Public transport is in crisis – clean air technology could be the solution


To coincide with the company’s appearance at the UITP Asia-Pacific Conference this week, Marc Ottolini, CEO of AirLabs writes of the potential for air cleaning technology to solve the public transport crisis caused by COVID-19.

The public transport industry is under strain.

The global lockdowns at the start of the COVID-19 crisis led to a staggering 90% drop in revenue and the recovery has been sluggish, with revenues still down by almost half and not expected to return to normal until 2024 at the earliest.

Public transport providers have played a valiant role in supporting our economies and helping commuters into work during the pandemic, often running increased services despite significantly reduced passenger numbers due to social distancing. But they cannot continue to do that forever. Already we have seen a number of providers warn that their businesses are under serious threat, which will only get worse the longer the pandemic continues.

Customer confidence is at an all time low and recent research has shown that 70% of Londoners no longer feel comfortable with the idea of commuting to work via public transport, so how can we make public transport COVID-safe and persuade the public to get back on board?

Airborne coronavirus

To reduce the risk of catching coronavirus we must first understand how it is spread.

Everyone is now familiar with three of the key prevention methods – washing your hands, wearing a mask and maintaining social distance. These measures avoid people catching the virus by transmission from surfaces and from droplets, which can occur when in close contact to others.

However, there is a third, less well-known way of transmitting the virus, which is via aerosols – small particles that we transmit when we breathe out, talk, sneeze, laugh or cough.

Imagine them as the clouds of steam that you breathe out on a cold day. You will notice that the cloud is most concentrated nearest to you but can travel significant distances before dispersing.

Leading scientists have been campaigning for more attention to be paid to the airborne route of transmission throughout the year and the World Health Organisation and CDC have since acknowledged that coronavirus can be spread via airborne transmission.

Social distancing can help to protect the public from this invisible threat, however, evidence shows that coronavirus particles can remain live and suspended in the air for up to three hours in enclosed spaces.

Masks are effective at containing larger droplets, but studies have shown they can allow as much as 70% of infected aerosols to pass.

This means that on public transport one infected passenger could potentially contaminate the whole vehicle.

The role of technology

Ventilation is at the heart of the solution for airborne coronavirus but in a transport setting can prove challenging.

Weather and customer comfort make opening windows a challenge and vehicle ventilation and air conditioning systems can be more dangerous by re-distributing contaminated air throughout the vehicle.

The key is to be able to efficiently filter the air of airborne pathogens and deliver enough clean air to create a “clean air zone” for passengers and drivers.

Our AirBubbl in-vehicle air cleaning device does just that and is already being used to protect bus drivers in Europe and the US in addition to being used in private hire and patient transport vehicles dealing with the pandemic.

The device, which is roughly the size of a Bluetooth speaker, removes more than 95% of airborne viruses and contaminated particulate matter and floods the space with over 30,000 litres of clean air every hour to keep drivers and passengers safe.


The AirBubbl is the perfect device for small spaces, however the passenger cabins of public transportation provide a different challenge.

That’s why we’ve developed the AiroSafe, which is specifically designed to remove airborne viruses and contaminated particles from the passenger cabins of public transportation, including buses, coaches and trains. It does that by providing each passenger with a personal clean air zone at their seat.

A single person exhales eight litres of air per minute, while the AiroSafe filters an impressive 600 litres of air in the same time ensuring that every passenger seat is flooded with clean air.

Like the AirBubbl, the device filters more than 95% of airborne viruses and contaminated particles, as well as other harmful pollutants including PM2.5, PM10, nitrogen dioxide and ozone, which are known to cause heart, lung and other diseases. This means that it will keep passengers safe even after the threat of coronavirus has passed.

The cost per installation is low, as running costs are recouped with just one ticket sale and the per installation cost return on investment can be achieved within a very short time.

Getting public transport back on track

At AirLabs we fully understand the crisis that the industry faces.

