In a paper, published today in the journal Environmental Pollution, researchers from King’s and Airparif found that despite efforts, both cities do not meet legal limits for nitrogen dioxide and airborne particle pollution set by the World Health Organisation.
Many polices are in place to combat air pollution at European-wide, city-wide and local scales. This study found that since 2010, these have led to improvements in nitrogen dioxide and particle concentrations across both cities. However, the rate of change has not been enough to achieve compliance with legal limits. They note that nitrogen dioxide from traffic in London has deteriorated alongside some roads.
Looking at two time periods, 2005-2009 and 2010-2016, they also found that:
- As the legal compliance approached in 2010, nitrogen dioxide in both cities was getting worse and not better. Despite passing ever tighter laboratory tests, new diesel cars failed to achieve anticipated reductions when driven on the roads. This suggests that if feedback between air pollution surveillance and policy makers was better, it could have allowed for a more agile response, as conditions changed from the expected trajectory.
- From 2010 to the end of 2016, the large decline in particle pollution in London and Paris can be explained by the implementation of the Euro 5 standards on diesel cars and vans.
- There is some evidence that the introduction of newer diesel lorries and buses manufactured after 2009 lead to decreased nitrogen dioxide.
- In London, schemes to update bus fleets lead to rapid improvements alongside some roads. However, an increase in motorcycles in London since 2010 may have offset some of the improvements from other vehicle types. This highlights the less stringent exhaust standards applied to motorbikes compared with other vehicles.