During 2016, the 60th anniversary of the Clean Air Act, the team at King's updated one of the original techniques for measuring pollution to allow it to be used in the modern world.

For many decades of the 20th century, one of the main way to measure urban air pollution was to measure the darkness of particles collected on a filter. At its peak, the UK had over 1,200 air pollution monitoring sites taking measurements of so-called 'black smoke'.

Although no-longer used for air quality assessment, the darkness of filters collected in the field is still used by epidemiologists studying the health impacts from the air that we breathe.

Dr Pamela Davy and team analysed over 3,000 filters to update the black smoke method to measure the black carbon particles in our cities today using the old refectometer instruments and the new Sootscan Transmissometer from Magee Scientific.

They then used the updated method to measure changes in black carbon along Oxford Street and Earls Court Road. In contrast to the expectation from exhaust abatement policies, black carbon concentrations were found to have increased between 2011 and 2013.

Dr Pamela Davy who undertook the work as part of her PhD said: "Air pollution filter samples that are collected for gravimetric or chemical analysis can now be used to measure black carbon too so that we can check if policies to clean diesel exhaust are working."

Dr Gary Fuller who supervised the work said: "This technique provides opportunities for health researchers to reanalyse previous studies to provide better insight into the black carbon particles that people are breathing and its associations with ill health."

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Item date 06/06/2017