It is only by embracing this new technology that public transport providers will be able to confront this challenge and see passenger numbers and revenues return to pre-COVID levels.


Marc Ottolini, CEO, AirLabs

We must act smarter to solve air pollution crisis


Air pollution is without question one of the greatest public health concerns of our time, contributing to 9% of all deaths globally.¹

These health impacts have been brought into focus by COVID-19, as there is a growing body of scientific research which suggests a strong link between exposure to air pollution and mortality rates for COVID-19. Even a small, one percentage point increase in people’s long-term exposure to particulate matter raises infections and admissions by about 10% and deaths by 15%.²

This has caused an increase in support for action against air pollution. The public overwhelmingly feel that the issue of clean air is more important than ever before and want businesses to act now to improve air quality as we rebuild following the virus.³

We are already seeing local authorities start to implement new measures to reorganise and transform travel in cities by bringing in new pedestrianised areas and cycle lanes, so now is the perfect time for public health officials and city planners to take long-term action to protect the public from this invisible killer.

Air pollution monitoring – A shot in the dark

There is undoubtably a willingness from government, councils and the public to tackle the air pollution crisis across the globe. However, if we want to have a long-term and lasting impact on air quality then we need to act smarter.

Air pollution monitoring up until now has been a shot in the dark, as most cities only install a limited number of monitoring stations in a few sections of the city where air quality is expected to be a problem.

While this setup can indicate air conditions in a city, crucially, it lacks the ability to pick up on localised hotspots of pollution.

This is a profound issue as air pollution is extremely dynamic, fluctuating significantly in time as well as location. For example, monitoring pollution in London by Imperial College⁴ regularly shows that air quality can be four times worse in some streets than others, even within the same district.

Well-intentioned local authorities rightly want to improve the air quality in their urban spaces. But the limited data they have means that they are spending significant sums of public money to address the issue, with only a tiny fragment of the picture necessary to make informed and impactful decisions.

This has to change, and it will only change by using monitoring technology that gives decision makers a full and detailed picture of the air pollution problem in their city.

Around every corner, there is a unique story and that story changes day by day, therefore, it is crucial that air monitoring networks reflect this.

Smart cities need smart technology

A truly smart city is one that is interactive, using real-time information to make decisions for the good of the city and its population. As part of that, an air monitoring network should not be considered as merely a data collection system but as a decision-making tool.

By creating a dense, high resolution network of air monitoring sensors, city leaders are able to assess air pollution data in many locations across an entire city, every minute of the day.

From this they can build an accurate and useful picture of a city’s air conditions – creating a detailed map which can be used by city planners to gain a full understanding of pollution hotspots and can provide real insight into which mitigations will be most impactful to protect the public.

A pioneering project

At AirLabs we’re doing exactly that as part of a new project with ADEPT SIMULATE Live Lab. Working with Staffordshire County Council and Amey, we have installed a first-of-its-kind, dense network of 19 sensors around a busy road in Newcastle Under Lyme.

Our AirNode sensors, which are low cost and low maintenance whilst meeting the requirements for accuracy of the EU Air Quality Directive, are being installed on lampposts around 100m apart to detect the variations of pollutant concentration in space and time throughout the area.

This innovative project not only aims to monitor air pollution, but to test a variety of mitigation solutions in a real-world setting. Those range from using artificial intelligence to monitor and predict traffic, installing an active ‘green wall’ to absorb dangerous air pollutants and deploying e-scooters and e-bikes to encourage alternative transport options.

It will then use the in-depth data obtained using the monitoring network to compare and evaluate which mitigations are most effective.

This will provide a model that can be replicated by councils and city planners around the world to make impactful decisions on air pollution in a cost effective way.

Now is the time to take action for our cities to clean our air and protect the public. The appetite is there from the public, the technology is in place and we’re remodelling our cities in response to COVID-19, so let’s do it in a smart way to deliver real, long term change.

