PM2.5 Air Particle Monitoring
Background
Salisbury does have issues with air pollution. Although vastly improved, in some areas, we continue to have higher levels of nitrogen dioxide than the national threshold. Now a new concern is PM2.5 (particles at or below 2.5 micrometres in diameter). Many emitters of these pollutants also contribute to other greenhouse gases and climate change. Furthermore, it is now believed that PM2.5 is the most dangerous to health, including increasing the risk of cancer. It is therefore important to understand the levels of these in the city.
In 2007 Wiltshire Council declared three areas, known as Air Quality Management Areas (AQMAs), in Salisbury where nitrogen dioxide levels exceeded the national threshold. This is the highest number of local AQMAs in Wiltshire. Although things have significantly improved since 2007, to date, none of these AQMAs have been revoked. It should also be noted that the English threshold is 4x higher than that recommended by the World Health Organisation (WHO).
In addition, new legislation associated with reduced thresholds for PM2.5 is due to come into effect in 2028. Therefore, it is reasonable to assume that even if AQMAs are revoked for nitrogen dioxide, it is possible they will be replaced by new ones for PM2.5.
Until now, Wiltshire Council had no reference monitors for concentrations of PM2.5 in the city. STC has worked with Wiltshire and Salisbury City Councils to run a pilot citizen scientist project monitoring PM2.5 with the aim of understanding the levels in the city, where hotspots might exist and raise awareness of this pollutant.
Project Update
Towards the end of 2022, STC was awarded £500 from the Salisbury Area Board to purchase 8 low cost PM2.5 sensors. These were given to Salisbury citizens across the city. STC is grateful to those who came forward for the sensors, many of which have been running for nearly 3 years now. The aim has been to help us understand the levels of PM2.5 across the city. This has been mostly successful as an initial project. Wiltshire Council has now rolled out a larger project across the county, with improved low cost sensors that are now installed at over 100 locations, around 19 of them in Salisbury. Wiltshire Council will also install a specific reference system dedicated to detecting PM2.5 so that we will obtain a more comprehensive understanding of PM2.5 levels.
STC sensors will continue to collect data across the city and the information obtained will be used with the WC systems. STC will continue to work with Salisbury City Council in this area and provide information to SCC's Environmental Action Group.
Maps of the sensor locations
You can still get involved
Sadly, STC no longer has sensors to give away, but you can purchase your own from the Sensor Community and have ready access to their data, or if preferred, you could purchase the more expensive systems used by WC.
You can always see what is happening using the links on the maps of the sensors above, or this link to the reference system in Exeter Street.