Urban Pollution - harmful contamination from tyre wear

 

 

Tyre wear produces 1,000 times MORE harmful pollution than car exhausts.

Tyre wear particles

Particles from the wearing of car tyres while they are driven pollute the air we breathe. The long-term effects on our health from such particles is potentially especially damaging due to the toxic chemicals that they are made from.

In London alone there are 2.6 million registered vehicles emitting approximately 9 million kg of tyre wear particles per year, releasing a range of toxins into the environment¹.

Tyre wear particles contribute significantly to the amount of synthetic (or polymeric) particulate pollution being released into our environment. While large particles are transported by road runoff due to rainwater, resulting in the leaching of toxic chemicals and damaging the environment, smaller particles, of the micro and nanoscale, are small enough to become airborne and breathed in². (Wagner et al., 2018).

In urban areas some 10% of tyre wear particles are expelled into the air and both micro and nano sized particles can travel hundreds of metres, potentially ending up indoors^1,3.

In a typical home inside air leaks out and outside air leaks in, typically resulting in new air from the outside replacing the existing air inside every hour or so. 

This is not a design fault, without a substantial amount of air circulating between the outside and inside our homes can become “sick”, with condensation and mould damaging the walls and fabric of our houses, aggravating allergies and

This then is the conundrum, we need air to circulate from outside to inside, but in areas with high external pollution that circulation continuously brings outside pollution into our homes.

Tyre wear particles and human health

The impact of tyre wear particles on human health is an increasing cause for concern. During the manufacturing process, chemicals are combined to form high-endurance rubber, which is then cast into a tyre form. Ingredients include harmful substances including polyaromatic hydrocarbons (PAHs), benzothiazoles (BZTs) and isoprene⁴.

Toxicology studies into ambient particulate matter, which includes TWP, report that these particles contribute to negative cardiopulmonary, developmental, reproductive and cancer outcomes⁵.

Then along came Airora…

Let us return to where we started, outdoors;

Outdoors, nature wages a powerful and successful war of attrition against atmospheric pollution by employing natural chemical and photochemical interactions to create an abundance of ‘hydroxyl radicals’ (known as ‘Nature’s Detergent’ by scientists) which attack and neutralise a wide range of pollutants. 

But hydroxyls are not abundant indoors, only outdoors. Airora is the only technology that can create that same safe and effective Hydroxyl Cascade inside your home, attacking and neutralise a wide range of pollutants.

Airora is not a filter, the air to be cleaned does not have to pass through the device, Airora’s molecular cascade reaction spreads the hydroxyls throughout the air in a room in seconds, ultimately degrading PAHs, BZTs and Isoprene into harmless carbon dioxide, water, and other small inorganic molecules.

 

 

How Airora degrades and destroys PAHs, BZTs and isoprene

Polyaromatic hydrocarbons (PAHs)

Hydroxyl radicals are known to effectively degrade and destroy polyaromatic hydrocarbons (PAHs) through oxidative reactions⁹. Polyaromatic hydrocarbons are a class of organic compounds composed of two or more fused aromatic rings, and they are considered persistent environmental pollutants.

Hydroxyl radicals are highly reactive and can readily participate in oxidation reactions with PAHs, adding to the aromatic rings of PAHs and leading to the formation of unstable hydroxylated intermediates.

These intermediates then undergo further oxidation, ring-opening, and fragmentation reactions, eventually breaking down the PAH structure into carbon dioxide, water, and other small inorganic molecules.

Benzothiazoles (BZTs)

Hydroxyl radicals are known to effectively degrade and destroy benzothiazoles through oxidative reactions¹⁰.

Benzothiazoles are a class of heterocyclic organic compounds that consist of a benzene ring fused to a thiazole ring. They are used in a variety of applications, including as vulcanization accelerators in the rubber industry, corrosion inhibitors, and fungicides. However, benzothiazoles have also been identified as environmental pollutants, and their removal from various matrices is of importance.

Hydroxyl radicals are highly reactive and can readily participate in oxidation reactions with benzothiazoles.

The hydroxyl radical can add to the aromatic benzene ring of the benzothiazole structure, leading to the formation of unstable hydroxylated intermediates.

These intermediates can then undergo further oxidation, ring-opening, and fragmentation reactions, eventually breaking down the benzothiazole structure.

The continued oxidation and fragmentation of benzothiazoles by hydroxyl radicals  ultimately results in the complete mineralization of the compounds, converting them into carbon dioxide, water, and other small inorganic molecules.

Isoprene

Hydroxyl radicals are known to effectively degrade and destroy isoprene through oxidative reactions¹¹.

Isoprene is a volatile organic compound (VOC) that is naturally produced by many plants and is also generated as a byproduct of various industrial processes. It is an important precursor for the formation of tropospheric ozone and secondary organic aerosols, which can have significant impacts on air quality and climate.

The reaction between isoprene and hydroxyl radicals is initiated by the addition of the hydroxyl radical to the carbon-carbon double bonds in the isoprene molecule.

This addition forms unstable hydroxylated intermediate radical species, which can further undergo a series of reactions, ultimately breaking down the isoprene structure.

The continued oxidation and fragmentation of isoprene by hydroxyl radicals  ultimately results in the complete mineralization of the compound, converting it into carbon dioxide, water, and other small inorganic molecules.

 

 

You can find out all about Airora at airora.com

And contact us at support@airora.com

References:

1. Kole, P. J. et al., (2017) Wear and Tear of Tyres: A Stealthy Source of Microplastics in the Environment. Int J Environ Res Public Health. 14 (10).
2. Wagner, S et al., (2018) Tire wear particles in the aquatic environment - A review on generation, analysis, occurrence, fate and effects. Water Research. 139, 83-100.
3. Raza, M. at el., (2018) A Review of Particulate Number (PN) Emissions from Gasoline Direct Injection (GDI) Engines and Their Control Techniques. Energies. 6 and .
4. Halsband, C. et al., (2020) Car Tire Crumb Rubber: Does Leaching Produce a Toxic Chemical Cocktail in Coastal Marine Systems? Frontiers in Environmental Science. 8.
5. Baensch-Baltruschat, B. Et al., (2021) Tyre and road wear particles – A calculation of generation, transport and release to water and soil with special regard to German roads. Sci Total Environ. 752, 141939.
6. Patel, A. B. et al., (2020) Polycyclic Aromatic Hydrocarbons: Sources, Toxicity, and Remediation Approaches. Front Microbiology. 11, 562813
7. Liao, C. et al., A Review of Environmental Occurrence, Fate, Exposure, and Toxicity of Benzothiazoles. Environmental Science & Technology. 52 (9), 5007-5026.
8. Melnick, R. (1994) NTP Technical Report on Toxicity Studies of Isoprene.
9. Preety G. et al., (2021) Sonochemical degradation of polycyclic aromatic hydrocarbons: a review Environmental Chemistry Letters
10. Chen Y. et al., (2018) Degradation of 1H-benzotriazole by UV/H2O2 and UV/TiO2: kinetics, mechanisms, products and toxicology. Environmental Science: Water Research & Technology (RSC Publishing)
11. Torsten B. et al., (2019) First oxidation products from the reaction of hydroxyl radicals with isoprene for pristine environmental conditions. Communications Chemistry volume 2, Article number: 21