How can ordinary white socks have a lasting impact on school travel plans ?
It sounds an unlikely link but, in Plymouth, Manadon Vale Primary School pupils found out exactly what socks can do when they were used as a way of testing the impact of air pollution; with the results helping to inform an important aspect of sustainable transport….the journey to and from school.

But why consider the impact of air pollution in the first place ?
Air pollution is a global threat to health and wellbeing; a threat closely related to our ever-growing reliance on transport. First addressed in the UK by the 1956 Clean Air Act, and managed ever since by successive UK and EU legislation, the responsibility for local air quality has been devolved to local authorities. In Plymouth, there are four designated Air Quality Management Areas (AQMAs).

With 40,000 deaths every year in the UK attributable to damaging emissions, air pollution can also cause, or contribute to, a wide range of long term medical conditions. Vulnerability can also be heightened in lower income communities and the damage can occur across a lifetime as a result of high-level acute, or prolonged low-level, exposure. It is harmful to everyone but there are some factors that make some people far more vulnerable.
One of these factors is living, learning or working near busy roads – a factor that makes an understanding of the impact of air quality an essential element of school travel plans.

To Contact Plymouth’s Public Health Team :
Email : Claire Turbutt at
Tel : 01752 304568
Website :
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Plymouth’s air quality pilot project was an excellent example of a collaborative approach; with multiple partners and the involvement of Manadon Vale’s senior staff, pupils and parents…..all those who might be affected by local air quality. This was important as the school’s location was already of interest as it lies just under the key Manadon interchange on the A38 where it is vulnerable to heightened emission levels at different times of the day. With over half the school arriving by car, the impact of ‘idling’ (waiting with the car engine running) was also included in the study; a topic that also created congestion, illegal parking issues and the need to discourage stationary vehicles from running their engines. However, rather than focusing on enforcement, the pilot focused on education and awareness to influence driver behaviour. Initiated by a letter introducing the project and a leaflet setting out the harm caused by idling and the benefits of adopting the cleverly entitled ‘park and stride’ approach to dropping off points, the project began by engaging the parents and carers.

The next step was to establish some baseline data. Using new monitors funded by DEFRA, two Public Health Officers conducted three data recordings from the local Morrison’s supermarket close to the school – one walking, one in a large diesel engine motor vehicle and one in a small, petrol engine car. Morrison’s was chosen due to its proximity to the school and for its potential as the allotted parking stop for the ‘park and stride’ initiative. The route tested included passing over, or through, the very busy Manadon roundabout which lies only a few hundred metres from the school.

Not surprisingly, there was a significantly higher ‘black carbon’ reading for the journey in the diesel vehicle but, more surprisingly, and of considerable concern was the extremely high recording taken whilst walking over the roundabout which was approximately 4.5 times that of the same journey in the diesel vehicle.
The project’s work on awareness was extended to the whole school with an assembly session on the topic of air pollution that included the positive and negative health impacts of different forms of travel to and from school. The assembly was concluded by Plymouth City Council’s Road Safety Officer and road safety mascot Ricky the Dog who highlighted the importance of reducing accidents and keeping yourself safe on the journey.
The school also helped with a travel survey. At the beginning of the week approximately half of the pupils walked to school whilst the other half were driven. Towards the end of the week it showed that pupils were more likely to use active forms of transport such as scooting, cycling and walking. In addition, teaching sessions backed up the educational presentations and provided an opportunity to test and compare emissions from petrol and diesel vehicles. This is where the socks were used. The car exhaust test was conducted by placing a white cotton sock over the tail pipe of a small petrol car and a larger diesel vehicle. After five minutes the engines were turned off and the socks were removed and turned inside out so that the children could examine and discuss the findings….with one sock ending up much blacker than the other. A very visual way of illustrating the impact of particulate pollution !

To back up the data for the project, a Year 5 student was chosen to monitor his usual walk to and from school using the black carbon monitor. Using maps and local knowledge the student also planned alternative routes that he considered to be less polluted. His average walk to and from school was 12 minutes and it involved crossing the very busy Manadon roundabout as well as walking along a busy main road. Although he could not plan a practical route that avoided the roundabout, he could avoid the busy road and the pollution he anticipated from it so, by taking a slightly different route, he was able to show a considerable difference in the concentration of black carbon he was exposed to. Interestingly his return home also highlighted the difference in pollution during rush hour traffic.
The school’s anti-idling campaign was boosted by a morning of action where children could question parents about idling and a competition to design an A4 poster that would be transformed in to a large outdoor banner to promote the anti-idling message. The children taking part designed a questionnaire to use as an awareness raising aid with the parents and carers around the school entrance and, although the children could not approach idling vehicles directly, it was hoped that the visual presence of the staff and children would have the required impact on changing behaviours. A total of 80 adults were questioned. Both the levels of black carbon and the responses were tested a week apart on the same day and at the exact time to support the project’s data.

The figures showed that there was an overall reduction in the average black carbon concentration after the campaign and there was a small reduction in the number of cars idling. However the high levels of dangerous and illegal parking were of far more concern …an issue that was reported to the school authorities.
In conclusion, it was noted that all the air quality recordings around the school could have been heavily influenced by the weather and wind direction. With this in mind it was agreed that a more effective approach would be to find routes to and from the school that avoided passing through or over the areas of high pollution. Investing in an urban waking route map would be crucial to developing this.
It was also agreed that the initial recordings were relatively simple and that a more rigorous approach to recording data would be needed for future projects. Multiple readings of both black carbon and travel surveys over several weeks would give a far better indication of pollution levels around the school gates. It was agreed though that the results could inform further work that could include exploring the health impacts of moving the school start time to ensure children travel to and from school during the lower pollution times in the day.

For Reference : The Background Legislation
• The Clean Air Act 1956 – introduced in response to the London smogs of 1952 :
• The Clean Air Act 1993 –
• The Environmental Protection Act 1990 :
• The Environment Act 1995 – introduced Air Quality Management Areas :
• “ Part IV of the Environment Act 1995 requires local authorities in the UK to review air quality in their area and designate air quality management areas if improvements are necessary. Where an air quality management area is designated, local authorities are also required to work towards the Strategy’s objectives prescribed in regulations for that purpose. An air quality action plan describing the pollution reduction measures must then be put in place. These plans contribute to the achievement of air quality limit values at local level.
• The UK’s National Air Quality Strategy was last updated in 2007 and can be found at :

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