New methodology brings low cost sensors into the front line of monitoring

New research by a team from the University of Birmingham has found that a combination of low cost sensors and new methodology can be used for effective air quality monitoring at sites of specific concern.

Although they are becoming increasingly more dependable, lower cost sensors do not offer the same level of accuracy as regulatory monitors and need sophisticated statistical analyses and calibration to provide reliable results. 

The techniques used in this project were Positive Matrix Factorisation (PMF) and k-means clustering. The approaches in themselves are very different from each other but their outcomes are complementary, providing ‘a clearer picture of the sources of pollution and the conditions that affect the extent of their impact.’

The team used k-means clustering and PMF analyses on the particulate matter size distributions measured by sensors in three locations that required boundary line monitoring: a construction site, a quarry and a roadside location. They found that individual sources of PM could be identified and their contribution to overall PM concentrations could be apportioned. 

An HS2 construction site in the heart of Birmingham was one of the sites used to test the new methodology. The team were able to identify two hotspots of particle emissions on the site, as well as being able to filter out background pollution, providing an insight into the real-world conditions on a site and demonstrates how real-time monitoring of air quality could be achieved in construction.

Francis Pope, Professor of Atmospheric Science at the University of Birmingham and senior author of the paper said: ‘Successful air quality management and control not only requires measurement of air pollution levels, but it also requires information on the sources and their relative importance. Without this critical, targeted information on pollution sources, it is difficult to plan and enact cost effective control measures with which to reduce air pollution. Low-cost sensors already help in the measurement of air quality but there is still a major gap for source apportionment.

‘This latest study showcases the combination of an elegant methodology for analysing real-time data from inexpensive sensors. It provides a potentially powerful solution for industry, local government and a whole host of other organisations to understand the air quality around them, and also provides a way forward to meet the Government’s legal duty on air quality standards.’

Andrea Davidson, Head of Environmental Sciences for HS2 Ltd said: ‘HS2 has ambitious environmental targets, including dust mitigation, strict emission standards and moving to all diesel-free construction sites by 2029, aimed at reducing impacts on local air quality. This is a great example of how HS2 works with researchers and manufacturers to support positive change across the construction sector. Advances in dust monitoring, like this, will increase confidence in controls, and support the whole sector’s move towards cleaner construction.’

The paper can be read here