustibles are listed in order of free-radical intensity.
For example: fatwood (kindling wood) has the most volatile "smoking" component, generating
40 times the amount of free-radicals than those found in tobacco smoke tar.

 Type             Amount*        Factor
Fatwood      1.2 × 10ˆ18        40X
Pine            9.1 × 10ˆ17        30X
Coal, Bt       4.4 × 10ˆ17        15X
Coal, An      2.3 × 10ˆ17         8X
PM 2.5        1.5 × 10ˆ17         5X
Tobacco      3.0 × 10ˆ16         1X

* number of unpaired electrons per gram of fuel

Note: Free radicals in the human body can accelerate aging and induce cellular damage.

Free radicals and antioxidants in human health: current status and future prospects.


Wood smoke is rich in cell-damaging free radicals

PostPosted: Sat Jul 17, 2010 6:36 pm
by Wilberforce

What are free radicals?

PostPosted: Sat Feb 12, 2011 7:59 pm
by Wilberforce
What are free radicals?

Free radicals are molecules or atoms with unpaired electrons. This open shell configuration is highly reactive, making the molecule or atom extremely likely to take part in a chemical reaction. Generally, radicals can be formed by homolytic bond cleavage usually between 2 atoms of similar electronegativity (often O-O or O-N bonds), or by single electron oxidation or reduction of an atom or molecule (eg, production of superoxide anions). Molecular oxygen is an example of a stable radical. Vitamin E forms a relatively stable (resonance stabilization) free radical intermediate during the repair of free radical damage. Persistent radicals are also relatively stable due to steric hindrance near the radical center, making it more difficult for the radical to react with another molecule. Examples of peristent radicals are nitroxides. Stable radicals and persistent radicals are examples of long lived radicals.

Biology of free radicals

Generally, free radicals react with other molecules, damaging them. However some processes such as the killing of bacteria by neutrophil granulocytes is beneficial. The most important oxygen-based free radicals are superoxide and the hydroxyl radical, produced from the reduction of molecular oxygen. These free radicals are extremely reactive and are often associated with cell damage, mutations, and even malignancies. Symptoms of aging such as atherosclerosis is thought to be due to oxidation by free radicals. The free radical theory of aging postulates that free radical damage is the primary mechanism of aging. Free radicals are also associated with liver damage due to alcohol and the development of emphysema from ciagrette smoking. The body has developed a number of mechanisms to minimize free radical damage and even repair damage. Enzymes such as superoxide dismutase, catalase, [[glutathione peroxidase]], and glutathione reductase, as well as antioxidants such as vitamin A, vitamin C, vitamin E, and polyphenols play important roles in protecting the body from free radical damage.

Mitochondria and free radicals
Free radicals can be produced inside mitochondria and are frequently released into the cytosol. The production of ATP in the mitochondria involves the transport of protons across the inner mitochondrial membrane via the electron transport chain. The electron transport chain passes electrons among molecules with each successive molecule having a greater reduction potential. The final electron acceptor is an oxygen molecule that normally is reduced to water, but in a small but significant percent of cases (1-2%), a superoxide anion results. The superoxide anion will take an extra electron from mtDNA, the mitochondrial membrane, proteins, resulting in mitochondrial damage. If too much damage takes place, the cell will undergo apoptosis. Apoptosis occurs due to a cascade initiated by Bcl-2 proteins on the surface of mitochondria. The free radical theory of aging states that aging occurs due to a loss of energy producing cells when mitochondria begin to die due to free radical damage.

Free radical defense

Superoxide dismutase (SOD) is present in both the mitochondria and the cytosol. SOD reacts with 2 superoxide anions to form 1 molecule of hydrogen peroxide. Hydrogen peroxide can be easily transformed into the dangerous hydroxyl radical via reaction with Fe2+. Catalase reacts with hydrogen peroxide to form water and oxygen. Glutathione peroxidase can also react with hydrogen peroxide, by reducing hydrogen peroxide and oxidizing glutathione. Glutathione is an antioxidant. Antioxidants are an important part of the free radical defense mechanism along with the enzymatic processes.


Re: Free Radicals in Wood Smoke Emissions

PostPosted: Thu Dec 19, 2013 6:02 pm
by Wilberforce
Secondary organic aerosol formation and primary organic aerosol oxidation from biomass-burning smoke
in a flow reactor during FLAME-3

A. M. Ortega1,2, D. A. Day1,3, M. J. Cubison1,3,*, W. H. Brune4, D. Bon1,3,5,**, J. A. de Gouw1,5, and J. L. Jimenez1,3 ... -2013.html

"Hydroxyl (OH) radical concentrations in the reactor reached up to ~1000 times average tropospheric levels"


Re: Free Radicals in Wood Smoke Emissions

PostPosted: Sun Nov 29, 2015 6:51 pm
by Wilberforce ... 012-0052OC
Radical-Containing Ultrafine Particulate Matter Initiates Epithelial-to-Mesenchymal Transitions in Airway Epithelial Cells
Thevenot et al
abstract [partial]
Environmentally persistent free radicals (EPFRs) in combustion-generated particulate matter (PM) are capable of inducing pulmonary pathologies and contributing to the development of environmental asthma

Re: Free Radicals in Wood Smoke Emissions

PostPosted: Fri Mar 25, 2016 4:12 pm
by Wilberforce
Exposure to combustion generated environmentally persistent free radicals enhances severity of influenza virus infection
Greg I Lee, Jordy Saravia, Dahui You, Bishwas Shrestha, Sridhar Jaligama, Valerie Y Hebert, Tammy R Dugas and Stephania A Cormier
http://particleandfibretoxicology.biome ... 014-0057-1
We demonstrate that EPFRs associated with combustion derived PM are important in enhancing severity and mortality following respiratory tract viral infections.
Our data demonstrate the benefit of antioxidant supplementation in reversing the enhanced disease due to influenza infection in the context of EPFR-containing
PM exposure. The antioxidant data further suggest that it may be clinically beneficial to identify at-risk infants (i.e., those who reside in high traffic areas, reside
in homes with smokers, live in homes where biomass fuels are used, etc.), so that supplementation with antioxidants prior to influenza season may be employed
to reduce disease burden.