EarthSense were asked to design and implement the pollution monitoring system used in the BBC’s Fighting for Air feature on aired 10th Jan 2018. This blog post details the measurements taken, and the analysis performed to deliver the headline figures for the programme.
'Fighting for Air' is one of the first large scale community projects to reduce air pollution for the community’s local area. Run by the BBC, the project aim was to assess whether individuals and communities could make a difference using best available science and technology resources. To assess the effectiveness of any intervention, measurements must be taken before and after the event so any change in pollution levels can be identified.
EarthSense Zephyr® sensors were identified as a good quality, easily deploy-able and low cost solution to provide the level of monitoring required for this project, so during a very cold week in December 2017 our team worked with the BBC on placing our sensors in the project test area.
The Technology : Zephyr® Sensors
We tested, calibrated and deployed 2 of our new Zephyr® units around King's Heath in advance of the day of action on 1st December.
On the high street, the sensors were located at about 3 metre height above the pavement, getting a great measure of pedestrian exposure. The measurements were directly behind the additional vegetation the BBC added as a green shield as part of the day of action.
What we Measured
We compared measurements against monitors operated as part the DEFRA’s AURN network at background and roadside locations in Birmingham. Over the three days before the day of action, the concentrations along the high street, and by St Dunstan’s Catholic Primary School, which is just off the high street, were monitored, and the pattern against the reference sites was established.
On average, the School measured around 5% above the background site, and the high-street measured 30-40% above the background concentration of NO2. In contrast, the reference major roadside site in Birmingham measured approximately 50-60% above the background site.
The high street measured approximately 15-25% above the background during the day of action, which was 5-15% below the level it had been during the previous 3 days. Therefore a 10% reduction was declared.
This experiment was obviously very short-term, and therefore is subject to a range of uncertainties based on meteorology and localised effects. However, by referencing to local AURN sites, the variability of regional air quality was removed, and the relative change in Kings Heath could be isolated from all other signals with a fair degree of confidence. This means that community groups can see the direct impact of any intervention they undertake, providing evidence to support ongoing activity and community buy in.