The Go-Ahead Group is to expand its landmark "air-filtering" bus programme following a successful 100-day pilot and 9,000 miles covered in Southampton.
The trial, which launched in September 2018, saw Go-Ahead subsidiary Bluestar operating the bus mounted with a unique filter on the roof. It cleaned 3.2 million cubic metres of the city's air. The filter exceeded all expectations for its potential benefit to the environment, extracting particulate matter (PM10) weighing a total of 65g from Southampton's air - roughly the same weight as a tennis ball - over the course of the trial.
Following the trial's success, all five of Bluestar's buses on Southampton's Route 7 will be fitted with air filters, cleaning the air on an 11.5-mile path running across the city.
While the single bus has the capacity to clean the air on its route every 215 days, to a height of 10 metres, it will take just nine days for the newly expanded fleet to achieve the same feat.
Go-Ahead's estimates show that the expanded fleet could remove as much as 1.25kg of PM10 from the air every year. If the air filter was deployed on 2,500 buses, it could remove as much as 588kg of PM10 particles every year. In parallel, Bluestar has been fitting solar panels to buses, with a total of 19 vehicles to have them in place by the end of July. When five further buses are fitted with air filters, one of them will have a solar panel as well. This will enable a trial later this year to see whether solar energy can be used to make the air filter completely self-sufficient.
Go-Ahead Group Chief Executive David Brown said: "When we launched the air filtering pilot, we wanted to play our part in tackling the crisis in urban air quality and show that buses could be an answer to pollution in cities. We already know that a fully loaded double decker bus can take up to 75 cars off the road, reducing both congestion and pollution. Now we have hard data that shows air filters on buses can actively improve air quality.
"Our air-filtering system has exceeded expectations on how it benefits the environment. Rolling it out on more buses is the next step for Go-Ahead, and we would encourage authorities to get involved and help us roll this out at a faster rate."
Southampton was chosen as the location for the pilot following a 2018 World Health Organisation (WHO) report, which warned that the city is at its limit of unsafe air pollution.
The filter was designed and manufactured in collaboration with PALL Aerospace. It is made in an engine barrier-type filter construction and designed to remove up to 99.5% of particles from the air without any impact on the passenger or travel experience. It was deployed on one of Bluestar's low-emission Euro VI buses, which produce no more than 0.08g/km of nitrogen oxide.
During the trial, the filter cleaned 3.2million cubic metres, the equivalent to the volume of 1,288 Olympic swimming pools. The air filter takes in one cubic metre of air per second, which means that in one hour it filters the same volume of air as 6,000 people breathing.
PM10 is generated by vehicles, construction and other sources in the urban environment and has been linked with cardiovascular illness and respiratory diseases. In the UK, the Department for Environment Food and Rural Affairs (DEFRA) estimates that particulate air pollution reduces the life expectancy of residents by six months on average.
Go-Ahead reveals industry-first supply chain sustainability charter
The Go-Ahead Group has announced its Sustainable Procurement Charter, the industry's first comprehensive supply chain policy that establishes minimum criteria in core areas of corporate social responsibility. Under the charter, suppliers must demonstrate a commitment to sustainable innovation, employee wellness and company diversity.
Mandating high standards for suppliers will help Go-Ahead establish its position as best in class for sustainable procurement.
The sustainable supply chain charter has five themes: happier customers, stronger communities, better teams, cleaner environment and smarter technology. The charter's area of focus within these have been chosen in partnership with suppliers including Michelin, Siemens and Alexander Dennis.
The charter, which can be found on the company's website, has been designed with the United Nations' Sustainable Development Goals in mind.
Specific measures include:
• Elimination of enforced zero hours contracts for all suppliers.
• Eliminating any use of unpaid work – for example, unpaid internships.
• A requirement for larger suppliers to declare what percentage of their workforces comes from under-represented groups.
• Reporting (for larger suppliers) on how many employees are receiving equalities and diversity training.
• Disclosure of gender pay gaps and a thorough action plan to target any gap.
• Plan for reducing emissions and compliance with air quality requirements.
• Measures by suppliers to encourage employees to contribute to the low carbon economy by reporting what percentage of their workforce use public transport to commute.
Elodie Brian, Chief Financial Officer of The Go-Ahead Group said: "Introducing the Sustainable Procurement Charter will help us to hold our suppliers to a higher level of commitment; ensuring our suppliers uphold the same values as we do ourselves, and therefore increase the rate of positive change in the industry."
The charter's emphasis on reducing gender pay gaps underpins Go-Ahead's goal of establishing a minimum 20% diversity level across all teams and business units.
Shaun McCarthy OBE, Director of Action Sustainability, said: "It has been a pleasure working with The Go-Ahead Group to develop this charter. In order to be the best in class for sustainable procurement, it is necessary to deliver best in class procurement – and Go-Ahead's high-class procurement team has excellent processes and supplier relationships. I am confident they will be using the guidance in the supply chain international standard ISO 20400 to deliver measurable sustainable benefits through their supply chains for many years to come."