Pollution levels inside cars could be around 20% higher than on the road outside a pilot study has found, raising fears among experts for the safety of professional drivers.
A mobile air quality laboratory – nicknamed the smogmobile - found that on a journey from Reading to central London levels of nitrogen dioxide (NO2) were on average 21% higher inside with the windows shut than on the road.
Dr Ben Barratt, a lecturer in air quality science at King’s College London, said: ‘This illustrative study adds to mounting evidence that vehicles provide little protection from harmful traffic pollution, and drivers and their passengers may even be exposed to higher levels than on the road outside.
‘These initial findings highlight the urgent need for further investigation into the health risks faced by motorists and their passengers. It is especially important to understand the impacts of air pollution on professional motorists such as taxi and lorry drivers, who spend many hours behind the wheel each day.’
NO2 has been linked with tens of thousands of deaths a year and the widespread failure of Britain to minimise pollution levels has seen it fall foul of European law.
Of the UK’s 43 air quality zones, 38 are currently exceeding the annual mean limit value for NO2, according to a government report released in September last year.
Frank Kelly, professor of environmental health at King’s College London, who is also chairman of the government advisory body, the Committee on the Medical Effects of Air Pollutants, said: ‘Air pollution is the world’s single largest environmental health risk. It shortens life expectancy, reduces lung function and worsens the symptoms of asthma, chronic obstructive pulmonary disease and heart disease.’
Duncan Mounsor, managing director of Enviro Technology Services, which provides the smogmobile told Transport Network: 'The thing is with a lot of modern urban pollution, you can’t see it or smell it. We think high levels inside the car come from the concentration of pollution in a confined space.
'Traditionally we measure air quality from fixed locations. The Government has a network of around 150 monitoring stations at major towns and cities but they are only in one position and do not measure real driving conditions.
‘The smogmobile is 100% electric so it doesn’t add to the pollution. It is a Nissan e-NV200 van, the van version of the Nissan leaf, and it allows councils to target hotspots or routes through urban areas.’
The vehicle is available for hire by local authorities and interested parties with costs ranging from roughly £500 to £1,200 a day.
The pilot NO2 study took place on a two-hour journey from Reading along the M4 and through central London to Waterloo Bridge using its new capabilities. Mean average concentrations of NO2 outside the vehicle were 66 µg m3 (micrograms per cubic metre) but 21% higher inside the vehicle at 80 µg m3.
For brief periods in London levels of NO2 inside the vehicle reached up to 350µg m3 -75% higher than the EU hourly safety limit of 200 µg m3.