DEMiSt: The driver Diesel Exposure Mitigation Study

There is a wealth of data demonstrating that exposure to traffic derived pollutants, or residential proximity to busy roads, is associated with negative health impacts. While these associations have been identified in the general population existing studies have missed one very significant exposure group; vehicle drivers themselves. Preliminary data indicate that the personal exposure of drivers to traffic derived pollutants is often significantly greater than that of cyclists, pedestrians, or individuals living near busy roads.
The overarching aim of DEMiSt is to parameterise risk of harm to professional drivers from exposure to diesel exhaust, allowing formulation of risk reduction strategies. This aim will be achieved through a series of objectives:

  • Characterise driver exposure to inhaled diesel emissions under a range of occupational settings, vehicle types and driving conditions.
  • Parameterise driver exposure allowing identification of dominant variables dictating increased risk of harm from diesel emissions.
  • Identify and trial potential intervention methods for health improvement, focusing on strategies that can be applied to the existing vehicle fleet or working practices.
  • Establish a database of contextualised driver diesel exposure measurements.
  • Collect blood from drivers for bio-banking for future studies investigating potential biomarkers of traffic exposure for integration into future occupational and public health research.
The project will comprise four phases:
Phase 1: engagement and recruitment: We will approach gatekeepers to a number of industries and public services employing large driver fleets including freight distribution, parcel delivery, postal services, emergency services (police, ambulance and fire), construction workers, taxi and private hire companies and request permission to recruit from their driver fleet. Approximately 20 drivers will be recruited from each sector, totalling 200 participants. Recruitment will be centred on London and the South East for practical reasons.
Phase 2: exposure monitoring: Each participant will be asked to carry a portable diesel pollution monitor and GPS watch for four days, including while at work, home and leisure activities. The monitors will continuously log location, driving conditions and pollution concentrations at 20 second intervals throughout the 96 hour period. Afterwards, the units will be collected and a researcher will ask the participant a series of questions relating to their working hours, vehicle details (fuel, age, make and model), driving behaviour (idling, ventilation) and access to other vehicles. Smoking habits will also be recorded. With consent, a blood sample will be taken. A subset of 30 participants will be asked to repeat the monitoring the subsequent week with the following interventions: driving with vehicle ventilation set to recirculate and windows closed, replacement of existing air inlet filter with high specification scrubbing filter, switching off engine while stationary.
Phase 3: exposure characterisation and modelling: Diesel exposure levels will be characterised against a large number of variables for the cohort, including profession, vehicle details, driving conditions, driving behaviour, meteorology, background pollutant concentrations etc. A Mixed Effect modelling technique will be used to identify the parameters dictating driver exposure. Blood samples will be anonymised and stored under suitable environmental conditions at the National Phenome Centre for future biomarker analysis.
Phase 4: dissemination and recommendations: Two reports will be prepared detailing study findings. The first will be a technical report for publication in peer reviewed literature and policy advice. The second will be a lay summary suitable for dissemination to driver industries and services. Each will include a series of recommendations for reducing driver exposure. We will assist participating organisation with the production of internal health and safety leaflets and advice. The study is funded by the Institute of Occupational Safety and Health (https://www.iosh.co.uk) and supported by Transport for London through the LoCITY programme (https://locity.org.uk). We welcome approaches from additional partners from organisations representing driver occupations.

Please get in contact if you would like more information (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/contact.aspx).

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