Nitrogen dioxide (NO₂) is a harmful air pollutant primarily generated from traffic and the combustion of fossil fuels. It worsens respiratory health, contributes to smog and acid rain, and forms fine particles and ozone. NO₂ is a key indicator of urban air pollution and a target for clean air and sustainability policies.
As part of Lambeth’s commitment to improving air quality, the council uses diffusion tubes to monitor nitrogen dioxide levels around the borough. To collect these samples, they work with Gophr, who collects and replaces over 120 samples monthly using bicycle couriers — making sure the monitoring project doesn’t contribute to poor air quality.
“1,200+ tubes collected · 625km cycled · 105kg of CO₂ saved vs. car-based collection.” Lambeth Council × Gophr, 2023–2025
Lambeth Council: leading London’s air quality fight
Air quality in Lambeth is improving. Since 2017, there has been a 26% fall in the concentration of nitrogen dioxide on Brixton Road. But there are still several places where pollution exceeds the government’s air quality objectives, and much of the borough has air quality worse than what is recommended by the World Health Organisation.
Air pollution is the presence of substances (pollutants) in the air that have a harmful effect on humans. Nitrogen dioxide (NO₂) and particulate matter (PM) are among the most dangerous pollutants. They can directly affect those with asthma and existing respiratory and heart conditions, and long-term exposure has been shown to cause medical conditions such as lung cancer, type 2 diabetes, and heart and lung diseases.
The challenge: monitoring NO₂ without adding to it
Lambeth is tackling and reducing air pollution through its Air Quality Action Plan (AQAP) and has committed to improving its air quality, breaking the association between poor air quality and inner-London living. The plan outlines actions and commitments to reducing air pollution and improving access to clean air.
To measure progress against these actions, Lambeth uses diffusion tubes to gather data on nitrogen dioxide levels and monitor changes in air pollution. The council works with Gophr to collect these diffusion tube samples on a monthly basis and send them for testing.
120 diffusion tubes, one day, zero emissions
Diffusion tubes are small plastic cylinders attached to lampposts across the borough. Inside the tubes are small pieces of gauze doused in a chemical that reacts with nitrogen dioxide. These diffusion tubes are collected and sent monthly to a laboratory for analysis. The laboratory can calculate nitrogen dioxide concentrations from the gauze samples in the tubes.
There are over 120 diffusion tube locations across the borough. Every month, Lambeth coordinates with Gophr couriers to collect all the tubes in one day and replace them with new ones. All the samples must be collected on the same day to ensure consistency in the data and analysis.
Gophr uses pushbike couriers to collect all 120 diffusion tubes, ensuring the collection method doesn’t also contribute to poor air quality.
Why cycle couriers work for council monitoring
- Quieter: Less noise pollution contributes to more liveable city environments.
- Accessibility: Able to deliver to places inaccessible to larger vehicles, such as pedestrian zones or narrow alleyways.
- Cost-effective: Lower operational costs than motor vehicles (no fuel, minimal maintenance).
- Speed: Pushbike couriers can often move faster than cars or vans in dense city traffic by using bike lanes, side streets, and shortcuts.
- Easier parking: Not affected by parking issues or road closures to the same extent as motor vehicles.
- Environmentally friendly: Zero carbon emissions during operation. Contributes to reduced air and noise pollution in cities.
The results: 625km covered, 105kg of CO₂ saved
Since switching to bike couriers, Gophr has replaced over 1,200 diffuser tubes and covered over 625km around Lambeth — resulting in 105kg LESS carbon emissions than cars completing the same journeys.
Committing to using low- or zero-carbon couriers demonstrates to other organisations and businesses how it is possible to make the switch, become more sustainable, reduce air pollution, and maintain delivery times. The hope is that others will consider switching to clean transport methods and encourage walking, wheeling, and travelling more sustainably around the borough.
How Gophr keeps local delivery low-carbon
Reducing delivery emissions is a challenge for every carrier, especially when working with self-employed professional couriers, and the costs of electrification remain high. But there are key ways Gophr makes local deliveries less harmful to the environment:
- Route optimisation: Gophr’s despatcher algorithm is built from scratch to minimise ’empty miles’, ensuring vehicles are as full as possible to minimise emissions per delivery.
- Zero emissions fleet: Gophr has one of the largest remaining pushbike delivery circuits in London, meaning the company can support clients — like Lambeth Council — who want to minimise their carbon footprint.
- Offsetting: Some deliveries still require traditional IC vehicles, and Gophr is committed to offsetting 100% of those emissions through Ecologi, one of the leading offsetting platforms.
If you have any questions about Gophr’s low-carbon delivery service or want to chat, please get in touch at partnerships@gophr.com.
