Why monitor Chippenham air quality?

Air quality is a major concern nationally and in certain areas of Chippenham we are no exception. With the ongoing future development of more housing in the town we have concerns that the problem will continue to get worse. Air quality is a health and climate emergency, which is why we have fundraised for equipment collecting Air Quality data, highlighting the dangers and tackling this in our community. Thank you to Chippenham Area Board for funding to support this project.

Citizen Science

Our Air Quality monitoring project uses Citizen Science Air Quality monitors based around the Pimoroni Enviro Urban board. Four Chippenham locations are monitored with live data dashboards updated once per hour with readings every 15 minutes. The data will be used to highlight the reality of our air quality in Chippenham to our fellow residents and also approach policy makers to consider making appropriate changes to planning and other investments to ensure there is a sensible transition to zero carbon and clean air in future.

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The Equipment

Locations

Four locations are monitored

Langley Road
Marshfield Road
Rowden Hill
Wood Lane

Validity of Data

Whilst not a lab calibrated system the PMSA003 sensor used to measure PM10 and PM2.5 particulate pollution has been field evaluated in a study here It has been showed to have an R squared correlation of 0.83 to 0.90, with 1.0 being the ideal. For high relative humidities > 75% a bias of +14.7% has been noted in the study. Hence the RH sensor data is shown next to the measurements for comparison.

The Equipment

The project is based around the Raspberry Pi Pico W board, and in particular the Pimoroni Enviro Urban kit found here. The Pico Pi and Sensors are battery powered and sit in a weather proof Stevenson Screen mounted at approx 1m to 2m high and 5m from the main road in a front garden. Measurements are automatically taken every 15 minutes and uploaded over wifi once per hour to the adafruit.io cloud server.

See the live Environmental dashboard

You can click on the button below to visit the external adafruit.io website dashboard where the live environmental data is uploaded. Note it will open in a new window. Caveats: Though the sensor has shown good correlation with laboratory calibrated sensors, it is not a laboratory calibrated sensor. It is known to read up to 15% high in relative humidities greater than 75%, hence particulate readings are shown next to the humidity reading to allow some context.

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Marshfield Road Environmental Dashboard

Rowden Hill Environmental Dashboard

Chippenham

Air Quality Monitors

Langley Road Environmental Dashboard

Wood Lane Environmental Dashboard

Wiltshire Council Purple Air monitors

What is the Wiltshire Council Sheme?

The Wiltshire Council Community Air quality monitoring scheme is a new citizen science community project run by Wiltshire Council, aimed at measuring PM2.5 particulates across the county.

Zero Chippenham have one of the Wiltshire Council Purple Air monitors co-located with our Langley Road Air Quality monitor. This will help us correlate our own air quality sensor readings with the co-located Purple Air Sensor.

Open Purple Air Map in new window

What Particulate Levels are acceptable?

What are Particulates?

PM 10 Particulates are small particles less than 10 micometres in diameter (10 to the power -6 of a metre). PM 2.5 Particulates are less 2.5 micrometers in diameter. They consist of non gaseous particles in the atmosphere that can enter the blood stream lodging in the heart brain and other organs. Particulates are of considerable concern to human health.

What are the limits?

The Air Quality Standards Regulations 2010 require that concentrations of PM in the UK must not exceed:

An annual average of 40 µg/m³ for PM10;
A 24-hour average of 50 µg/m³ more than 35 times in a single year for PM10;
An annual average of 20 µg/m³ for PM2.5.

World Health Organisation

The WHO has set tighter limits for particulates. The current guidelines state that annual average concentrations of PM_2.5 should not exceed 5 µg/m³, while 24-hour average exposures should not exceed 15 µg/m³ more than 3 – 4 days per year.

PM₁₀ (particulate matter with a diameter of 10 microns or less) concentrations of 15 µg/m³annual mean, 45 µg/m³ 24-hour mean.