If news emerged that a virus was killing thousands of vulnerable Londoners every year then there would justifiably be public alarm, followed by swift political action. Yet the impacts of this imaginary scenario are similar to what air pollution has been inflicting on Londoners for many years, while the political response has been slow. According to the most up-to-date and comprehensive research, air pollution reduces Londoners’ life expectancy equivalent to the death of 9,400 people of average age every year (5,900 due to NO2 and 3,500 due to PM2.5) as well as exacerbating respiratory diseases in vulnerable populations. Despite the severity of these impacts, it has become standard practice over the last decade for national government and the London Mayor to gloss-over the problem, downplay continued breaches of European law, and for politicians to delay taking any significant responses.

The current London mayor, Boris Johnson, has been slow to face up to the challenge. His tenure began by removing the western extension to the Congestion Charging Zone, thus increasing vehicle numbers in Inner West London, and opting out of using the Congestion Charge to tax the most polluting vehicles. This would have boosted the adoption of hybrid and electric vehicles (still only a meagre 1% of new cars) and reduced heavy emitters in Central London. Furthermore Johnson has not succeeded in comprehensively upgrading London’s bus and taxi fleet to hybrid and electric vehicles, instead embarking on an expensive new Routemaster project which still produces substantial emissions and currently makes up a minority of the overwhelmingly diesel bus fleet.

As recently as 2014, Johnson was still playing down the air pollution problem, in the face of strong evidence of London’s busiest streets like Oxford Street having amongst the highest concentrations of nitrogen dioxide in the world. For much of his time as mayor, he has assumed that the issue is not a public priority, and that driver and transport demands trump health concerns. This approach looks more questionable by the day. Evidence continues to mount that air quality is comparable in its health impacts to passive smoking and obesity. The consequences of the current Volkswagen scandal are still emerging as the huge gap between the advertised environmental performance of diesel vehicles and what we are really breathing in our cities is revealed. And the full costs of poor air quality are only beginning to be counted (e.g. billions of pounds added to NHS bills).

Looking to the future, London must now tackle the air pollution problem with a new mayor in the upcoming 2016 elections. The scope for change looks positive, as the main candidates on both the left and right have been openly discussing the need for change. What then could a new mayor do to address air quality and improve the health of Londoners?

Pricing Out Polluting Vehicles with the Ultra Low Emission Zone
To be fair to Boris Johnson, he did finally respond to pressure and announce a significant air pollution policy in 2013, dubbed the ‘Ultra-Low Emissions Zone‘. The ULEZ is set to come into effect in 2020 and essentially uses the Congestion Charging infrastructure to tackle the most polluting vehicles (similar to what Livingstone proposed way back in 2006). The question is whether the ULEZ goes far enough. It’s based on Euro emission standards, which measure NO2 and PM10/2.5 as well as CO2 emissions. It correctly targets diesel vehicles, requiring them to meet the Euro 6 standard, which only came into force in September 2015, so almost all current diesels on the road would have to change or pay the charge. This means that the main source of NO2 emissions will be appropriately targeted.

There are limitations however. The charge is only going to be £11.50 (except for large buses and HGVs), so it likely many diesel users will continue to drive into Central London and pay the charge. Furthermore the ULEZ will only affect Central London; the rules on diesel taxis and private hire vehicles have not been decided; and ULEZ zone residents get an overly generous exemption until 2023.

The next mayor will have a number of options that could be pursued if they want to be bolder than Johnson’s ULEZ proposal. These include increasing the ULEZ charge and/or Congestion Charge, bringing the ULEZ implementation forward to an earlier date, and potentially reintroducing the Congestion Charge Western Extension. All of these would make significant improvements to air quality, but would be controversial with drivers, many of whom were mis-sold diesel vehicles in the past as a supposedly environmentally benign option. The mayor may also want to re-examine the wider Low Emission Zone (LEZ) that tackles very polluting vehicles entering the whole of Greater London, as this affects the entire city and has not changed since 2012.

Banning Diesel?
A more radical approach currently being proposed for Paris is to ban diesel cars all together. This would certainly make a huge improvement to air quality. The problem for London would be that the city’s bus and taxi fleet would fail this restriction, and there would likely be a backlash from thousands of car and van drivers. This would be a very confrontational approach for a new mayor.

The more pragmatic solution for London would be to work with the ULEZ framework, considering stricter measures and higher charges, and implementing the policy earlier. One very important issue for the new mayor is emerging from the current Volkswagen emissions scandal. It looks like the latest Euro 6 diesels produce significantly higher NO2 emissions in real world driving conditions compared to the misleading testing conditions. If this is the case then the proposed ULEZ will be much less effective in improving air quality (as Euro 6 diesels will be exempt from the charge). The ULEZ may have to charge all diesel vehicles, regardless of their Euro rating. This decision would need to made very early, so that there is sufficient time for car users to adjust behaviours accordingly.

Pedestrianising Streets and Upgrading the Bus Fleet
Oxford Street is London’s busiest pedestrian street and has some of the worst NO2 pollution in Europe. A response that is gaining popularity is to pedestrianise the whole street. Certainly this would be an iconic change to both the image of London, and to the experience of the city for thousands of Londoners and tourists. The challenge for this measure is avoiding creating bus jams at either end of Oxford Street, and handling the extra demand levels that would be placed on the already congested Central Line. These challenges are not necessarily permanent however, as the arrival of Crossrail in 2018 (which follows the west to east Central Line route through Inner London) has been described as a ‘game changer’ that makes pedestrianising Oxford Street a realistic option. The new mayor should certainly pursue this possibility.

The wider challenge for the mayor is not to just think about Oxford Street, but to accelerate the upgrading of the entire bus and taxi fleet towards zero emission vehicles and develop wider pedestrianisation policies. This would improve air quality for all of London’s high streets. London is still at the trial stage of pure electric double-decker buses, which represents disappointingly slow progress considering how long we have known about air pollution problems. There’s been better progress on electric/hydrogen single-deckers. Considerable investment will be needed to upgrade the bus fleet, with decision-making based on real evidence and value-for-money. Johnson’s Routemaster project has failed both these criteria, and better leadership is now required.

Heathrow Third Runway
All the main candidates for the London Mayor oppose the expansion of Heathrow, with air pollution alongside noise pollution amongst the most important factors. You can see how Heathrow already dramatically increases emissions in West London in the NO2 annual concentration map at the top of this article using the London Atmospheric Emissions Inventory data. This is due both to emissions for aircraft engines, and the thousands of cars driving to and from Heathrow everyday. The challenge will be how effectively the new mayor can challenge the UK government to reject the Heathrow expansion option.

Overall, the issue of air pollution has gained unprecedented prominence as we approach the 2016 mayoral elections. The main candidates need to respond accordingly in their manifesto commitments, with London having a lot of catching up to do after eight years of little change. It will be interesting to see which candidates are prepared to be bolder.