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To stop the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, social distancing and lockdown measures were administered worldwide. Amidst the crisis, major city air pollution reduced by up to 50%, owing to the global reduction in manufacturing, traveling, and construction. This article discusses how a novel nanoarchitecture technology-based air purifying system aids in the reduction of air pollution.
The Consequences of Air Pollution
Air pollution reductions have indicated how modern society is dependent on the combustion of fossil fuels. The burning of fossil fuels leads to the release of toxic gases such as volatile organic compounds (VOCs), nitrogen oxides, and poisonous carbon monoxide gas. These gases are extremely harmful to human health and the environment. For example, VOCs such as formaldehyde can cause cancer, and it has been reported that an ozone molecule is created when VOCs react with nitrogen oxides. This causes breathing problems and even premature death. The World Health Organization (WHO) stated that every year seven million people lose their lives due to poor air quality.
In 1950, mechanical engineer Eugene Houdry first invented the catalytic converter to address the black smog that was choking Los Angeles and other American cities. Catalytic converters utilize expensive metals such as platinum or palladium. These catalysts help to speed up the chemical conversion of harmful air pollutants to fewer toxic byproducts such as carbon dioxide, water vapor, and nitrogen. Researchers across the globe are working extensively to create effective and economical air purifying systems to decrease the pollution level in the air.
Technologies that are commonly used for air purification are based on adsorption, filtration, ionization or attraction of particulates, and production of highly reactive radicals that can breakdown various pollutants. However, these technologies are inefficient and often require complex maintenance such as frequent replacement of filters and adsorbents that also results in the production of toxic secondary pollutants.
Nanoarchitecture Technology and Development of an Air Purifying System
Researchers have understood the need for the development of a technology that would not only be efficient in decreasing the air pollution levels but also make the parts of the catalytic converters flexible, detachable, and cost-effective.
While solving the above-stated problem, a team of researchers at The Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) realized that nature has already created an amazing technology millions of years ago: “butterfly wings”.
When studying butterfly wings under a microscope, scientists observed that the surface of a butterfly's wing consists of a porous and rigid architecture. These features impart unique physical properties to the butterfly’s wing such as water resistance, color, stability, and temperature control. The team recognized that they could mimic this nanoscale architecture and develop a customizable scaffold for catalysts. Such architecture would offer control over the size, composition, and position of the catalytic nanoparticles and help the shape and pattern of the scaffold.
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The research team recently announced its startup company called Metalmark, which has recently licensed the catalytic nanoarchitecture technology and will produce an efficient air purification system for removing harmful pathogens such as SARS-CoV-2, and other pollutants from indoors and in-cabin air in airplanes.
Metalmark and its Advanced Air Purifying System
During the development of a prototype, nanoparticles of the catalyst were positioned at specific points on the honeycomb-like organic colloid scaffold. Such placements ensure that every part of the catalyst is exposed to exhaust, reducing waste, and ensuring an efficient cleaning system.
This technology can also work efficiently at lower temperatures than a common catalytic converter and reduces ‘cold’ engine pollution. This technology can be easily incorporated into the commonly used catalytic converter production process. A simple switch to Metalmarks technology would bring down the production costs of catalytic converters required for air purification.
Tanya Shirman, VP of Material Design at Metalmark, listed three major drawbacks of the current catalytic converters. These are:
- Expensive because of the use of costly metals
- Inefficient as the entire catalyst does not meet the air that is subjected to the treatment
- The emissions of the ‘cold’ engines are left untreated as the catalysts only work within a specific temperature range.
She highlighted that Metalmarks technology has been successful in solving all the above-stated drawbacks.
Elijah Shirman, VP of Technology at Metalmark, said that most of the novel technologies developed in academic labs are not commercialized. This is because mass production is often very difficult in terms of preserving the functions and doing that can lead to a high cost of production.
Metalmarks has envisioned marketing the technology for large industrial plants and cars and the production of indoor air purification systems for offices, homes, and other buildings.
While explaining the technology, Sissi Liu, CEO, and co-founder of Metalmark stated why its technology is more advanced than existing ones. She explained that its air purification system filters out harmful substances while breaking down toxic pollutants and inactivating viruses and pathogens.
Metalmark’s most recent prototype was validated by a specialized national laboratory and is now being tested by an industrial partner. The company has also signed contracts with major multinational corporate customers.
References and Further Readings
Brownell, L. (2020) Cooler catalytic converters: Cleaner air for all. [Online] Phy.org. Available at: https://phys.org/news/2020-04-cooler-catalytic-cleaner-air.html
Brownell, L. (2020) Metalmark launches to make clean air affordable for all. [Online] Available at: https://wyss.harvard.edu/news/metalmark-launches-to-make-clean-air-affordable-for-all/
Wyss Institute. Nanoarchitectures for Air Purification. [Online] Available at: https://wyss.harvard.edu/technology/nanoarchitectures-for-air-purification/
Shirman, T. et al. (2019) Advanced nanostructured catalysts for efficient in-cabin air purification. 49th International Conference on Environmental Systems. ICES-2019-157 7-11 Boston, Massachusetts. https://ttu-ir.tdl.org/handle/2346/84927
Metalmark. [Online] Available at: https://www.metalmark.xyz/