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What do air purifiers and buses have in common? A Bus Stop!

Updated: Jul 6, 2021

Sino Inno lab and Arup launched their innovative solutions to target some of the most pressing environmental and health issues. With a futuristic design, the bus stop CAPS 2.0 has proved to reduce pollution, removing 99.95% of PM0.1 particles, and killing even viruses, bacteria and fungi, improving air quality in its surroundings. It is basically a giant air purifier for cities.

But how does it work? Simply put, it employs a series of purifying features like Plasma air sanitation that kills viruses, bacteria, and fungi and multi-HEPA filters that remove harmful suspended particles.

Plascide micro-lightning technology. Source:

For the “nerds” like me, here is a more detailed explanation. The bus stop draws in the air from its surroundings that is first purified through the Plascide air sanitiser. The Plascide air sanitiser is a plasma filter-less air purification technology developed in Hong Kong by A-oneTech Limited and patented worldwide.

The Plascide generates micro-lightning plasma thunderclouds that electrocute airborne micro and nano-particles like viruses and bacteria in just 0.1 seconds. Plasma is the fourth state of matter after the gas state. At high temperature, gases become plasma due to ionisation.


The most common form of plasma in nature is given by lightning strikes. The lightning ionises the air, creating a column of plasma along the high voltage electrical path that charge the electrons so much that they “get excited” and leave their atom to stay alone in the air as negatively charged particles. Understandably, to keep the matter at a plasma state a constant source of high energy is needed. The bus stop generates and sustains this 4th state of matter within its Plascide generator that works as an energised container. Its air sanitisation capability is based on the generation of energetic charged particles (electrons and ions) and the associated physio-chemical effects that destroy by electrocution microbes and Volatile Organic Compounds (VOCs) like Formaldehyde, Benzene.

Moreover, since sanitisation takes place within the Plascide generator, no ions are released into the air. This technology has been tested and verified by independent laboratories like the MRIGlobal (USA), LMS Technologies (USA), the Center for Disease Control of China (PRC), the Société Générale de Surveillance (SGS) and the University of Hong Kong. The results show that Plascide has a much higher and faster sanitisation efficacy than other alternative technologies like UV.


​Once the Plascide technology, like a silent hit-man, kills viruses, bacteria and fungi, it’s time for the Multi-Hepa Filter system to capture fine airborne suspended particles (PM10 and PM2.5). By utilising an anti-bacteria, nano-porous filtration system, volatile organic compounds are decomposed, and microbes definitely eliminated. Finally, the sanitised cleaner air is released by the vents installed within the meatal cone-shaped columns of the bus stop.

During this process, a barrier of air curtain is created to shield the canopy underside preventing polluting air from entering the bus stop. It is like the invisible cloak of Harry Potter. It’s there, but you cannot see it. And if you thought that having a giant bus stop purifier surrounded by an aura of magic was already good enough, probably you did not think it all through. But Sino Inno lab and Arup did. So, they decided to make CAPS 2.0 a totally self-sustaining technology. Indeed, the process described above is powered by solar energy through 23m2 of photovoltaic panels installed on the roof of the bus stop. Furthermore, energy-saving aerofoil electronically commutated (EC) plug fans also ensure power is self-sustaining while consumption is kept to a minimum.

But, if a deadly (for viruses and bacteria), magic, self-sustained technology is still not enough for you, then what about “smart”? As reported on the website of Sino Inno lab “by embracing cloud technology, CAPS connects through IoT and mobile internet access for real-time monitoring, data comparison and interactive displays. Useful daily information on weather, air quality, bus schedules and other live data is provided”.

CAPS 2.0 in Hong Kong. Source:

The public in Hong Kong already had a first-hand experience of CAPS 2.0 at Central and Western District Promenade (Central Section). No complaints were raised. However, we thought about one. Indeed, CAPS 2.0 does not brew coffee or beer while waiting for your bus! Are we sure we want to see something like this on our streets?

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