New Work to Improve Air Quality Monitoring Data

Featured story25 February 2022

RSSB launched the Stations Air Quality Monitoring Network (AQMN) in winter 2021 and it has got off to a busy start. There are four key highlights: the adoption of the most recent types of diffusion tubes; installation of reference monitors at stations; trial of low-cost sensors in stations environment; how the data will be used and shared.

Funding by the Department for Transport (DfT) has enabled RSSB to launch the Stations Air Quality Monitoring Network. This is GB rail’s most detailed and systematic examination of air quality to date. The programme is designed to help the industry understand and act on pollution at stations on a nationwide scale more effectively.

An important first step is to ensure that the most appropriate type of monitoring equipment is being used, at the most suitable locations. The project is using the latest diffusion tubes which have a filter at the open end, reducing the effect of wind turbulence at the end of the tube. This improves data quality. The UK Urban NO2 Network (UUNN)has already used these diffusion tubes successfully, with their benefit evaluated independently and presented in a peer-reviewed academic paper and we have installed them at all of the 104 selected stations for the project.

We are also installing reference monitors at London Marylebone and Birmingham New Street stations. These reference monitors measure NOx, NO2, PM10 and PM2.5 concentrations accurately and continuously. There is a potential to install a maximum of eight additional reference monitors at other station sites. We expect at least one reference monitor to be in operation on the AQMN project by April 2022.

Low-cost sensors are known to be sensitive to the environment they are operating in, and therefore we are testing their real-world performance in station sites at London Marylebone and Birmingham New Street as a first step. If any are suitable, we will consider rolling them out more widely, so we look forward to the results from the tests at these sites.

Finally, data collection on the AQMN project has already started, and we will be analysing it to identify ‘priority locations’ where improvements are needed. We will publish air quality monitoring data in a single accessible format and will announce the planned format and timescales soon. This evidence and our analysis will help the rail industry collaborate to develop air quality improvement plans. These will ensure that air quality inside stations meet the targets the Government will set.