¹ Our World In Data – Air Pollution

² IZA –

³ Global Action Plan – Air pollution and COVID-19 survey

Three key urban air pollutants


AirLabs technology filters the air of the three major pollutants:

  1. Nitrogen Oxides
  2. Particulate Matter
  3. Ozone

AirLabs technology filters the air of the three major pollutants: ozone, particulate matter, and nitrogen oxides. These species are listed as ‘criteria pollutants’ by the World Health Organisation. The criteria pollutants are generated from a myriad of human activities including industry, transport, and building emissions, and effect humans in every aspect of their daily lives. AirLabs technology is different from others because it is small, effective, and efficient. There is less air flow resistance, so less energy is needed than common air filters. Our technology can be tailored to treat specific the ‘pollution cocktails’ made of varying amounts of the key pollutants found in different urban areas.

Nitrogen Oxides (NOx)

NOx includes NO and NO2 and is formed from the nitrogen and oxygen in the atmosphere when air is exposed to intense heat. This heat can be generated by lightning or combustion, making cities packed with vehicles extremely prone to this form of pollution.

NOx is particularly dangerous because it is a catalyst for the formation of additional pollution, including ozone and particulate matter.

Particulate Matter (PM)

Particulate matter is a solid or liquid state pollutant that comes in varying sizes. These sizes are represented as PM10, PM2.5, and PM0.1, ranging from coarse to ultra-fine particles, depending on their diameter. See the diagram below to understand the scale.

The composition and size of PM is highly variable and there are multiple primary sources. PM can enter the air through direct release from different sources such as fires or transport. PM can also be the result of reactions in the atmosphere, from NOx for example.

Ozone (O3)

Ozone in the stratosphere, an atmospheric layer many kilometres away from earth, absorbs ultraviolet light from the sun, protecting life on Earth from this damaging radiation. In contrast, ozone in the troposphere is very dangerous. Simply put, ozone breaks many molecules into dangerous substances, such as acids and ketones. This also happens in the human body when ozone from the air enters it, leading to upsetting health concerns such as cancer. Ozone plays a large role in the NOx formation seen above.

The Sources of Toxic Air


Every year, during the month of November companies and individuals alike come together to raise awareness of common life-threatening diseases and cancers, including rare diseases that develop in the lungs. As individuals become increasingly concerned over environmental pollution and airborne contaminants, combined awareness efforts engage, educate, and encourage individuals and community leaders to address air quality; such as the presence of carcinogenic materials and air pollutants resulting from heavy manufacturing, traffic congestion and more.

However, although advancements in air monitoring and filtration equipment have made it easier for both individuals and communities to track and manage pollution, it is crucial to health, to know exactly how and which airborne contaminants and pollutants cause respiratory health concerns and numbers don’t lie. Nearly 1 in 8 deaths are attributed to air pollution, making pollution one of the largest environmental health concerns at present. Other environmental health concerns such as airborne asbestos or erionite fibers are just as concerning, so in observation of Lung Cancer Awareness month this November, we’ve joined forces with the Mesothelioma + Asbestos Awareness Center to raise awareness of harmful airborne pollutants and carcinogens to prevent their exposure and draw attention to the health concerns associated with air pollution.

Carcinogenic Materials:

Over the past 100 years, manufacturing processes have changed significantly. However, some industries still utilise carcinogenic minerals or additives for a verity of different purposes. For example, the naturally occurring mineral asbestos maintains fire-resistant properties under direct contact with an open flame. Once processed, the brittle and fibrous mineral became a common ingredient within thousands of products stretching across the construction and manufacturing industries. Due to the malleability and fibrous nature of asbestos, it found its way into a variety of different applications, world-wide including plumbing, HVAC, electric, insulation, roofing, tiling, cement, concrete, paints, gaskets, and other materials found in structures or machines built prior to 1980.

