Determinants of Oxidative Potential, A Health-Based Metric to Assess Particulate Matter Toxicity

Lead Research Organisation: King's College London
Department Name: Pharmaceutical Sciences


Particles which are so small as to be invisible to the naked eye are very abundant in the atmosphere. They come from a wide range of sources (e.g. road traffic) and are diverse in terms of their particle sizes and chemical composition. Earlier epidemiological studies have shown clearly that exposure to airborne particles has an impact on human health with more deaths and hospital admissions for respiratory and cardiovascular diseases on high pollution days and those immediately following. However, to date the epidemiology has focussed very largely on the mass of particles in wide size ranges known as PM2.5 and PM10 and has not discovered whether particular properties of the particle such as their size or chemical composition determine the relative toxicity. There would be great benefit in doing so as abatement strategies could then focus on the sources emitting the most toxic particles. In this project it is proposed to collect large samples of airborne particles in different size fractions including the ultrafine fraction (of less than 100 nanometres diameter) which is believed to have a higher toxicity per unit mass. The samples of particles will be subjected to detailed chemical analysis in the laboratory as well as being tested for their ability to exert oxidative potential, in other words, to consume the body's anti-oxidant defences. The overall aim is to understand which properties of the particles have the greatest influence on their oxidative potential which could then inform the design of epidemiological studies to investigate the links between those particle properties and effects on human health.


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Description Airborne particulate matter comprises tiny solid and liquid particles of matter floating in the air which can be breathed deep into the lung causing adverse effects on health. Oxidative potential is one measure of the capacity of these particles to damage health and this project was concerned with collecting airborne particles from sites adjacent to London schools, measurement of the chemical composition of the particles and determination of their oxidative potential. In sampling the particles, they were fractionated into a number of different particle size ranges and the composition and oxidative potential was measured on each. The most important finding of the project is that the oxidative potential of the particles expressed per unit mass of particles is not related significantly to the size of the particles, but is related to their chemical composition. This has significant implications for air quality policy.
Exploitation Route These results have considerable significance for air quality improvement by allowing better targeting of abatement measures on sources presenting the greatest threat to human health. Both PIs in the project are heavily engaged in giving advice to UK government, European Union and the World Health Organisation. Their knowledge learnt from this and related projects has been passed on appropriately.
Sectors Environment

Description The findings of our work have fed into a broader understanding of the mechanisms of toxicity of airborne particulate matter. This continues to be a very lively area of research with high policy relevance.
Sector Environment
Impact Types Policy & public services

Description Many lectures to scientific audiences 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Many better informed people

More invitations to lecture
Year(s) Of Engagement Activity 2008,2009,2010,2011,2012,2013,2014