Londoners measure personal air pollution exposure

The results of a pilot study which saw London volunteers wear air quality monitors for the day to measure personal exposure to pollution were presented by King’s College researchers last night (January 16).

The study showed clear peaks in exposure to particulate matter (PM) at times in the day when volunteers were travelling to and from work or school, and also during trips out of premises during lunch breaks.

Dr Ben Barratt presented the findings of the study at a public meeting at Guy's Hospital near London Bridge

Dr Ben Barratt presented the findings of the study at a public meeting at Guy’s Hospital near London Bridge

Results were also compared between motorists, cyclists and pedestrians, which suggested that exposure to pollution can be higher inside a vehicle than outside on the street, as PM concentrations can get trapped inside the cab of a car.

The study involved several volunteers of various ages and occupations in London wearing personal air quality monitors during an average weekday in November. They were monitored from around 8am until 2am in order to measure various peaks and troughs in their exposure to particulate matter.

Volunteers included a cycle courier, an ambulance driver, an office worker, a home worker, a pensioner, a secondary school pupil and a nursery toddler.

Organised by King’s College London’s Environment Research Group (ERG) and Guy’s and St Thomas’ Foundation Trust, the results of the pilot research were presented yesterday evening at a public meeting at the National Institute for Health Research (NIHR) Biomedical Research Centre at Guy’s Hospital.

In attendance at the meeting were some of the volunteers involved in the study, as well as air quality campaigners and other south London residents.

It is hoped that wider studies throughout London could be carried out in future in order to learn more about how personal behaviour, such as travel methods and times, can affect exposure. The ultimate aim of the researcher is to improve communication with the public on the dangers of air pollution and how they can best limit their exposure to it.

The study was carried out by King’s College ERG’s senior research fellow Dr Ben Barratt and senior air quality analyst Andrew Grieve, as well as PHD student James Smith.

Speaking at the event, Dr Barratt said: “The pilot was more of a success than I could have possibly hoped. Nothing broke or went wrong and we collected some interesting findings. We had a very good response from a variety of people from different areas and communities.”

He added: “We want to try and improve both air quality and the communication about air quality in London. We want to make politicians listen to people in the community on air quality and improve public health – there are things we can do to avoid exposure to air pollution.

“But we want to improve both air quality and also levels of exposure to air quality. We need to both to work in parallel – not just one or the other.”

Study findings

A comparison of results from the ambulance driver and the cycle courier, who both spent the day travelling around busy London areas, found that the former was exposed to much higher levels of particulate matter – some readings even measuring PM exposure nearly as high as 60 micrograms per cubic metre.

Dr Barrat explained: “This is because levels of PM get trapped in the cab of the ambulance. It is a similar issue on Putney High Street, which is certainly not the busiest street in London, but PM levels are high there because the street is quite narrow so PM gets trapped, which increases measured concentrations.

He added: “This suggests that the exposure to pollution may actually be higher for someone driving a car around busy roads than doing so on a bike. This is a simple message that we can tell people so we can reduce levels of exposure to some people from around 60 to 20 micrograms per cubic metre.”

The results also suggested that the office worker had the cleanest air pollution environment of all the volunteers during the day. Levels of exposure in the office were measured even lower than at home, leading Dr Barratt to joke “so the message is don’t go out for lunch and sleep in the office at night.”

The school pupil walked to school in the morning, but travelled back home in the afternoon by bus, giving very different readings of pollution exposure. However, although exposure in the bus was monitored at higher levels than by foot, the route took in different roads and the journey by bus was much quicker.

Dr Barratt commented: “This information is exactly what we want as it allows us to say which route is the best to get to school, so you can start to tell pupils whether they are better off travelling by bus or walking. But, the question is whether it is a greater risk to cycle or walk due to pollution exposure and road safety in comparison to the benefits to your health of cycling and getting exercise.”

Future plans

Dr Barratt went on to explain that Kings wanted to expand on the pilot research and encouraged those in the audience to get actively involved.

He said: “We want to use this to engage with the public and extend our research. We want to start a feedback loop where we do not simply tell people what to do as researchers, but form a group to empower and engage with people. We have a number of activities planned for this research.

He added: “We want to know what information that we gather is useful, and once we do that we can roll it out across London. We want to know if the policy message is right.

“In future we would be looking to extend the use of pollution monitors. The Holy Grail would be if we can monitor behaviour to change behaviour and collect strong evidence on how we can actually improve people’s health.”

Dr Barratt’s comments at the public engagement event come after European officials also called for improved communication to improve public awareness of air quality issues at a conference to launch the EU ‘Year of Air’ 2013 in Brussels last week (see airqualitynews.com story).

King’s College ERG is also engaged in ongoing research into London’s Low Emission Zone, which has involved the assessment schoolchildren’s health in Hackney and Tower Hamlets. The research suggested the children’s lung capacity was being reduced by air pollution (see airqualitynews.com story).