Exposure to airborne asbestos is especially hazardous, causing severe lung damage, inflammation, and eventually, asbestosis or mesothelioma, a life-threatening rare disease, which develops in the lining of the lungs, abdomen or heart. Although classified as a rare disease, the only scientifically proven cause of mesothelioma is a result of asbestos inhalation or ingestion. Erionite is another similar, fibrous mineral, which has been linked to peritoneal mesothelioma of the abdomen, so it is crucial to health that workers in high risk occupations such as; construction, manufacturing, plumbing, mining, railroads, and shipbuilding are informed and aware of the dangers of such carcinogens.

Heavy Manufacturing & Combustion:

Pollution generation from manufacturing, industrial practices and combustion, vehicle exhaust, and even construction debris, can toxify and contaminate air quality with particulate matter and Nitrogen Dioxide (NO2), directly affect human health. Such processes produce, often-invisible clouds of airborne hazards that are known to cause respiratory health concerns including asthma, lung disease and cancer.

Depending on the source, particulate matter (PM), dust or pollen, mould spores, soot, and airborne acids, may also be released into the air as a result of the above processes, posing additional threat to health. With extended exposure, individuals may experience worsening allergies or respiratory issues and are at risk of developing more serious complications such as COPD.

Vehicle Exhaust and NO2

 There are two main sources of air pollution: mobile sources and stationary sources. Mobile sources including cars, buses, vans, motorbikes or cycles, planes and trains, which each contribute to pollution. Mobile sources running on diesel fuel especially, release NO2 into the air, as well as PM, which pose respiratory health concerns such as intense asthma, coughing, bronchitis, among other issues, to those who inhale it. NO2 also plays a large roll in smog formation, which is prevalent in cities across the globe.

Vehicle exhaust also emits Nitrogen Oxides (NOx) including NO and NO2, formed from nitrogen and oxygen in the atmosphere when air is exposed to intense heat such as with lightning or combustion, making cities packed with vehicles, extremely prone to nitrogen oxide pollution.

With every breath of polluted air consumed each day, the lungs, one of the 5 vital organs essential to human life, are directly affected. Little by little and especially over time, lung function is impaired, which as a result directly affects blood-flow and health of other parts of the body.

World-renowned astrophysicist, Stephen Hawking once stated that, “air pollution is one of the top 3 threats to our global society.” His statement is simple, yet profound and based on fact as the World Health Organisation attributed nearly 7 million deaths to our global air problem, air pollution, in 2012. Considering this number aside the 1.69 million lives attributed to lung cancer, air pollution, airborne toxins and carcinogens deserve attention year round, in addition to Lung Cancer Awareness Month.

Can you add filters directly to the exhaust of a vehicle to reduce roadside air pollution?


It is a tricky situation to add a pollution removal system to the exhaust pipe of a car. Any such system would have to address the problem of dilution. As soon as pollution leaves a car it quickly becomes diluted and that means that you would have to treat a very large volume of air in order to solve the problem.

A quick example is that the polluted boundary layer over a city could be a kilometre thick. Imagine a car able to remove all pollution from the air going through the engine bay. A one square meter grill moving at 10 m/s can treat 10 cubic meters per second. To remove pollution from the atmosphere over a 1 km by 1 km area of a city would require 100 million seconds for one car; to do it in an hour would require 30,000 vehicles with the perfect system running continuously.

A major manufacturer played with the idea of putting a pollution control catalyst on the radiators of cars in the 1980s, and they ended the project due to the fact that even if the catalyst removed all pollution, it would not have had a significant effect on urban air pollution.

Because of the problem of dilution, most effort has gone into controlling pollution at the source by developing emissions catalysts, de-nox systems, particle filters, or by removing the engine altogether. For example over half of new car sales in Norway today are for electric vehicles. However, there is still the problem of road dust, and particles from tires and brakes. One solution to reduce roadside pollution: ride a bicycle to work as they do in Copenhagen.